DATAMONGO-955 - After release cleanups.

PartTreeMongoQuery now explicitly check the presence of a manually defined field spec on the query method and creates a new Query if so.

Original pull request: #188.

CONTRIBUTING.MD

@@ -0,0 +1 @@
+You find the contribution guidelines for Spring Data projects [here](https://github.com/spring-projects/spring-data-build/blob/master/CONTRIBUTING.md).

README.md

@@ -1,19 +1,19 @@
 # Spring Data MongoDB
 
-The primary goal of the [Spring Data](http://www.springsource.org/spring-data) project is to make it easier to build Spring-powered applications that use new data access technologies such as non-relational databases, map-reduce frameworks, and cloud based data services.
+The primary goal of the [Spring Data](http://projects.spring.io/spring-data) project is to make it easier to build Spring-powered applications that use new data access technologies such as non-relational databases, map-reduce frameworks, and cloud based data services.
 
 The Spring Data MongoDB project aims to provide a familiar and consistent Spring-based programming model for new datastores while retaining store-specific features and capabilities. The Spring Data MongoDB project provides integration with the MongoDB document database. Key functional areas of Spring Data MongoDB are a POJO centric model for interacting with a MongoDB DBCollection and easily writing a repository style data access layer.
 
 ## Getting Help
 
-For a comprehensive treatmet of all the Spring Data MongoDB features, please refer to:
+For a comprehensive treatment of all the Spring Data MongoDB features, please refer to:
 
-* the [User Guide](http://static.springsource.org/spring-data/data-mongodb/docs/current/reference/html/) 
-* the [JavaDocs](http://static.springsource.org/spring-data/data-mongodb/docs/current/api/) have extensive comments in them as well.
-* the home page of [Spring Data MongoDB](http://www.springsource.org/spring-data/mongodb) contains links to articles and other resources.
-* for more detailed questions, use the [forum](http://forum.springsource.org/forumdisplay.php?f=80). 
+* the [User Guide](http://docs.spring.io/spring-data/mongodb/docs/current/reference/html/)
+* the [JavaDocs](http://docs.spring.io/spring-data/mongodb/docs/current/api/) have extensive comments in them as well.
+* the home page of [Spring Data MongoDB](http://projects.spring.io/spring-data-mongodb) contains links to articles and other resources.
+* for more detailed questions, use the [forum](http://forum.spring.io/forum/spring-projects/data/nosql).
 
-If you are new to Spring as well as to Spring Data, look for information about [Spring projects](http://www.springsource.org/projects). 
+If you are new to Spring as well as to Spring Data, look for information about [Spring projects](http://projects.spring.io/).
 
 
 ## Quick Start
@@ -26,7 +26,7 @@ Add the Maven dependency:
 <dependency>
   <groupId>org.springframework.data</groupId>
   <artifactId>spring-data-mongodb</artifactId>
-  <version>1.2.1.RELEASE</version>
+  <version>1.4.2.RELEASE</version>
 </dependency>
 ```
 
@@ -36,13 +36,13 @@ If you'd rather like the latest snapshots of the upcoming major version, use our
 <dependency>
   <groupId>org.springframework.data</groupId>
   <artifactId>spring-data-mongodb</artifactId>
-  <version>1.2.1.RELEASE</version>
+  <version>1.5.0.BUILD-SNAPSHOT</version>
 </dependency>
 
 <repository>
   <id>spring-libs-snapshot</id>
   <name>Spring Snapshot Repository</name>
-  <url>http://repo.springsource.org/libs-snapshot</url>
+  <url>http://repo.spring.io/libs-snapshot</url>
 </repository>
 ```
 
@@ -53,11 +53,11 @@ MongoTemplate is the central support class for Mongo database operations. It pro
 * Basic POJO mapping support to and from BSON
 * Convenience methods to interact with the store (insert object, update objects) and MongoDB specific ones (geo-spatial operations, upserts, map-reduce etc.)
 * Connection affinity callback
-* Exception translation into Spring's [technology agnostic DAO exception hierarchy](http://static.springsource.org/spring/docs/3.0.x/spring-framework-reference/html/dao.html#dao-exceptions).
+* Exception translation into Spring's [technology agnostic DAO exception hierarchy](http://docs.spring.io/spring/docs/current/spring-framework-reference/html/dao.html#dao-exceptions).
 
 ### Spring Data repositories
 
-To simplify the creation of data repositories Sprin Data MongoDB provides a generic repository programming model. It will automatically create a repository proxy for you that adds implementations of finder methods you specify on an interface.  
+To simplify the creation of data repositories Spring Data MongoDB provides a generic repository programming model. It will automatically create a repository proxy for you that adds implementations of finder methods you specify on an interface.  
 
 For example, given a `Person` class with first and last name properties, a `PersonRepository` interface that can query for `Person` by last name and when the first name matches a like expression is shown below:
 
@@ -70,7 +70,7 @@ public interface PersonRepository extends CrudRepository<Person, Long> {
 }
 ```
 
-The queries issued on execution will be derived from the method name. Exending `CrudRepository` causes CRUD methods being pulled into the interface so that you can easily save and find single entities and collections of them.
+The queries issued on execution will be derived from the method name. Extending `CrudRepository` causes CRUD methods being pulled into the interface so that you can easily save and find single entities and collections of them.
 
 You can have Spring automatically create a proxy for the interface by using the following JavaConfig:
 
@@ -81,7 +81,7 @@ class ApplicationConfig extends AbstractMongoConfiguration {
 
   @Override
   public Mongo mongo() throws Exception {
-    return new Mongo();
+    return new MongoClient();
   }
 
   @Override
@@ -94,9 +94,9 @@ class ApplicationConfig extends AbstractMongoConfiguration {
 This sets up a connection to a local MongoDB instance and enables the detection of Spring Data repositories (through `@EnableMongoRepositories`). The same configuration would look like this in XML:
 
 ```xml
-<bean id="template" class="org.springframework.data.document.mongodb.MongoTemplate">
+<bean id="template" class="org.springframework.data.mongodb.core.MongoTemplate">
   <constructor-arg>
-    <bean class="com.mongodb.Mongo">
+    <bean class="com.mongodb.MongoClient">
        <constructor-arg value="localhost" />
        <constructor-arg value="27017" />
     </bean>
@@ -139,9 +139,9 @@ public class MyService {
 
 Here are some ways for you to get involved in the community:
 
-* Get involved with the Spring community on the Spring Community Forums.  Please help out on the [forum](http://forum.springsource.org/forumdisplay.php?f=80) by responding to questions and joining the debate.
+* Get involved with the Spring community on the Spring Community Forums.  Please help out on the [forum](http://forum.spring.io/forum/spring-projects/data/nosql) by responding to questions and joining the debate.
 * Create [JIRA](https://jira.springframework.org/browse/DATADOC) tickets for bugs and new features and comment and vote on the ones that you are interested in.  
 * Github is for social coding: if you want to write code, we encourage contributions through pull requests from [forks of this repository](http://help.github.com/forking/). If you want to contribute code this way, please reference a JIRA ticket as well covering the specific issue you are addressing.
-* Watch for upcoming articles on Spring by [subscribing](http://www.springsource.org/node/feed) to springframework.org
+* Watch for upcoming articles on Spring by [subscribing](http://spring.io/blog) to spring.io.
 
 Before we accept a non-trivial patch or pull request we will need you to sign the [contributor's agreement](https://support.springsource.com/spring_committer_signup).  Signing the contributor's agreement does not grant anyone commit rights to the main repository, but it does mean that we can accept your contributions, and you will get an author credit if we do.  Active contributors might be asked to join the core team, and given the ability to merge pull requests.

etc/formatting.xml

@@ -73,7 +73,7 @@
 <setting id="org.eclipse.jdt.core.formatter.insert_space_before_opening_brace_in_enum_declaration" value="insert"/>
 <setting id="org.eclipse.jdt.core.formatter.insert_space_before_opening_angle_bracket_in_type_parameters" value="do not insert"/>
 <setting id="org.eclipse.jdt.core.formatter.comment.clear_blank_lines_in_block_comment" value="false"/>
-<setting id="org.eclipse.jdt.core.formatter.insert_new_line_in_empty_type_declaration" value="insert"/>
+<setting id="org.eclipse.jdt.core.formatter.insert_new_line_in_empty_type_declaration" value="do not insert"/>
 <setting id="org.eclipse.jdt.core.formatter.lineSplit" value="120"/>
 <setting id="org.eclipse.jdt.core.formatter.insert_space_before_opening_paren_in_if" value="insert"/>
 <setting id="org.eclipse.jdt.core.formatter.insert_space_between_brackets_in_array_type_reference" value="do not insert"/>
@@ -102,7 +102,7 @@
 <setting id="org.eclipse.jdt.core.formatter.alignment_for_parameters_in_constructor_declaration" value="16"/>
 <setting id="org.eclipse.jdt.core.formatter.insert_space_after_colon_in_labeled_statement" value="insert"/>
 <setting id="org.eclipse.jdt.core.formatter.brace_position_for_annotation_type_declaration" value="end_of_line"/>
-<setting id="org.eclipse.jdt.core.formatter.insert_new_line_in_empty_method_body" value="insert"/>
+<setting id="org.eclipse.jdt.core.formatter.insert_new_line_in_empty_method_body" value="do not insert"/>
 <setting id="org.eclipse.jdt.core.formatter.alignment_for_method_declaration" value="0"/>
 <setting id="org.eclipse.jdt.core.formatter.insert_space_before_closing_paren_in_method_invocation" value="do not insert"/>
 <setting id="org.eclipse.jdt.core.formatter.insert_space_before_closing_paren_in_try" value="do not insert"/>
@@ -124,7 +124,7 @@
 <setting id="org.eclipse.jdt.core.formatter.insert_space_before_parenthesized_expression_in_throw" value="insert"/>
 <setting id="org.eclipse.jdt.core.formatter.insert_space_before_comma_in_type_arguments" value="do not insert"/>
 <setting id="org.eclipse.jdt.core.compiler.problem.enumIdentifier" value="error"/>
-<setting id="org.eclipse.jdt.core.formatter.indent_switchstatements_compare_to_switch" value="false"/>
+<setting id="org.eclipse.jdt.core.formatter.indent_switchstatements_compare_to_switch" value="true"/>
 <setting id="org.eclipse.jdt.core.formatter.insert_space_before_ellipsis" value="do not insert"/>
 <setting id="org.eclipse.jdt.core.formatter.brace_position_for_block" value="end_of_line"/>
 <setting id="org.eclipse.jdt.core.formatter.insert_space_before_comma_in_for_inits" value="do not insert"/>
@@ -135,9 +135,9 @@
 <setting id="org.eclipse.jdt.core.formatter.insert_space_after_comma_in_for_increments" value="insert"/>
 <setting id="org.eclipse.jdt.core.formatter.format_line_comment_starting_on_first_column" value="true"/>
 <setting id="org.eclipse.jdt.core.formatter.insert_space_before_closing_bracket_in_array_reference" value="do not insert"/>
-<setting id="org.eclipse.jdt.core.formatter.insert_new_line_after_annotation_on_field" value="insert"/>
-<setting id="org.eclipse.jdt.core.formatter.brace_position_for_enum_constant" value="end_of_line"/>
+<setting id="org.eclipse.jdt.core.formatter.insert_new_line_after_annotation_on_field" value="do not insert"/>
 <setting id="org.eclipse.jdt.core.formatter.comment.indent_root_tags" value="true"/>
+<setting id="org.eclipse.jdt.core.formatter.brace_position_for_enum_constant" value="end_of_line"/>
 <setting id="org.eclipse.jdt.core.formatter.insert_space_before_comma_in_enum_declarations" value="do not insert"/>
 <setting id="org.eclipse.jdt.core.formatter.alignment_for_union_type_in_multicatch" value="16"/>
 <setting id="org.eclipse.jdt.core.formatter.insert_space_after_comma_in_explicitconstructorcall_arguments" value="insert"/>
@@ -150,12 +150,12 @@
 <setting id="org.eclipse.jdt.core.formatter.insert_new_line_after_opening_brace_in_array_initializer" value="do not insert"/>
 <setting id="org.eclipse.jdt.core.formatter.insert_space_after_closing_brace_in_block" value="insert"/>
 <setting id="org.eclipse.jdt.core.formatter.insert_space_before_opening_bracket_in_array_reference" value="do not insert"/>
-<setting id="org.eclipse.jdt.core.formatter.insert_new_line_in_empty_enum_constant" value="insert"/>
+<setting id="org.eclipse.jdt.core.formatter.insert_new_line_in_empty_enum_constant" value="do not insert"/>
 <setting id="org.eclipse.jdt.core.formatter.insert_space_after_opening_angle_bracket_in_type_arguments" value="do not insert"/>
 <setting id="org.eclipse.jdt.core.formatter.insert_space_before_opening_paren_in_constructor_declaration" value="do not insert"/>
 <setting id="org.eclipse.jdt.core.formatter.insert_space_before_comma_in_constructor_declaration_throws" value="do not insert"/>
 <setting id="org.eclipse.jdt.core.formatter.insert_space_after_opening_paren_in_if" value="do not insert"/>
-<setting id="org.eclipse.jdt.core.formatter.comment.clear_blank_lines_in_javadoc_comment" value="false"/>
+<setting id="org.eclipse.jdt.core.formatter.comment.clear_blank_lines_in_javadoc_comment" value="true"/>
 <setting id="org.eclipse.jdt.core.formatter.alignment_for_throws_clause_in_constructor_declaration" value="16"/>
 <setting id="org.eclipse.jdt.core.formatter.insert_space_after_assignment_operator" value="insert"/>
 <setting id="org.eclipse.jdt.core.formatter.insert_space_before_assignment_operator" value="insert"/>
@@ -182,11 +182,11 @@
 <setting id="org.eclipse.jdt.core.formatter.insert_space_before_closing_angle_bracket_in_parameterized_type_reference" value="do not insert"/>
 <setting id="org.eclipse.jdt.core.formatter.insert_space_before_opening_brace_in_anonymous_type_declaration" value="insert"/>
 <setting id="org.eclipse.jdt.core.formatter.keep_empty_array_initializer_on_one_line" value="false"/>
-<setting id="org.eclipse.jdt.core.formatter.insert_new_line_in_empty_enum_declaration" value="insert"/>
+<setting id="org.eclipse.jdt.core.formatter.insert_new_line_in_empty_enum_declaration" value="do not insert"/>
 <setting id="org.eclipse.jdt.core.formatter.keep_imple_if_on_one_line" value="false"/>
 <setting id="org.eclipse.jdt.core.formatter.insert_space_before_comma_in_constructor_declaration_parameters" value="do not insert"/>
 <setting id="org.eclipse.jdt.core.formatter.insert_space_after_closing_angle_bracket_in_type_parameters" value="insert"/>
-<setting id="org.eclipse.jdt.core.formatter.insert_new_line_at_end_of_file_if_missing" value="do not insert"/>
+<setting id="org.eclipse.jdt.core.formatter.insert_new_line_at_end_of_file_if_missing" value="insert"/>
 <setting id="org.eclipse.jdt.core.formatter.insert_space_after_colon_in_for" value="insert"/>
 <setting id="org.eclipse.jdt.core.formatter.insert_space_before_colon_in_labeled_statement" value="do not insert"/>
 <setting id="org.eclipse.jdt.core.formatter.insert_space_before_comma_in_parameterized_type_reference" value="do not insert"/>
@@ -237,7 +237,7 @@
 <setting id="org.eclipse.jdt.core.formatter.alignment_for_throws_clause_in_method_declaration" value="16"/>
 <setting id="org.eclipse.jdt.core.formatter.insert_space_before_closing_angle_bracket_in_type_parameters" value="do not insert"/>
 <setting id="org.eclipse.jdt.core.formatter.insert_space_before_opening_bracket_in_array_allocation_expression" value="do not insert"/>
-<setting id="org.eclipse.jdt.core.formatter.insert_new_line_in_empty_anonymous_type_declaration" value="insert"/>
+<setting id="org.eclipse.jdt.core.formatter.insert_new_line_in_empty_anonymous_type_declaration" value="do not insert"/>
 <setting id="org.eclipse.jdt.core.formatter.insert_space_after_colon_in_conditional" value="insert"/>
 <setting id="org.eclipse.jdt.core.formatter.insert_space_after_opening_angle_bracket_in_parameterized_type_reference" value="do not insert"/>
 <setting id="org.eclipse.jdt.core.formatter.insert_space_before_closing_paren_in_for" value="do not insert"/>
@@ -251,12 +251,12 @@
 <setting id="org.eclipse.jdt.core.compiler.codegen.targetPlatform" value="1.7"/>
 <setting id="org.eclipse.jdt.core.formatter.alignment_for_resources_in_try" value="80"/>
 <setting id="org.eclipse.jdt.core.formatter.use_tabs_only_for_leading_indentations" value="false"/>
-<setting id="org.eclipse.jdt.core.formatter.alignment_for_arguments_in_annotation" value="0"/>
+<setting id="org.eclipse.jdt.core.formatter.alignment_for_arguments_in_annotation" value="16"/>
 <setting id="org.eclipse.jdt.core.formatter.comment.format_header" value="false"/>
 <setting id="org.eclipse.jdt.core.formatter.comment.format_block_comments" value="false"/>
 <setting id="org.eclipse.jdt.core.formatter.insert_space_before_closing_paren_in_enum_constant" value="do not insert"/>
 <setting id="org.eclipse.jdt.core.formatter.alignment_for_enum_constants" value="0"/>
-<setting id="org.eclipse.jdt.core.formatter.insert_new_line_in_empty_block" value="insert"/>
+<setting id="org.eclipse.jdt.core.formatter.insert_new_line_in_empty_block" value="do not insert"/>
 <setting id="org.eclipse.jdt.core.formatter.indent_body_declarations_compare_to_annotation_declaration_header" value="true"/>
 <setting id="org.eclipse.jdt.core.formatter.insert_space_before_closing_paren_in_parenthesized_expression" value="do not insert"/>
 <setting id="org.eclipse.jdt.core.formatter.insert_space_before_opening_paren_in_parenthesized_expression" value="do not insert"/>

pom.xml

@@ -1,21 +1,21 @@
-<?xml version="1.0" encoding="UTF-8"?>
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
 <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
 
 	<modelVersion>4.0.0</modelVersion>
 	
 	<groupId>org.springframework.data</groupId>
 	<artifactId>spring-data-mongodb-parent</artifactId>
-	<version>1.3.0.M1</version>
+	<version>1.4.4.BUILD-SNAPSHOT</version>
 	<packaging>pom</packaging>
 
 	<name>Spring Data MongoDB</name>
 	<description>MongoDB support for Spring Data</description>
-	<url>http://www.springsource.org/spring-data/mongodb</url>
+	<url>http://projects.spring.io/spring-data-mongodb</url>
 
 	<parent>
 		<groupId>org.springframework.data.build</groupId>
 		<artifactId>spring-data-parent</artifactId>
-		<version>1.1.0.RELEASE</version>
+		<version>1.3.4.BUILD-SNAPSHOT</version>
 		<relativePath>../spring-data-build/parent/pom.xml</relativePath>
 	</parent>
 	
@@ -29,19 +29,20 @@
 	<properties>
 		<project.type>multi</project.type>
 		<dist.id>spring-data-mongodb</dist.id>
-		<springdata.commons>1.6.0.M1</springdata.commons>
-		<mongo>2.10.1</mongo>
+		<springdata.commons>1.7.4.BUILD-SNAPSHOT</springdata.commons>
+		<mongo>2.11.4</mongo>
+		<mongo-osgi>${mongo}</mongo-osgi>
 	</properties>
 	
 	<developers>
 		<developer>
 			<id>ogierke</id>
 			<name>Oliver Gierke</name>
-			<email>ogierke at vmware.com</email>
-			<organization>SpringSource</organization>
-			<organizationUrl>http://www.springsource.com</organizationUrl>
+			<email>ogierke at gopivotal.com</email>
+			<organization>Pivotal</organization>
+			<organizationUrl>http://www.gopivotal.com</organizationUrl>
 			<roles>
-				<role>Project Lean</role>
+				<role>Project Lead</role>
 			</roles>
 			<timezone>+1</timezone>
 		</developer>
@@ -49,8 +50,8 @@
 			<id>trisberg</id>
 			<name>Thomas Risberg</name>
 			<email>trisberg at vmware.com</email>
-			<organization>SpringSource</organization>
-			<organizationUrl>http://www.springsource.com</organizationUrl>
+			<organization>Pivotal</organization>
+			<organizationUrl>http://www.gopivotal.com</organizationUrl>
 			<roles>
 				<role>Developer</role>
 			</roles>
@@ -59,9 +60,9 @@
 		<developer>
 			<id>mpollack</id>
 			<name>Mark Pollack</name>
-			<email>mpollack at vmware.com</email>
-			<organization>SpringSource</organization>
-			<organizationUrl>http://www.springsource.com</organizationUrl>
+			<email>mpollack at gopivotal.com</email>
+			<organization>Pivotal</organization>
+			<organizationUrl>http://www.gopivotal.com</organizationUrl>
 			<roles>
 				<role>Developer</role>
 			</roles>
@@ -70,16 +71,48 @@
 		<developer>
 			<id>jbrisbin</id>
 			<name>Jon Brisbin</name>
-			<email>jbrisbin at vmware.com</email>
-			<organization>SpringSource</organization>
-			<organizationUrl>http://www.springsource.com</organizationUrl>
+			<email>jbrisbin at gopivotal.com</email>
+			<organization>Pivotal</organization>
+			<organizationUrl>http://www.gopivotal.com</organizationUrl>
 			<roles>
 				<role>Developer</role>
 			</roles>
 			<timezone>-6</timezone>
 		</developer>
+		<developer>
+			<id>tdarimont</id>
+			<name>Thomas Darimont</name>
+			<email>tdarimont at gopivotal.com</email>
+			<organization>Pivotal</organization>
+			<organizationUrl>http://www.gopivotal.com</organizationUrl>
+			<roles>
+				<role>Developer</role>
+			</roles>
+			<timezone>+1</timezone>
+		</developer>
+		<developer>
+			<id>cstrobl</id>
+			<name>Christoph Strobl</name>
+			<email>cstrobl at gopivotal.com</email>
+			<organization>Pivotal</organization>
+			<organizationUrl>http://www.gopivotal.com</organizationUrl>
+			<roles>
+				<role>Developer</role>
+			</roles>
+			<timezone>+1</timezone>
+		</developer>
 	</developers>
 
+	<profiles>
+		<profile>
+			<id>mongo-next</id>
+			<properties>
+				<mongo>2.12.0</mongo>
+				<mongo-osgi>2.12.0</mongo-osgi>
+			</properties>
+		</profile>
+	</profiles>
+
 	<dependencies>
 		<!-- MongoDB -->
 		<dependency>
@@ -91,9 +124,20 @@
 	
 	<repositories>
 		<repository>
-			<id>spring-lib-milestone</id>
-			<url>http://repo.springsource.org/libs-milestone-local</url>
+			<id>spring-libs-snapshopt</id>
+			<url>http://repo.spring.io/libs-snapshot</url>
 		</repository>
-	</repositories>
+	<repository>
+      <id>spring-libs-snapshot</id>
+      <url>http://repo.spring.io/libs-snapshot</url>
+    </repository>
+  </repositories>
+	
+	<pluginRepositories>
+		<pluginRepository>
+			<id>spring-plugins-release</id>
+			<url>http://repo.spring.io/plugins-release</url>
+		</pluginRepository>
+	</pluginRepositories>
 
 </project>

spring-data-mongodb-cross-store/pom.xml

@@ -6,12 +6,12 @@
 	<parent>
 		<groupId>org.springframework.data</groupId>
 		<artifactId>spring-data-mongodb-parent</artifactId>
-		<version>1.3.0.M1</version>
+		<version>1.4.4.BUILD-SNAPSHOT</version>
 		<relativePath>../pom.xml</relativePath>
 	</parent>
 	
 	<artifactId>spring-data-mongodb-cross-store</artifactId>
-	<name>Spring Data MongoDB - Cross-Store Persistence Support</name>
+	<name>Spring Data MongoDB - Cross-Store Support</name>
 	
 	<properties>
 		<jpa>1.0.0.Final</jpa>
@@ -24,7 +24,6 @@
 		<dependency>
 			<groupId>org.springframework</groupId>
 			<artifactId>spring-beans</artifactId>
-			<version>${spring}</version>
 			<exclusions>
 				<exclusion>
 					<groupId>commons-logging</groupId>
@@ -35,24 +34,21 @@
 		<dependency>
 			<groupId>org.springframework</groupId>
 			<artifactId>spring-tx</artifactId>
-			<version>${spring}</version>
 		</dependency>
 		<dependency>
 			<groupId>org.springframework</groupId>
 			<artifactId>spring-aspects</artifactId>
-			<version>${spring}</version>
 		</dependency>
 		<dependency>
 			<groupId>org.springframework</groupId>
 			<artifactId>spring-orm</artifactId>
-			<version>${spring}</version>
 		</dependency>
 
 		<!-- Spring Data -->
 		<dependency>
 			<groupId>org.springframework.data</groupId>
 			<artifactId>spring-data-mongodb</artifactId>
-			<version>1.3.0.M1</version>
+			<version>1.4.4.BUILD-SNAPSHOT</version>
 		</dependency>
 
 		<dependency>
@@ -60,17 +56,13 @@
 			<artifactId>aspectjrt</artifactId>
 			<version>${aspectj}</version>
 		</dependency>
-		<dependency>
-			<groupId>cglib</groupId>
-			<artifactId>cglib</artifactId>
-			<version>2.2</version>
-		</dependency>
 
 		<!-- JPA -->
 		<dependency>
 			<groupId>org.hibernate.javax.persistence</groupId>
 			<artifactId>hibernate-jpa-2.0-api</artifactId>
 			<version>${jpa}</version>
+			<optional>true</optional>
 		</dependency>
 
 		<!-- For Tests -->

spring-data-mongodb-cross-store/src/main/java/org/springframework/data/mongodb/crossstore/MongoChangeSetPersister.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2011-2013 the original author or authors.
+ * Copyright 2011-2014 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -41,17 +41,13 @@ import com.mongodb.MongoException;
 public class MongoChangeSetPersister implements ChangeSetPersister<Object> {
 
 	private static final String ENTITY_CLASS = "_entity_class";
-
 	private static final String ENTITY_ID = "_entity_id";
-
 	private static final String ENTITY_FIELD_NAME = "_entity_field_name";
-
 	private static final String ENTITY_FIELD_CLASS = "_entity_field_class";
 
 	protected final Logger log = LoggerFactory.getLogger(getClass());
 
 	private MongoTemplate mongoTemplate;
-
 	private EntityManagerFactory entityManagerFactory;
 
 	public void setMongoTemplate(MongoTemplate mongoTemplate) {
@@ -113,12 +109,14 @@ public class MongoChangeSetPersister implements ChangeSetPersister<Object> {
 	 * @see org.springframework.data.crossstore.ChangeSetPersister#getPersistentId(org.springframework.data.crossstore.ChangeSetBacked, org.springframework.data.crossstore.ChangeSet)
 	 */
 	public Object getPersistentId(ChangeSetBacked entity, ChangeSet cs) throws DataAccessException {
+
 		log.debug("getPersistentId called on " + entity);
+
 		if (entityManagerFactory == null) {
 			throw new DataAccessResourceFailureException("EntityManagerFactory cannot be null");
 		}
-		Object o = entityManagerFactory.getPersistenceUnitUtil().getIdentifier(entity);
-		return o;
+
+		return entityManagerFactory.getPersistenceUnitUtil().getIdentifier(entity);
 	}
 
 	/*

spring-data-mongodb-cross-store/src/main/java/org/springframework/data/mongodb/crossstore/package-info.java

@@ -0,0 +1,5 @@
+/**
+ * Infrastructure for Spring Data's MongoDB cross store support.
+ */
+package org.springframework.data.mongodb.crossstore;
+

spring-data-mongodb-cross-store/template.mf

@@ -1,18 +1,18 @@
 Bundle-SymbolicName: org.springframework.data.mongodb.crossstore
 Bundle-Name: Spring Data MongoDB Cross Store Support
-Bundle-Vendor: SpringSource
+Bundle-Vendor: Pivotal Software, Inc.
 Bundle-ManifestVersion: 2
 Import-Package: 
  sun.reflect;version="0";resolution:=optional
 Export-Template:
  org.springframework.data.mongodb.crossstore.*;version="${project.version}"
 Import-Template: 
- com.mongodb.*;version="0",
+ com.mongodb.*;version="${mongo-osgi:[=.=.=,+1.0.0)}",
  javax.persistence.*;version="${jpa:[=.=.=,+1.0.0)}",
  org.aspectj.*;version="${aspectj:[1.0.0, 2.0.0)}",
  org.bson.*;version="0",
  org.slf4j.*;version="${slf4j:[=.=.=,+1.0.0)}",
- org.springframework.*;version="${spring30:[=.=.=.=,+1.0.0)}",
+ org.springframework.*;version="${spring:[=.=.=.=,+1.0.0)}",
  org.springframework.data.*;version="${springdata.commons:[=.=.=.=,+1.0.0)}",
  org.springframework.data.mongodb.*;version="${project.version:[=.=.=.=,+1.0.0)}",
  org.w3c.dom.*;version="0"

spring-data-mongodb-distribution/pom.xml

@@ -13,7 +13,7 @@
 	<parent>
 		<groupId>org.springframework.data</groupId>
 		<artifactId>spring-data-mongodb-parent</artifactId>
-		<version>1.3.0.M1</version>
+		<version>1.4.4.BUILD-SNAPSHOT</version>
 		<relativePath>../pom.xml</relativePath>
 	</parent>
 	

spring-data-mongodb-log4j/README.md

@@ -32,7 +32,7 @@ An example log entry might look like:
     {
       "_id" : ObjectId("4d89341a8ef397e06940d5cd"),
       "applicationId" : "my.application",
-      "name" : "org.springframework.data.mongodb.log4j.AppenderTest",
+      "name" : "org.springframework.data.mongodb.log4j.MongoLog4jAppenderIntegrationTests",
       "level" : "DEBUG",
       "timestamp" : ISODate("2011-03-23T16:53:46.778Z"),
       "properties" : {

spring-data-mongodb-log4j/pom.xml

@@ -5,7 +5,7 @@
 	<parent>
 		<groupId>org.springframework.data</groupId>
 		<artifactId>spring-data-mongodb-parent</artifactId>
-		<version>1.3.0.M1</version>
+		<version>1.4.4.BUILD-SNAPSHOT</version>
 		<relativePath>../pom.xml</relativePath>
 	</parent>
 

spring-data-mongodb-log4j/src/main/java/org/springframework/data/mongodb/log4j/package-info.java

@@ -0,0 +1,5 @@
+/**
+ * Infrastructure for to use MongoDB as a logging sink.
+ */
+package org.springframework.data.mongodb.log4j;
+

spring-data-mongodb-log4j/src/test/java/org/springframework/data/mongodb/log4j/MongoLog4jAppenderIntegrationTests.java

@@ -1,11 +1,11 @@
 /*
- * Copyright (c) 2011 by the original author(s).
+ * Copyright 2011-2013 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
- *     http://www.apache.org/licenses/LICENSE-2.0
+ *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
@@ -13,63 +13,65 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-
 package org.springframework.data.mongodb.log4j;
 
 import static org.hamcrest.Matchers.*;
 import static org.junit.Assert.*;
 
-import java.net.UnknownHostException;
 import java.util.Calendar;
 
-import com.mongodb.DB;
-import com.mongodb.DBCursor;
-import com.mongodb.Mongo;
 import org.apache.log4j.Logger;
 import org.apache.log4j.MDC;
 import org.junit.Before;
 import org.junit.Test;
 
-/**
- * @author Jon Brisbin <jbrisbin@vmware.com>
- */
-public class AppenderTest {
+import com.mongodb.DB;
+import com.mongodb.DBCursor;
+import com.mongodb.Mongo;
 
-	private static final String NAME = AppenderTest.class.getName();
-	private Logger log = Logger.getLogger(NAME);
-	private Mongo mongo;
-	private DB db;
-	private String collection;
+/**
+ * Integration tests for {@link MongoLog4jAppender}.
+ * 
+ * @author Jon Brisbin
+ * @author Oliver Gierke
+ */
+public class MongoLog4jAppenderIntegrationTests {
+
+	static final String NAME = MongoLog4jAppenderIntegrationTests.class.getName();
+
+	Logger log = Logger.getLogger(NAME);
+	Mongo mongo;
+	DB db;
+	String collection;
 
 	@Before
-	public void setup() {
-		try {
-			mongo = new Mongo("localhost", 27017);
-			db = mongo.getDB("logs");
-			Calendar now = Calendar.getInstance();
-			collection = String.valueOf(now.get(Calendar.YEAR)) + String.format("%1$02d", now.get(Calendar.MONTH) + 1);
-			db.getCollection(collection).drop();
-		} catch (UnknownHostException e) {
-			throw new RuntimeException(e.getMessage(), e);
-		}
+	public void setUp() throws Exception {
+
+		mongo = new Mongo("localhost", 27017);
+		db = mongo.getDB("logs");
+
+		Calendar now = Calendar.getInstance();
+		collection = String.valueOf(now.get(Calendar.YEAR)) + String.format("%1$02d", now.get(Calendar.MONTH) + 1);
+		db.getCollection(collection).drop();
 	}
 
 	@Test
 	public void testLogging() {
+
 		log.debug("DEBUG message");
 		log.info("INFO message");
 		log.warn("WARN message");
 		log.error("ERROR message");
 
 		DBCursor msgs = db.getCollection(collection).find();
-		assertThat(msgs.count(), is(4));
 
+		assertThat(msgs.count(), is(4));
 	}
 
 	@Test
 	public void testProperties() {
+
 		MDC.put("property", "one");
 		log.debug("DEBUG message");
 	}
-
 }

spring-data-mongodb-log4j/src/test/resources/log4j.properties

@@ -10,11 +10,4 @@ log4j.appender.stdout.collectionPattern = %X{year}%X{month}
 log4j.appender.stdout.applicationId = my.application
 log4j.appender.stdout.warnOrHigherWriteConcern = FSYNC_SAFE
 
-log4j.category.org.apache.activemq=ERROR
-log4j.category.org.springframework.batch=DEBUG
-log4j.category.org.springframework.data.document.mongodb=DEBUG
-log4j.category.org.springframework.transaction=INFO
-
-log4j.category.org.hibernate.SQL=DEBUG
-# for debugging datasource initialization
-# log4j.category.test.jdbc=DEBUG
+log4j.category.org.springframework.data.mongodb=DEBUG

spring-data-mongodb-log4j/template.mf

@@ -1,9 +1,9 @@
 Bundle-SymbolicName: org.springframework.data.mongodb.log4j
 Bundle-Name: Spring Data Mongo DB Log4J Appender
-Bundle-Vendor: SpringSource
+Bundle-Vendor: Pivotal Software, Inc.
 Bundle-ManifestVersion: 2
 Import-Package:
  sun.reflect;version="0";resolution:=optional
 Import-Template:
- com.mongodb.*;version="${mongo:[=.=,+1.0.0)}",
+ com.mongodb.*;version="${mongo-osgi:[=.=.=,+1.0.0)}",
  org.apache.log4j.*;version="${log4j:[=.=.=,+1.0.0)}"

spring-data-mongodb/Spring Data MongoDB.sonargraph

@@ -1,153 +1,176 @@
 <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
-<context version="7.1.7.187">
-    <scope name="spring-data-mongodb" type="Project">
-        <element name="Filter" type="TypeFilterReferenceOverridden">
-            <element name="org.springframework.data.mongodb.**" type="IncludeTypePattern"/>
+<context version="7.1.9.205">
+    <scope type="Project" name="spring-data-mongodb">
+        <element type="TypeFilterReferenceOverridden" name="Filter">
+            <element type="IncludeTypePattern" name="org.springframework.data.mongodb.**"/>
         </element>
         <architecture>
-            <element name="Config" type="Layer">
-                <element name="Assignment" type="TypeFilter">
-                    <element name="**.config.**" type="WeakTypePattern"/>
+            <element type="Layer" name="Config">
+                <element type="TypeFilter" name="Assignment">
+                    <element type="WeakTypePattern" name="**.config.**"/>
                 </element>
-                <dependency type="AllowedDependency" toName="Project|spring-data-mongodb::Layer|Core"/>
-                <dependency type="AllowedDependency" toName="Project|spring-data-mongodb::Layer|GridFS"/>
-                <dependency type="AllowedDependency" toName="Project|spring-data-mongodb::Layer|Monitoring"/>
-                <dependency type="AllowedDependency" toName="Project|spring-data-mongodb::Layer|Repositories"/>
+                <dependency toName="Project|spring-data-mongodb::Layer|Core" type="AllowedDependency"/>
+                <dependency toName="Project|spring-data-mongodb::Layer|GridFS" type="AllowedDependency"/>
+                <dependency toName="Project|spring-data-mongodb::Layer|Monitoring" type="AllowedDependency"/>
+                <dependency toName="Project|spring-data-mongodb::Layer|Repositories" type="AllowedDependency"/>
             </element>
-            <element name="Repositories" type="Layer">
-                <element name="Assignment" type="TypeFilter">
-                    <element name="**.repository.**" type="IncludeTypePattern"/>
+            <element type="Layer" name="Repositories">
+                <element type="TypeFilter" name="Assignment">
+                    <element type="IncludeTypePattern" name="**.repository.**"/>
                 </element>
-                <element name="API" type="Subsystem">
-                    <element name="Assignment" type="TypeFilter">
-                        <element name="**.repository.*" type="IncludeTypePattern"/>
+                <element type="Subsystem" name="API">
+                    <element type="TypeFilter" name="Assignment">
+                        <element type="IncludeTypePattern" name="**.repository.*"/>
                     </element>
                 </element>
-                <element name="Query" type="Subsystem">
-                    <element name="Assignment" type="TypeFilter">
-                        <element name="**.query.**" type="IncludeTypePattern"/>
+                <element type="Subsystem" name="Query">
+                    <element type="TypeFilter" name="Assignment">
+                        <element type="IncludeTypePattern" name="**.query.**"/>
                     </element>
-                    <dependency type="AllowedDependency" toName="Project|spring-data-mongodb::Layer|Repositories::Subsystem|API"/>
+                    <dependency toName="Project|spring-data-mongodb::Layer|Repositories::Subsystem|API" type="AllowedDependency"/>
                 </element>
-                <element name="Implementation" type="Subsystem">
-                    <element name="Assignment" type="TypeFilter">
-                        <element name="**.support.**" type="IncludeTypePattern"/>
+                <element type="Subsystem" name="Implementation">
+                    <element type="TypeFilter" name="Assignment">
+                        <element type="IncludeTypePattern" name="**.support.**"/>
                     </element>
-                    <dependency type="AllowedDependency" toName="Project|spring-data-mongodb::Layer|Repositories::Subsystem|API"/>
-                    <dependency type="AllowedDependency" toName="Project|spring-data-mongodb::Layer|Repositories::Subsystem|Query"/>
+                    <dependency toName="Project|spring-data-mongodb::Layer|Repositories::Subsystem|API" type="AllowedDependency"/>
+                    <dependency toName="Project|spring-data-mongodb::Layer|Repositories::Subsystem|Query" type="AllowedDependency"/>
                 </element>
-                <element name="Config" type="Subsystem">
-                    <element name="Assignment" type="TypeFilter">
-                        <element name="**.config.**" type="IncludeTypePattern"/>
+                <element type="Subsystem" name="Config">
+                    <element type="TypeFilter" name="Assignment">
+                        <element type="IncludeTypePattern" name="**.config.**"/>
                     </element>
-                    <dependency type="AllowedDependency" toName="Project|spring-data-mongodb::Layer|Repositories::Subsystem|Implementation"/>
+                    <dependency toName="Project|spring-data-mongodb::Layer|Repositories::Subsystem|Implementation" type="AllowedDependency"/>
                 </element>
-                <dependency type="AllowedDependency" toName="Project|spring-data-mongodb::Layer|Core"/>
+                <dependency toName="Project|spring-data-mongodb::Layer|Core" type="AllowedDependency"/>
             </element>
-            <element name="Monitoring" type="Layer">
-                <element name="Assignment" type="TypeFilter">
-                    <element name="**.monitor.**" type="IncludeTypePattern"/>
+            <element type="Layer" name="Monitoring">
+                <element type="TypeFilter" name="Assignment">
+                    <element type="IncludeTypePattern" name="**.monitor.**"/>
                 </element>
-                <dependency type="AllowedDependency" toName="Project|spring-data-mongodb::Layer|Core"/>
+                <dependency toName="Project|spring-data-mongodb::Layer|Core" type="AllowedDependency"/>
             </element>
-            <element name="GridFS" type="Layer">
-                <element name="Assignment" type="TypeFilter">
-                    <element name="**.gridfs.**" type="IncludeTypePattern"/>
+            <element type="Layer" name="GridFS">
+                <element type="TypeFilter" name="Assignment">
+                    <element type="IncludeTypePattern" name="**.gridfs.**"/>
                 </element>
-                <dependency type="AllowedDependency" toName="Project|spring-data-mongodb::Layer|Core"/>
+                <dependency toName="Project|spring-data-mongodb::Layer|Core" type="AllowedDependency"/>
             </element>
-            <element name="Core" type="Layer">
-                <element name="Assignment" type="TypeFilter">
-                    <element name="**.core.**" type="IncludeTypePattern"/>
+            <element type="Layer" name="Core">
+                <element type="TypeFilter" name="Assignment">
+                    <element type="IncludeTypePattern" name="**.core.**"/>
                 </element>
-                <element name="Mapping" type="Subsystem">
-                    <element name="Assignment" type="TypeFilter">
-                        <element name="**.mapping.**" type="IncludeTypePattern"/>
+                <element type="Subsystem" name="Mapping">
+                    <element type="TypeFilter" name="Assignment">
+                        <element type="IncludeTypePattern" name="**.mapping.**"/>
                     </element>
                 </element>
-                <element name="Geospatial" type="Subsystem">
-                    <element name="Assignment" type="TypeFilter">
-                        <element name="**.geo.**" type="IncludeTypePattern"/>
+                <element type="Subsystem" name="Geospatial">
+                    <element type="TypeFilter" name="Assignment">
+                        <element type="IncludeTypePattern" name="**.geo.**"/>
                     </element>
-                    <dependency type="AllowedDependency" toName="Project|spring-data-mongodb::Layer|Core::Subsystem|Mapping"/>
+                    <dependency toName="Project|spring-data-mongodb::Layer|Core::Subsystem|Mapping" type="AllowedDependency"/>
                 </element>
-                <element name="Query" type="Subsystem">
-                    <element name="Assignment" type="TypeFilter">
-                        <element name="**.query.**" type="IncludeTypePattern"/>
+                <element type="Subsystem" name="Query">
+                    <element type="TypeFilter" name="Assignment">
+                        <element type="IncludeTypePattern" name="**.query.**"/>
                     </element>
-                    <dependency type="AllowedDependency" toName="Project|spring-data-mongodb::Layer|Core::Subsystem|Geospatial"/>
+                    <dependency toName="Project|spring-data-mongodb::Layer|Core::Subsystem|Geospatial" type="AllowedDependency"/>
                 </element>
-                <element name="Index" type="Subsystem">
-                    <element name="Assignment" type="TypeFilter">
-                        <element name="**.index.**" type="IncludeTypePattern"/>
+                <element type="Subsystem" name="Conversion">
+                    <element type="TypeFilter" name="Assignment">
+                        <element type="IncludeTypePattern" name="**.convert.**"/>
                     </element>
-                    <dependency type="AllowedDependency" toName="Project|spring-data-mongodb::Layer|Core::Subsystem|Mapping"/>
-                    <dependency type="AllowedDependency" toName="Project|spring-data-mongodb::Layer|Core::Subsystem|Query"/>
+                    <dependency toName="Project|spring-data-mongodb::Layer|Core::Subsystem|Mapping" type="AllowedDependency"/>
+                    <dependency toName="Project|spring-data-mongodb::Layer|Core::Subsystem|Query" type="AllowedDependency"/>
                 </element>
-                <element name="Core" type="Subsystem">
-                    <element name="Assignment" type="TypeFilter">
-                        <element name="**.core.**" type="WeakTypePattern"/>
+                <element type="Subsystem" name="SpEL">
+                    <element type="TypeFilter" name="Assignment">
+                        <element type="IncludeTypePattern" name="**.spel.**"/>
                     </element>
-                    <dependency type="AllowedDependency" toName="Project|spring-data-mongodb::Layer|Core::Subsystem|Geospatial"/>
-                    <dependency type="AllowedDependency" toName="Project|spring-data-mongodb::Layer|Core::Subsystem|Index"/>
-                    <dependency type="AllowedDependency" toName="Project|spring-data-mongodb::Layer|Core::Subsystem|Mapping"/>
-                    <dependency type="AllowedDependency" toName="Project|spring-data-mongodb::Layer|Core::Subsystem|Query"/>
+                </element>
+                <element type="Subsystem" name="Aggregation">
+                    <element type="TypeFilter" name="Assignment">
+                        <element type="IncludeTypePattern" name="**.aggregation.**"/>
+                    </element>
+                    <dependency toName="Project|spring-data-mongodb::Layer|Core::Subsystem|Conversion" type="AllowedDependency"/>
+                    <dependency toName="Project|spring-data-mongodb::Layer|Core::Subsystem|Mapping" type="AllowedDependency"/>
+                    <dependency toName="Project|spring-data-mongodb::Layer|Core::Subsystem|Query" type="AllowedDependency"/>
+                    <dependency toName="Project|spring-data-mongodb::Layer|Core::Subsystem|SpEL" type="AllowedDependency"/>
+                </element>
+                <element type="Subsystem" name="Index">
+                    <element type="TypeFilter" name="Assignment">
+                        <element type="IncludeTypePattern" name="**.index.**"/>
+                    </element>
+                    <dependency toName="Project|spring-data-mongodb::Layer|Core::Subsystem|Mapping" type="AllowedDependency"/>
+                    <dependency toName="Project|spring-data-mongodb::Layer|Core::Subsystem|Query" type="AllowedDependency"/>
+                </element>
+                <element type="Subsystem" name="Core">
+                    <element type="TypeFilter" name="Assignment">
+                        <element type="WeakTypePattern" name="**.core.**"/>
+                    </element>
+                    <dependency toName="Project|spring-data-mongodb::Layer|Core::Subsystem|Aggregation" type="AllowedDependency"/>
+                    <dependency toName="Project|spring-data-mongodb::Layer|Core::Subsystem|Conversion" type="AllowedDependency"/>
+                    <dependency toName="Project|spring-data-mongodb::Layer|Core::Subsystem|Geospatial" type="AllowedDependency"/>
+                    <dependency toName="Project|spring-data-mongodb::Layer|Core::Subsystem|Index" type="AllowedDependency"/>
+                    <dependency toName="Project|spring-data-mongodb::Layer|Core::Subsystem|Mapping" type="AllowedDependency"/>
+                    <dependency toName="Project|spring-data-mongodb::Layer|Core::Subsystem|Query" type="AllowedDependency"/>
                 </element>
             </element>
-            <element name="API" type="Subsystem">
-                <element name="Assignment" type="TypeFilter">
-                    <element name="org.springframework.data.mongodb.*" type="IncludeTypePattern"/>
+            <element type="Subsystem" name="API">
+                <element type="TypeFilter" name="Assignment">
+                    <element type="IncludeTypePattern" name="org.springframework.data.mongodb.*"/>
                 </element>
                 <stereotype name="Public"/>
             </element>
         </architecture>
         <workspace>
-            <element name="src/main/java" type="JavaRootDirectory">
+            <element type="JavaRootDirectory" name="src/main/java">
                 <reference name="Project|spring-data-mongodb::BuildUnit|spring-data-mongodb"/>
             </element>
-            <element name="target/classes" type="JavaRootDirectory">
+            <element type="JavaRootDirectory" name="target/classes">
                 <reference name="Project|spring-data-mongodb::BuildUnit|spring-data-mongodb"/>
             </element>
         </workspace>
         <physical>
-            <element name="spring-data-mongodb" type="BuildUnit"/>
+            <element type="BuildUnit" name="spring-data-mongodb"/>
         </physical>
     </scope>
-    <scope name="External" type="External">
-        <element name="Filter" type="TypeFilter">
-            <element name="**" type="IncludeTypePattern"/>
-            <element name="java.**" type="ExcludeTypePattern"/>
-            <element name="javax.**" type="ExcludeTypePattern"/>
+    <scope type="External" name="External">
+        <element type="TypeFilter" name="Filter">
+            <element type="IncludeTypePattern" name="**"/>
+            <element type="ExcludeTypePattern" name="java.**"/>
+            <element type="ExcludeTypePattern" name="javax.**"/>
         </element>
         <architecture>
-            <element name="Spring" type="Subsystem">
-                <element name="Assignment" type="TypeFilter">
-                    <element name="org.springframework.**" type="IncludeTypePattern"/>
-                    <element name="org.springframework.data.**" type="ExcludeTypePattern"/>
+            <element type="Subsystem" name="Spring">
+                <element type="TypeFilter" name="Assignment">
+                    <element type="IncludeTypePattern" name="org.springframework.**"/>
+                    <element type="ExcludeTypePattern" name="org.springframework.data.**"/>
                 </element>
             </element>
-            <element name="Spring Data Core" type="Subsystem">
-                <element name="Assignment" type="TypeFilter">
-                    <element name="org.springframework.data.**" type="IncludeTypePattern"/>
+            <element type="Subsystem" name="Spring Data Core">
+                <element type="TypeFilter" name="Assignment">
+                    <element type="IncludeTypePattern" name="org.springframework.data.**"/>
                 </element>
             </element>
-            <element name="Mongo Java Driver" type="Subsystem">
-                <element name="Assignment" type="TypeFilter">
-                    <element name="com.mongodb.**" type="IncludeTypePattern"/>
-                    <element name="org.bson.**" type="IncludeTypePattern"/>
+            <element type="Subsystem" name="Mongo Java Driver">
+                <element type="TypeFilter" name="Assignment">
+                    <element type="IncludeTypePattern" name="com.mongodb.**"/>
+                    <element type="IncludeTypePattern" name="org.bson.**"/>
                 </element>
             </element>
-            <element name="Querydsl" type="Subsystem">
-                <element name="Assignment" type="TypeFilter">
-                    <element name="com.mysema.query.**" type="IncludeTypePattern"/>
+            <element type="Subsystem" name="Querydsl">
+                <element type="TypeFilter" name="Assignment">
+                    <element type="IncludeTypePattern" name="com.mysema.query.**"/>
                 </element>
             </element>
         </architecture>
     </scope>
-    <scope name="Global" type="Global">
-        <element name="Configuration" type="Configuration"/>
-        <element name="Filter" type="TypeFilter">
-            <element name="**" type="IncludeTypePattern"/>
+    <scope type="Global" name="Global">
+        <element type="Configuration" name="Configuration"/>
+        <element type="TypeFilter" name="Filter">
+            <element type="IncludeTypePattern" name="**"/>
         </element>
     </scope>
 </context>

spring-data-mongodb/pom.xml

@@ -11,12 +11,13 @@
 	<parent>
 		<groupId>org.springframework.data</groupId>
 		<artifactId>spring-data-mongodb-parent</artifactId>
-		<version>1.3.0.M1</version>
+		<version>1.4.4.BUILD-SNAPSHOT</version>
 		<relativePath>../pom.xml</relativePath>
 	</parent>
 
 	<properties>
 		<validation>1.0.0.GA</validation>
+		<objenesis>1.3</objenesis>
 	</properties>
 
 	<dependencies>
@@ -25,22 +26,18 @@
 		<dependency>
 			<groupId>org.springframework</groupId>
 			<artifactId>spring-tx</artifactId>
-			<version>${spring}</version>
 		</dependency>
 		<dependency>
 			<groupId>org.springframework</groupId>
 			<artifactId>spring-context</artifactId>
-			<version>${spring}</version>
 		</dependency>
 		<dependency>
 			<groupId>org.springframework</groupId>
 			<artifactId>spring-beans</artifactId>
-			<version>${spring}</version>
 		</dependency>
 		<dependency>
 			<groupId>org.springframework</groupId>
 			<artifactId>spring-core</artifactId>
-			<version>${spring}</version>
 			<exclusions>
 				<exclusion>
 					<groupId>commons-logging</groupId>
@@ -51,11 +48,10 @@
 		<dependency>
 			<groupId>org.springframework</groupId>
 			<artifactId>spring-expression</artifactId>
-			<version>${spring}</version>
 		</dependency>
 
 		<!--  Spring Data -->
-			<dependency>
+		<dependency>
 			<groupId>${project.groupId}</groupId>
 			<artifactId>spring-data-commons</artifactId>
 			<version>${springdata.commons}</version>
@@ -119,6 +115,13 @@
 			<version>${validation}</version>
 			<optional>true</optional>
 		</dependency>
+		
+		<dependency>
+			<groupId>org.objenesis</groupId>
+			<artifactId>objenesis</artifactId>
+			<version>${objenesis}</version>
+			<optional>true</optional>
+		</dependency>
 
 		<dependency>
 			<groupId>org.hibernate</groupId>
@@ -134,6 +137,13 @@
 			<scope>test</scope>
 		</dependency>
 		
+		<dependency>
+			<groupId>org.slf4j</groupId>
+			<artifactId>jul-to-slf4j</artifactId>
+			<version>${slf4j}</version>
+			<scope>test</scope>
+		</dependency>
+		
 	</dependencies>
 	
 	<build>
@@ -142,7 +152,7 @@
 			<plugin>
 				<groupId>com.mysema.maven</groupId>
 				<artifactId>apt-maven-plugin</artifactId>
-				<version>1.0.8</version>
+				<version>${apt}</version>
 				<dependencies>
 					<dependency>
 						<groupId>com.mysema.querydsl</groupId>

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/LazyLoadingException.java

@@ -0,0 +1,34 @@
+/*
+ * Copyright 2013 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.mongodb;
+
+import org.springframework.dao.UncategorizedDataAccessException;
+
+/**
+ * @author Oliver Gierke
+ */
+public class LazyLoadingException extends UncategorizedDataAccessException {
+
+	private static final long serialVersionUID = -7089224903873220037L;
+
+	/**
+	 * @param msg
+	 * @param cause
+	 */
+	public LazyLoadingException(String msg, Throwable cause) {
+		super(msg, cause);
+	}
+}

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/MongoDbFactory.java

@@ -1,6 +1,23 @@
+/*
+ * Copyright 2011-2013 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
 package org.springframework.data.mongodb;
 
 import org.springframework.dao.DataAccessException;
+import org.springframework.dao.support.PersistenceExceptionTranslator;
+import org.springframework.data.mongodb.core.MongoExceptionTranslator;
 
 import com.mongodb.DB;
 
@@ -8,6 +25,7 @@ import com.mongodb.DB;
  * Interface for factories creating {@link DB} instances.
  * 
  * @author Mark Pollack
+ * @author Thomas Darimont
  */
 public interface MongoDbFactory {
 
@@ -27,4 +45,11 @@ public interface MongoDbFactory {
 	 * @throws DataAccessException
 	 */
 	DB getDb(String dbName) throws DataAccessException;
+
+	/**
+	 * Exposes a shared {@link MongoExceptionTranslator}.
+	 * 
+	 * @return will never be {@literal null}.
+	 */
+	PersistenceExceptionTranslator getExceptionTranslator();
 }

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/config/AbstractMongoConfiguration.java

@@ -28,9 +28,12 @@ import org.springframework.core.type.filter.AnnotationTypeFilter;
 import org.springframework.data.annotation.Persistent;
 import org.springframework.data.authentication.UserCredentials;
 import org.springframework.data.mapping.context.MappingContextIsNewStrategyFactory;
+import org.springframework.data.mongodb.MongoDbFactory;
 import org.springframework.data.mongodb.core.MongoTemplate;
 import org.springframework.data.mongodb.core.SimpleMongoDbFactory;
 import org.springframework.data.mongodb.core.convert.CustomConversions;
+import org.springframework.data.mongodb.core.convert.DbRefResolver;
+import org.springframework.data.mongodb.core.convert.DefaultDbRefResolver;
 import org.springframework.data.mongodb.core.convert.MappingMongoConverter;
 import org.springframework.data.mongodb.core.mapping.CamelCaseAbbreviatingFieldNamingStrategy;
 import org.springframework.data.mongodb.core.mapping.Document;
@@ -47,6 +50,7 @@ import com.mongodb.Mongo;
  * 
  * @author Mark Pollack
  * @author Oliver Gierke
+ * @author Thomas Darimont
  */
 @Configuration
 public abstract class AbstractMongoConfiguration {
@@ -58,6 +62,16 @@ public abstract class AbstractMongoConfiguration {
 	 */
 	protected abstract String getDatabaseName();
 
+	/**
+	 * Return the name of the authentication database to use. Defaults to {@literal null} and will turn into the value
+	 * returned by {@link #getDatabaseName()} later on effectively.
+	 * 
+	 * @return
+	 */
+	protected String getAuthenticationDatabaseName() {
+		return null;
+	}
+
 	/**
 	 * Return the {@link Mongo} instance to connect to. Annotate with {@link Bean} in case you want to expose a
 	 * {@link Mongo} instance to the {@link org.springframework.context.ApplicationContext}.
@@ -88,15 +102,8 @@ public abstract class AbstractMongoConfiguration {
 	 * @throws Exception
 	 */
 	@Bean
-	public SimpleMongoDbFactory mongoDbFactory() throws Exception {
-
-		UserCredentials credentials = getUserCredentials();
-
-		if (credentials == null) {
-			return new SimpleMongoDbFactory(mongo(), getDatabaseName());
-		} else {
-			return new SimpleMongoDbFactory(mongo(), getDatabaseName(), credentials);
-		}
+	public MongoDbFactory mongoDbFactory() throws Exception {
+		return new SimpleMongoDbFactory(mongo(), getDatabaseName(), getUserCredentials(), getAuthenticationDatabaseName());
 	}
 
 	/**
@@ -109,7 +116,9 @@ public abstract class AbstractMongoConfiguration {
 	 *         entities.
 	 */
 	protected String getMappingBasePackage() {
-		return getClass().getPackage().getName();
+
+		Package mappingBasePackage = getClass().getPackage();
+		return mappingBasePackage == null ? null : mappingBasePackage.getName();
 	}
 
 	/**
@@ -178,8 +187,11 @@ public abstract class AbstractMongoConfiguration {
 	 */
 	@Bean
 	public MappingMongoConverter mappingMongoConverter() throws Exception {
-		MappingMongoConverter converter = new MappingMongoConverter(mongoDbFactory(), mongoMappingContext());
+
+		DbRefResolver dbRefResolver = new DefaultDbRefResolver(mongoDbFactory());
+		MappingMongoConverter converter = new MappingMongoConverter(dbRefResolver, mongoMappingContext());
 		converter.setCustomConversions(customConversions());
+
 		return converter;
 	}
 

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/config/EnableMongoAuditing.java

@@ -0,0 +1,70 @@
+/*
+ * Copyright 2013 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.mongodb.config;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Inherited;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+import org.springframework.context.annotation.Import;
+import org.springframework.data.auditing.DateTimeProvider;
+import org.springframework.data.domain.AuditorAware;
+
+/**
+ * Annotation to enable auditing in MongoDB via annotation configuration.
+ * 
+ * @author Thomas Darimont
+ * @author Oliver Gierke
+ */
+@Inherited
+@Documented
+@Target(ElementType.TYPE)
+@Retention(RetentionPolicy.RUNTIME)
+@Import(MongoAuditingRegistrar.class)
+public @interface EnableMongoAuditing {
+
+	/**
+	 * Configures the {@link AuditorAware} bean to be used to lookup the current principal.
+	 * 
+	 * @return
+	 */
+	String auditorAwareRef() default "";
+
+	/**
+	 * Configures whether the creation and modification dates are set. Defaults to {@literal true}.
+	 * 
+	 * @return
+	 */
+	boolean setDates() default true;
+
+	/**
+	 * Configures whether the entity shall be marked as modified on creation. Defaults to {@literal true}.
+	 * 
+	 * @return
+	 */
+	boolean modifyOnCreate() default true;
+
+	/**
+	 * Configures a {@link DateTimeProvider} bean name that allows customizing the {@link org.joda.time.DateTime} to be
+	 * used for setting creation and modification dates.
+	 * 
+	 * @return
+	 */
+	String dateTimeProviderRef() default "";
+}

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/config/GridFsTemplateParser.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013 the original author or authors.
+ * Copyright 2013-2014 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -57,6 +57,7 @@ class GridFsTemplateParser extends AbstractBeanDefinitionParser {
 
 		String converterRef = element.getAttribute("converter-ref");
 		String dbFactoryRef = element.getAttribute("db-factory-ref");
+		String bucket = element.getAttribute("bucket");
 
 		BeanDefinitionBuilder gridFsTemplateBuilder = BeanDefinitionBuilder.genericBeanDefinition(GridFsTemplate.class);
 
@@ -72,6 +73,10 @@ class GridFsTemplateParser extends AbstractBeanDefinitionParser {
 			gridFsTemplateBuilder.addConstructorArgReference(BeanNames.DEFAULT_CONVERTER_BEAN_NAME);
 		}
 
+		if (StringUtils.hasText(bucket)) {
+			gridFsTemplateBuilder.addConstructorArgValue(bucket);
+		}
+
 		return (AbstractBeanDefinition) helper.getComponentIdButFallback(gridFsTemplateBuilder, BeanNames.GRID_FS_TEMPLATE)
 				.getBeanDefinition();
 	}

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/config/MappingMongoConverterParser.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2011-2013 the original author or authors.
+ * Copyright 2011-2014 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -70,11 +70,13 @@ import org.w3c.dom.Element;
  * @author Jon Brisbin
  * @author Oliver Gierke
  * @author Maciej Walkowiak
+ * @author Thomas Darimont
+ * @author Christoph Strobl
  */
 public class MappingMongoConverterParser implements BeanDefinitionParser {
 
 	private static final String BASE_PACKAGE = "base-package";
-	private static final boolean jsr303Present = ClassUtils.isPresent("javax.validation.Validator",
+	private static final boolean JSR_303_PRESENT = ClassUtils.isPresent("javax.validation.Validator",
 			MappingMongoConverterParser.class.getClassLoader());
 
 	/* (non-Javadoc)
@@ -82,8 +84,11 @@ public class MappingMongoConverterParser implements BeanDefinitionParser {
 	 */
 	public BeanDefinition parse(Element element, ParserContext parserContext) {
 
-		BeanDefinitionRegistry registry = parserContext.getRegistry();
+		if (parserContext.isNested()) {
+			parserContext.getReaderContext().error("Mongo Converter must not be defined as nested bean.", element);
+		}
 
+		BeanDefinitionRegistry registry = parserContext.getRegistry();
 		String id = element.getAttribute(AbstractBeanDefinitionParser.ID_ATTRIBUTE);
 		id = StringUtils.hasText(id) ? id : "mappingConverter";
 
@@ -105,6 +110,11 @@ public class MappingMongoConverterParser implements BeanDefinitionParser {
 		converterBuilder.addConstructorArgReference(dbFactoryRef);
 		converterBuilder.addConstructorArgReference(ctxRef);
 
+		String typeMapperRef = element.getAttribute("type-mapper-ref");
+		if (StringUtils.hasText(typeMapperRef)) {
+			converterBuilder.addPropertyReference("typeMapper", typeMapperRef);
+		}
+
 		if (conversionsDefinition != null) {
 			converterBuilder.addPropertyValue("customConversions", conversionsDefinition);
 		}
@@ -160,7 +170,7 @@ public class MappingMongoConverterParser implements BeanDefinitionParser {
 
 	private RuntimeBeanReference getValidator(Object source, ParserContext parserContext) {
 
-		if (!jsr303Present) {
+		if (!JSR_303_PRESENT) {
 			return null;
 		}
 
@@ -189,7 +199,8 @@ public class MappingMongoConverterParser implements BeanDefinitionParser {
 		BeanDefinitionBuilder mappingContextBuilder = BeanDefinitionBuilder
 				.genericBeanDefinition(MongoMappingContext.class);
 
-		Set<String> classesToAdd = getInititalEntityClasses(element, mappingContextBuilder);
+		Set<String> classesToAdd = getInititalEntityClasses(element);
+
 		if (classesToAdd != null) {
 			mappingContextBuilder.addPropertyValue("initialEntitySet", classesToAdd);
 		}
@@ -256,7 +267,7 @@ public class MappingMongoConverterParser implements BeanDefinitionParser {
 		return null;
 	}
 
-	private static Set<String> getInititalEntityClasses(Element element, BeanDefinitionBuilder builder) {
+	private static Set<String> getInititalEntityClasses(Element element) {
 
 		String basePackage = element.getAttribute(BASE_PACKAGE);
 

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/config/MongoAuditingRegistrar.java

@@ -0,0 +1,131 @@
+/*
+ * Copyright 2013-2014 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.mongodb.config;
+
+import static org.springframework.beans.factory.config.BeanDefinition.*;
+import static org.springframework.data.mongodb.config.BeanNames.*;
+
+import java.lang.annotation.Annotation;
+
+import org.springframework.beans.factory.config.BeanDefinition;
+import org.springframework.beans.factory.support.AbstractBeanDefinition;
+import org.springframework.beans.factory.support.BeanDefinitionBuilder;
+import org.springframework.beans.factory.support.BeanDefinitionRegistry;
+import org.springframework.beans.factory.support.RootBeanDefinition;
+import org.springframework.context.annotation.ImportBeanDefinitionRegistrar;
+import org.springframework.core.type.AnnotationMetadata;
+import org.springframework.data.auditing.IsNewAwareAuditingHandler;
+import org.springframework.data.auditing.config.AnnotationAuditingConfiguration;
+import org.springframework.data.auditing.config.AuditingBeanDefinitionRegistrarSupport;
+import org.springframework.data.config.ParsingUtils;
+import org.springframework.data.mapping.context.MappingContextIsNewStrategyFactory;
+import org.springframework.data.mongodb.core.mapping.MongoMappingContext;
+import org.springframework.data.mongodb.core.mapping.event.AuditingEventListener;
+import org.springframework.data.support.IsNewStrategyFactory;
+import org.springframework.util.Assert;
+
+/**
+ * {@link ImportBeanDefinitionRegistrar} to enable {@link EnableMongoAuditing} annotation.
+ * 
+ * @author Thomas Darimont
+ * @author Oliver Gierke
+ */
+class MongoAuditingRegistrar extends AuditingBeanDefinitionRegistrarSupport {
+
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.auditing.config.AuditingBeanDefinitionRegistrarSupport#getAnnotation()
+	 */
+	@Override
+	protected Class<? extends Annotation> getAnnotation() {
+		return EnableMongoAuditing.class;
+	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.auditing.config.AuditingBeanDefinitionRegistrarSupport#registerBeanDefinitions(org.springframework.core.type.AnnotationMetadata, org.springframework.beans.factory.support.BeanDefinitionRegistry)
+	 */
+	@Override
+	public void registerBeanDefinitions(AnnotationMetadata annotationMetadata, BeanDefinitionRegistry registry) {
+
+		Assert.notNull(annotationMetadata, "AnnotationMetadata must not be null!");
+		Assert.notNull(registry, "BeanDefinitionRegistry must not be null!");
+
+		defaultDependenciesIfNecessary(registry, annotationMetadata);
+		super.registerBeanDefinitions(annotationMetadata, registry);
+	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.auditing.config.AuditingBeanDefinitionRegistrarSupport#getAuditHandlerBeanDefinitionBuilder(org.springframework.data.auditing.config.AnnotationAuditingConfiguration)
+	 */
+	@Override
+	protected BeanDefinitionBuilder getAuditHandlerBeanDefinitionBuilder(AnnotationAuditingConfiguration configuration) {
+
+		Assert.notNull(configuration, "AnnotationAuditingConfiguration must not be null!");
+
+		return configureDefaultAuditHandlerAttributes(configuration,
+				BeanDefinitionBuilder.rootBeanDefinition(IsNewAwareAuditingHandler.class)).addConstructorArgReference(
+				BeanNames.IS_NEW_STRATEGY_FACTORY);
+	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.auditing.config.AuditingBeanDefinitionRegistrarSupport#registerAuditListener(org.springframework.beans.factory.config.BeanDefinition, org.springframework.beans.factory.support.BeanDefinitionRegistry)
+	 */
+	@Override
+	protected void registerAuditListenerBeanDefinition(BeanDefinition auditingHandlerDefinition,
+			BeanDefinitionRegistry registry) {
+
+		Assert.notNull(auditingHandlerDefinition, "BeanDefinition must not be null!");
+		Assert.notNull(registry, "BeanDefinitionRegistry must not be null!");
+
+		registerInfrastructureBeanWithId(BeanDefinitionBuilder.rootBeanDefinition(AuditingEventListener.class)
+				.addConstructorArgValue(auditingHandlerDefinition).getRawBeanDefinition(),
+				AuditingEventListener.class.getName(), registry);
+	}
+
+	/**
+	 * Register default bean definitions for a {@link MongoMappingContext} and an {@link IsNewStrategyFactory} in case we
+	 * don't find beans with the assumed names in the registry.
+	 * 
+	 * @param registry the {@link BeanDefinitionRegistry} to use to register the components into.
+	 * @param source the source which the registered components shall be registered with
+	 */
+	private void defaultDependenciesIfNecessary(BeanDefinitionRegistry registry, Object source) {
+
+		if (!registry.containsBeanDefinition(MAPPING_CONTEXT)) {
+
+			RootBeanDefinition definition = new RootBeanDefinition(MongoMappingContext.class);
+			definition.setRole(ROLE_INFRASTRUCTURE);
+			definition.setSource(source);
+
+			registry.registerBeanDefinition(MAPPING_CONTEXT, definition);
+		}
+
+		if (!registry.containsBeanDefinition(IS_NEW_STRATEGY_FACTORY)) {
+
+			BeanDefinitionBuilder builder = BeanDefinitionBuilder
+					.rootBeanDefinition(MappingContextIsNewStrategyFactory.class);
+			builder.addConstructorArgReference(MAPPING_CONTEXT);
+
+			AbstractBeanDefinition definition = ParsingUtils.getSourceBeanDefinition(builder, source);
+			definition.setRole(ROLE_INFRASTRUCTURE);
+
+			registry.registerBeanDefinition(IS_NEW_STRATEGY_FACTORY, definition);
+		}
+	}
+}

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/config/MongoDbFactoryParser.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2011-2012 by the original author(s).
+ * Copyright 2011-2013 by the original author(s).
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -41,6 +41,7 @@ import com.mongodb.MongoURI;
  * 
  * @author Jon Brisbin
  * @author Oliver Gierke
+ * @author Thomas Darimont
  */
 public class MongoDbFactoryParser extends AbstractBeanDefinitionParser {
 
@@ -70,6 +71,7 @@ public class MongoDbFactoryParser extends AbstractBeanDefinitionParser {
 		String uri = element.getAttribute("uri");
 		String mongoRef = element.getAttribute("mongo-ref");
 		String dbname = element.getAttribute("dbname");
+
 		BeanDefinition userCredentials = getUserCredentialsBeanDefinition(element, parserContext);
 
 		// Common setup
@@ -92,12 +94,9 @@ public class MongoDbFactoryParser extends AbstractBeanDefinitionParser {
 			dbFactoryBuilder.addConstructorArgValue(registerMongoBeanDefinition(element, parserContext));
 		}
 
-		dbname = StringUtils.hasText(dbname) ? dbname : "db";
-		dbFactoryBuilder.addConstructorArgValue(dbname);
-
-		if (userCredentials != null) {
-			dbFactoryBuilder.addConstructorArgValue(userCredentials);
-		}
+		dbFactoryBuilder.addConstructorArgValue(StringUtils.hasText(dbname) ? dbname : "db");
+		dbFactoryBuilder.addConstructorArgValue(userCredentials);
+		dbFactoryBuilder.addConstructorArgValue(element.getAttribute("authentication-dbname"));
 
 		BeanDefinitionBuilder writeConcernPropertyEditorBuilder = getWriteConcernPropertyEditorBuilder();
 

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/config/MongoParsingUtils.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2011-2012 the original author or authors.
+ * Copyright 2011-2013 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -33,6 +33,7 @@ import org.w3c.dom.Element;
  * 
  * @author Mark Pollack
  * @author Oliver Gierke
+ * @author Thomas Darimont
  */
 abstract class MongoParsingUtils {
 
@@ -79,6 +80,8 @@ abstract class MongoParsingUtils {
 		setPropertyValue(optionsDefBuilder, optionsElement, "write-timeout", "writeTimeout");
 		setPropertyValue(optionsDefBuilder, optionsElement, "write-fsync", "writeFsync");
 		setPropertyValue(optionsDefBuilder, optionsElement, "slave-ok", "slaveOk");
+		setPropertyValue(optionsDefBuilder, optionsElement, "ssl", "ssl");
+		setPropertyReference(optionsDefBuilder, optionsElement, "ssl-socket-factory-ref", "sslSocketFactory");
 
 		mongoBuilder.addPropertyValue("mongoOptions", optionsDefBuilder.getBeanDefinition());
 		return true;

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/config/ServerAddressPropertyEditor.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2011 the original author or authors.
+ * Copyright 2011-2013 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,12 +16,14 @@
 package org.springframework.data.mongodb.config;
 
 import java.beans.PropertyEditorSupport;
+import java.net.InetAddress;
 import java.net.UnknownHostException;
 import java.util.HashSet;
 import java.util.Set;
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
+import org.springframework.util.Assert;
 import org.springframework.util.StringUtils;
 
 import com.mongodb.ServerAddress;
@@ -31,9 +33,15 @@ import com.mongodb.ServerAddress;
  * 
  * @author Mark Pollack
  * @author Oliver Gierke
+ * @author Thomas Darimont
  */
 public class ServerAddressPropertyEditor extends PropertyEditorSupport {
 
+	/**
+	 * A port is a number without a leading 0 at the end of the address that is proceeded by just a single :.
+	 */
+	private static final String HOST_PORT_SPLIT_PATTERN = "(?<!:):(?=[123456789]\\d*$)";
+	private static final String COULD_NOT_PARSE_ADDRESS_MESSAGE = "Could not parse address {} '{}'. Check your replica set configuration!";
 	private static final Logger LOG = LoggerFactory.getLogger(ServerAddressPropertyEditor.class);
 
 	/*
@@ -43,6 +51,11 @@ public class ServerAddressPropertyEditor extends PropertyEditorSupport {
 	@Override
 	public void setAsText(String replicaSetString) {
 
+		if (!StringUtils.hasText(replicaSetString)) {
+			setValue(null);
+			return;
+		}
+
 		String[] replicaSetStringArray = StringUtils.commaDelimitedListToStringArray(replicaSetString);
 		Set<ServerAddress> serverAddresses = new HashSet<ServerAddress>(replicaSetStringArray.length);
 
@@ -71,22 +84,53 @@ public class ServerAddressPropertyEditor extends PropertyEditorSupport {
 	 */
 	private ServerAddress parseServerAddress(String source) {
 
-		String[] hostAndPort = StringUtils.delimitedListToStringArray(source.trim(), ":");
+		if (!StringUtils.hasText(source)) {
+			LOG.warn(COULD_NOT_PARSE_ADDRESS_MESSAGE, "source", source);
+			return null;
+		}
 
-		if (!StringUtils.hasText(source) || hostAndPort.length > 2) {
-			LOG.warn("Could not parse address source '{}'. Check your replica set configuration!", source);
+		String[] hostAndPort = extractHostAddressAndPort(source.trim());
+
+		if (hostAndPort.length > 2) {
+			LOG.warn(COULD_NOT_PARSE_ADDRESS_MESSAGE, "source", source);
 			return null;
 		}
 
 		try {
-			return hostAndPort.length == 1 ? new ServerAddress(hostAndPort[0]) : new ServerAddress(hostAndPort[0],
-					Integer.parseInt(hostAndPort[1]));
+			InetAddress hostAddress = InetAddress.getByName(hostAndPort[0]);
+			Integer port = hostAndPort.length == 1 ? null : Integer.parseInt(hostAndPort[1]);
+
+			return port == null ? new ServerAddress(hostAddress) : new ServerAddress(hostAddress, port);
 		} catch (UnknownHostException e) {
-			LOG.warn("Could not parse host '{}'. Check your replica set configuration!", hostAndPort[0]);
+			LOG.warn(COULD_NOT_PARSE_ADDRESS_MESSAGE, "host", hostAndPort[0]);
 		} catch (NumberFormatException e) {
-			LOG.warn("Could not parse port '{}'. Check your replica set configuration!", hostAndPort[1]);
+			LOG.warn(COULD_NOT_PARSE_ADDRESS_MESSAGE, "port", hostAndPort[1]);
 		}
 
 		return null;
 	}
+
+	/**
+	 * Extract the host and port from the given {@link String}.
+	 * 
+	 * @param addressAndPortSource must not be {@literal null}.
+	 * @return
+	 */
+	private String[] extractHostAddressAndPort(String addressAndPortSource) {
+
+		Assert.notNull(addressAndPortSource, "Address and port source must not be null!");
+
+		String[] hostAndPort = addressAndPortSource.split(HOST_PORT_SPLIT_PATTERN);
+		String hostAddress = hostAndPort[0];
+
+		if (isHostAddressInIPv6BracketNotation(hostAddress)) {
+			hostAndPort[0] = hostAddress.substring(1, hostAddress.length() - 1);
+		}
+
+		return hostAndPort;
+	}
+
+	private boolean isHostAddressInIPv6BracketNotation(String hostAddress) {
+		return hostAddress.startsWith("[") && hostAddress.endsWith("]");
+	}
 }

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/DefaultIndexOperations.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2011 the original author or authors.
+ * Copyright 2011-2013 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -15,6 +15,8 @@
  */
 package org.springframework.data.mongodb.core;
 
+import static org.springframework.data.domain.Sort.Direction.*;
+
 import java.util.ArrayList;
 import java.util.List;
 
@@ -22,7 +24,6 @@ import org.springframework.dao.DataAccessException;
 import org.springframework.data.mongodb.core.index.IndexDefinition;
 import org.springframework.data.mongodb.core.index.IndexField;
 import org.springframework.data.mongodb.core.index.IndexInfo;
-import org.springframework.data.mongodb.core.query.Order;
 import org.springframework.util.Assert;
 
 import com.mongodb.DBCollection;
@@ -34,9 +35,13 @@ import com.mongodb.MongoException;
  * 
  * @author Mark Pollack
  * @author Oliver Gierke
+ * @author Komi Innocent
  */
 public class DefaultIndexOperations implements IndexOperations {
 
+	private static final Double ONE = Double.valueOf(1);
+	private static final Double MINUS_ONE = Double.valueOf(-1);
+
 	private final MongoOperations mongoOperations;
 	private final String collectionName;
 
@@ -135,12 +140,17 @@ public class DefaultIndexOperations implements IndexOperations {
 
 						Object value = keyDbObject.get(key);
 
-						if (Integer.valueOf(1).equals(value)) {
-							indexFields.add(IndexField.create(key, Order.ASCENDING));
-						} else if (Integer.valueOf(-1).equals(value)) {
-							indexFields.add(IndexField.create(key, Order.DESCENDING));
-						} else if ("2d".equals(value)) {
+						if ("2d".equals(value)) {
 							indexFields.add(IndexField.geo(key));
+						} else {
+
+							Double keyValue = new Double(value.toString());
+
+							if (ONE.equals(keyValue)) {
+								indexFields.add(IndexField.create(key, ASC));
+							} else if (MINUS_ONE.equals(keyValue)) {
+								indexFields.add(IndexField.create(key, DESC));
+							}
 						}
 					}
 

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MongoAdmin.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2011-2012 the original author or authors.
+ * Copyright 2011-2013 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -27,6 +27,7 @@ import com.mongodb.Mongo;
  * Mongo server administration exposed via JMX annotations
  * 
  * @author Mark Pollack
+ * @author Thomas Darimont
  */
 @ManagedResource(description = "Mongo Admin Operations")
 public class MongoAdmin implements MongoAdminOperations {
@@ -34,6 +35,7 @@ public class MongoAdmin implements MongoAdminOperations {
 	private final Mongo mongo;
 	private String username;
 	private String password;
+	private String authenticationDatabaseName;
 
 	public MongoAdmin(Mongo mongo) {
 		Assert.notNull(mongo);
@@ -82,7 +84,16 @@ public class MongoAdmin implements MongoAdminOperations {
 		this.password = password;
 	}
 
+	/**
+	 * Sets the authenticationDatabaseName to use to authenticate with the Mongo database.
+	 * 
+	 * @param authenticationDatabaseName The authenticationDatabaseName to use.
+	 */
+	public void setAuthenticationDatabaseName(String authenticationDatabaseName) {
+		this.authenticationDatabaseName = authenticationDatabaseName;
+	}
+
 	DB getDB(String databaseName) {
-		return MongoDbUtils.getDB(mongo, databaseName, new UserCredentials(username, password));
+		return MongoDbUtils.getDB(mongo, databaseName, new UserCredentials(username, password), authenticationDatabaseName);
 	}
 }

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MongoAdminOperations.java

@@ -1,16 +1,34 @@
+/*
+ * Copyright 2011-2014 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
 package org.springframework.data.mongodb.core;
 
 import org.springframework.jmx.export.annotation.ManagedOperation;
 
+/**
+ * @author Mark Pollack
+ * @author Oliver Gierke
+ */
 public interface MongoAdminOperations {
 
 	@ManagedOperation
-	public abstract void dropDatabase(String databaseName);
+	void dropDatabase(String databaseName);
 
 	@ManagedOperation
-	public abstract void createDatabase(String databaseName);
+	void createDatabase(String databaseName);
 
 	@ManagedOperation
-	public abstract String getDatabaseStats(String databaseName);
-
-}
+	String getDatabaseStats(String databaseName);
+}

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MongoDbUtils.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2011 the original author or authors.
+ * Copyright 2010-2013 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -26,14 +26,14 @@ import com.mongodb.DB;
 import com.mongodb.Mongo;
 
 /**
- * Helper class featuring helper methods for internal MongoDb classes.
- * <p/>
- * <p>
- * Mainly intended for internal use within the framework.
+ * Helper class featuring helper methods for internal MongoDb classes. Mainly intended for internal use within the
+ * framework.
  * 
  * @author Thomas Risberg
  * @author Graeme Rocher
  * @author Oliver Gierke
+ * @author Randy Watler
+ * @author Thomas Darimont
  * @since 1.0
  */
 public abstract class MongoDbUtils {
@@ -55,7 +55,7 @@ public abstract class MongoDbUtils {
 	 * @return the {@link DB} connection
 	 */
 	public static DB getDB(Mongo mongo, String databaseName) {
-		return doGetDB(mongo, databaseName, UserCredentials.NO_CREDENTIALS, true);
+		return doGetDB(mongo, databaseName, UserCredentials.NO_CREDENTIALS, true, databaseName);
 	}
 
 	/**
@@ -67,15 +67,22 @@ public abstract class MongoDbUtils {
 	 * @return the {@link DB} connection
 	 */
 	public static DB getDB(Mongo mongo, String databaseName, UserCredentials credentials) {
+		return getDB(mongo, databaseName, credentials, databaseName);
+	}
+
+	public static DB getDB(Mongo mongo, String databaseName, UserCredentials credentials,
+			String authenticationDatabaseName) {
 
 		Assert.notNull(mongo, "No Mongo instance specified!");
 		Assert.hasText(databaseName, "Database name must be given!");
 		Assert.notNull(credentials, "Credentials must not be null, use UserCredentials.NO_CREDENTIALS!");
+		Assert.hasText(authenticationDatabaseName, "Authentication database name must not be null or empty!");
 
-		return doGetDB(mongo, databaseName, credentials, true);
+		return doGetDB(mongo, databaseName, credentials, true, authenticationDatabaseName);
 	}
 
-	private static DB doGetDB(Mongo mongo, String databaseName, UserCredentials credentials, boolean allowCreate) {
+	private static DB doGetDB(Mongo mongo, String databaseName, UserCredentials credentials, boolean allowCreate,
+			String authenticationDatabaseName) {
 
 		DbHolder dbHolder = (DbHolder) TransactionSynchronizationManager.getResource(mongo);
 
@@ -104,14 +111,16 @@ public abstract class MongoDbUtils {
 		DB db = mongo.getDB(databaseName);
 		boolean credentialsGiven = credentials.hasUsername() && credentials.hasPassword();
 
-		synchronized (db) {
+		DB authDb = databaseName.equals(authenticationDatabaseName) ? db : mongo.getDB(authenticationDatabaseName);
 
-			if (credentialsGiven && !db.isAuthenticated()) {
+		synchronized (authDb) {
+
+			if (credentialsGiven && !authDb.isAuthenticated()) {
 
 				String username = credentials.getUsername();
 				String password = credentials.hasPassword() ? credentials.getPassword() : null;
 
-				if (!db.authenticate(username, password == null ? null : password.toCharArray())) {
+				if (!authDb.authenticate(username, password == null ? null : password.toCharArray())) {
 					throw new CannotGetMongoDbConnectionException("Failed to authenticate to database [" + databaseName + "], "
 							+ credentials.toString(), databaseName, credentials);
 				}
@@ -131,8 +140,11 @@ public abstract class MongoDbUtils {
 				holderToUse.addDB(databaseName, db);
 			}
 
-			TransactionSynchronizationManager.registerSynchronization(new MongoSynchronization(holderToUse, mongo));
-			holderToUse.setSynchronizedWithTransaction(true);
+			// synchronize holder only if not yet synchronized
+			if (!holderToUse.isSynchronizedWithTransaction()) {
+				TransactionSynchronizationManager.registerSynchronization(new MongoSynchronization(holderToUse, mongo));
+				holderToUse.setSynchronizedWithTransaction(true);
+			}
 
 			if (holderToUse != dbHolder) {
 				TransactionSynchronizationManager.bindResource(mongo, holderToUse);

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MongoExceptionTranslator.java

@@ -60,6 +60,11 @@ public class MongoExceptionTranslator implements PersistenceExceptionTranslator
 			return new DataAccessResourceFailureException(ex.getMessage(), ex);
 		}
 
+		// Driver 2.12 throws this to indicate connection problems. String comparison to avoid hard dependency
+		if (ex.getClass().getName().equals("com.mongodb.MongoServerSelectionException")) {
+			return new DataAccessResourceFailureException(ex.getMessage(), ex);
+		}
+
 		if (ex instanceof MongoInternalException) {
 			return new InvalidDataAccessResourceUsageException(ex.getMessage(), ex);
 		}

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MongoFactoryBean.java

@@ -15,7 +15,9 @@
  */
 package org.springframework.data.mongodb.core;
 
-import java.util.Arrays;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
 import java.util.List;
 
 import org.springframework.beans.factory.DisposableBean;
@@ -24,6 +26,7 @@ import org.springframework.beans.factory.InitializingBean;
 import org.springframework.dao.DataAccessException;
 import org.springframework.dao.support.PersistenceExceptionTranslator;
 import org.springframework.data.mongodb.CannotGetMongoDbConnectionException;
+import org.springframework.util.StringUtils;
 
 import com.mongodb.Mongo;
 import com.mongodb.MongoOptions;
@@ -36,6 +39,7 @@ import com.mongodb.WriteConcern;
  * @author Thomas Risberg
  * @author Graeme Rocher
  * @author Oliver Gierke
+ * @author Thomas Darimont
  * @since 1.0
  */
 public class MongoFactoryBean implements FactoryBean<Mongo>, InitializingBean, DisposableBean,
@@ -57,11 +61,38 @@ public class MongoFactoryBean implements FactoryBean<Mongo>, InitializingBean, D
 	}
 
 	public void setReplicaSetSeeds(ServerAddress[] replicaSetSeeds) {
-		this.replicaSetSeeds = Arrays.asList(replicaSetSeeds);
+		this.replicaSetSeeds = filterNonNullElementsAsList(replicaSetSeeds);
 	}
 
+	/**
+	 * @deprecated use {@link #setReplicaSetSeeds(ServerAddress[])} instead
+	 * 
+	 * @param replicaPair
+	 */
+	@Deprecated
 	public void setReplicaPair(ServerAddress[] replicaPair) {
-		this.replicaPair = Arrays.asList(replicaPair);
+		this.replicaPair = filterNonNullElementsAsList(replicaPair);
+	}
+
+	/**
+	 * @param elements the elements to filter <T>
+	 * @return a new unmodifiable {@link List#} from the given elements without nulls
+	 */
+	private <T> List<T> filterNonNullElementsAsList(T[] elements) {
+
+		if (elements == null) {
+			return Collections.emptyList();
+		}
+
+		List<T> candidateElements = new ArrayList<T>();
+
+		for (T element : elements) {
+			if (element != null) {
+				candidateElements.add(element);
+			}
+		}
+
+		return Collections.unmodifiableList(candidateElements);
 	}
 
 	public void setHost(String host) {
@@ -127,15 +158,15 @@ public class MongoFactoryBean implements FactoryBean<Mongo>, InitializingBean, D
 			mongoOptions = new MongoOptions();
 		}
 
-		if (replicaPair != null) {
+		if (!isNullOrEmpty(replicaPair)) {
 			if (replicaPair.size() < 2) {
 				throw new CannotGetMongoDbConnectionException("A replica pair must have two server entries");
 			}
 			mongo = new Mongo(replicaPair.get(0), replicaPair.get(1), mongoOptions);
-		} else if (replicaSetSeeds != null) {
+		} else if (!isNullOrEmpty(replicaSetSeeds)) {
 			mongo = new Mongo(replicaSetSeeds, mongoOptions);
 		} else {
-			String mongoHost = host != null ? host : defaultOptions.getHost();
+			String mongoHost = StringUtils.hasText(host) ? host : defaultOptions.getHost();
 			mongo = port != null ? new Mongo(new ServerAddress(mongoHost, port), mongoOptions) : new Mongo(mongoHost,
 					mongoOptions);
 		}
@@ -147,6 +178,10 @@ public class MongoFactoryBean implements FactoryBean<Mongo>, InitializingBean, D
 		this.mongo = mongo;
 	}
 
+	private boolean isNullOrEmpty(Collection<?> elements) {
+		return elements == null || elements.isEmpty();
+	}
+
 	/* 
 	 * (non-Javadoc)
 	 * @see org.springframework.beans.factory.DisposableBean#destroy()

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MongoOperations.java

@@ -1,6 +1,6 @@
 /*
- * Copyright 2010-2013 the original author or authors.
- *
+ * Copyright 2011-2014 the original author or authors.
+ * 
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
@@ -19,6 +19,9 @@ import java.util.Collection;
 import java.util.List;
 import java.util.Set;
 
+import org.springframework.data.mongodb.core.aggregation.Aggregation;
+import org.springframework.data.mongodb.core.aggregation.AggregationResults;
+import org.springframework.data.mongodb.core.aggregation.TypedAggregation;
 import org.springframework.data.mongodb.core.convert.MongoConverter;
 import org.springframework.data.mongodb.core.geo.GeoResult;
 import org.springframework.data.mongodb.core.geo.GeoResults;
@@ -45,6 +48,8 @@ import com.mongodb.WriteResult;
  * @author Thomas Risberg
  * @author Mark Pollack
  * @author Oliver Gierke
+ * @author Tobias Trelle
+ * @author Chuong Ngo
  */
 public interface MongoOperations {
 
@@ -247,7 +252,7 @@ public interface MongoOperations {
 	 * Query for a list of objects of type T from the collection used by the entity class.
 	 * <p/>
 	 * The object is converted from the MongoDB native representation using an instance of {@see MongoConverter}. Unless
-	 * configured otherwise, an instance of SimpleMongoConverter will be used.
+	 * configured otherwise, an instance of MappingMongoConverter will be used.
 	 * <p/>
 	 * If your collection does not contain a homogeneous collection of types, this operation will not be an efficient way
 	 * to map objects since the test for class type is done in the client and not on the server.
@@ -261,7 +266,7 @@ public interface MongoOperations {
 	 * Query for a list of objects of type T from the specified collection.
 	 * <p/>
 	 * The object is converted from the MongoDB native representation using an instance of {@see MongoConverter}. Unless
-	 * configured otherwise, an instance of SimpleMongoConverter will be used.
+	 * configured otherwise, an instance of MappingMongoConverter will be used.
 	 * <p/>
 	 * If your collection does not contain a homogeneous collection of types, this operation will not be an efficient way
 	 * to map objects since the test for class type is done in the client and not on the server.
@@ -301,6 +306,57 @@ public interface MongoOperations {
 	 */
 	<T> GroupByResults<T> group(Criteria criteria, String inputCollectionName, GroupBy groupBy, Class<T> entityClass);
 
+	/**
+	 * Execute an aggregation operation. The raw results will be mapped to the given entity class. The name of the
+	 * inputCollection is derived from the inputType of the aggregation.
+	 * 
+	 * @param aggregation The {@link TypedAggregation} specification holding the aggregation operations, must not be
+	 *          {@literal null}.
+	 * @param collectionName The name of the input collection to use for the aggreation.
+	 * @param outputType The parameterized type of the returned list, must not be {@literal null}.
+	 * @return The results of the aggregation operation.
+	 * @since 1.3
+	 */
+	<O> AggregationResults<O> aggregate(TypedAggregation<?> aggregation, String collectionName, Class<O> outputType);
+
+	/**
+	 * Execute an aggregation operation. The raw results will be mapped to the given entity class. The name of the
+	 * inputCollection is derived from the inputType of the aggregation.
+	 * 
+	 * @param aggregation The {@link TypedAggregation} specification holding the aggregation operations, must not be
+	 *          {@literal null}.
+	 * @param outputType The parameterized type of the returned list, must not be {@literal null}.
+	 * @return The results of the aggregation operation.
+	 * @since 1.3
+	 */
+	<O> AggregationResults<O> aggregate(TypedAggregation<?> aggregation, Class<O> outputType);
+
+	/**
+	 * Execute an aggregation operation. The raw results will be mapped to the given entity class.
+	 * 
+	 * @param aggregation The {@link Aggregation} specification holding the aggregation operations, must not be
+	 *          {@literal null}.
+	 * @param inputType the inputType where the aggregation operation will read from, must not be {@literal null} or
+	 *          empty.
+	 * @param outputType The parameterized type of the returned list, must not be {@literal null}.
+	 * @return The results of the aggregation operation.
+	 * @since 1.3
+	 */
+	<O> AggregationResults<O> aggregate(Aggregation aggregation, Class<?> inputType, Class<O> outputType);
+
+	/**
+	 * Execute an aggregation operation. The raw results will be mapped to the given entity class.
+	 * 
+	 * @param aggregation The {@link Aggregation} specification holding the aggregation operations, must not be
+	 *          {@literal null}.
+	 * @param collectionName the collection where the aggregation operation will read from, must not be {@literal null} or
+	 *          empty.
+	 * @param outputType The parameterized type of the returned list, must not be {@literal null}.
+	 * @return The results of the aggregation operation.
+	 * @since 1.3
+	 */
+	<O> AggregationResults<O> aggregate(Aggregation aggregation, String collectionName, Class<O> outputType);
+
 	/**
 	 * Execute a map-reduce operation. The map-reduce operation will be formed with an output type of INLINE
 	 * 
@@ -382,7 +438,7 @@ public interface MongoOperations {
 	 * specified type.
 	 * <p/>
 	 * The object is converted from the MongoDB native representation using an instance of {@see MongoConverter}. Unless
-	 * configured otherwise, an instance of SimpleMongoConverter will be used.
+	 * configured otherwise, an instance of MappingMongoConverter will be used.
 	 * <p/>
 	 * The query is specified as a {@link Query} which can be created either using the {@link BasicQuery} or the more
 	 * feature rich {@link Query}.
@@ -399,7 +455,7 @@ public interface MongoOperations {
 	 * type.
 	 * <p/>
 	 * The object is converted from the MongoDB native representation using an instance of {@see MongoConverter}. Unless
-	 * configured otherwise, an instance of SimpleMongoConverter will be used.
+	 * configured otherwise, an instance of MappingMongoConverter will be used.
 	 * <p/>
 	 * The query is specified as a {@link Query} which can be created either using the {@link BasicQuery} or the more
 	 * feature rich {@link Query}.
@@ -412,17 +468,39 @@ public interface MongoOperations {
 	 */
 	<T> T findOne(Query query, Class<T> entityClass, String collectionName);
 
+	/**
+	 * Determine result of given {@link Query} contains at least one element.
+	 * 
+	 * @param query the {@link Query} class that specifies the criteria used to find a record.
+	 * @param collectionName name of the collection to check for objects.
+	 * @return
+	 */
 	boolean exists(Query query, String collectionName);
 
+	/**
+	 * Determine result of given {@link Query} contains at least one element.
+	 * 
+	 * @param query the {@link Query} class that specifies the criteria used to find a record.
+	 * @param entityClass the parameterized type.
+	 * @return
+	 */
 	boolean exists(Query query, Class<?> entityClass);
 
+	/**
+	 * Determine result of given {@link Query} contains at least one element.
+	 * 
+	 * @param query the {@link Query} class that specifies the criteria used to find a record.
+	 * @param entityClass the parameterized type.
+	 * @param collectionName name of the collection to check for objects.
+	 * @return
+	 */
 	boolean exists(Query query, Class<?> entityClass, String collectionName);
 
 	/**
 	 * Map the results of an ad-hoc query on the collection for the entity class to a List of the specified type.
 	 * <p/>
 	 * The object is converted from the MongoDB native representation using an instance of {@see MongoConverter}. Unless
-	 * configured otherwise, an instance of SimpleMongoConverter will be used.
+	 * configured otherwise, an instance of MappingMongoConverter will be used.
 	 * <p/>
 	 * The query is specified as a {@link Query} which can be created either using the {@link BasicQuery} or the more
 	 * feature rich {@link Query}.
@@ -438,7 +516,7 @@ public interface MongoOperations {
 	 * Map the results of an ad-hoc query on the specified collection to a List of the specified type.
 	 * <p/>
 	 * The object is converted from the MongoDB native representation using an instance of {@see MongoConverter}. Unless
-	 * configured otherwise, an instance of SimpleMongoConverter will be used.
+	 * configured otherwise, an instance of MappingMongoConverter will be used.
 	 * <p/>
 	 * The query is specified as a {@link Query} which can be created either using the {@link BasicQuery} or the more
 	 * feature rich {@link Query}.
@@ -473,12 +551,58 @@ public interface MongoOperations {
 	 */
 	<T> T findById(Object id, Class<T> entityClass, String collectionName);
 
+	/**
+	 * Triggers <a href="http://docs.mongodb.org/manual/reference/method/db.collection.findAndModify/">findAndModify<a/>
+	 * to apply provided {@link Update} on documents matching {@link Criteria} of given {@link Query}.
+	 * 
+	 * @param query the {@link Query} class that specifies the {@link Criteria} used to find a record and also an optional
+	 *          fields specification.
+	 * @param update the {@link Update} to apply on matching documents.
+	 * @param entityClass the parameterized type.
+	 * @return
+	 */
 	<T> T findAndModify(Query query, Update update, Class<T> entityClass);
 
+	/**
+	 * Triggers <a href="http://docs.mongodb.org/manual/reference/method/db.collection.findAndModify/">findAndModify<a/>
+	 * to apply provided {@link Update} on documents matching {@link Criteria} of given {@link Query}.
+	 * 
+	 * @param query the {@link Query} class that specifies the {@link Criteria} used to find a record and also an optional
+	 *          fields specification.
+	 * @param update the {@link Update} to apply on matching documents.
+	 * @param entityClass the parameterized type.
+	 * @param collectionName the collection to query.
+	 * @return
+	 */
 	<T> T findAndModify(Query query, Update update, Class<T> entityClass, String collectionName);
 
+	/**
+	 * Triggers <a href="http://docs.mongodb.org/manual/reference/method/db.collection.findAndModify/">findAndModify<a/>
+	 * to apply provided {@link Update} on documents matching {@link Criteria} of given {@link Query} taking
+	 * {@link FindAndModifyOptions} into account.
+	 * 
+	 * @param query the {@link Query} class that specifies the {@link Criteria} used to find a record and also an optional
+	 *          fields specification.
+	 * @param update the {@link Update} to apply on matching documents.
+	 * @param options the {@link FindAndModifyOptions} holding additional information.
+	 * @param entityClass the parameterized type.
+	 * @return
+	 */
 	<T> T findAndModify(Query query, Update update, FindAndModifyOptions options, Class<T> entityClass);
 
+	/**
+	 * Triggers <a href="http://docs.mongodb.org/manual/reference/method/db.collection.findAndModify/">findAndModify<a/>
+	 * to apply provided {@link Update} on documents matching {@link Criteria} of given {@link Query} taking
+	 * {@link FindAndModifyOptions} into account.
+	 * 
+	 * @param query the {@link Query} class that specifies the {@link Criteria} used to find a record and also an optional
+	 *          fields specification.
+	 * @param update the {@link Update} to apply on matching documents.
+	 * @param options the {@link FindAndModifyOptions} holding additional information.
+	 * @param entityClass the parameterized type.
+	 * @param collectionName the collection to query.
+	 * @return
+	 */
 	<T> T findAndModify(Query query, Update update, FindAndModifyOptions options, Class<T> entityClass,
 			String collectionName);
 
@@ -504,7 +628,7 @@ public interface MongoOperations {
 	 * type. The first document that matches the query is returned and also removed from the collection in the database.
 	 * <p/>
 	 * The object is converted from the MongoDB native representation using an instance of {@see MongoConverter}. Unless
-	 * configured otherwise, an instance of SimpleMongoConverter will be used.
+	 * configured otherwise, an instance of MappingMongoConverter will be used.
 	 * <p/>
 	 * The query is specified as a {@link Query} which can be created either using the {@link BasicQuery} or the more
 	 * feature rich {@link Query}.
@@ -542,9 +666,9 @@ public interface MongoOperations {
 	 * <p/>
 	 * If you object has an "Id' property, it will be set with the generated Id from MongoDB. If your Id property is a
 	 * String then MongoDB ObjectId will be used to populate that string. Otherwise, the conversion from ObjectId to your
-	 * property type will be handled by Spring's BeanWrapper class that leverages Spring 3.0's new Type Conversion API.
-	 * See <a href="http://static.springsource.org/spring/docs/3.0.x/reference/validation.html#core-convert">Spring 3 Type
-	 * Conversion"</a> for more details.
+	 * property type will be handled by Spring's BeanWrapper class that leverages Type Conversion API. See <a
+	 * href="http://docs.spring.io/spring/docs/current/spring-framework-reference/html/validation.html#core-convert"
+	 * >Spring's Type Conversion"</a> for more details.
 	 * <p/>
 	 * <p/>
 	 * Insert is used to initially store the object into the database. To update an existing object use the save method.
@@ -557,7 +681,7 @@ public interface MongoOperations {
 	 * Insert the object into the specified collection.
 	 * <p/>
 	 * The object is converted to the MongoDB native representation using an instance of {@see MongoConverter}. Unless
-	 * configured otherwise, an instance of SimpleMongoConverter will be used.
+	 * configured otherwise, an instance of MappingMongoConverter will be used.
 	 * <p/>
 	 * Insert is used to initially store the object into the database. To update an existing object use the save method.
 	 * 
@@ -595,13 +719,13 @@ public interface MongoOperations {
 	 * object is not already present, that is an 'upsert'.
 	 * <p/>
 	 * The object is converted to the MongoDB native representation using an instance of {@see MongoConverter}. Unless
-	 * configured otherwise, an instance of SimpleMongoConverter will be used.
+	 * configured otherwise, an instance of MappingMongoConverter will be used.
 	 * <p/>
 	 * If you object has an "Id' property, it will be set with the generated Id from MongoDB. If your Id property is a
 	 * String then MongoDB ObjectId will be used to populate that string. Otherwise, the conversion from ObjectId to your
-	 * property type will be handled by Spring's BeanWrapper class that leverages Spring 3.0's new Type Conversion API.
-	 * See <a href="http://static.springsource.org/spring/docs/3.0.x/reference/validation.html#core-convert">Spring 3 Type
-	 * Conversion"</a> for more details.
+	 * property type will be handled by Spring's BeanWrapper class that leverages Type Conversion API. See <a
+	 * href="http://docs.spring.io/spring/docs/current/spring-framework-reference/html/validation.html#core-convert"
+	 * >Spring's Type Conversion"</a> for more details.
 	 * 
 	 * @param objectToSave the object to store in the collection
 	 */
@@ -612,13 +736,13 @@ public interface MongoOperations {
 	 * is an 'upsert'.
 	 * <p/>
 	 * The object is converted to the MongoDB native representation using an instance of {@see MongoConverter}. Unless
-	 * configured otherwise, an instance of SimpleMongoConverter will be used.
+	 * configured otherwise, an instance of MappingMongoConverter will be used.
 	 * <p/>
 	 * If you object has an "Id' property, it will be set with the generated Id from MongoDB. If your Id property is a
 	 * String then MongoDB ObjectId will be used to populate that string. Otherwise, the conversion from ObjectId to your
-	 * property type will be handled by Spring's BeanWrapper class that leverages Spring 3.0's new Type Cobnversion API.
-	 * See <a href="http://static.springsource.org/spring/docs/3.0.x/reference/validation.html#core-convert">Spring 3 Type
-	 * Conversion"</a> for more details.
+	 * property type will be handled by Spring's BeanWrapper class that leverages Type Cobnversion API. See <a
+	 * http://docs.spring.io/spring/docs/current/spring-framework-reference/html/validation.html#core-convert">Spring's
+	 * Type Conversion"</a> for more details.
 	 * 
 	 * @param objectToSave the object to store in the collection
 	 * @param collectionName name of the collection to store the object in
@@ -648,6 +772,18 @@ public interface MongoOperations {
 	 */
 	WriteResult upsert(Query query, Update update, String collectionName);
 
+	/**
+	 * Performs an upsert. If no document is found that matches the query, a new document is created and inserted by
+	 * combining the query document and the update document.
+	 * 
+	 * @param query the query document that specifies the criteria used to select a record to be upserted
+	 * @param update the update document that contains the updated object or $ operators to manipulate the existing object
+	 * @param entityClass class of the pojo to be operated on
+	 * @param collectionName name of the collection to update the object in
+	 * @return the WriteResult which lets you access the results of the previous write.
+	 */
+	WriteResult upsert(Query query, Update update, Class<?> entityClass, String collectionName);
+
 	/**
 	 * Updates the first object that is found in the collection of the entity class that matches the query document with
 	 * the provided update document.
@@ -672,6 +808,19 @@ public interface MongoOperations {
 	 */
 	WriteResult updateFirst(Query query, Update update, String collectionName);
 
+	/**
+	 * Updates the first object that is found in the specified collection that matches the query document criteria with
+	 * the provided updated document.
+	 * 
+	 * @param query the query document that specifies the criteria used to select a record to be updated
+	 * @param update the update document that contains the updated object or $ operators to manipulate the existing
+	 *          object.
+	 * @param entityClass class of the pojo to be operated on
+	 * @param collectionName name of the collection to update the object in
+	 * @return the WriteResult which lets you access the results of the previous write.
+	 */
+	WriteResult updateFirst(Query query, Update update, Class<?> entityClass, String collectionName);
+
 	/**
 	 * Updates all objects that are found in the collection for the entity class that matches the query document criteria
 	 * with the provided updated document.
@@ -696,6 +845,19 @@ public interface MongoOperations {
 	 */
 	WriteResult updateMulti(Query query, Update update, String collectionName);
 
+	/**
+	 * Updates all objects that are found in the collection for the entity class that matches the query document criteria
+	 * with the provided updated document.
+	 * 
+	 * @param query the query document that specifies the criteria used to select a record to be updated
+	 * @param update the update document that contains the updated object or $ operators to manipulate the existing
+	 *          object.
+	 * @param entityClass class of the pojo to be operated on
+	 * @param collectionName name of the collection to update the object in
+	 * @return the WriteResult which lets you access the results of the previous write.
+	 */
+	WriteResult updateMulti(final Query query, final Update update, Class<?> entityClass, String collectionName);
+
 	/**
 	 * Remove the given object from the collection by id.
 	 * 
@@ -720,6 +882,14 @@ public interface MongoOperations {
 	 */
 	void remove(Query query, Class<?> entityClass);
 
+	/**
+	 * Remove all documents that match the provided query document criteria from the the collection used to store the
+	 * entityClass. The Class parameter is also used to help convert the Id of the object if it is present in the query.
+	 * 
+	 * @param query
+	 * @param entityClass
+	 * @param collectionName
+	 */
 	void remove(Query query, Class<?> entityClass, String collectionName);
 
 	/**

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MongoOptionsFactoryBean.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2011 the original author or authors.
+ * Copyright 2010-2014 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -15,129 +15,92 @@
  */
 package org.springframework.data.mongodb.core;
 
-import com.mongodb.MongoOptions;
+import javax.net.ssl.SSLSocketFactory;
 
 import org.springframework.beans.factory.FactoryBean;
 import org.springframework.beans.factory.InitializingBean;
 
+import com.mongodb.MongoOptions;
+
 /**
- * A factory bean for construction of a MongoOptions instance
+ * A factory bean for construction of a {@link MongoOptions} instance.
  * 
  * @author Graeme Rocher
- * @Author Mark Pollack
+ * @author Mark Pollack
+ * @author Mike Saavedra
+ * @author Thomas Darimont
  */
+@SuppressWarnings("deprecation")
 public class MongoOptionsFactoryBean implements FactoryBean<MongoOptions>, InitializingBean {
 
-	private static final MongoOptions MONGO_OPTIONS = new MongoOptions();
-	/**
-	 * number of connections allowed per host will block if run out
-	 */
-	private int connectionsPerHost = MONGO_OPTIONS.connectionsPerHost;
+	private static final MongoOptions DEFAULT_MONGO_OPTIONS = new MongoOptions();
+
+	private int connectionsPerHost = DEFAULT_MONGO_OPTIONS.connectionsPerHost;
+	private int threadsAllowedToBlockForConnectionMultiplier = DEFAULT_MONGO_OPTIONS.threadsAllowedToBlockForConnectionMultiplier;
+	private int maxWaitTime = DEFAULT_MONGO_OPTIONS.maxWaitTime;
+	private int connectTimeout = DEFAULT_MONGO_OPTIONS.connectTimeout;
+	private int socketTimeout = DEFAULT_MONGO_OPTIONS.socketTimeout;
+	private boolean socketKeepAlive = DEFAULT_MONGO_OPTIONS.socketKeepAlive;
+	private boolean autoConnectRetry = DEFAULT_MONGO_OPTIONS.autoConnectRetry;
+	private long maxAutoConnectRetryTime = DEFAULT_MONGO_OPTIONS.maxAutoConnectRetryTime;
+	private int writeNumber = DEFAULT_MONGO_OPTIONS.w;
+	private int writeTimeout = DEFAULT_MONGO_OPTIONS.wtimeout;
+	private boolean writeFsync = DEFAULT_MONGO_OPTIONS.fsync;
+	private boolean slaveOk = DEFAULT_MONGO_OPTIONS.slaveOk;
+	private boolean ssl;
+	private SSLSocketFactory sslSocketFactory;
+
+	private MongoOptions options;
 
 	/**
-	 * multiplier for connectionsPerHost for # of threads that can block if connectionsPerHost is 10, and
-	 * threadsAllowedToBlockForConnectionMultiplier is 5, then 50 threads can block more than that and an exception will
-	 * be throw
-	 */
-	private int threadsAllowedToBlockForConnectionMultiplier = MONGO_OPTIONS.threadsAllowedToBlockForConnectionMultiplier;
-
-	/**
-	 * max wait time of a blocking thread for a connection
-	 */
-	private int maxWaitTime = MONGO_OPTIONS.maxWaitTime;
-
-	/**
-	 * connect timeout in milliseconds. 0 is default and infinite
-	 */
-	private int connectTimeout = MONGO_OPTIONS.connectTimeout;
-
-	/**
-	 * socket timeout. 0 is default and infinite
-	 */
-	private int socketTimeout = MONGO_OPTIONS.socketTimeout;
-
-	/**
-	 * This controls whether or not to have socket keep alive turned on (SO_KEEPALIVE).
+	 * Configures the maximum number of connections allowed per host until we will block.
 	 * 
-	 * defaults to false
-	 */
-	public boolean socketKeepAlive = MONGO_OPTIONS.socketKeepAlive;
-
-	/**
-	 * this controls whether or not on a connect, the system retries automatically
-	 */
-	private boolean autoConnectRetry = MONGO_OPTIONS.autoConnectRetry;
-
-	private long maxAutoConnectRetryTime = MONGO_OPTIONS.maxAutoConnectRetryTime;
-
-	/**
-	 * This specifies the number of servers to wait for on the write operation, and exception raising behavior.
-	 * 
-	 * Defaults to 0.
-	 */
-	private int writeNumber;
-
-	/**
-	 * This controls timeout for write operations in milliseconds.
-	 * 
-	 * Defaults to 0 (indefinite). Greater than zero is number of milliseconds to wait.
-	 */
-	private int writeTimeout;
-
-	/**
-	 * This controls whether or not to fsync.
-	 * 
-	 * Defaults to false.
-	 */
-	private boolean writeFsync;
-
-	/**
-	 * Specifies if the driver is allowed to read from secondaries or slaves.
-	 * 
-	 * Defaults to false
-	 */
-	@SuppressWarnings("deprecation")
-	private boolean slaveOk = MONGO_OPTIONS.slaveOk;
-
-	/**
-	 * number of connections allowed per host will block if run out
+	 * @param connectionsPerHost
 	 */
 	public void setConnectionsPerHost(int connectionsPerHost) {
 		this.connectionsPerHost = connectionsPerHost;
 	}
 
 	/**
-	 * multiplier for connectionsPerHost for # of threads that can block if connectionsPerHost is 10, and
-	 * threadsAllowedToBlockForConnectionMultiplier is 5, then 50 threads can block more than that and an exception will
-	 * be throw
+	 * A multiplier for connectionsPerHost for # of threads that can block a connection. If connectionsPerHost is 10, and
+	 * threadsAllowedToBlockForConnectionMultiplier is 5, then 50 threads can block. If more threads try to block an
+	 * exception will be thrown.
+	 * 
+	 * @param threadsAllowedToBlockForConnectionMultiplier
 	 */
 	public void setThreadsAllowedToBlockForConnectionMultiplier(int threadsAllowedToBlockForConnectionMultiplier) {
 		this.threadsAllowedToBlockForConnectionMultiplier = threadsAllowedToBlockForConnectionMultiplier;
 	}
 
 	/**
-	 * max wait time of a blocking thread for a connection
+	 * Max wait time of a blocking thread for a connection.
+	 * 
+	 * @param maxWaitTime
 	 */
 	public void setMaxWaitTime(int maxWaitTime) {
 		this.maxWaitTime = maxWaitTime;
 	}
 
 	/**
-	 * connect timeout in milliseconds. 0 is default and infinite
+	 * Configures the connect timeout in milliseconds. Defaults to 0 (infinite time).
+	 * 
+	 * @param connectTimeout
 	 */
 	public void setConnectTimeout(int connectTimeout) {
 		this.connectTimeout = connectTimeout;
 	}
 
 	/**
-	 * socket timeout. 0 is default and infinite
+	 * Configures the socket timeout. Defaults to 0 (infinite time).
+	 * 
+	 * @param socketTimeout
 	 */
 	public void setSocketTimeout(int socketTimeout) {
 		this.socketTimeout = socketTimeout;
 	}
 
 	/**
-	 * This controls whether or not to have socket keep alive
+	 * Configures whether or not to have socket keep alive turned on (SO_KEEPALIVE). Defaults to {@literal false}.
 	 * 
 	 * @param socketKeepAlive
 	 */
@@ -152,7 +115,7 @@ public class MongoOptionsFactoryBean implements FactoryBean<MongoOptions>, Initi
 	 * <li>-1 = don't even report network errors</li>
 	 * <li>0 = default, don't call getLastError by default</li>
 	 * <li>1 = basic, call getLastError, but don't wait for slaves</li>
-	 * <li>2+= wait for slaves</li>
+	 * <li>2 += wait for slaves</li>
 	 * </ul>
 	 * 
 	 * @param writeNumber the number of servers to wait for on the write operation, and exception raising behavior.
@@ -162,33 +125,33 @@ public class MongoOptionsFactoryBean implements FactoryBean<MongoOptions>, Initi
 	}
 
 	/**
-	 * This controls timeout for write operations in milliseconds. The 'wtimeout' option to the getlasterror command.
+	 * Configures the timeout for write operations in milliseconds. This defaults to {@literal 0} (indefinite).
 	 * 
-	 * @param writeTimeout Defaults to 0 (indefinite). Greater than zero is number of milliseconds to wait.
+	 * @param writeTimeout
 	 */
 	public void setWriteTimeout(int writeTimeout) {
 		this.writeTimeout = writeTimeout;
 	}
 
 	/**
-	 * This controls whether or not to fsync. The 'fsync' option to the getlasterror command. Defaults to false.
+	 * Configures whether or not to fsync. The 'fsync' option to the getlasterror command. Defaults to {@literal false}.
 	 * 
-	 * @param writeFsync to fsync on write (true), otherwise false.
+	 * @param writeFsync to fsync on <code>write (true)<code>, otherwise {@literal false}.
 	 */
 	public void setWriteFsync(boolean writeFsync) {
 		this.writeFsync = writeFsync;
 	}
 
 	/**
-	 * this controls whether or not on a connect, the system retries automatically
+	 * Configures whether or not the system retries automatically on a failed connect. This defaults to {@literal false}.
 	 */
 	public void setAutoConnectRetry(boolean autoConnectRetry) {
 		this.autoConnectRetry = autoConnectRetry;
 	}
 
 	/**
-	 * The maximum amount of time in millisecons to spend retrying to open connection to the same server. Default is 0,
-	 * which means to use the default 15s if autoConnectRetry is on.
+	 * Configures the maximum amount of time in millisecons to spend retrying to open connection to the same server. This
+	 * defaults to {@literal 0}, which means to use the default {@literal 15s} if {@link #autoConnectRetry} is on.
 	 * 
 	 * @param maxAutoConnectRetryTime the maxAutoConnectRetryTime to set
 	 */
@@ -197,7 +160,7 @@ public class MongoOptionsFactoryBean implements FactoryBean<MongoOptions>, Initi
 	}
 
 	/**
-	 * Specifies if the driver is allowed to read from secondaries or slaves. Defaults to false.
+	 * Specifies if the driver is allowed to read from secondaries or slaves. Defaults to {@literal false}.
 	 * 
 	 * @param slaveOk true if the driver should read from secondaries or slaves.
 	 */
@@ -205,32 +168,81 @@ public class MongoOptionsFactoryBean implements FactoryBean<MongoOptions>, Initi
 		this.slaveOk = slaveOk;
 	}
 
-	@SuppressWarnings("deprecation")
+	/**
+	 * Specifies if the driver should use an SSL connection to Mongo. This defaults to {@literal false}. By default
+	 * {@link SSLSocketFactory#getDefault()} will be used. See {@link #setSslSocketFactory(SSLSocketFactory)} if you want
+	 * to configure a custom factory.
+	 * 
+	 * @param ssl true if the driver should use an SSL connection.
+	 * @see #setSslSocketFactory(SSLSocketFactory)
+	 */
+	public void setSsl(boolean ssl) {
+		this.ssl = ssl;
+	}
+
+	/**
+	 * Specifies the {@link SSLSocketFactory} to use for creating SSL connections to Mongo. Defaults to
+	 * {@link SSLSocketFactory#getDefault()}. Implicitly activates {@link #setSsl(boolean)} if a non-{@literal null} value
+	 * is given.
+	 * 
+	 * @param sslSocketFactory the sslSocketFactory to use.
+	 * @see #setSsl(boolean)
+	 */
+	public void setSslSocketFactory(SSLSocketFactory sslSocketFactory) {
+
+		setSsl(sslSocketFactory != null);
+		this.sslSocketFactory = sslSocketFactory;
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.beans.factory.InitializingBean#afterPropertiesSet()
+	 */
 	public void afterPropertiesSet() {
-		MONGO_OPTIONS.connectionsPerHost = connectionsPerHost;
-		MONGO_OPTIONS.threadsAllowedToBlockForConnectionMultiplier = threadsAllowedToBlockForConnectionMultiplier;
-		MONGO_OPTIONS.maxWaitTime = maxWaitTime;
-		MONGO_OPTIONS.connectTimeout = connectTimeout;
-		MONGO_OPTIONS.socketTimeout = socketTimeout;
-		MONGO_OPTIONS.socketKeepAlive = socketKeepAlive;
-		MONGO_OPTIONS.autoConnectRetry = autoConnectRetry;
-		MONGO_OPTIONS.maxAutoConnectRetryTime = maxAutoConnectRetryTime;
-		MONGO_OPTIONS.slaveOk = slaveOk;
-		MONGO_OPTIONS.w = writeNumber;
-		MONGO_OPTIONS.wtimeout = writeTimeout;
-		MONGO_OPTIONS.fsync = writeFsync;
+
+		MongoOptions options = new MongoOptions();
+
+		options.connectionsPerHost = connectionsPerHost;
+		options.threadsAllowedToBlockForConnectionMultiplier = threadsAllowedToBlockForConnectionMultiplier;
+		options.maxWaitTime = maxWaitTime;
+		options.connectTimeout = connectTimeout;
+		options.socketTimeout = socketTimeout;
+		options.socketKeepAlive = socketKeepAlive;
+		options.autoConnectRetry = autoConnectRetry;
+		options.maxAutoConnectRetryTime = maxAutoConnectRetryTime;
+		options.slaveOk = slaveOk;
+		options.w = writeNumber;
+		options.wtimeout = writeTimeout;
+		options.fsync = writeFsync;
+
+		if (ssl) {
+			options.setSocketFactory(sslSocketFactory != null ? sslSocketFactory : SSLSocketFactory.getDefault());
+		}
+
+		this.options = options;
 	}
 
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.beans.factory.FactoryBean#getObject()
+	 */
 	public MongoOptions getObject() {
-		return MONGO_OPTIONS;
+		return this.options;
 	}
 
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.beans.factory.FactoryBean#getObjectType()
+	 */
 	public Class<?> getObjectType() {
 		return MongoOptions.class;
 	}
 
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.beans.factory.FactoryBean#isSingleton()
+	 */
 	public boolean isSingleton() {
 		return true;
 	}
-
 }

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MongoSynchronization.java

@@ -1,8 +1,26 @@
+/*
+ * Copyright 2012-2014 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
 package org.springframework.data.mongodb.core;
 
 import org.springframework.transaction.support.ResourceHolder;
 import org.springframework.transaction.support.ResourceHolderSynchronization;
 
+/**
+ * @author Oliver Gierke
+ */
 class MongoSynchronization extends ResourceHolderSynchronization<ResourceHolder, Object> {
 
 	public MongoSynchronization(ResourceHolder resourceHolder, Object resourceKey) {

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MongoTemplate.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2013 the original author or authors.
+ * Copyright 2010-2014 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -46,6 +46,7 @@ import org.springframework.core.io.ResourceLoader;
 import org.springframework.dao.DataAccessException;
 import org.springframework.dao.InvalidDataAccessApiUsageException;
 import org.springframework.dao.OptimisticLockingFailureException;
+import org.springframework.dao.support.PersistenceExceptionTranslator;
 import org.springframework.data.authentication.UserCredentials;
 import org.springframework.data.convert.EntityReader;
 import org.springframework.data.mapping.PersistentEntity;
@@ -53,10 +54,19 @@ import org.springframework.data.mapping.context.MappingContext;
 import org.springframework.data.mapping.model.BeanWrapper;
 import org.springframework.data.mapping.model.MappingException;
 import org.springframework.data.mongodb.MongoDbFactory;
+import org.springframework.data.mongodb.core.aggregation.Aggregation;
+import org.springframework.data.mongodb.core.aggregation.AggregationOperationContext;
+import org.springframework.data.mongodb.core.aggregation.AggregationResults;
+import org.springframework.data.mongodb.core.aggregation.Fields;
+import org.springframework.data.mongodb.core.aggregation.TypeBasedAggregationOperationContext;
+import org.springframework.data.mongodb.core.aggregation.TypedAggregation;
+import org.springframework.data.mongodb.core.convert.DbRefResolver;
+import org.springframework.data.mongodb.core.convert.DefaultDbRefResolver;
 import org.springframework.data.mongodb.core.convert.MappingMongoConverter;
 import org.springframework.data.mongodb.core.convert.MongoConverter;
 import org.springframework.data.mongodb.core.convert.MongoWriter;
 import org.springframework.data.mongodb.core.convert.QueryMapper;
+import org.springframework.data.mongodb.core.convert.UpdateMapper;
 import org.springframework.data.mongodb.core.geo.Distance;
 import org.springframework.data.mongodb.core.geo.GeoResult;
 import org.springframework.data.mongodb.core.geo.GeoResults;
@@ -113,6 +123,11 @@ import com.mongodb.util.JSONParseException;
  * @author Oliver Gierke
  * @author Amol Nayak
  * @author Patryk Wasik
+ * @author Tobias Trelle
+ * @author Sebastian Herold
+ * @author Thomas Darimont
+ * @author Chuong Ngo
+ * @author Christoph Strobl
  */
 public class MongoTemplate implements MongoOperations, ApplicationContextAware {
 
@@ -134,8 +149,9 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware {
 	private final MongoConverter mongoConverter;
 	private final MappingContext<? extends MongoPersistentEntity<?>, MongoPersistentProperty> mappingContext;
 	private final MongoDbFactory mongoDbFactory;
-	private final MongoExceptionTranslator exceptionTranslator = new MongoExceptionTranslator();
-	private final QueryMapper mapper;
+	private final PersistenceExceptionTranslator exceptionTranslator;
+	private final QueryMapper queryMapper;
+	private final UpdateMapper updateMapper;
 
 	private WriteConcern writeConcern;
 	private WriteConcernResolver writeConcernResolver = DefaultWriteConcernResolver.INSTANCE;
@@ -187,8 +203,10 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware {
 		Assert.notNull(mongoDbFactory);
 
 		this.mongoDbFactory = mongoDbFactory;
+		this.exceptionTranslator = mongoDbFactory.getExceptionTranslator();
 		this.mongoConverter = mongoConverter == null ? getDefaultMongoConverter(mongoDbFactory) : mongoConverter;
-		this.mapper = new QueryMapper(this.mongoConverter);
+		this.queryMapper = new QueryMapper(this.mongoConverter);
+		this.updateMapper = new UpdateMapper(this.mongoConverter);
 
 		// We always have a mapping context in the converter, whether it's a simple one or not
 		mappingContext = this.mongoConverter.getMappingContext();
@@ -334,7 +352,7 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware {
 	}
 
 	public void executeQuery(Query query, String collectionName, DocumentCallbackHandler dch) {
-		executeQuery(query, collectionName, dch, new QueryCursorPreparer(query));
+		executeQuery(query, collectionName, dch, new QueryCursorPreparer(query, null));
 	}
 
 	/**
@@ -352,12 +370,12 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware {
 
 		Assert.notNull(query);
 
-		DBObject queryObject = query.getQueryObject();
+		DBObject queryObject = queryMapper.getMappedObject(query.getQueryObject(), null);
 		DBObject sortObject = query.getSortObject();
 		DBObject fieldsObject = query.getFieldsObject();
 
 		if (LOGGER.isDebugEnabled()) {
-			LOGGER.debug(String.format("Executing query: %s sort: %s fields: %s in collection: $s",
+			LOGGER.debug(String.format("Executing query: %s sort: %s fields: %s in collection: %s",
 					serializeToJsonSafely(queryObject), sortObject, fieldsObject, collectionName));
 		}
 
@@ -495,7 +513,7 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware {
 			throw new InvalidDataAccessApiUsageException("Query passed in to exist can't be null");
 		}
 
-		DBObject mappedQuery = mapper.getMappedObject(query.getQueryObject(), getPersistentEntity(entityClass));
+		DBObject mappedQuery = queryMapper.getMappedObject(query.getQueryObject(), getPersistentEntity(entityClass));
 		return execute(collectionName, new FindCallback(mappedQuery)).hasNext();
 	}
 
@@ -512,7 +530,7 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware {
 		}
 
 		return doFind(collectionName, query.getQueryObject(), query.getFieldsObject(), entityClass,
-				new QueryCursorPreparer(query));
+				new QueryCursorPreparer(query, entityClass));
 	}
 
 	public <T> T findById(Object id, Class<T> entityClass) {
@@ -553,8 +571,26 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware {
 				mongoConverter, entityClass), near.getMetric());
 		List<GeoResult<T>> result = new ArrayList<GeoResult<T>>(results.size());
 
+		int index = 0;
+		int elementsToSkip = near.getSkip() != null ? near.getSkip() : 0;
+
 		for (Object element : results) {
-			result.add(callback.doWith((DBObject) element));
+
+			/*
+			 * As MongoDB currently (2.4.4) doesn't support the skipping of elements in near queries
+			 * we skip the elements ourselves to avoid at least the document 2 object mapping overhead.
+			 * 
+			 * @see https://jira.mongodb.org/browse/SERVER-3925
+			 */
+			if (index >= elementsToSkip) {
+				result.add(callback.doWith((DBObject) element));
+			}
+			index++;
+		}
+
+		if (elementsToSkip > 0) {
+			// as we skipped some elements we have to calculate the averageDistance ourselves:
+			return new GeoResults<T>(result, near.getMetric());
 		}
 
 		DBObject stats = (DBObject) commandResult.get("stats");
@@ -576,8 +612,8 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware {
 
 	public <T> T findAndModify(Query query, Update update, FindAndModifyOptions options, Class<T> entityClass,
 			String collectionName) {
-		return doFindAndModify(collectionName, query.getQueryObject(), query.getFieldsObject(), query.getSortObject(),
-				entityClass, update, options);
+		return doFindAndModify(collectionName, query.getQueryObject(), query.getFieldsObject(),
+				getMappedSortObject(query, entityClass), entityClass, update, options);
 	}
 
 	// Find methods that take a Query to express the query and that return a single object that is also removed from the
@@ -588,8 +624,9 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware {
 	}
 
 	public <T> T findAndRemove(Query query, Class<T> entityClass, String collectionName) {
-		return doFindAndRemove(collectionName, query.getQueryObject(), query.getFieldsObject(), query.getSortObject(),
-				entityClass);
+
+		return doFindAndRemove(collectionName, query.getQueryObject(), query.getFieldsObject(),
+				getMappedSortObject(query, entityClass), entityClass);
 	}
 
 	public long count(Query query, Class<?> entityClass) {
@@ -604,7 +641,7 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware {
 	private long count(Query query, Class<?> entityClass, String collectionName) {
 
 		Assert.hasText(collectionName);
-		final DBObject dbObject = query == null ? null : mapper.getMappedObject(query.getQueryObject(),
+		final DBObject dbObject = query == null ? null : queryMapper.getMappedObject(query.getQueryObject(),
 				entityClass == null ? null : mappingContext.getPersistentEntity(entityClass));
 
 		return execute(collectionName, new CollectionCallback<Long>() {
@@ -669,10 +706,9 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware {
 
 		initializeVersionProperty(objectToSave);
 
-		BasicDBObject dbDoc = new BasicDBObject();
-
 		maybeEmitEvent(new BeforeConvertEvent<T>(objectToSave));
-		writer.write(objectToSave, dbDoc);
+
+		DBObject dbDoc = toDbObject(objectToSave, writer);
 
 		maybeEmitEvent(new BeforeSaveEvent<T>(objectToSave, dbDoc));
 		Object id = insertDBObject(collectionName, dbDoc, objectToSave.getClass());
@@ -681,6 +717,26 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware {
 		maybeEmitEvent(new AfterSaveEvent<T>(objectToSave, dbDoc));
 	}
 
+	/**
+	 * @param objectToSave
+	 * @param writer
+	 * @return
+	 */
+	private <T> DBObject toDbObject(T objectToSave, MongoWriter<T> writer) {
+
+		if (!(objectToSave instanceof String)) {
+			DBObject dbDoc = new BasicDBObject();
+			writer.write(objectToSave, dbDoc);
+			return dbDoc;
+		} else {
+			try {
+				return (DBObject) JSON.parse((String) objectToSave);
+			} catch (JSONParseException e) {
+				throw new MappingException("Could not parse given String to save into a JSON document!", e);
+			}
+		}
+	}
+
 	private void initializeVersionProperty(Object entity) {
 
 		MongoPersistentEntity<?> mongoPersistentEntity = getPersistentEntity(entity.getClass());
@@ -820,19 +876,9 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware {
 
 		assertUpdateableIdIfNotSet(objectToSave);
 
-		DBObject dbDoc = new BasicDBObject();
-
 		maybeEmitEvent(new BeforeConvertEvent<T>(objectToSave));
 
-		if (!(objectToSave instanceof String)) {
-			writer.write(objectToSave, dbDoc);
-		} else {
-			try {
-				dbDoc = (DBObject) JSON.parse((String) objectToSave);
-			} catch (JSONParseException e) {
-				throw new MappingException("Could not parse given String to save into a JSON document!", e);
-			}
-		}
+		DBObject dbDoc = toDbObject(objectToSave, writer);
 
 		maybeEmitEvent(new BeforeSaveEvent<T>(objectToSave, dbDoc));
 		Object id = saveDBObject(collectionName, dbDoc, objectToSave.getClass());
@@ -916,6 +962,10 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware {
 		return doUpdate(collectionName, query, update, null, true, false);
 	}
 
+	public WriteResult upsert(Query query, Update update, Class<?> entityClass, String collectionName) {
+		return doUpdate(collectionName, query, update, entityClass, true, false);
+	}
+
 	public WriteResult updateFirst(Query query, Update update, Class<?> entityClass) {
 		return doUpdate(determineCollectionName(entityClass), query, update, entityClass, false, false);
 	}
@@ -924,6 +974,10 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware {
 		return doUpdate(collectionName, query, update, null, false, false);
 	}
 
+	public WriteResult updateFirst(Query query, Update update, Class<?> entityClass, String collectionName) {
+		return doUpdate(collectionName, query, update, entityClass, false, false);
+	}
+
 	public WriteResult updateMulti(Query query, Update update, Class<?> entityClass) {
 		return doUpdate(determineCollectionName(entityClass), query, update, entityClass, false, true);
 	}
@@ -932,6 +986,10 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware {
 		return doUpdate(collectionName, query, update, null, false, true);
 	}
 
+	public WriteResult updateMulti(final Query query, final Update update, Class<?> entityClass, String collectionName) {
+		return doUpdate(collectionName, query, update, entityClass, false, true);
+	}
+
 	protected WriteResult doUpdate(final String collectionName, final Query query, final Update update,
 			final Class<?> entityClass, final boolean upsert, final boolean multi) {
 
@@ -940,10 +998,12 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware {
 
 				MongoPersistentEntity<?> entity = entityClass == null ? null : getPersistentEntity(entityClass);
 
-				DBObject queryObj = query == null ? new BasicDBObject()
-						: mapper.getMappedObject(query.getQueryObject(), entity);
-				DBObject updateObj = update == null ? new BasicDBObject() : mapper.getMappedObject(update.getUpdateObject(),
+				increaseVersionForUpdateIfNecessary(entity, update);
+
+				DBObject queryObj = query == null ? new BasicDBObject() : queryMapper.getMappedObject(query.getQueryObject(),
 						entity);
+				DBObject updateObj = update == null ? new BasicDBObject() : updateMapper.getMappedObject(
+						update.getUpdateObject(), entity);
 
 				if (LOGGER.isDebugEnabled()) {
 					LOGGER.debug("Calling update using query: " + queryObj + " and update: " + updateObj + " in collection: "
@@ -957,7 +1017,7 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware {
 						: collection.update(queryObj, updateObj, upsert, multi, writeConcernToUse);
 
 				if (entity != null && entity.hasVersionProperty() && !multi) {
-					if (writeResult.getN() == 0) {
+					if (writeResult.getN() == 0 && dbObjectContainsVersionProperty(queryObj, entity)) {
 						throw new OptimisticLockingFailureException("Optimistic lock exception on saving entity: "
 								+ updateObj.toMap().toString() + " to collection " + collectionName);
 					}
@@ -969,6 +1029,25 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware {
 		});
 	}
 
+	private void increaseVersionForUpdateIfNecessary(MongoPersistentEntity<?> persistentEntity, Update update) {
+
+		if (persistentEntity != null && persistentEntity.hasVersionProperty()) {
+			String versionFieldName = persistentEntity.getVersionProperty().getFieldName();
+			if (!update.modifies(versionFieldName)) {
+				update.inc(versionFieldName, 1L);
+			}
+		}
+	}
+
+	private boolean dbObjectContainsVersionProperty(DBObject dbObject, MongoPersistentEntity<?> persistentEntity) {
+
+		if (persistentEntity == null || !persistentEntity.hasVersionProperty()) {
+			return false;
+		}
+
+		return dbObject.containsField(persistentEntity.getVersionProperty().getFieldName());
+	}
+
 	public void remove(Object object) {
 
 		if (object == null) {
@@ -1061,7 +1140,7 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware {
 
 				maybeEmitEvent(new BeforeDeleteEvent<T>(queryObject, entityClass));
 
-				DBObject dboq = mapper.getMappedObject(queryObject, entity);
+				DBObject dboq = queryMapper.getMappedObject(queryObject, entity);
 
 				MongoAction mongoAction = new MongoAction(writeConcern, MongoActionOperation.REMOVE, collectionName,
 						entityClass, null, queryObject);
@@ -1111,6 +1190,7 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware {
 
 	public <T> MapReduceResults<T> mapReduce(Query query, String inputCollectionName, String mapFunction,
 			String reduceFunction, MapReduceOptions mapReduceOptions, Class<T> entityClass) {
+
 		String mapFunc = replaceWithResourceIfNecessary(mapFunction);
 		String reduceFunc = replaceWithResourceIfNecessary(reduceFunction);
 		DBCollection inputCollection = getCollection(inputCollectionName);
@@ -1135,12 +1215,12 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware {
 		MapReduceOutput mapReduceOutput = new MapReduceOutput(inputCollection, commandObject, commandResult);
 		List<T> mappedResults = new ArrayList<T>();
 		DbObjectCallback<T> callback = new ReadDbObjectCallback<T>(mongoConverter, entityClass);
+
 		for (DBObject dbObject : mapReduceOutput.results()) {
 			mappedResults.add(callback.doWith(dbObject));
 		}
 
-		MapReduceResults<T> mapReduceResult = new MapReduceResults<T>(mappedResults, commandResult);
-		return mapReduceResult;
+		return new MapReduceResults<T>(mappedResults, commandResult);
 	}
 
 	public <T> GroupByResults<T> group(String inputCollectionName, GroupBy groupBy, Class<T> entityClass) {
@@ -1156,7 +1236,7 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware {
 		if (criteria == null) {
 			dbo.put("cond", null);
 		} else {
-			dbo.put("cond", mapper.getMappedObject(criteria.getCriteriaObject(), null));
+			dbo.put("cond", queryMapper.getMappedObject(criteria.getCriteriaObject(), null));
 		}
 		// If initial document was a JavaScript string, potentially loaded by Spring's Resource abstraction, load it and
 		// convert to DBObject
@@ -1194,15 +1274,72 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware {
 
 		@SuppressWarnings("unchecked")
 		Iterable<DBObject> resultSet = (Iterable<DBObject>) commandResult.get("retval");
-
 		List<T> mappedResults = new ArrayList<T>();
 		DbObjectCallback<T> callback = new ReadDbObjectCallback<T>(mongoConverter, entityClass);
+
 		for (DBObject dbObject : resultSet) {
 			mappedResults.add(callback.doWith(dbObject));
 		}
-		GroupByResults<T> groupByResult = new GroupByResults<T>(mappedResults, commandResult);
-		return groupByResult;
 
+		return new GroupByResults<T>(mappedResults, commandResult);
+	}
+
+	@Override
+	public <O> AggregationResults<O> aggregate(TypedAggregation<?> aggregation, Class<O> outputType) {
+		return aggregate(aggregation, determineCollectionName(aggregation.getInputType()), outputType);
+	}
+
+	@Override
+	public <O> AggregationResults<O> aggregate(TypedAggregation<?> aggregation, String inputCollectionName,
+			Class<O> outputType) {
+
+		Assert.notNull(aggregation, "Aggregation pipeline must not be null!");
+
+		AggregationOperationContext context = new TypeBasedAggregationOperationContext(aggregation.getInputType(),
+				mappingContext, queryMapper);
+		return aggregate(aggregation, inputCollectionName, outputType, context);
+	}
+
+	@Override
+	public <O> AggregationResults<O> aggregate(Aggregation aggregation, Class<?> inputType, Class<O> outputType) {
+
+		return aggregate(aggregation, determineCollectionName(inputType), outputType,
+				new TypeBasedAggregationOperationContext(inputType, mappingContext, queryMapper));
+	}
+
+	@Override
+	public <O> AggregationResults<O> aggregate(Aggregation aggregation, String collectionName, Class<O> outputType) {
+		return aggregate(aggregation, collectionName, outputType, null);
+	}
+
+	protected <O> AggregationResults<O> aggregate(Aggregation aggregation, String collectionName, Class<O> outputType,
+			AggregationOperationContext context) {
+
+		Assert.hasText(collectionName, "Collection name must not be null or empty!");
+		Assert.notNull(aggregation, "Aggregation pipeline must not be null!");
+		Assert.notNull(outputType, "Output type must not be null!");
+
+		AggregationOperationContext rootContext = context == null ? Aggregation.DEFAULT_CONTEXT : context;
+		DBObject command = aggregation.toDbObject(collectionName, rootContext);
+
+		if (LOGGER.isDebugEnabled()) {
+			LOGGER.debug("Executing aggregation: {}", serializeToJsonSafely(command));
+		}
+
+		CommandResult commandResult = executeCommand(command);
+		handleCommandError(commandResult, command);
+
+		// map results
+		@SuppressWarnings("unchecked")
+		Iterable<DBObject> resultSet = (Iterable<DBObject>) commandResult.get("result");
+		List<O> mappedResults = new ArrayList<O>();
+		DbObjectCallback<O> callback = new UnwrapAndReadDbObjectCallback<O>(mongoConverter, outputType);
+
+		for (DBObject dbObject : resultSet) {
+			mappedResults.add(callback.doWith(dbObject));
+		}
+
+		return new AggregationResults<O>(mappedResults, commandResult);
 	}
 
 	protected String replaceWithResourceIfNecessary(String function) {
@@ -1234,13 +1371,13 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware {
 						"Can not use skip or field specification with map reduce operations");
 			}
 			if (query.getQueryObject() != null) {
-				copyMapReduceOptions.put("query", query.getQueryObject());
+				copyMapReduceOptions.put("query", queryMapper.getMappedObject(query.getQueryObject(), null));
 			}
 			if (query.getLimit() > 0) {
 				copyMapReduceOptions.put("limit", query.getLimit());
 			}
 			if (query.getSortObject() != null) {
-				copyMapReduceOptions.put("sort", query.getSortObject());
+				copyMapReduceOptions.put("sort", queryMapper.getMappedObject(query.getSortObject(), null));
 			}
 		}
 		return copyMapReduceOptions;
@@ -1313,57 +1450,28 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware {
 	}
 
 	/**
-	 * Map the results of an ad-hoc query on the default MongoDB collection to an object using the template's converter
-	 * <p/>
-	 * The query document is specified as a standard DBObject and so is the fields specification.
+	 * Map the results of an ad-hoc query on the default MongoDB collection to an object using the template's converter.
+	 * The query document is specified as a standard {@link DBObject} and so is the fields specification.
 	 * 
-	 * @param collectionName name of the collection to retrieve the objects from
-	 * @param query the query document that specifies the criteria used to find a record
-	 * @param fields the document that specifies the fields to be returned
+	 * @param collectionName name of the collection to retrieve the objects from.
+	 * @param query the query document that specifies the criteria used to find a record.
+	 * @param fields the document that specifies the fields to be returned.
 	 * @param entityClass the parameterized type of the returned list.
-	 * @return the List of converted objects.
+	 * @return the {@link List} of converted objects.
 	 */
 	protected <T> T doFindOne(String collectionName, DBObject query, DBObject fields, Class<T> entityClass) {
-		EntityReader<? super T, DBObject> readerToUse = this.mongoConverter;
-		MongoPersistentEntity<?> entity = mappingContext.getPersistentEntity(entityClass);
-		DBObject mappedQuery = mapper.getMappedObject(query, entity);
-
-		return executeFindOneInternal(new FindOneCallback(mappedQuery, fields), new ReadDbObjectCallback<T>(readerToUse,
-				entityClass), collectionName);
-	}
-
-	/**
-	 * Map the results of an ad-hoc query on the default MongoDB collection to a List of the specified type. The object is
-	 * converted from the MongoDB native representation using an instance of {@see MongoConverter}. Unless configured
-	 * otherwise, an instance of SimpleMongoConverter will be used. The query document is specified as a standard DBObject
-	 * and so is the fields specification. Can be overridden by subclasses.
-	 * 
-	 * @param collectionName name of the collection to retrieve the objects from
-	 * @param query the query document that specifies the criteria used to find a record
-	 * @param fields the document that specifies the fields to be returned
-	 * @param entityClass the parameterized type of the returned list.
-	 * @param preparer allows for customization of the DBCursor used when iterating over the result set, (apply limits,
-	 *          skips and so on).
-	 * @return the List of converted objects.
-	 */
-	protected <T> List<T> doFind(String collectionName, DBObject query, DBObject fields, Class<T> entityClass,
-			CursorPreparer preparer) {
-		return doFind(collectionName, query, fields, entityClass, preparer, new ReadDbObjectCallback<T>(mongoConverter,
-				entityClass));
-	}
-
-	protected <S, T> List<T> doFind(String collectionName, DBObject query, DBObject fields, Class<S> entityClass,
-			CursorPreparer preparer, DbObjectCallback<T> objectCallback) {
 
 		MongoPersistentEntity<?> entity = mappingContext.getPersistentEntity(entityClass);
+		DBObject mappedQuery = queryMapper.getMappedObject(query, entity);
+		DBObject mappedFields = fields == null ? null : queryMapper.getMappedObject(fields, entity);
 
 		if (LOGGER.isDebugEnabled()) {
-			LOGGER.debug(String.format("find using query: %s fields: %s for class: %s in collection: %s",
-					serializeToJsonSafely(query), fields, entityClass, collectionName));
+			LOGGER.debug(String.format("findOne using query: %s fields: %s for class: %s in collection: %s",
+					serializeToJsonSafely(query), mappedFields, entityClass, collectionName));
 		}
 
-		return executeFindMultiInternal(new FindCallback(mapper.getMappedObject(query, entity), fields), preparer,
-				objectCallback, collectionName);
+		return executeFindOneInternal(new FindOneCallback(mappedQuery, mappedFields), new ReadDbObjectCallback<T>(
+				this.mongoConverter, entityClass), collectionName);
 	}
 
 	/**
@@ -1377,14 +1485,43 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware {
 	 * @return the List of converted objects.
 	 */
 	protected <T> List<T> doFind(String collectionName, DBObject query, DBObject fields, Class<T> entityClass) {
-		if (LOGGER.isDebugEnabled()) {
-			LOGGER.debug("find using query: " + query + " fields: " + fields + " for class: " + entityClass
-					+ " in collection: " + collectionName);
-		}
-		EntityReader<? super T, DBObject> readerToUse = this.mongoConverter;
+		return doFind(collectionName, query, fields, entityClass, null, new ReadDbObjectCallback<T>(this.mongoConverter,
+				entityClass));
+	}
+
+	/**
+	 * Map the results of an ad-hoc query on the default MongoDB collection to a List of the specified type. The object is
+	 * converted from the MongoDB native representation using an instance of {@see MongoConverter}. The query document is
+	 * specified as a standard DBObject and so is the fields specification.
+	 * 
+	 * @param collectionName name of the collection to retrieve the objects from.
+	 * @param query the query document that specifies the criteria used to find a record.
+	 * @param fields the document that specifies the fields to be returned.
+	 * @param entityClass the parameterized type of the returned list.
+	 * @param preparer allows for customization of the {@link DBCursor} used when iterating over the result set, (apply
+	 *          limits, skips and so on).
+	 * @return the {@link List} of converted objects.
+	 */
+	protected <T> List<T> doFind(String collectionName, DBObject query, DBObject fields, Class<T> entityClass,
+			CursorPreparer preparer) {
+		return doFind(collectionName, query, fields, entityClass, preparer, new ReadDbObjectCallback<T>(mongoConverter,
+				entityClass));
+	}
+
+	protected <S, T> List<T> doFind(String collectionName, DBObject query, DBObject fields, Class<S> entityClass,
+			CursorPreparer preparer, DbObjectCallback<T> objectCallback) {
+
 		MongoPersistentEntity<?> entity = mappingContext.getPersistentEntity(entityClass);
-		return executeFindMultiInternal(new FindCallback(mapper.getMappedObject(query, entity), fields), null,
-				new ReadDbObjectCallback<T>(readerToUse, entityClass), collectionName);
+		DBObject mappedFields = fields == null ? null : queryMapper.getMappedObject(fields, entity);
+		DBObject mappedQuery = queryMapper.getMappedObject(query, entity);
+
+		if (LOGGER.isDebugEnabled()) {
+			LOGGER.debug(String.format("find using query: %s fields: %s for class: %s in collection: %s",
+					serializeToJsonSafely(query), mappedFields, entityClass, collectionName));
+		}
+
+		return executeFindMultiInternal(new FindCallback(mappedQuery, mappedFields), preparer, objectCallback,
+				collectionName);
 	}
 
 	protected DBObject convertToDbObject(CollectionOptions collectionOptions) {
@@ -1422,7 +1559,7 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware {
 					+ entityClass + " in collection: " + collectionName);
 		}
 		MongoPersistentEntity<?> entity = mappingContext.getPersistentEntity(entityClass);
-		return executeFindOneInternal(new FindAndRemoveCallback(mapper.getMappedObject(query, entity), fields, sort),
+		return executeFindOneInternal(new FindAndRemoveCallback(queryMapper.getMappedObject(query, entity), fields, sort),
 				new ReadDbObjectCallback<T>(readerToUse, entityClass), collectionName);
 	}
 
@@ -1437,19 +1574,17 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware {
 
 		MongoPersistentEntity<?> entity = mappingContext.getPersistentEntity(entityClass);
 
-		DBObject updateObj = update.getUpdateObject();
-		for (String key : updateObj.keySet()) {
-			updateObj.put(key, mongoConverter.convertToMongoType(updateObj.get(key)));
-		}
+		increaseVersionForUpdateIfNecessary(entity, update);
 
-		DBObject mappedQuery = mapper.getMappedObject(query, entity);
+		DBObject mappedQuery = queryMapper.getMappedObject(query, entity);
+		DBObject mappedUpdate = updateMapper.getMappedObject(update.getUpdateObject(), entity);
 
 		if (LOGGER.isDebugEnabled()) {
 			LOGGER.debug("findAndModify using query: " + mappedQuery + " fields: " + fields + " sort: " + sort
-					+ " for class: " + entityClass + " and update: " + updateObj + " in collection: " + collectionName);
+					+ " for class: " + entityClass + " and update: " + mappedUpdate + " in collection: " + collectionName);
 		}
 
-		return executeFindOneInternal(new FindAndModifyCallback(mappedQuery, fields, sort, updateObj, options),
+		return executeFindOneInternal(new FindAndModifyCallback(mappedQuery, fields, sort, mappedUpdate, options),
 				new ReadDbObjectCallback<T>(readerToUse, entityClass), collectionName);
 	}
 
@@ -1717,11 +1852,23 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware {
 	}
 
 	private static final MongoConverter getDefaultMongoConverter(MongoDbFactory factory) {
-		MappingMongoConverter converter = new MappingMongoConverter(factory, new MongoMappingContext());
+
+		DbRefResolver dbRefResolver = new DefaultDbRefResolver(factory);
+		MappingMongoConverter converter = new MappingMongoConverter(dbRefResolver, new MongoMappingContext());
 		converter.afterPropertiesSet();
 		return converter;
 	}
 
+	private DBObject getMappedSortObject(Query query, Class<?> type) {
+
+		if (query == null || query.getSortObject() == null) {
+			return null;
+		}
+
+		MongoPersistentEntity<?> entity = mappingContext.getPersistentEntity(type);
+		return queryMapper.getMappedObject(query.getSortObject(), entity);
+	}
+
 	// Callback implementations
 
 	/**
@@ -1874,6 +2021,35 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware {
 		}
 	}
 
+	class UnwrapAndReadDbObjectCallback<T> extends ReadDbObjectCallback<T> {
+
+		public UnwrapAndReadDbObjectCallback(EntityReader<? super T, DBObject> reader, Class<T> type) {
+			super(reader, type);
+		}
+
+		@Override
+		public T doWith(DBObject object) {
+
+			Object idField = object.get(Fields.UNDERSCORE_ID);
+
+			if (!(idField instanceof DBObject)) {
+				return super.doWith(object);
+			}
+
+			DBObject toMap = new BasicDBObject();
+			DBObject nested = (DBObject) idField;
+			toMap.putAll(nested);
+
+			for (String key : object.keySet()) {
+				if (!Fields.UNDERSCORE_ID.equals(key)) {
+					toMap.put(key, object.get(key));
+				}
+			}
+
+			return super.doWith(toMap);
+		}
+	}
+
 	private enum DefaultWriteConcernResolver implements WriteConcernResolver {
 
 		INSTANCE;
@@ -1886,9 +2062,12 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware {
 	class QueryCursorPreparer implements CursorPreparer {
 
 		private final Query query;
+		private final Class<?> type;
+
+		public QueryCursorPreparer(Query query, Class<?> type) {
 
-		public QueryCursorPreparer(Query query) {
 			this.query = query;
+			this.type = type;
 		}
 
 		/*
@@ -1916,7 +2095,8 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware {
 					cursorToUse = cursorToUse.limit(query.getLimit());
 				}
 				if (query.getSortObject() != null) {
-					cursorToUse = cursorToUse.sort(query.getSortObject());
+					DBObject sortDbo = type != null ? getMappedSortObject(query, type) : query.getSortObject();
+					cursorToUse = cursorToUse.sort(sortDbo);
 				}
 				if (StringUtils.hasText(query.getHint())) {
 					cursorToUse = cursorToUse.hint(query.getHint());

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/SimpleMongoDbFactory.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2011-2012 the original author or authors.
+ * Copyright 2011-2013 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -19,9 +19,11 @@ import java.net.UnknownHostException;
 
 import org.springframework.beans.factory.DisposableBean;
 import org.springframework.dao.DataAccessException;
+import org.springframework.dao.support.PersistenceExceptionTranslator;
 import org.springframework.data.authentication.UserCredentials;
 import org.springframework.data.mongodb.MongoDbFactory;
 import org.springframework.util.Assert;
+import org.springframework.util.StringUtils;
 
 import com.mongodb.DB;
 import com.mongodb.Mongo;
@@ -34,6 +36,7 @@ import com.mongodb.WriteConcern;
  * 
  * @author Mark Pollack
  * @author Oliver Gierke
+ * @author Thomas Darimont
  */
 public class SimpleMongoDbFactory implements DisposableBean, MongoDbFactory {
 
@@ -41,6 +44,9 @@ public class SimpleMongoDbFactory implements DisposableBean, MongoDbFactory {
 	private final String databaseName;
 	private final boolean mongoInstanceCreated;
 	private final UserCredentials credentials;
+	private final PersistenceExceptionTranslator exceptionTranslator;
+	private final String authenticationDatabaseName;
+
 	private WriteConcern writeConcern;
 
 	/**
@@ -50,7 +56,7 @@ public class SimpleMongoDbFactory implements DisposableBean, MongoDbFactory {
 	 * @param databaseName database name, not be {@literal null} or empty.
 	 */
 	public SimpleMongoDbFactory(Mongo mongo, String databaseName) {
-		this(mongo, databaseName, UserCredentials.NO_CREDENTIALS, false);
+		this(mongo, databaseName, null);
 	}
 
 	/**
@@ -61,7 +67,20 @@ public class SimpleMongoDbFactory implements DisposableBean, MongoDbFactory {
 	 * @param credentials username and password.
 	 */
 	public SimpleMongoDbFactory(Mongo mongo, String databaseName, UserCredentials credentials) {
-		this(mongo, databaseName, credentials, false);
+		this(mongo, databaseName, credentials, false, null);
+	}
+
+	/**
+	 * Create an instance of SimpleMongoDbFactory given the Mongo instance, database name, and username/password
+	 * 
+	 * @param mongo Mongo instance, must not be {@literal null}.
+	 * @param databaseName Database name, must not be {@literal null} or empty.
+	 * @param credentials username and password.
+	 * @param authenticationDatabaseName the database name to use for authentication
+	 */
+	public SimpleMongoDbFactory(Mongo mongo, String databaseName, UserCredentials credentials,
+			String authenticationDatabaseName) {
+		this(mongo, databaseName, credentials, false, authenticationDatabaseName);
 	}
 
 	/**
@@ -72,12 +91,14 @@ public class SimpleMongoDbFactory implements DisposableBean, MongoDbFactory {
 	 * @throws UnknownHostException
 	 * @see MongoURI
 	 */
+	@SuppressWarnings("deprecation")
 	public SimpleMongoDbFactory(MongoURI uri) throws MongoException, UnknownHostException {
-		this(new Mongo(uri), uri.getDatabase(), new UserCredentials(uri.getUsername(), parseChars(uri.getPassword())), true);
+		this(new Mongo(uri), uri.getDatabase(), new UserCredentials(uri.getUsername(), parseChars(uri.getPassword())),
+				true, uri.getDatabase());
 	}
 
 	private SimpleMongoDbFactory(Mongo mongo, String databaseName, UserCredentials credentials,
-			boolean mongoInstanceCreated) {
+			boolean mongoInstanceCreated, String authenticationDatabaseName) {
 
 		Assert.notNull(mongo, "Mongo must not be null");
 		Assert.hasText(databaseName, "Database name must not be empty");
@@ -88,6 +109,12 @@ public class SimpleMongoDbFactory implements DisposableBean, MongoDbFactory {
 		this.databaseName = databaseName;
 		this.mongoInstanceCreated = mongoInstanceCreated;
 		this.credentials = credentials == null ? UserCredentials.NO_CREDENTIALS : credentials;
+		this.exceptionTranslator = new MongoExceptionTranslator();
+		this.authenticationDatabaseName = StringUtils.hasText(authenticationDatabaseName) ? authenticationDatabaseName
+				: databaseName;
+
+		Assert.isTrue(this.authenticationDatabaseName.matches("[\\w-]+"),
+				"Authentication database name must only contain letters, numbers, underscores and dashes!");
 	}
 
 	/**
@@ -115,7 +142,7 @@ public class SimpleMongoDbFactory implements DisposableBean, MongoDbFactory {
 
 		Assert.hasText(dbName, "Database name must not be empty.");
 
-		DB db = MongoDbUtils.getDB(mongo, dbName, credentials);
+		DB db = MongoDbUtils.getDB(mongo, dbName, credentials, authenticationDatabaseName);
 
 		if (writeConcern != null) {
 			db.setWriteConcern(writeConcern);
@@ -138,4 +165,13 @@ public class SimpleMongoDbFactory implements DisposableBean, MongoDbFactory {
 	private static String parseChars(char[] chars) {
 		return chars == null ? null : String.valueOf(chars);
 	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.MongoDbFactory#getExceptionTranslator()
+	 */
+	@Override
+	public PersistenceExceptionTranslator getExceptionTranslator() {
+		return this.exceptionTranslator;
+	}
 }

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/Aggregation.java

@@ -0,0 +1,305 @@
+/*
+ * Copyright 2013-2014 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.mongodb.core.aggregation;
+
+import static org.springframework.data.mongodb.core.aggregation.Fields.*;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+import org.springframework.data.domain.Sort;
+import org.springframework.data.domain.Sort.Direction;
+import org.springframework.data.mongodb.core.aggregation.ExposedFields.ExposedField;
+import org.springframework.data.mongodb.core.aggregation.ExposedFields.FieldReference;
+import org.springframework.data.mongodb.core.aggregation.Fields.AggregationField;
+import org.springframework.data.mongodb.core.query.Criteria;
+import org.springframework.data.mongodb.core.query.SerializationUtils;
+import org.springframework.util.Assert;
+
+import com.mongodb.BasicDBObject;
+import com.mongodb.DBObject;
+
+/**
+ * An {@code Aggregation} is a representation of a list of aggregation steps to be performed by the MongoDB Aggregation
+ * Framework.
+ * 
+ * @author Tobias Trelle
+ * @author Thomas Darimont
+ * @author Oliver Gierke
+ * @since 1.3
+ */
+public class Aggregation {
+
+	public static final AggregationOperationContext DEFAULT_CONTEXT = new NoOpAggregationOperationContext();
+
+	private final List<AggregationOperation> operations;
+
+	/**
+	 * Creates a new {@link Aggregation} from the given {@link AggregationOperation}s.
+	 * 
+	 * @param operations must not be {@literal null} or empty.
+	 */
+	public static Aggregation newAggregation(List<? extends AggregationOperation> operations) {
+		return newAggregation(operations.toArray(new AggregationOperation[operations.size()]));
+	}
+
+	/**
+	 * Creates a new {@link Aggregation} from the given {@link AggregationOperation}s.
+	 * 
+	 * @param operations must not be {@literal null} or empty.
+	 */
+	public static Aggregation newAggregation(AggregationOperation... operations) {
+		return new Aggregation(operations);
+	}
+
+	/**
+	 * Creates a new {@link TypedAggregation} for the given type and {@link AggregationOperation}s.
+	 * 
+	 * @param type must not be {@literal null}.
+	 * @param operations must not be {@literal null} or empty.
+	 */
+	public static <T> TypedAggregation<T> newAggregation(Class<T> type, List<? extends AggregationOperation> operations) {
+		return newAggregation(type, operations.toArray(new AggregationOperation[operations.size()]));
+	}
+
+	/**
+	 * Creates a new {@link TypedAggregation} for the given type and {@link AggregationOperation}s.
+	 * 
+	 * @param type must not be {@literal null}.
+	 * @param operations must not be {@literal null} or empty.
+	 */
+	public static <T> TypedAggregation<T> newAggregation(Class<T> type, AggregationOperation... operations) {
+		return new TypedAggregation<T>(type, operations);
+	}
+
+	/**
+	 * Creates a new {@link Aggregation} from the given {@link AggregationOperation}s.
+	 * 
+	 * @param aggregationOperations must not be {@literal null} or empty.
+	 */
+	protected Aggregation(AggregationOperation... aggregationOperations) {
+
+		Assert.notNull(aggregationOperations, "AggregationOperations must not be null!");
+		Assert.isTrue(aggregationOperations.length > 0, "At least one AggregationOperation has to be provided");
+
+		this.operations = Arrays.asList(aggregationOperations);
+	}
+
+	/**
+	 * A pointer to the previous {@link AggregationOperation}.
+	 * 
+	 * @return
+	 */
+	public static String previousOperation() {
+		return "_id";
+	}
+
+	/**
+	 * Creates a new {@link ProjectionOperation} including the given fields.
+	 * 
+	 * @param fields must not be {@literal null}.
+	 * @return
+	 */
+	public static ProjectionOperation project(String... fields) {
+		return project(fields(fields));
+	}
+
+	/**
+	 * Creates a new {@link ProjectionOperation} includeing the given {@link Fields}.
+	 * 
+	 * @param fields must not be {@literal null}.
+	 * @return
+	 */
+	public static ProjectionOperation project(Fields fields) {
+		return new ProjectionOperation(fields);
+	}
+
+	/**
+	 * Factory method to create a new {@link UnwindOperation} for the field with the given name.
+	 * 
+	 * @param fieldName must not be {@literal null} or empty.
+	 * @return
+	 */
+	public static UnwindOperation unwind(String field) {
+		return new UnwindOperation(field(field));
+	}
+
+	/**
+	 * Creates a new {@link GroupOperation} for the given fields.
+	 * 
+	 * @param fields must not be {@literal null}.
+	 * @return
+	 */
+	public static GroupOperation group(String... fields) {
+		return group(fields(fields));
+	}
+
+	/**
+	 * Creates a new {@link GroupOperation} for the given {@link Fields}.
+	 * 
+	 * @param fields must not be {@literal null}.
+	 * @return
+	 */
+	public static GroupOperation group(Fields fields) {
+		return new GroupOperation(fields);
+	}
+
+	/**
+	 * Factory method to create a new {@link SortOperation} for the given {@link Sort}.
+	 * 
+	 * @param sort must not be {@literal null}.
+	 * @return
+	 */
+	public static SortOperation sort(Sort sort) {
+		return new SortOperation(sort);
+	}
+
+	/**
+	 * Factory method to create a new {@link SortOperation} for the given sort {@link Direction} and {@code fields}.
+	 * 
+	 * @param direction must not be {@literal null}.
+	 * @param fields must not be {@literal null}.
+	 * @return
+	 */
+	public static SortOperation sort(Direction direction, String... fields) {
+		return new SortOperation(new Sort(direction, fields));
+	}
+
+	/**
+	 * Creates a new {@link SkipOperation} skipping the given number of elements.
+	 * 
+	 * @param elementsToSkip must not be less than zero.
+	 * @return
+	 */
+	public static SkipOperation skip(int elementsToSkip) {
+		return new SkipOperation(elementsToSkip);
+	}
+
+	/**
+	 * Creates a new {@link LimitOperation} limiting the result to the given number of elements.
+	 * 
+	 * @param maxElements must not be less than zero.
+	 * @return
+	 */
+	public static LimitOperation limit(long maxElements) {
+		return new LimitOperation(maxElements);
+	}
+
+	/**
+	 * Creates a new {@link MatchOperation} using the given {@link Criteria}.
+	 * 
+	 * @param criteria must not be {@literal null}.
+	 * @return
+	 */
+	public static MatchOperation match(Criteria criteria) {
+		return new MatchOperation(criteria);
+	}
+
+	/**
+	 * Creates a new {@link Fields} instance for the given field names.
+	 * 
+	 * @see Fields#fields(String...)
+	 * @param fields must not be {@literal null}.
+	 * @return
+	 */
+	public static Fields fields(String... fields) {
+		return Fields.fields(fields);
+	}
+
+	/**
+	 * Creates a new {@link Fields} instance from the given field name and target reference.
+	 * 
+	 * @param name must not be {@literal null} or empty.
+	 * @param target must not be {@literal null} or empty.
+	 * @return
+	 */
+	public static Fields bind(String name, String target) {
+		return Fields.from(field(name, target));
+	}
+
+	/**
+	 * Converts this {@link Aggregation} specification to a {@link DBObject}.
+	 * 
+	 * @param inputCollectionName the name of the input collection
+	 * @return the {@code DBObject} representing this aggregation
+	 */
+	public DBObject toDbObject(String inputCollectionName, AggregationOperationContext rootContext) {
+
+		AggregationOperationContext context = rootContext;
+		List<DBObject> operationDocuments = new ArrayList<DBObject>(operations.size());
+
+		for (AggregationOperation operation : operations) {
+
+			operationDocuments.add(operation.toDBObject(context));
+
+			if (operation instanceof FieldsExposingAggregationOperation) {
+				FieldsExposingAggregationOperation exposedFieldsOperation = (FieldsExposingAggregationOperation) operation;
+				context = new ExposedFieldsAggregationOperationContext(exposedFieldsOperation.getFields(), rootContext);
+			}
+		}
+
+		DBObject command = new BasicDBObject("aggregate", inputCollectionName);
+		command.put("pipeline", operationDocuments);
+
+		return command;
+	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see java.lang.Object#toString()
+	 */
+	@Override
+	public String toString() {
+		return SerializationUtils
+				.serializeToJsonSafely(toDbObject("__collection__", new NoOpAggregationOperationContext()));
+	}
+
+	/**
+	 * Simple {@link AggregationOperationContext} that just returns {@link FieldReference}s as is.
+	 * 
+	 * @author Oliver Gierke
+	 */
+	private static class NoOpAggregationOperationContext implements AggregationOperationContext {
+
+		/* 
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperationContext#getMappedObject(com.mongodb.DBObject)
+		 */
+		@Override
+		public DBObject getMappedObject(DBObject dbObject) {
+			return dbObject;
+		}
+
+		/* 
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperationContext#getReference(org.springframework.data.mongodb.core.aggregation.ExposedFields.AvailableField)
+		 */
+		@Override
+		public FieldReference getReference(Field field) {
+			return new FieldReference(new ExposedField(field, true));
+		}
+
+		/* 
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperationContext#getReference(java.lang.String)
+		 */
+		@Override
+		public FieldReference getReference(String name) {
+			return new FieldReference(new ExposedField(new AggregationField(name), true));
+		}
+	}
+}

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/AggregationExpressionTransformer.java

@@ -0,0 +1,82 @@
+/*
+ * Copyright 2013 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.mongodb.core.aggregation;
+
+import org.springframework.data.mongodb.core.aggregation.AggregationExpressionTransformer.AggregationExpressionTransformationContext;
+import org.springframework.data.mongodb.core.aggregation.ExposedFields.FieldReference;
+import org.springframework.data.mongodb.core.spel.ExpressionNode;
+import org.springframework.data.mongodb.core.spel.ExpressionTransformationContextSupport;
+import org.springframework.data.mongodb.core.spel.ExpressionTransformer;
+import org.springframework.util.Assert;
+
+import com.mongodb.DBObject;
+
+/**
+ * Interface to type an {@link ExpressionTransformer} to the contained
+ * {@link AggregationExpressionTransformationContext}.
+ * 
+ * @author Oliver Gierke
+ */
+interface AggregationExpressionTransformer extends
+		ExpressionTransformer<AggregationExpressionTransformationContext<ExpressionNode>> {
+
+	/**
+	 * A special {@link ExpressionTransformationContextSupport} to be aware of the {@link AggregationOperationContext}.
+	 * 
+	 * @author Oliver Gierke
+	 * @author Thomas Darimont
+	 */
+	public static class AggregationExpressionTransformationContext<T extends ExpressionNode> extends
+			ExpressionTransformationContextSupport<T> {
+
+		private final AggregationOperationContext aggregationContext;
+
+		/**
+		 * Creates an {@link AggregationExpressionTransformationContext}.
+		 * 
+		 * @param currentNode must not be {@literal null}.
+		 * @param parentNode
+		 * @param previousOperationObject
+		 * @param aggregationContext must not be {@literal null}.
+		 */
+		public AggregationExpressionTransformationContext(T currentNode, ExpressionNode parentNode,
+				DBObject previousOperationObject, AggregationOperationContext context) {
+
+			super(currentNode, parentNode, previousOperationObject);
+
+			Assert.notNull(context, "AggregationOperationContext must not be null!");
+			this.aggregationContext = context;
+		}
+
+		/**
+		 * Returns the underlying {@link AggregationOperationContext}.
+		 * 
+		 * @return
+		 */
+		public AggregationOperationContext getAggregationContext() {
+			return aggregationContext;
+		}
+
+		/**
+		 * Returns the {@link FieldReference} for the current {@link ExpressionNode}.
+		 * 
+		 * @return
+		 */
+		public FieldReference getFieldReference() {
+			return aggregationContext.getReference(getCurrentNode().getName());
+		}
+	}
+}

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/AggregationOperation.java

@@ -0,0 +1,37 @@
+/*
+ * Copyright 2013 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.mongodb.core.aggregation;
+
+import com.mongodb.DBObject;
+
+/**
+ * Represents one single operation in an aggregation pipeline.
+ * 
+ * @author Sebastian Herold
+ * @author Thomas Darimont
+ * @author Oliver Gierke
+ * @since 1.3
+ */
+public interface AggregationOperation {
+
+	/**
+	 * Turns the {@link AggregationOperation} into a {@link DBObject} by using the given
+	 * {@link AggregationOperationContext}.
+	 * 
+	 * @return the DBObject
+	 */
+	DBObject toDBObject(AggregationOperationContext context);
+}

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/AggregationOperationContext.java

@@ -0,0 +1,55 @@
+/*
+ * Copyright 2013 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.mongodb.core.aggregation;
+
+import org.springframework.data.mongodb.core.aggregation.ExposedFields.FieldReference;
+
+import com.mongodb.DBObject;
+
+/**
+ * The context for an {@link AggregationOperation}.
+ * 
+ * @author Oliver Gierke
+ * @since 1.3
+ */
+public interface AggregationOperationContext {
+
+	/**
+	 * Returns the mapped {@link DBObject}, potentially converting the source considering mapping metadata etc.
+	 * 
+	 * @param dbObject will never be {@literal null}.
+	 * @return must not be {@literal null}.
+	 */
+	DBObject getMappedObject(DBObject dbObject);
+
+	/**
+	 * Returns a {@link FieldReference} for the given field or {@literal null} if the context does not expose the given
+	 * field.
+	 * 
+	 * @param field must not be {@literal null}.
+	 * @return
+	 */
+	FieldReference getReference(Field field);
+
+	/**
+	 * Returns the {@link FieldReference} for the field with the given name or {@literal null} if the context does not
+	 * expose a field with the given name.
+	 * 
+	 * @param name must not be {@literal null} or empty.
+	 * @return
+	 */
+	FieldReference getReference(String name);
+}

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/AggregationResults.java

@@ -0,0 +1,98 @@
+/*
+ * Copyright 2013 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.mongodb.core.aggregation;
+
+import java.util.Collections;
+import java.util.Iterator;
+import java.util.List;
+
+import org.springframework.util.Assert;
+
+import com.mongodb.DBObject;
+
+/**
+ * Collects the results of executing an aggregation operation.
+ * 
+ * @author Tobias Trelle
+ * @author Oliver Gierke
+ * @param <T> The class in which the results are mapped onto.
+ * @since 1.3
+ */
+public class AggregationResults<T> implements Iterable<T> {
+
+	private final List<T> mappedResults;
+	private final DBObject rawResults;
+	private final String serverUsed;
+
+	/**
+	 * Creates a new {@link AggregationResults} instance from the given mapped and raw results.
+	 * 
+	 * @param mappedResults must not be {@literal null}.
+	 * @param rawResults must not be {@literal null}.
+	 */
+	public AggregationResults(List<T> mappedResults, DBObject rawResults) {
+
+		Assert.notNull(mappedResults);
+		Assert.notNull(rawResults);
+
+		this.mappedResults = Collections.unmodifiableList(mappedResults);
+		this.rawResults = rawResults;
+		this.serverUsed = parseServerUsed();
+	}
+
+	/**
+	 * Returns the aggregation results.
+	 * 
+	 * @return
+	 */
+	public List<T> getMappedResults() {
+		return mappedResults;
+	}
+
+	/**
+	 * Returns the unique mapped result. Assumes no result or exactly one.
+	 * 
+	 * @return
+	 * @throws IllegalArgumentException in case more than one result is available.
+	 */
+	public T getUniqueMappedResult() {
+		Assert.isTrue(mappedResults.size() < 2, "Expected unique result or null, but got more than one!");
+		return mappedResults.size() == 1 ? mappedResults.get(0) : null;
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see java.lang.Iterable#iterator()
+	 */
+	public Iterator<T> iterator() {
+		return mappedResults.iterator();
+	}
+
+	/**
+	 * Returns the server that has been used to perform the aggregation.
+	 * 
+	 * @return
+	 */
+	public String getServerUsed() {
+		return serverUsed;
+	}
+
+	private String parseServerUsed() {
+
+		Object object = rawResults.get("serverUsed");
+		return object instanceof String ? (String) object : null;
+	}
+}

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/ExposedFields.java

@@ -0,0 +1,413 @@
+/*
+ * Copyright 2013-2014 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.mongodb.core.aggregation;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.Iterator;
+import java.util.List;
+
+import org.springframework.data.mongodb.core.aggregation.ExposedFields.ExposedField;
+import org.springframework.util.Assert;
+import org.springframework.util.CompositeIterator;
+
+/**
+ * Value object to capture the fields exposed by an {@link AggregationOperation}.
+ * 
+ * @author Oliver Gierke
+ * @author Thomas Darimont
+ * @since 1.3
+ */
+public final class ExposedFields implements Iterable<ExposedField> {
+
+	private static final List<ExposedField> NO_FIELDS = Collections.emptyList();
+	private static final ExposedFields EMPTY = new ExposedFields(NO_FIELDS, NO_FIELDS);
+
+	private final List<ExposedField> originalFields;
+	private final List<ExposedField> syntheticFields;
+
+	/**
+	 * Creates a new {@link ExposedFields} instance from the given {@link ExposedField}s.
+	 * 
+	 * @param fields must not be {@literal null}.
+	 * @return
+	 */
+	public static ExposedFields from(ExposedField... fields) {
+		return from(Arrays.asList(fields));
+	}
+
+	/**
+	 * Creates a new {@link ExposedFields} instance from the given {@link ExposedField}s.
+	 * 
+	 * @param fields must not be {@literal null}.
+	 * @return
+	 */
+	private static ExposedFields from(List<ExposedField> fields) {
+
+		ExposedFields result = EMPTY;
+
+		for (ExposedField field : fields) {
+			result = result.and(field);
+		}
+
+		return result;
+	}
+
+	/**
+	 * Creates synthetic {@link ExposedFields} from the given {@link Fields}.
+	 * 
+	 * @param fields must not be {@literal null}.
+	 * @return
+	 */
+	public static ExposedFields synthetic(Fields fields) {
+		return createFields(fields, true);
+	}
+
+	/**
+	 * Creates non-synthetic {@link ExposedFields} from the given {@link Fields}.
+	 * 
+	 * @param fields must not be {@literal null}.
+	 * @return
+	 */
+	public static ExposedFields nonSynthetic(Fields fields) {
+		return createFields(fields, false);
+	}
+
+	/**
+	 * Creates a new {@link ExposedFields} instance for the given fields in either sythetic or non-synthetic way.
+	 * 
+	 * @param fields must not be {@literal null}.
+	 * @param synthetic
+	 * @return
+	 */
+	private static ExposedFields createFields(Fields fields, boolean synthetic) {
+
+		Assert.notNull(fields, "Fields must not be null!");
+		List<ExposedField> result = new ArrayList<ExposedField>();
+
+		for (Field field : fields) {
+			result.add(new ExposedField(field, synthetic));
+		}
+
+		return ExposedFields.from(result);
+	}
+
+	/**
+	 * Creates a new {@link ExposedFields} with the given orignals and synthetics.
+	 * 
+	 * @param originals must not be {@literal null}.
+	 * @param synthetic must not be {@literal null}.
+	 */
+	private ExposedFields(List<ExposedField> originals, List<ExposedField> synthetic) {
+
+		this.originalFields = originals;
+		this.syntheticFields = synthetic;
+	}
+
+	/**
+	 * Creates a new {@link ExposedFields} adding the given {@link ExposedField}.
+	 * 
+	 * @param field must not be {@literal null}.
+	 * @return
+	 */
+	public ExposedFields and(ExposedField field) {
+
+		Assert.notNull(field, "Exposed field must not be null!");
+
+		ArrayList<ExposedField> result = new ArrayList<ExposedField>();
+		result.addAll(field.synthetic ? syntheticFields : originalFields);
+		result.add(field);
+
+		return new ExposedFields(field.synthetic ? originalFields : result, field.synthetic ? result : syntheticFields);
+	}
+
+	/**
+	 * Returns the field with the given name or {@literal null} if no field with the given name is available.
+	 * 
+	 * @param name
+	 * @return
+	 */
+	public ExposedField getField(String name) {
+
+		for (ExposedField field : this) {
+			if (field.canBeReferredToBy(name)) {
+				return field;
+			}
+		}
+
+		return null;
+	}
+
+	/**
+	 * Returns whether the {@link ExposedFields} exposes no non-synthetic fields at all.
+	 * 
+	 * @return
+	 */
+	boolean exposesNoNonSyntheticFields() {
+		return originalFields.isEmpty();
+	}
+
+	/**
+	 * Returns whether the {@link ExposedFields} exposes a single non-synthetic field only.
+	 * 
+	 * @return
+	 */
+	boolean exposesSingleNonSyntheticFieldOnly() {
+		return originalFields.size() == 1;
+	}
+
+	/**
+	 * Returns whether the {@link ExposedFields} exposes no fields at all.
+	 * 
+	 * @return
+	 */
+	boolean exposesNoFields() {
+		return exposedFieldsCount() == 0;
+	}
+
+	/**
+	 * Returns whether the {@link ExposedFields} exposes a single field only.
+	 * 
+	 * @return
+	 */
+	boolean exposesSingleFieldOnly() {
+		return exposedFieldsCount() == 1;
+	}
+
+	/**
+	 * @return
+	 */
+	private int exposedFieldsCount() {
+		return originalFields.size() + syntheticFields.size();
+	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see java.lang.Iterable#iterator()
+	 */
+	@Override
+	public Iterator<ExposedField> iterator() {
+
+		CompositeIterator<ExposedField> iterator = new CompositeIterator<ExposedField>();
+		iterator.add(syntheticFields.iterator());
+		iterator.add(originalFields.iterator());
+
+		return iterator;
+	}
+
+	/**
+	 * A single exposed field.
+	 * 
+	 * @author Oliver Gierke
+	 */
+	static class ExposedField implements Field {
+
+		private final boolean synthetic;
+		private final Field field;
+
+		/**
+		 * Creates a new {@link ExposedField} with the given key.
+		 * 
+		 * @param key must not be {@literal null} or empty.
+		 * @param synthetic whether the exposed field is synthetic.
+		 */
+		public ExposedField(String key, boolean synthetic) {
+			this(Fields.field(key), synthetic);
+		}
+
+		/**
+		 * Creates a new {@link ExposedField} for the given {@link Field}.
+		 * 
+		 * @param delegate must not be {@literal null}.
+		 * @param synthetic whether the exposed field is synthetic.
+		 */
+		public ExposedField(Field delegate, boolean synthetic) {
+
+			this.field = delegate;
+			this.synthetic = synthetic;
+		}
+
+		/* 
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.core.aggregation.Field#getKey()
+		 */
+		@Override
+		public String getName() {
+			return field.getName();
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.core.aggregation.Field#getTarget()
+		 */
+		@Override
+		public String getTarget() {
+			return field.getTarget();
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.core.aggregation.Field#isAliased()
+		 */
+		@Override
+		public boolean isAliased() {
+			return field.isAliased();
+		}
+
+		/**
+		 * @return the synthetic
+		 */
+		public boolean isSynthetic() {
+			return synthetic;
+		}
+
+		/**
+		 * Returns whether the field can be referred to using the given name.
+		 * 
+		 * @param name
+		 * @return
+		 */
+		public boolean canBeReferredToBy(String name) {
+			return getName().equals(name) || getTarget().equals(name);
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see java.lang.Object#toString()
+		 */
+		@Override
+		public String toString() {
+			return String.format("AggregationField: %s, synthetic: %s", field, synthetic);
+		}
+
+		/* 
+		 * (non-Javadoc)
+		 * @see java.lang.Object#equals(java.lang.Object)
+		 */
+		@Override
+		public boolean equals(Object obj) {
+
+			if (this == obj) {
+				return true;
+			}
+
+			if (!(obj instanceof ExposedField)) {
+				return false;
+			}
+
+			ExposedField that = (ExposedField) obj;
+
+			return this.field.equals(that.field) && this.synthetic == that.synthetic;
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see java.lang.Object#hashCode()
+		 */
+		@Override
+		public int hashCode() {
+
+			int result = 17;
+
+			result += 31 * field.hashCode();
+			result += 31 * (synthetic ? 0 : 1);
+
+			return result;
+		}
+	}
+
+	/**
+	 * A reference to an {@link ExposedField}.
+	 * 
+	 * @author Oliver Gierke
+	 */
+	static class FieldReference {
+
+		private final ExposedField field;
+
+		/**
+		 * Creates a new {@link FieldReference} for the given {@link ExposedField}.
+		 * 
+		 * @param field must not be {@literal null}.
+		 */
+		public FieldReference(ExposedField field) {
+
+			Assert.notNull(field, "ExposedField must not be null!");
+
+			this.field = field;
+		}
+
+		/**
+		 * Returns the raw, unqualified reference, i.e. the field reference without a {@literal $} prefix.
+		 * 
+		 * @return
+		 */
+		public String getRaw() {
+
+			String target = field.getTarget();
+			return field.synthetic ? target : String.format("%s.%s", Fields.UNDERSCORE_ID, target);
+		}
+
+		/**
+		 * Returns the referenve value for the given field reference. Will return 1 for a synthetic, unaliased field or the
+		 * raw rendering of the reference otherwise.
+		 * 
+		 * @return
+		 */
+		public Object getReferenceValue() {
+			return field.synthetic && !field.isAliased() ? 1 : toString();
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see java.lang.Object#toString()
+		 */
+		@Override
+		public String toString() {
+			return String.format("$%s", getRaw());
+		}
+
+		/* 
+		 * (non-Javadoc)
+		 * @see java.lang.Object#equals(java.lang.Object)
+		 */
+		@Override
+		public boolean equals(Object obj) {
+
+			if (this == obj) {
+				return true;
+			}
+
+			if (!(obj instanceof FieldReference)) {
+				return false;
+			}
+
+			FieldReference that = (FieldReference) obj;
+
+			return this.field.equals(that.field);
+		}
+
+		/* 
+		 * (non-Javadoc)
+		 * @see java.lang.Object#hashCode()
+		 */
+		@Override
+		public int hashCode() {
+			return field.hashCode();
+		}
+	}
+}

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/ExposedFieldsAggregationOperationContext.java

@@ -0,0 +1,117 @@
+/*
+ * Copyright 2013-2014 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.mongodb.core.aggregation;
+
+import org.springframework.data.mongodb.core.aggregation.ExposedFields.ExposedField;
+import org.springframework.data.mongodb.core.aggregation.ExposedFields.FieldReference;
+import org.springframework.util.Assert;
+
+import com.mongodb.DBObject;
+
+/**
+ * {@link AggregationOperationContext} that combines the available field references from a given
+ * {@code AggregationOperationContext} and an {@link FieldsExposingAggregationOperation}.
+ * 
+ * @author Thomas Darimont
+ * @author Oliver Gierke
+ * @since 1.4
+ */
+class ExposedFieldsAggregationOperationContext implements AggregationOperationContext {
+
+	private final ExposedFields exposedFields;
+	private final AggregationOperationContext rootContext;
+
+	/**
+	 * Creates a new {@link ExposedFieldsAggregationOperationContext} from the given {@link ExposedFields}. Uses the given
+	 * {@link AggregationOperationContext} to perform a mapping to mongo types if necessary.
+	 * 
+	 * @param exposedFields must not be {@literal null}.
+	 * @param rootContext must not be {@literal null}.
+	 */
+	public ExposedFieldsAggregationOperationContext(ExposedFields exposedFields, AggregationOperationContext rootContext) {
+
+		Assert.notNull(exposedFields, "ExposedFields must not be null!");
+		Assert.notNull(rootContext, "RootContext must not be null!");
+
+		this.exposedFields = exposedFields;
+		this.rootContext = rootContext;
+	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperationContext#getMappedObject(com.mongodb.DBObject)
+	 */
+	@Override
+	public DBObject getMappedObject(DBObject dbObject) {
+		return rootContext.getMappedObject(dbObject);
+	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperationContext#getReference(org.springframework.data.mongodb.core.aggregation.ExposedFields.AvailableField)
+	 */
+	@Override
+	public FieldReference getReference(Field field) {
+		return getReference(field, field.getTarget());
+	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperationContext#getReference(java.lang.String)
+	 */
+	@Override
+	public FieldReference getReference(String name) {
+		return getReference(null, name);
+	}
+
+	/**
+	 * Returns a {@link FieldReference} to the given {@link Field} with the given {@code name}.
+	 * 
+	 * @param field may be {@literal null}
+	 * @param name must not be {@literal null}
+	 * @return
+	 */
+	private FieldReference getReference(Field field, String name) {
+
+		Assert.notNull(name, "Name must not be null!");
+
+		ExposedField exposedField = exposedFields.getField(name);
+
+		if (exposedField != null) {
+
+			if (field != null) {
+				// we return a FieldReference to the given field directly to make sure that we reference the proper alias here.
+				return new FieldReference(new ExposedField(field, exposedField.isSynthetic()));
+			}
+
+			return new FieldReference(exposedField);
+		}
+
+		if (name.contains(".")) {
+
+			// for nested field references we only check that the root field exists.
+			ExposedField rootField = exposedFields.getField(name.split("\\.")[0]);
+
+			if (rootField != null) {
+
+				// We have to synthetic to true, in order to render the field-name as is.
+				return new FieldReference(new ExposedField(name, true));
+			}
+		}
+
+		throw new IllegalArgumentException(String.format("Invalid reference '%s'!", name));
+	}
+}

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/Field.java

@@ -0,0 +1,46 @@
+/*
+ * Copyright 2013 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.mongodb.core.aggregation;
+
+/**
+ * Abstraction for a field.
+ * 
+ * @author Oliver Gierke
+ * @since 1.3
+ */
+public interface Field {
+
+	/**
+	 * Returns the name of the field.
+	 * 
+	 * @return must not be {@literal null}.
+	 */
+	String getName();
+
+	/**
+	 * Returns the target of the field. In case no explicit target is available {@link #getName()} should be returned.
+	 * 
+	 * @return must not be {@literal null}.
+	 */
+	String getTarget();
+
+	/**
+	 * Returns whether the Field is aliased, which means it has a name set different from the target.
+	 * 
+	 * @return
+	 */
+	boolean isAliased();
+}

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/Fields.java

@@ -0,0 +1,293 @@
+/*
+ * Copyright 2013-2014 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.mongodb.core.aggregation;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+
+import org.springframework.util.Assert;
+import org.springframework.util.ObjectUtils;
+import org.springframework.util.StringUtils;
+
+/**
+ * Value object to capture a list of {@link Field} instances.
+ * 
+ * @author Oliver Gierke
+ * @since 1.3
+ */
+public final class Fields implements Iterable<Field> {
+
+	private static final String AMBIGUOUS_EXCEPTION = "Found two fields both using '%s' as name: %s and %s! Please "
+			+ "customize your field definitions to get to unique field names!";
+
+	public static final String UNDERSCORE_ID = "_id";
+	public static final String UNDERSCORE_ID_REF = "$_id";
+
+	private final List<Field> fields;
+
+	/**
+	 * Creates a new {@link Fields} instance from the given {@link Fields}.
+	 * 
+	 * @param fields must not be {@literal null} or empty.
+	 * @return
+	 */
+	public static Fields from(Field... fields) {
+
+		Assert.notNull(fields, "Fields must not be null!");
+		return new Fields(Arrays.asList(fields));
+	}
+
+	/**
+	 * Creates a new {@link Fields} instance for {@link Field}s with the given names.
+	 * 
+	 * @param names must not be {@literal null}.
+	 * @return
+	 */
+	public static Fields fields(String... names) {
+
+		Assert.notNull(names, "Field names must not be null!");
+
+		List<Field> fields = new ArrayList<Field>();
+
+		for (String name : names) {
+			fields.add(field(name));
+		}
+
+		return new Fields(fields);
+	}
+
+	/**
+	 * Creates a {@link Field} with the given name.
+	 * 
+	 * @param name must not be {@literal null} or empty.
+	 * @return
+	 */
+	public static Field field(String name) {
+		return new AggregationField(name);
+	}
+
+	public static Field field(String name, String target) {
+		Assert.hasText(target, "Target must not be null or empty!");
+		return new AggregationField(name, target);
+	}
+
+	/**
+	 * Creates a new {@link Fields} instance using the given {@link Field}s.
+	 * 
+	 * @param fields must not be {@literal null}.
+	 */
+	private Fields(List<Field> fields) {
+
+		Assert.notNull(fields, "Fields must not be null!");
+
+		this.fields = verify(fields);
+	}
+
+	private static final List<Field> verify(List<Field> fields) {
+
+		Map<String, Field> reference = new HashMap<String, Field>();
+
+		for (Field field : fields) {
+
+			String name = field.getName();
+			Field found = reference.get(name);
+
+			if (found != null) {
+				throw new IllegalArgumentException(String.format(AMBIGUOUS_EXCEPTION, name, found, field));
+			}
+
+			reference.put(name, field);
+		}
+
+		return fields;
+	}
+
+	private Fields(Fields existing, Field tail) {
+
+		this.fields = new ArrayList<Field>(existing.fields.size() + 1);
+		this.fields.addAll(existing.fields);
+		this.fields.add(tail);
+	}
+
+	/**
+	 * Creates a new {@link Fields} instance with a new {@link Field} of the given name added.
+	 * 
+	 * @param name must not be {@literal null}.
+	 * @return
+	 */
+	public Fields and(String name) {
+		return and(new AggregationField(name));
+	}
+
+	public Fields and(String name, String target) {
+		return and(new AggregationField(name, target));
+	}
+
+	public Fields and(Field field) {
+		return new Fields(this, field);
+	}
+
+	public Fields and(Fields fields) {
+
+		Fields result = this;
+
+		for (Field field : fields) {
+			result = result.and(field);
+		}
+
+		return result;
+	}
+
+	public Field getField(String name) {
+
+		for (Field field : fields) {
+			if (field.getName().equals(name)) {
+				return field;
+			}
+		}
+
+		return null;
+	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see java.lang.Iterable#iterator()
+	 */
+	@Override
+	public Iterator<Field> iterator() {
+		return fields.iterator();
+	}
+
+	/**
+	 * Value object to encapsulate a field in an aggregation operation.
+	 * 
+	 * @author Oliver Gierke
+	 */
+	static class AggregationField implements Field {
+
+		private final String name;
+		private final String target;
+
+		/**
+		 * Creates an aggregation fieldwith the given name. As no target is set explicitly, the name will be used as target
+		 * as well.
+		 * 
+		 * @param key
+		 */
+		public AggregationField(String key) {
+			this(key, null);
+		}
+
+		public AggregationField(String name, String target) {
+
+			String nameToSet = cleanUp(name);
+			String targetToSet = cleanUp(target);
+
+			Assert.hasText(nameToSet, "AggregationField name must not be null or empty!");
+
+			if (target == null && name.contains(".")) {
+				this.name = nameToSet.substring(nameToSet.indexOf('.') + 1);
+				this.target = nameToSet;
+			} else {
+				this.name = nameToSet;
+				this.target = targetToSet;
+			}
+		}
+
+		private static final String cleanUp(String source) {
+
+			if (source == null) {
+				return source;
+			}
+
+			int dollarIndex = source.lastIndexOf('$');
+			return dollarIndex == -1 ? source : source.substring(dollarIndex + 1);
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.core.aggregation.Field#getKey()
+		 */
+		public String getName() {
+			return name;
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.core.aggregation.Field#getAlias()
+		 */
+		public String getTarget() {
+			return StringUtils.hasText(this.target) ? this.target : this.name;
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.core.aggregation.Field#isAliased()
+		 */
+		@Override
+		public boolean isAliased() {
+			return !getName().equals(getTarget());
+		}
+
+		/* 
+		 * (non-Javadoc)
+		 * @see java.lang.Object#toString()
+		 */
+		@Override
+		public String toString() {
+			return String.format("AggregationField - name: %s, target: %s", name, target);
+		}
+
+		/* 
+		 * (non-Javadoc)
+		 * @see java.lang.Object#equals(java.lang.Object)
+		 */
+		@Override
+		public boolean equals(Object obj) {
+
+			if (this == obj) {
+				return true;
+			}
+
+			if (!(obj instanceof AggregationField)) {
+				return false;
+			}
+
+			AggregationField that = (AggregationField) obj;
+
+			return this.name.equals(that.name) && ObjectUtils.nullSafeEquals(this.target, that.target);
+		}
+
+		/* 
+		 * (non-Javadoc)
+		 * @see java.lang.Object#hashCode()
+		 */
+		@Override
+		public int hashCode() {
+
+			int result = 17;
+
+			result += 31 * name.hashCode();
+			result += 31 * ObjectUtils.nullSafeHashCode(target);
+
+			return result;
+		}
+	}
+}

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/FieldsExposingAggregationOperation.java

@@ -0,0 +1,32 @@
+/*
+ * Copyright 2013 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.mongodb.core.aggregation;
+
+/**
+ * {@link AggregationOperation} that exposes new {@link ExposedFields} that can be used for later aggregation pipeline
+ * {@code AggregationOperation}s.
+ * 
+ * @author Thomas Darimont
+ */
+public interface FieldsExposingAggregationOperation extends AggregationOperation {
+
+	/**
+	 * Returns the fields exposed by the {@link AggregationOperation}.
+	 * 
+	 * @return will never be {@literal null}.
+	 */
+	ExposedFields getFields();
+}

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/GeoNearOperation.java

@@ -0,0 +1,46 @@
+/*
+ * Copyright 2013 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.mongodb.core.aggregation;
+
+import org.springframework.data.mongodb.core.query.NearQuery;
+import org.springframework.util.Assert;
+
+import com.mongodb.BasicDBObject;
+import com.mongodb.DBObject;
+
+/**
+ * @author Thomas Darimont
+ * @since 1.3
+ */
+public class GeoNearOperation implements AggregationOperation {
+
+	private final NearQuery nearQuery;
+
+	public GeoNearOperation(NearQuery nearQuery) {
+
+		Assert.notNull(nearQuery);
+		this.nearQuery = nearQuery;
+	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperation#toDBObject(org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)
+	 */
+	@Override
+	public DBObject toDBObject(AggregationOperationContext context) {
+		return new BasicDBObject("$geoNear", context.getMappedObject(nearQuery.toDBObject()));
+	}
+}

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/GroupOperation.java

@@ -0,0 +1,375 @@
+/*
+ * Copyright 2013-2014 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.mongodb.core.aggregation;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+import java.util.Locale;
+
+import org.springframework.data.mongodb.core.aggregation.ExposedFields.ExposedField;
+import org.springframework.data.mongodb.core.aggregation.ExposedFields.FieldReference;
+import org.springframework.util.Assert;
+import org.springframework.util.StringUtils;
+
+import com.mongodb.BasicDBObject;
+import com.mongodb.DBObject;
+
+/**
+ * Encapsulates the aggregation framework {@code $group}-operation.
+ * 
+ * @see http://docs.mongodb.org/manual/reference/aggregation/group/#stage._S_group
+ * @author Sebastian Herold
+ * @author Thomas Darimont
+ * @author Oliver Gierke
+ * @since 1.3
+ */
+public class GroupOperation implements FieldsExposingAggregationOperation {
+
+	/**
+	 * Holds the non-synthetic fields which are the fields of the group-id structure.
+	 */
+	private final ExposedFields idFields;
+
+	private final List<Operation> operations;
+
+	/**
+	 * Creates a new {@link GroupOperation} including the given {@link Fields}.
+	 * 
+	 * @param fields must not be {@literal null}.
+	 */
+	public GroupOperation(Fields fields) {
+
+		this.idFields = ExposedFields.nonSynthetic(fields);
+		this.operations = new ArrayList<Operation>();
+	}
+
+	/**
+	 * Creates a new {@link GroupOperation} from the given {@link GroupOperation}.
+	 * 
+	 * @param groupOperation must not be {@literal null}.
+	 */
+	protected GroupOperation(GroupOperation groupOperation) {
+		this(groupOperation, Collections.<Operation> emptyList());
+	}
+
+	/**
+	 * Creates a new {@link GroupOperation} from the given {@link GroupOperation} and the given {@link Operation}s.
+	 * 
+	 * @param groupOperation
+	 * @param nextOperations
+	 */
+	private GroupOperation(GroupOperation groupOperation, List<Operation> nextOperations) {
+
+		Assert.notNull(groupOperation, "GroupOperation must not be null!");
+		Assert.notNull(nextOperations, "NextOperations must not be null!");
+
+		this.idFields = groupOperation.idFields;
+		this.operations = new ArrayList<Operation>(nextOperations.size() + 1);
+		this.operations.addAll(groupOperation.operations);
+		this.operations.addAll(nextOperations);
+	}
+
+	/**
+	 * Creates a new {@link GroupOperation} from the current one adding the given {@link Operation}.
+	 * 
+	 * @param operation must not be {@literal null}.
+	 * @return
+	 */
+	protected GroupOperation and(Operation operation) {
+		return new GroupOperation(this, Arrays.asList(operation));
+	}
+
+	/**
+	 * Builder for {@link GroupOperation}s on a field.
+	 * 
+	 * @author Thomas Darimont
+	 */
+	public static final class GroupOperationBuilder {
+
+		private final GroupOperation groupOperation;
+		private final Operation operation;
+
+		/**
+		 * Creates a new {@link GroupOperationBuilder} from the given {@link GroupOperation} and {@link Operation}.
+		 * 
+		 * @param groupOperation
+		 * @param operation
+		 */
+		private GroupOperationBuilder(GroupOperation groupOperation, Operation operation) {
+
+			Assert.notNull(groupOperation, "GroupOperation must not be null!");
+			Assert.notNull(operation, "Operation must not be null!");
+
+			this.groupOperation = groupOperation;
+			this.operation = operation;
+		}
+
+		/**
+		 * Allows to specify an alias for the new-operation operation.
+		 * 
+		 * @param alias
+		 * @return
+		 */
+		public GroupOperation as(String alias) {
+			return this.groupOperation.and(operation.withAlias(alias));
+		}
+	}
+
+	/**
+	 * Generates an {@link GroupOperationBuilder} for a {@code $sum}-expression.
+	 * <p>
+	 * Count expressions are emulated via {@code $sum: 1}.
+	 * <p>
+	 * 
+	 * @return
+	 */
+	public GroupOperationBuilder count() {
+		return newBuilder(GroupOps.SUM, null, 1);
+	}
+
+	/**
+	 * Generates an {@link GroupOperationBuilder} for a {@code $sum}-expression for the given field-reference.
+	 * 
+	 * @param reference
+	 * @return
+	 */
+	public GroupOperationBuilder sum(String reference) {
+		return sum(reference, null);
+	}
+
+	private GroupOperationBuilder sum(String reference, Object value) {
+		return newBuilder(GroupOps.SUM, reference, value);
+	}
+
+	/**
+	 * Generates an {@link GroupOperationBuilder} for an {@code $add_to_set}-expression for the given field-reference.
+	 * 
+	 * @param reference
+	 * @return
+	 */
+	public GroupOperationBuilder addToSet(String reference) {
+		return addToSet(reference, null);
+	}
+
+	/**
+	 * Generates an {@link GroupOperationBuilder} for an {@code $add_to_set}-expression for the given value.
+	 * 
+	 * @param value
+	 * @return
+	 */
+	public GroupOperationBuilder addToSet(Object value) {
+		return addToSet(null, value);
+	}
+
+	private GroupOperationBuilder addToSet(String reference, Object value) {
+		return newBuilder(GroupOps.ADD_TO_SET, reference, value);
+	}
+
+	/**
+	 * Generates an {@link GroupOperationBuilder} for an {@code $last}-expression for the given field-reference.
+	 * 
+	 * @param reference
+	 * @return
+	 */
+	public GroupOperationBuilder last(String reference) {
+		return newBuilder(GroupOps.LAST, reference, null);
+	}
+
+	/**
+	 * Generates an {@link GroupOperationBuilder} for a {@code $first}-expression for the given field-reference.
+	 * 
+	 * @param reference
+	 * @return
+	 */
+	public GroupOperationBuilder first(String reference) {
+		return newBuilder(GroupOps.FIRST, reference, null);
+	}
+
+	/**
+	 * Generates an {@link GroupOperationBuilder} for an {@code $avg}-expression for the given field-reference.
+	 * 
+	 * @param reference
+	 * @return
+	 */
+	public GroupOperationBuilder avg(String reference) {
+		return newBuilder(GroupOps.AVG, reference, null);
+	}
+
+	/**
+	 * Generates an {@link GroupOperationBuilder} for an {@code $push}-expression for the given field-reference.
+	 * 
+	 * @param reference
+	 * @return
+	 */
+	public GroupOperationBuilder push(String reference) {
+		return push(reference, null);
+	}
+
+	/**
+	 * Generates an {@link GroupOperationBuilder} for an {@code $push}-expression for the given value.
+	 * 
+	 * @param value
+	 * @return
+	 */
+	public GroupOperationBuilder push(Object value) {
+		return push(null, value);
+	}
+
+	private GroupOperationBuilder push(String reference, Object value) {
+		return newBuilder(GroupOps.PUSH, reference, value);
+	}
+
+	/**
+	 * Generates an {@link GroupOperationBuilder} for an {@code $min}-expression that for the given field-reference.
+	 * 
+	 * @param reference
+	 * @return
+	 */
+	public GroupOperationBuilder min(String reference) {
+		return newBuilder(GroupOps.MIN, reference, null);
+	}
+
+	/**
+	 * Generates an {@link GroupOperationBuilder} for an {@code $max}-expression that for the given field-reference.
+	 * 
+	 * @param reference
+	 * @return
+	 */
+	public GroupOperationBuilder max(String reference) {
+		return newBuilder(GroupOps.MAX, reference, null);
+	}
+
+	private GroupOperationBuilder newBuilder(Keyword keyword, String reference, Object value) {
+		return new GroupOperationBuilder(this, new Operation(keyword, null, reference, value));
+	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperationContext#getFields()
+	 */
+	@Override
+	public ExposedFields getFields() {
+
+		ExposedFields fields = this.idFields.and(new ExposedField(Fields.UNDERSCORE_ID, true));
+
+		for (Operation operation : operations) {
+			fields = fields.and(operation.asField());
+		}
+
+		return fields;
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperation#toDBObject(org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)
+	 */
+	@Override
+	public com.mongodb.DBObject toDBObject(AggregationOperationContext context) {
+
+		BasicDBObject operationObject = new BasicDBObject();
+
+		if (idFields.exposesNoNonSyntheticFields()) {
+
+			operationObject.put(Fields.UNDERSCORE_ID, null);
+
+		} else if (idFields.exposesSingleNonSyntheticFieldOnly()) {
+
+			FieldReference reference = context.getReference(idFields.iterator().next());
+			operationObject.put(Fields.UNDERSCORE_ID, reference.toString());
+
+		} else {
+
+			BasicDBObject inner = new BasicDBObject();
+
+			for (ExposedField field : idFields) {
+				FieldReference reference = context.getReference(field);
+				inner.put(field.getName(), reference.toString());
+			}
+
+			operationObject.put(Fields.UNDERSCORE_ID, inner);
+		}
+
+		for (Operation operation : operations) {
+			operationObject.putAll(operation.toDBObject(context));
+		}
+
+		return new BasicDBObject("$group", operationObject);
+	}
+
+	interface Keyword {
+
+		String toString();
+	}
+
+	private static enum GroupOps implements Keyword {
+
+		SUM, LAST, FIRST, PUSH, AVG, MIN, MAX, ADD_TO_SET, COUNT;
+
+		@Override
+		public String toString() {
+
+			String[] parts = name().split("_");
+
+			StringBuilder builder = new StringBuilder();
+
+			for (String part : parts) {
+				String lowerCase = part.toLowerCase(Locale.US);
+				builder.append(builder.length() == 0 ? lowerCase : StringUtils.capitalize(lowerCase));
+			}
+
+			return "$" + builder.toString();
+		}
+	}
+
+	static class Operation implements AggregationOperation {
+
+		private final Keyword op;
+		private final String key;
+		private final String reference;
+		private final Object value;
+
+		public Operation(Keyword op, String key, String reference, Object value) {
+
+			this.op = op;
+			this.key = key;
+			this.reference = reference;
+			this.value = value;
+		}
+
+		public Operation withAlias(String key) {
+			return new Operation(op, key, reference, value);
+		}
+
+		public ExposedField asField() {
+			return new ExposedField(key, true);
+		}
+
+		public DBObject toDBObject(AggregationOperationContext context) {
+			return new BasicDBObject(key, new BasicDBObject(op.toString(), getValue(context)));
+		}
+
+		public Object getValue(AggregationOperationContext context) {
+			return reference == null ? value : context.getReference(reference).toString();
+		}
+
+		@Override
+		public String toString() {
+			return "Operation [op=" + op + ", key=" + key + ", reference=" + reference + ", value=" + value + "]";
+		}
+	}
+}

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/LimitOperation.java

@@ -0,0 +1,52 @@
+/*
+ * Copyright 2013 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.mongodb.core.aggregation;
+
+import org.springframework.util.Assert;
+
+import com.mongodb.BasicDBObject;
+import com.mongodb.DBObject;
+
+/**
+ * Encapsulates the {@code $limit}-operation
+ * 
+ * @see http://docs.mongodb.org/manual/reference/aggregation/limit/
+ * @author Thomas Darimont
+ * @author Oliver Gierke
+ * @since 1.3
+ */
+class LimitOperation implements AggregationOperation {
+
+	private final long maxElements;
+
+	/**
+	 * @param maxElements Number of documents to consider.
+	 */
+	public LimitOperation(long maxElements) {
+
+		Assert.isTrue(maxElements >= 0, "Maximum number of elements must be greater or equal to zero!");
+		this.maxElements = maxElements;
+	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperation#toDBObject(org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)
+	 */
+	@Override
+	public DBObject toDBObject(AggregationOperationContext context) {
+		return new BasicDBObject("$limit", maxElements);
+	}
+}

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/MatchOperation.java

@@ -0,0 +1,56 @@
+/*
+ * Copyright 2013 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.mongodb.core.aggregation;
+
+import org.springframework.data.mongodb.core.query.Criteria;
+import org.springframework.util.Assert;
+
+import com.mongodb.BasicDBObject;
+import com.mongodb.DBObject;
+
+/**
+ * Encapsulates the {@code $match}-operation
+ * 
+ * @see http://docs.mongodb.org/manual/reference/aggregation/match/
+ * @author Sebastian Herold
+ * @author Thomas Darimont
+ * @author Oliver Gierke
+ * @since 1.3
+ */
+public class MatchOperation implements AggregationOperation {
+
+	private final Criteria criteria;
+
+	/**
+	 * Creates a new {@link MatchOperation} for the given {@link Criteria}.
+	 * 
+	 * @param criteria must not be {@literal null}.
+	 */
+	public MatchOperation(Criteria criteria) {
+
+		Assert.notNull(criteria, "Criteria must not be null!");
+		this.criteria = criteria;
+	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperation#toDBObject(org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)
+	 */
+	@Override
+	public DBObject toDBObject(AggregationOperationContext context) {
+		return new BasicDBObject("$match", context.getMappedObject(criteria.getCriteriaObject()));
+	}
+}

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/ProjectionOperation.java

@@ -0,0 +1,775 @@
+/*
+ * Copyright 2013-2014 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.mongodb.core.aggregation;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+
+import org.springframework.data.mongodb.core.aggregation.ExposedFields.ExposedField;
+import org.springframework.data.mongodb.core.aggregation.ProjectionOperation.ProjectionOperationBuilder.FieldProjection;
+import org.springframework.util.Assert;
+
+import com.mongodb.BasicDBList;
+import com.mongodb.BasicDBObject;
+import com.mongodb.DBObject;
+
+/**
+ * Encapsulates the aggregation framework {@code $project}-operation. Projection of field to be used in an
+ * {@link Aggregation}. A projection is similar to a {@link Field} inclusion/exclusion but more powerful. It can
+ * generate new fields, change values of given field etc.
+ * <p>
+ * 
+ * @see http://docs.mongodb.org/manual/reference/aggregation/project/
+ * @author Tobias Trelle
+ * @author Thomas Darimont
+ * @author Oliver Gierke
+ * @since 1.3
+ */
+public class ProjectionOperation implements FieldsExposingAggregationOperation {
+
+	private static final List<Projection> NONE = Collections.emptyList();
+	private static final String EXCLUSION_ERROR = "Exclusion of field %s not allowed. Projections by the mongodb "
+			+ "aggregation framework only support the exclusion of the %s field!";
+
+	private final List<Projection> projections;
+
+	/**
+	 * Creates a new empty {@link ProjectionOperation}.
+	 */
+	public ProjectionOperation() {
+		this(NONE, NONE);
+	}
+
+	/**
+	 * Creates a new {@link ProjectionOperation} including the given {@link Fields}.
+	 * 
+	 * @param fields must not be {@literal null}.
+	 */
+	public ProjectionOperation(Fields fields) {
+		this(NONE, ProjectionOperationBuilder.FieldProjection.from(fields));
+	}
+
+	/**
+	 * Copy constructor to allow building up {@link ProjectionOperation} instances from already existing
+	 * {@link Projection}s.
+	 * 
+	 * @param current must not be {@literal null}.
+	 * @param projections must not be {@literal null}.
+	 */
+	private ProjectionOperation(List<? extends Projection> current, List<? extends Projection> projections) {
+
+		Assert.notNull(current, "Current projections must not be null!");
+		Assert.notNull(projections, "Projections must not be null!");
+
+		this.projections = new ArrayList<ProjectionOperation.Projection>(current.size() + projections.size());
+		this.projections.addAll(current);
+		this.projections.addAll(projections);
+	}
+
+	/**
+	 * Creates a new {@link ProjectionOperation} with the current {@link Projection}s and the given one.
+	 * 
+	 * @param projection must not be {@literal null}.
+	 * @return
+	 */
+	private ProjectionOperation and(Projection projection) {
+		return new ProjectionOperation(this.projections, Arrays.asList(projection));
+	}
+
+	/**
+	 * Creates a new {@link ProjectionOperation} with the current {@link Projection}s replacing the last current one with
+	 * the given one.
+	 * 
+	 * @param projection must not be {@literal null}.
+	 * @return
+	 */
+	private ProjectionOperation andReplaceLastOneWith(Projection projection) {
+
+		List<Projection> projections = this.projections.isEmpty() ? Collections.<Projection> emptyList() : this.projections
+				.subList(0, this.projections.size() - 1);
+		return new ProjectionOperation(projections, Arrays.asList(projection));
+	}
+
+	/**
+	 * Creates a new {@link ProjectionOperationBuilder} to define a projection for the field with the given name.
+	 * 
+	 * @param name must not be {@literal null} or empty.
+	 * @return
+	 */
+	public ProjectionOperationBuilder and(String name) {
+		return new ProjectionOperationBuilder(name, this, null);
+	}
+
+	public ExpressionProjectionOperationBuilder andExpression(String expression, Object... params) {
+		return new ExpressionProjectionOperationBuilder(expression, this, params);
+	}
+
+	/**
+	 * Excludes the given fields from the projection.
+	 * 
+	 * @param fieldNames must not be {@literal null}.
+	 * @return
+	 */
+	public ProjectionOperation andExclude(String... fieldNames) {
+
+		for (String fieldName : fieldNames) {
+			Assert.isTrue(Fields.UNDERSCORE_ID.equals(fieldName),
+					String.format(EXCLUSION_ERROR, fieldName, Fields.UNDERSCORE_ID));
+		}
+
+		List<FieldProjection> excludeProjections = FieldProjection.from(Fields.fields(fieldNames), false);
+		return new ProjectionOperation(this.projections, excludeProjections);
+	}
+
+	/**
+	 * Includes the given fields into the projection.
+	 * 
+	 * @param fieldNames must not be {@literal null}.
+	 * @return
+	 */
+	public ProjectionOperation andInclude(String... fieldNames) {
+
+		List<FieldProjection> projections = FieldProjection.from(Fields.fields(fieldNames), true);
+		return new ProjectionOperation(this.projections, projections);
+	}
+
+	/**
+	 * Includes the given fields into the projection.
+	 * 
+	 * @param fields must not be {@literal null}.
+	 * @return
+	 */
+	public ProjectionOperation andInclude(Fields fields) {
+		return new ProjectionOperation(this.projections, FieldProjection.from(fields, true));
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.FieldsExposingAggregationOperation#getFields()
+	 */
+	@Override
+	public ExposedFields getFields() {
+
+		ExposedFields fields = null;
+
+		for (Projection projection : projections) {
+			ExposedField field = projection.getExposedField();
+			fields = fields == null ? ExposedFields.from(field) : fields.and(field);
+		}
+
+		return fields;
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperation#toDBObject(org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)
+	 */
+	@Override
+	public DBObject toDBObject(AggregationOperationContext context) {
+
+		BasicDBObject fieldObject = new BasicDBObject();
+
+		for (Projection projection : projections) {
+			fieldObject.putAll(projection.toDBObject(context));
+		}
+
+		return new BasicDBObject("$project", fieldObject);
+	}
+
+	/**
+	 * Base class for {@link ProjectionOperationBuilder}s.
+	 * 
+	 * @author Thomas Darimont
+	 */
+	private static abstract class AbstractProjectionOperationBuilder implements AggregationOperation {
+
+		protected final Object value;
+		protected final ProjectionOperation operation;
+
+		/**
+		 * Creates a new {@link AbstractProjectionOperationBuilder} fot the given value and {@link ProjectionOperation}.
+		 * 
+		 * @param value must not be {@literal null}.
+		 * @param operation must not be {@literal null}.
+		 */
+		public AbstractProjectionOperationBuilder(Object value, ProjectionOperation operation) {
+
+			Assert.notNull(value, "value must not be null or empty!");
+			Assert.notNull(operation, "ProjectionOperation must not be null!");
+
+			this.value = value;
+			this.operation = operation;
+		}
+
+		/* 
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperation#toDBObject(org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)
+		 */
+		@Override
+		public DBObject toDBObject(AggregationOperationContext context) {
+			return this.operation.toDBObject(context);
+		}
+
+		/**
+		 * Returns the finally to be applied {@link ProjectionOperation} with the given alias.
+		 * 
+		 * @param alias will never be {@literal null} or empty.
+		 * @return
+		 */
+		public abstract ProjectionOperation as(String alias);
+	}
+
+	/**
+	 * @author Thomas Darimont
+	 */
+	public static class ExpressionProjectionOperationBuilder extends AbstractProjectionOperationBuilder {
+
+		private final Object[] params;
+
+		/**
+		 * Creates a new {@link ExpressionProjectionOperationBuilder} for the given value, {@link ProjectionOperation} and
+		 * parameters.
+		 * 
+		 * @param value must not be {@literal null}.
+		 * @param operation must not be {@literal null}.
+		 * @param parameters
+		 */
+		public ExpressionProjectionOperationBuilder(Object value, ProjectionOperation operation, Object[] parameters) {
+
+			super(value, operation);
+			this.params = parameters.clone();
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.core.aggregation.ProjectionOperation.AbstractProjectionOperationBuilder#as(java.lang.String)
+		 */
+		@Override
+		public ProjectionOperation as(String alias) {
+
+			Field expressionField = Fields.field(alias, alias);
+			return this.operation.and(new ExpressionProjection(expressionField, this.value.toString(), params));
+		}
+
+		/**
+		 * A {@link Projection} based on a SpEL expression.
+		 * 
+		 * @author Thomas Darimont
+		 * @author Oliver Gierke
+		 */
+		static class ExpressionProjection extends Projection {
+
+			private static final SpelExpressionTransformer TRANSFORMER = new SpelExpressionTransformer();
+
+			private final String expression;
+			private final Object[] params;
+
+			/**
+			 * Creates a new {@link ExpressionProjection} for the given field, SpEL expression and parameters.
+			 * 
+			 * @param field must not be {@literal null}.
+			 * @param expression must not be {@literal null} or empty.
+			 * @param parameters must not be {@literal null}.
+			 */
+			public ExpressionProjection(Field field, String expression, Object[] parameters) {
+
+				super(field);
+
+				Assert.hasText(expression, "Expression must not be null!");
+				Assert.notNull(parameters, "Parameters must not be null!");
+
+				this.expression = expression;
+				this.params = parameters.clone();
+			}
+
+			/* 
+			 * (non-Javadoc)
+			 * @see org.springframework.data.mongodb.core.aggregation.ProjectionOperation.Projection#toDBObject(org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)
+			 */
+			@Override
+			public DBObject toDBObject(AggregationOperationContext context) {
+				return new BasicDBObject(getExposedField().getName(), TRANSFORMER.transform(expression, context, params));
+			}
+		}
+	}
+
+	/**
+	 * Builder for {@link ProjectionOperation}s on a field.
+	 * 
+	 * @author Oliver Gierke
+	 * @author Thomas Darimont
+	 */
+	public static class ProjectionOperationBuilder extends AbstractProjectionOperationBuilder {
+
+		private static final String NUMBER_NOT_NULL = "Number must not be null!";
+		private static final String FIELD_REFERENCE_NOT_NULL = "Field reference must not be null!";
+
+		private final String name;
+		private final ProjectionOperation operation;
+		private final OperationProjection previousProjection;
+
+		/**
+		 * Creates a new {@link ProjectionOperationBuilder} for the field with the given name on top of the given
+		 * {@link ProjectionOperation}.
+		 * 
+		 * @param name must not be {@literal null} or empty.
+		 * @param operation must not be {@literal null}.
+		 * @param previousProjection the previous operation projection, may be {@literal null}.
+		 */
+		public ProjectionOperationBuilder(String name, ProjectionOperation operation, OperationProjection previousProjection) {
+			super(name, operation);
+
+			this.name = name;
+			this.operation = operation;
+			this.previousProjection = previousProjection;
+		}
+
+		/**
+		 * Projects the result of the previous operation onto the current field. Will automatically add an exclusion for
+		 * {@code _id} as what would be held in it by default will now go into the field just projected into.
+		 * 
+		 * @return
+		 */
+		public ProjectionOperation previousOperation() {
+
+			return this.operation.andExclude(Fields.UNDERSCORE_ID) //
+					.and(new PreviousOperationProjection(name));
+		}
+
+		/**
+		 * Defines a nested field binding for the current field.
+		 * 
+		 * @param fields must not be {@literal null}.
+		 * @return
+		 */
+		public ProjectionOperation nested(Fields fields) {
+			return this.operation.and(new NestedFieldProjection(name, fields));
+		}
+
+		/**
+		 * Allows to specify an alias for the previous projection operation.
+		 * 
+		 * @param string
+		 * @return
+		 */
+		@Override
+		public ProjectionOperation as(String alias) {
+
+			if (this.previousProjection != null) {
+				return this.operation.andReplaceLastOneWith(this.previousProjection.withAlias(alias));
+			} else {
+				return this.operation.and(new FieldProjection(Fields.field(alias, name), null));
+			}
+		}
+
+		/**
+		 * Generates an {@code $add} expression that adds the given number to the previously mentioned field.
+		 * 
+		 * @param number
+		 * @return
+		 */
+		public ProjectionOperationBuilder plus(Number number) {
+
+			Assert.notNull(number, NUMBER_NOT_NULL);
+			return project("add", number);
+		}
+
+		/**
+		 * Generates an {@code $add} expression that adds the value of the given field to the previously mentioned field.
+		 * 
+		 * @param fieldReference
+		 * @return
+		 */
+		public ProjectionOperationBuilder plus(String fieldReference) {
+
+			Assert.notNull(fieldReference, "Field reference must not be null!");
+			return project("add", Fields.field(fieldReference));
+		}
+
+		/**
+		 * Generates an {@code $subtract} expression that subtracts the given number to the previously mentioned field.
+		 * 
+		 * @param number
+		 * @return
+		 */
+		public ProjectionOperationBuilder minus(Number number) {
+
+			Assert.notNull(number, "Number must not be null!");
+			return project("subtract", number);
+		}
+
+		/**
+		 * Generates an {@code $subtract} expression that subtracts the value of the given field to the previously mentioned
+		 * field.
+		 * 
+		 * @param fieldReference
+		 * @return
+		 */
+		public ProjectionOperationBuilder minus(String fieldReference) {
+
+			Assert.notNull(fieldReference, FIELD_REFERENCE_NOT_NULL);
+			return project("subtract", Fields.field(fieldReference));
+		}
+
+		/**
+		 * Generates an {@code $multiply} expression that multiplies the given number with the previously mentioned field.
+		 * 
+		 * @param number
+		 * @return
+		 */
+		public ProjectionOperationBuilder multiply(Number number) {
+
+			Assert.notNull(number, NUMBER_NOT_NULL);
+			return project("multiply", number);
+		}
+
+		/**
+		 * Generates an {@code $multiply} expression that multiplies the value of the given field with the previously
+		 * mentioned field.
+		 * 
+		 * @param fieldReference
+		 * @return
+		 */
+		public ProjectionOperationBuilder multiply(String fieldReference) {
+
+			Assert.notNull(fieldReference, FIELD_REFERENCE_NOT_NULL);
+			return project("multiply", Fields.field(fieldReference));
+		}
+
+		/**
+		 * Generates an {@code $divide} expression that divides the previously mentioned field by the given number.
+		 * 
+		 * @param number
+		 * @return
+		 */
+		public ProjectionOperationBuilder divide(Number number) {
+
+			Assert.notNull(number, FIELD_REFERENCE_NOT_NULL);
+			Assert.isTrue(Math.abs(number.intValue()) != 0, "Number must not be zero!");
+			return project("divide", number);
+		}
+
+		/**
+		 * Generates an {@code $divide} expression that divides the value of the given field by the previously mentioned
+		 * field.
+		 * 
+		 * @param fieldReference
+		 * @return
+		 */
+		public ProjectionOperationBuilder divide(String fieldReference) {
+
+			Assert.notNull(fieldReference, FIELD_REFERENCE_NOT_NULL);
+			return project("divide", Fields.field(fieldReference));
+		}
+
+		/**
+		 * Generates an {@code $mod} expression that divides the previously mentioned field by the given number and returns
+		 * the remainder.
+		 * 
+		 * @param number
+		 * @return
+		 */
+		public ProjectionOperationBuilder mod(Number number) {
+
+			Assert.notNull(number, NUMBER_NOT_NULL);
+			Assert.isTrue(Math.abs(number.intValue()) != 0, "Number must not be zero!");
+			return project("mod", number);
+		}
+
+		/**
+		 * Generates an {@code $mod} expression that divides the value of the given field by the previously mentioned field
+		 * and returns the remainder.
+		 * 
+		 * @param fieldReference
+		 * @return
+		 */
+		public ProjectionOperationBuilder mod(String fieldReference) {
+
+			Assert.notNull(fieldReference, FIELD_REFERENCE_NOT_NULL);
+			return project("mod", Fields.field(fieldReference));
+		}
+
+		/* 
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperation#toDBObject(org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)
+		 */
+		@Override
+		public DBObject toDBObject(AggregationOperationContext context) {
+			return this.operation.toDBObject(context);
+		}
+
+		/**
+		 * Adds a generic projection for the current field.
+		 * 
+		 * @param operation the operation key, e.g. {@code $add}.
+		 * @param values the values to be set for the projection operation.
+		 * @return
+		 */
+		public ProjectionOperationBuilder project(String operation, Object... values) {
+			OperationProjection projectionOperation = new OperationProjection(Fields.field(name), operation, values);
+			return new ProjectionOperationBuilder(name, this.operation.and(projectionOperation), projectionOperation);
+		}
+
+		/**
+		 * A {@link Projection} to pull in the result of the previous operation.
+		 * 
+		 * @author Oliver Gierke
+		 */
+		static class PreviousOperationProjection extends Projection {
+
+			private final String name;
+
+			/**
+			 * Creates a new {@link PreviousOperationProjection} for the field with the given name.
+			 * 
+			 * @param name must not be {@literal null} or empty.
+			 */
+			public PreviousOperationProjection(String name) {
+				super(Fields.field(name));
+				this.name = name;
+			}
+
+			/* 
+			 * (non-Javadoc)
+			 * @see org.springframework.data.mongodb.core.aggregation.ProjectionOperation.Projection#toDBObject(org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)
+			 */
+			@Override
+			public DBObject toDBObject(AggregationOperationContext context) {
+				return new BasicDBObject(name, Fields.UNDERSCORE_ID_REF);
+			}
+		}
+
+		/**
+		 * A {@link FieldProjection} to map a result of a previous {@link AggregationOperation} to a new field.
+		 * 
+		 * @author Oliver Gierke
+		 * @author Thomas Darimont
+		 */
+		static class FieldProjection extends Projection {
+
+			private final Field field;
+			private final Object value;
+
+			/**
+			 * Creates a new {@link FieldProjection} for the field of the given name, assigning the given value.
+			 * 
+			 * @param name must not be {@literal null} or empty.
+			 * @param value
+			 */
+			public FieldProjection(String name, Object value) {
+				this(Fields.field(name), value);
+			}
+
+			private FieldProjection(Field field, Object value) {
+
+				super(field);
+
+				this.field = field;
+				this.value = value;
+			}
+
+			/**
+			 * Factory method to easily create {@link FieldProjection}s for the given {@link Fields}. Fields are projected as
+			 * references with their given name. A field {@code foo} will be projected as: {@code foo : 1 } .
+			 * 
+			 * @param fields the {@link Fields} to in- or exclude, must not be {@literal null}.
+			 * @return
+			 */
+			public static List<? extends Projection> from(Fields fields) {
+				return from(fields, null);
+			}
+
+			/**
+			 * Factory method to easily create {@link FieldProjection}s for the given {@link Fields}.
+			 * 
+			 * @param fields the {@link Fields} to in- or exclude, must not be {@literal null}.
+			 * @param value to use for the given field.
+			 * @return
+			 */
+			public static List<FieldProjection> from(Fields fields, Object value) {
+
+				Assert.notNull(fields, "Fields must not be null!");
+				List<FieldProjection> projections = new ArrayList<FieldProjection>();
+
+				for (Field field : fields) {
+					projections.add(new FieldProjection(field, value));
+				}
+
+				return projections;
+			}
+
+			/* 
+			 * (non-Javadoc)
+			 * @see org.springframework.data.mongodb.core.aggregation.ProjectionOperation.Projection#toDBObject(org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)
+			 */
+			@Override
+			public DBObject toDBObject(AggregationOperationContext context) {
+				return new BasicDBObject(field.getName(), renderFieldValue(context));
+			}
+
+			private Object renderFieldValue(AggregationOperationContext context) {
+
+				// implicit reference or explicit include?
+				if (value == null || Boolean.TRUE.equals(value)) {
+
+					// check whether referenced field exists in the context
+					return context.getReference(field).getReferenceValue();
+
+				} else if (Boolean.FALSE.equals(value)) {
+
+					// render field as excluded
+					return 0;
+				}
+
+				return value;
+			}
+		}
+
+		static class OperationProjection extends Projection {
+
+			private final Field field;
+			private final String operation;
+			private final List<Object> values;
+
+			/**
+			 * Creates a new {@link OperationProjection} for the given field.
+			 * 
+			 * @param name the name of the field to add the operation projection for, must not be {@literal null} or empty.
+			 * @param operation the actual operation key, must not be {@literal null} or empty.
+			 * @param values the values to pass into the operation, must not be {@literal null}.
+			 */
+			public OperationProjection(Field field, String operation, Object[] values) {
+
+				super(field);
+
+				Assert.hasText(operation, "Operation must not be null or empty!");
+				Assert.notNull(values, "Values must not be null!");
+
+				this.field = field;
+				this.operation = operation;
+				this.values = Arrays.asList(values);
+			}
+
+			/* 
+			 * (non-Javadoc)
+			 * @see org.springframework.data.mongodb.core.aggregation.ProjectionOperation.Projection#toDBObject(org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)
+			 */
+			@Override
+			public DBObject toDBObject(AggregationOperationContext context) {
+
+				BasicDBList values = new BasicDBList();
+				values.addAll(buildReferences(context));
+
+				DBObject inner = new BasicDBObject("$" + operation, values);
+
+				return new BasicDBObject(this.field.getName(), inner);
+			}
+
+			private List<Object> buildReferences(AggregationOperationContext context) {
+
+				List<Object> result = new ArrayList<Object>(values.size());
+				result.add(context.getReference(field.getTarget()).toString());
+
+				for (Object element : values) {
+					result.add(element instanceof Field ? context.getReference((Field) element).toString() : element);
+				}
+
+				return result;
+			}
+
+			/**
+			 * Creates a new instance of this {@link OperationProjection} with the given alias.
+			 * 
+			 * @param alias the alias to set
+			 * @return
+			 */
+			public OperationProjection withAlias(String alias) {
+				return new OperationProjection(Fields.field(alias, this.field.getName()), operation, values.toArray());
+			}
+		}
+
+		static class NestedFieldProjection extends Projection {
+
+			private final String name;
+			private final Fields fields;
+
+			public NestedFieldProjection(String name, Fields fields) {
+
+				super(Fields.field(name));
+				this.name = name;
+				this.fields = fields;
+			}
+
+			/* 
+			 * (non-Javadoc)
+			 * @see org.springframework.data.mongodb.core.aggregation.ProjectionOperation.Projection#toDBObject(org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)
+			 */
+			@Override
+			public DBObject toDBObject(AggregationOperationContext context) {
+
+				DBObject nestedObject = new BasicDBObject();
+
+				for (Field field : fields) {
+					nestedObject.put(field.getName(), context.getReference(field.getTarget()).toString());
+				}
+
+				return new BasicDBObject(name, nestedObject);
+			}
+		}
+	}
+
+	/**
+	 * Base class for {@link Projection} implementations.
+	 * 
+	 * @author Oliver Gierke
+	 */
+	private static abstract class Projection {
+
+		private final ExposedField field;
+
+		/**
+		 * Creates new {@link Projection} for the given {@link Field}.
+		 * 
+		 * @param field must not be {@literal null}.
+		 */
+		public Projection(Field field) {
+
+			Assert.notNull(field, "Field must not be null!");
+			this.field = new ExposedField(field, true);
+		}
+
+		/**
+		 * Returns the field exposed by the {@link Projection}.
+		 * 
+		 * @return will never be {@literal null}.
+		 */
+		public ExposedField getExposedField() {
+			return field;
+		}
+
+		/**
+		 * Renders the current {@link Projection} into a {@link DBObject} based on the given
+		 * {@link AggregationOperationContext}.
+		 * 
+		 * @param context will never be {@literal null}.
+		 * @return
+		 */
+		public abstract DBObject toDBObject(AggregationOperationContext context);
+	}
+
+}

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/SkipOperation.java

@@ -0,0 +1,54 @@
+/*
+ * Copyright 2013 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.mongodb.core.aggregation;
+
+import org.springframework.util.Assert;
+
+import com.mongodb.BasicDBObject;
+import com.mongodb.DBObject;
+
+/**
+ * Encapsulates the aggregation framework {@code $skip}-operation.
+ * 
+ * @see http://docs.mongodb.org/manual/reference/aggregation/skip/
+ * @author Thomas Darimont
+ * @author Oliver Gierke
+ * @since 1.3
+ */
+public class SkipOperation implements AggregationOperation {
+
+	private final long skipCount;
+
+	/**
+	 * Creates a new {@link SkipOperation} skipping the given number of elements.
+	 * 
+	 * @param skipCount number of documents to skip.
+	 */
+	public SkipOperation(long skipCount) {
+
+		Assert.isTrue(skipCount >= 0, "Skip count must not be negative!");
+		this.skipCount = skipCount;
+	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperation#toDBObject(org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)
+	 */
+	@Override
+	public DBObject toDBObject(AggregationOperationContext context) {
+		return new BasicDBObject("$skip", skipCount);
+	}
+}

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/SortOperation.java

@@ -0,0 +1,76 @@
+/*
+ * Copyright 2013 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.mongodb.core.aggregation;
+
+import org.springframework.data.domain.Sort;
+import org.springframework.data.domain.Sort.Direction;
+import org.springframework.data.domain.Sort.Order;
+import org.springframework.data.mongodb.core.aggregation.ExposedFields.FieldReference;
+import org.springframework.util.Assert;
+
+import com.mongodb.BasicDBObject;
+import com.mongodb.DBObject;
+
+/**
+ * Encapsulates the aggregation framework {@code $sort}-operation.
+ * 
+ * @see http://docs.mongodb.org/manual/reference/aggregation/sort/#pipe._S_sort
+ * @author Thomas Darimont
+ * @author Oliver Gierke
+ * @since 1.3
+ */
+public class SortOperation implements AggregationOperation {
+
+	private final Sort sort;
+
+	/**
+	 * Creates a new {@link SortOperation} for the given {@link Sort} instance.
+	 * 
+	 * @param sort must not be {@literal null}.
+	 */
+	public SortOperation(Sort sort) {
+
+		Assert.notNull(sort, "Sort must not be null!");
+		this.sort = sort;
+	}
+
+	public SortOperation and(Direction direction, String... fields) {
+		return and(new Sort(direction, fields));
+	}
+
+	public SortOperation and(Sort sort) {
+		return new SortOperation(this.sort.and(sort));
+	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperation#toDBObject(org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)
+	 */
+	@Override
+	public DBObject toDBObject(AggregationOperationContext context) {
+
+		BasicDBObject object = new BasicDBObject();
+
+		for (Order order : sort) {
+
+			// Check reference
+			FieldReference reference = context.getReference(order.getProperty());
+			object.put(reference.getRaw(), order.isAscending() ? 1 : -1);
+		}
+
+		return new BasicDBObject("$sort", object);
+	}
+}

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/SpelExpressionTransformer.java

@@ -0,0 +1,513 @@
+/*
+ * Copyright 2013-2014 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.mongodb.core.aggregation;
+
+import static org.springframework.data.mongodb.util.DBObjectUtils.*;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+import org.springframework.core.GenericTypeResolver;
+import org.springframework.data.mongodb.core.spel.ExpressionNode;
+import org.springframework.data.mongodb.core.spel.ExpressionTransformationContextSupport;
+import org.springframework.data.mongodb.core.spel.LiteralNode;
+import org.springframework.data.mongodb.core.spel.MethodReferenceNode;
+import org.springframework.data.mongodb.core.spel.OperatorNode;
+import org.springframework.expression.spel.ExpressionState;
+import org.springframework.expression.spel.SpelNode;
+import org.springframework.expression.spel.SpelParserConfiguration;
+import org.springframework.expression.spel.ast.CompoundExpression;
+import org.springframework.expression.spel.ast.Indexer;
+import org.springframework.expression.spel.ast.InlineList;
+import org.springframework.expression.spel.ast.PropertyOrFieldReference;
+import org.springframework.expression.spel.standard.SpelExpression;
+import org.springframework.expression.spel.standard.SpelExpressionParser;
+import org.springframework.expression.spel.support.StandardEvaluationContext;
+import org.springframework.util.Assert;
+import org.springframework.util.NumberUtils;
+
+import com.mongodb.BasicDBList;
+import com.mongodb.BasicDBObject;
+import com.mongodb.DBObject;
+
+/**
+ * Renders the AST of a SpEL expression as a MongoDB Aggregation Framework projection expression.
+ * 
+ * @author Thomas Darimont
+ */
+class SpelExpressionTransformer implements AggregationExpressionTransformer {
+
+	// TODO: remove explicit usage of a configuration once SPR-11031 gets fixed
+	private static final SpelParserConfiguration CONFIG = new SpelParserConfiguration(false, false);
+	private static final SpelExpressionParser PARSER = new SpelExpressionParser(CONFIG);
+	private final List<ExpressionNodeConversion<? extends ExpressionNode>> conversions;
+
+	/**
+	 * Creates a new {@link SpelExpressionTransformer}.
+	 */
+	public SpelExpressionTransformer() {
+
+		List<ExpressionNodeConversion<? extends ExpressionNode>> conversions = new ArrayList<ExpressionNodeConversion<? extends ExpressionNode>>();
+		conversions.add(new OperatorNodeConversion(this));
+		conversions.add(new LiteralNodeConversion(this));
+		conversions.add(new IndexerNodeConversion(this));
+		conversions.add(new InlineListNodeConversion(this));
+		conversions.add(new PropertyOrFieldReferenceNodeConversion(this));
+		conversions.add(new CompoundExpressionNodeConversion(this));
+		conversions.add(new MethodReferenceNodeConversion(this));
+
+		this.conversions = Collections.unmodifiableList(conversions);
+	}
+
+	/**
+	 * Transforms the given SpEL expression to a corresponding MongoDB expression against the given
+	 * {@link AggregationOperationContext} {@code context}.
+	 * <p>
+	 * Exposes the given @{code params} as <code>[0] ... [n]</code>.
+	 * 
+	 * @param expression must not be {@literal null}
+	 * @param context must not be {@literal null}
+	 * @param params must not be {@literal null}
+	 * @return
+	 */
+	public Object transform(String expression, AggregationOperationContext context, Object... params) {
+
+		Assert.notNull(expression, "Expression must not be null!");
+		Assert.notNull(context, "AggregationOperationContext must not be null!");
+		Assert.notNull(params, "Parameters must not be null!");
+
+		SpelExpression spelExpression = (SpelExpression) PARSER.parseExpression(expression);
+		ExpressionState state = new ExpressionState(new StandardEvaluationContext(params), CONFIG);
+		ExpressionNode node = ExpressionNode.from(spelExpression.getAST(), state);
+
+		return transform(new AggregationExpressionTransformationContext<ExpressionNode>(node, null, null, context));
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.spel.ExpressionTransformer#transform(org.springframework.data.mongodb.core.spel.ExpressionTransformationContextSupport)
+	 */
+	public Object transform(AggregationExpressionTransformationContext<ExpressionNode> context) {
+		return lookupConversionFor(context.getCurrentNode()).convert(context);
+	}
+
+	/**
+	 * Returns an appropriate {@link ExpressionNodeConversion} for the given {@code node}. Throws an
+	 * {@link IllegalArgumentException} if no conversion could be found.
+	 * 
+	 * @param node
+	 * @return the appropriate {@link ExpressionNodeConversion} for the given {@link ExpressionNode}.
+	 */
+	@SuppressWarnings("unchecked")
+	private ExpressionNodeConversion<ExpressionNode> lookupConversionFor(ExpressionNode node) {
+
+		for (ExpressionNodeConversion<? extends ExpressionNode> candidate : conversions) {
+			if (candidate.supports(node)) {
+				return (ExpressionNodeConversion<ExpressionNode>) candidate;
+			}
+		}
+
+		throw new IllegalArgumentException("Unsupported Element: " + node + " Type: " + node.getClass()
+				+ " You probably have a syntax error in your SpEL expression!");
+	}
+
+	/**
+	 * Abstract base class for {@link SpelNode} to (Db)-object conversions.
+	 * 
+	 * @author Thomas Darimont
+	 * @author Oliver Gierke
+	 */
+	private static abstract class ExpressionNodeConversion<T extends ExpressionNode> implements
+			AggregationExpressionTransformer {
+
+		private final AggregationExpressionTransformer transformer;
+		private final Class<? extends ExpressionNode> nodeType;
+
+		/**
+		 * Creates a new {@link ExpressionNodeConversion}.
+		 * 
+		 * @param transformer must not be {@literal null}.
+		 */
+		@SuppressWarnings("unchecked")
+		public ExpressionNodeConversion(AggregationExpressionTransformer transformer) {
+
+			Assert.notNull(transformer, "Transformer must not be null!");
+
+			this.nodeType = (Class<? extends ExpressionNode>) GenericTypeResolver.resolveTypeArgument(this.getClass(),
+					ExpressionNodeConversion.class);
+			this.transformer = transformer;
+		}
+
+		/**
+		 * Returns whether the current conversion supports the given {@link ExpressionNode}. By default we will match the
+		 * node type against the genric type the subclass types the type parameter to.
+		 * 
+		 * @param node will never be {@literal null}.
+		 * @return true if {@literal this} conversion can be applied to the given {@code node}.
+		 */
+		protected boolean supports(ExpressionNode node) {
+			return nodeType.equals(node.getClass());
+		}
+
+		/**
+		 * Triggers the transformation for the given {@link ExpressionNode} and the given current context.
+		 * 
+		 * @param node must not be {@literal null}.
+		 * @param context must not be {@literal null}.
+		 * @return
+		 */
+		protected Object transform(ExpressionNode node, AggregationExpressionTransformationContext<?> context) {
+
+			Assert.notNull(node, "ExpressionNode must not be null!");
+			Assert.notNull(context, "AggregationExpressionTransformationContext must not be null!");
+
+			return transform(node, context.getParentNode(), null, context);
+		}
+
+		/**
+		 * Triggers the transformation with the given new {@link ExpressionNode}, new parent node, the current operation and
+		 * the previous context.
+		 * 
+		 * @param node must not be {@literal null}.
+		 * @param parent
+		 * @param operation
+		 * @param context must not be {@literal null}.
+		 * @return
+		 */
+		protected Object transform(ExpressionNode node, ExpressionNode parent, DBObject operation,
+				AggregationExpressionTransformationContext<?> context) {
+
+			Assert.notNull(node, "ExpressionNode must not be null!");
+			Assert.notNull(context, "AggregationExpressionTransformationContext must not be null!");
+
+			return transform(new AggregationExpressionTransformationContext<ExpressionNode>(node, parent, operation,
+					context.getAggregationContext()));
+		}
+
+		/* 
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.core.aggregation.SpelExpressionTransformer.NodeConversion#transform(org.springframework.data.mongodb.core.aggregation.AggregationExpressionTransformer.AggregationExpressionTransformationContext)
+		 */
+		@Override
+		public Object transform(AggregationExpressionTransformationContext<ExpressionNode> context) {
+			return transformer.transform(context);
+		}
+
+		/**
+		 * Performs the actual conversion from {@link SpelNode} to the corresponding representation for MongoDB.
+		 * 
+		 * @param context
+		 * @return
+		 */
+		protected abstract Object convert(AggregationExpressionTransformationContext<T> context);
+	}
+
+	/**
+	 * A {@link ExpressionNodeConversion} that converts arithmetic operations.
+	 * 
+	 * @author Thomas Darimont
+	 */
+	private static class OperatorNodeConversion extends ExpressionNodeConversion<OperatorNode> {
+
+		public OperatorNodeConversion(AggregationExpressionTransformer transformer) {
+			super(transformer);
+		}
+
+		/* 
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.core.aggregation.SpelExpressionTransformer.SpelNodeWrapper#convertSpelNodeToMongoObjectExpression(org.springframework.data.mongodb.core.aggregation.SpelExpressionTransformer.ExpressionConversionContext)
+		 */
+		@Override
+		protected Object convert(AggregationExpressionTransformationContext<OperatorNode> context) {
+
+			OperatorNode currentNode = context.getCurrentNode();
+
+			DBObject operationObject = createOperationObjectAndAddToPreviousArgumentsIfNecessary(context, currentNode);
+			Object leftResult = transform(currentNode.getLeft(), currentNode, operationObject, context);
+
+			if (currentNode.isUnaryMinus()) {
+				return convertUnaryMinusOp(context, leftResult);
+			}
+
+			// we deliberately ignore the RHS result
+			transform(currentNode.getRight(), currentNode, operationObject, context);
+
+			return operationObject;
+		}
+
+		private DBObject createOperationObjectAndAddToPreviousArgumentsIfNecessary(
+				AggregationExpressionTransformationContext<OperatorNode> context, OperatorNode currentNode) {
+
+			DBObject nextDbObject = new BasicDBObject(currentNode.getMongoOperator(), new BasicDBList());
+
+			if (!context.hasPreviousOperation()) {
+				return nextDbObject;
+			}
+
+			if (context.parentIsSameOperation()) {
+
+				// same operator applied in a row e.g. 1 + 2 + 3 carry on with the operation and render as $add: [1, 2 ,3]
+				nextDbObject = context.getPreviousOperationObject();
+			} else if (!currentNode.isUnaryOperator()) {
+
+				// different operator -> add context object for next level to list if arguments of previous expression
+				context.addToPreviousOperation(nextDbObject);
+			}
+
+			return nextDbObject;
+		}
+
+		private Object convertUnaryMinusOp(ExpressionTransformationContextSupport<OperatorNode> context, Object leftResult) {
+
+			Object result = leftResult instanceof Number ? leftResult
+					: new BasicDBObject("$multiply", dbList(-1, leftResult));
+
+			if (leftResult != null && context.hasPreviousOperation()) {
+				context.addToPreviousOperation(result);
+			}
+
+			return result;
+		}
+
+		/* 
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.core.aggregation.SpelExpressionTransformer.SpelNodeWrapper#supports(java.lang.Class)
+		 */
+		@Override
+		protected boolean supports(ExpressionNode node) {
+			return node.isMathematicalOperation();
+		}
+	}
+
+	/**
+	 * A {@link ExpressionNodeConversion} that converts indexed expressions.
+	 * 
+	 * @author Thomas Darimont
+	 * @author Oliver Gierke
+	 */
+	private static class IndexerNodeConversion extends ExpressionNodeConversion<ExpressionNode> {
+
+		public IndexerNodeConversion(AggregationExpressionTransformer transformer) {
+			super(transformer);
+		}
+
+		/* 
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.core.aggregation.SpelExpressionTransformer.SpelNodeWrapper#convertSpelNodeToMongoObjectExpression(org.springframework.data.mongodb.core.aggregation.SpelExpressionTransformer.ExpressionConversionContext)
+		 */
+		@Override
+		protected Object convert(AggregationExpressionTransformationContext<ExpressionNode> context) {
+			return context.addToPreviousOrReturn(context.getCurrentNode().getValue());
+		}
+
+		/* 
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.core.aggregation.SpelExpressionTransformer.NodeConversion#supports(org.springframework.data.mongodb.core.spel.ExpressionNode)
+		 */
+		@Override
+		protected boolean supports(ExpressionNode node) {
+			return node.isOfType(Indexer.class);
+		}
+	}
+
+	/**
+	 * A {@link ExpressionNodeConversion} that converts in-line list expressions.
+	 * 
+	 * @author Thomas Darimont
+	 */
+	private static class InlineListNodeConversion extends ExpressionNodeConversion<ExpressionNode> {
+
+		public InlineListNodeConversion(AggregationExpressionTransformer transformer) {
+			super(transformer);
+		}
+
+		/* 
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.core.aggregation.SpelExpressionTransformer.SpelNodeWrapper#convertSpelNodeToMongoObjectExpression(org.springframework.data.mongodb.core.aggregation.SpelExpressionTransformer.ExpressionConversionContext)
+		 */
+		@Override
+		protected Object convert(AggregationExpressionTransformationContext<ExpressionNode> context) {
+
+			ExpressionNode currentNode = context.getCurrentNode();
+
+			if (!currentNode.hasChildren()) {
+				return null;
+			}
+
+			// just take the first item
+			return transform(currentNode.getChild(0), currentNode, null, context);
+		}
+
+		/* 
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.core.aggregation.SpelExpressionTransformer.NodeConversion#supports(org.springframework.data.mongodb.core.spel.ExpressionNode)
+		 */
+		@Override
+		protected boolean supports(ExpressionNode node) {
+			return node.isOfType(InlineList.class);
+		}
+	}
+
+	/**
+	 * A {@link ExpressionNodeConversion} that converts property or field reference expressions.
+	 * 
+	 * @author Thomas Darimont
+	 * @author Oliver Gierke
+	 */
+	private static class PropertyOrFieldReferenceNodeConversion extends ExpressionNodeConversion<ExpressionNode> {
+
+		public PropertyOrFieldReferenceNodeConversion(AggregationExpressionTransformer transformer) {
+			super(transformer);
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.core.aggregation.SpelExpressionTransformer.NodeConversion#convert(org.springframework.data.mongodb.core.aggregation.SpelExpressionTransformer.ExpressionTransformationContext)
+		 */
+		@Override
+		protected Object convert(AggregationExpressionTransformationContext<ExpressionNode> context) {
+
+			String fieldReference = context.getFieldReference().toString();
+			return context.addToPreviousOrReturn(fieldReference);
+		}
+
+		/* 
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.core.aggregation.SpelExpressionTransformer.NodeConversion#supports(org.springframework.data.mongodb.core.spel.ExpressionNode)
+		 */
+		@Override
+		protected boolean supports(ExpressionNode node) {
+			return node.isOfType(PropertyOrFieldReference.class);
+		}
+	}
+
+	/**
+	 * A {@link ExpressionNodeConversion} that converts literal expressions.
+	 * 
+	 * @author Thomas Darimont
+	 * @author Oliver Gierke
+	 */
+	private static class LiteralNodeConversion extends ExpressionNodeConversion<LiteralNode> {
+
+		public LiteralNodeConversion(AggregationExpressionTransformer transformer) {
+			super(transformer);
+		}
+
+		/* 
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.core.aggregation.SpelExpressionTransformer.SpelNodeWrapper#convertSpelNodeToMongoObjectExpression(org.springframework.data.mongodb.core.aggregation.SpelExpressionTransformer.ExpressionConversionContext)
+		 */
+		@Override
+		@SuppressWarnings("unchecked")
+		protected Object convert(AggregationExpressionTransformationContext<LiteralNode> context) {
+
+			LiteralNode node = context.getCurrentNode();
+			Object value = node.getValue();
+
+			if (context.hasPreviousOperation()) {
+
+				if (node.isUnaryMinus(context.getParentNode())) {
+					// unary minus operator
+					return NumberUtils.convertNumberToTargetClass(((Number) value).doubleValue() * -1,
+							(Class<Number>) value.getClass()); // retain type, e.g. int to -int
+				}
+
+				return context.addToPreviousOperation(value);
+			}
+
+			return value;
+		}
+
+		/* 
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.core.aggregation.SpelExpressionTransformer.SpelNodeWrapper#supports(org.springframework.expression.spel.SpelNode)
+		 */
+		@Override
+		protected boolean supports(ExpressionNode node) {
+			return node.isLiteral();
+		}
+	}
+
+	/**
+	 * A {@link ExpressionNodeConversion} that converts method reference expressions.
+	 * 
+	 * @author Thomas Darimont
+	 * @author Oliver Gierke
+	 */
+	private static class MethodReferenceNodeConversion extends ExpressionNodeConversion<MethodReferenceNode> {
+
+		public MethodReferenceNodeConversion(AggregationExpressionTransformer transformer) {
+			super(transformer);
+		}
+
+		/* 
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.core.aggregation.SpelExpressionTransformer.SpelNodeWrapper#convertSpelNodeToMongoObjectExpression(org.springframework.data.mongodb.core.aggregation.SpelExpressionTransformer.ExpressionConversionContext)
+		 */
+		@Override
+		protected Object convert(AggregationExpressionTransformationContext<MethodReferenceNode> context) {
+
+			MethodReferenceNode node = context.getCurrentNode();
+			List<Object> args = new ArrayList<Object>();
+
+			for (ExpressionNode childNode : node) {
+				args.add(transform(childNode, context));
+			}
+
+			return context.addToPreviousOrReturn(new BasicDBObject(node.getMethodName(), dbList(args.toArray())));
+		}
+	}
+
+	/**
+	 * A {@link ExpressionNodeConversion} that converts method compound expressions.
+	 * 
+	 * @author Thomas Darimont
+	 * @author Oliver Gierke
+	 */
+	private static class CompoundExpressionNodeConversion extends ExpressionNodeConversion<ExpressionNode> {
+
+		public CompoundExpressionNodeConversion(AggregationExpressionTransformer transformer) {
+			super(transformer);
+		}
+
+		/* 
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.core.aggregation.SpelExpressionTransformer.SpelNodeWrapper#convertSpelNodeToMongoObjectExpression(org.springframework.data.mongodb.core.aggregation.SpelExpressionTransformer.ExpressionConversionContext)
+		 */
+		@Override
+		protected Object convert(AggregationExpressionTransformationContext<ExpressionNode> context) {
+
+			ExpressionNode currentNode = context.getCurrentNode();
+
+			if (currentNode.hasfirstChildNotOfType(Indexer.class)) {
+				// we have a property path expression like: foo.bar -> render as reference
+				return context.addToPreviousOrReturn(context.getFieldReference().toString());
+			}
+
+			return context.addToPreviousOrReturn(currentNode.getValue());
+		}
+
+		/* 
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.core.aggregation.SpelExpressionTransformer.NodeConversion#supports(org.springframework.data.mongodb.core.spel.ExpressionNode)
+		 */
+		@Override
+		protected boolean supports(ExpressionNode node) {
+			return node.isOfType(CompoundExpression.class);
+		}
+	}
+}

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/TypeBasedAggregationOperationContext.java

@@ -0,0 +1,103 @@
+/*
+ * Copyright 2013 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.mongodb.core.aggregation;
+
+import static org.springframework.data.mongodb.core.aggregation.Fields.*;
+
+import org.springframework.data.mapping.PropertyPath;
+import org.springframework.data.mapping.context.MappingContext;
+import org.springframework.data.mapping.context.PersistentPropertyPath;
+import org.springframework.data.mongodb.core.aggregation.ExposedFields.ExposedField;
+import org.springframework.data.mongodb.core.aggregation.ExposedFields.FieldReference;
+import org.springframework.data.mongodb.core.convert.QueryMapper;
+import org.springframework.data.mongodb.core.mapping.MongoPersistentEntity;
+import org.springframework.data.mongodb.core.mapping.MongoPersistentProperty;
+import org.springframework.util.Assert;
+
+import com.mongodb.DBObject;
+
+/**
+ * {@link AggregationOperationContext} aware of a particular type and a {@link MappingContext} to potentially translate
+ * property references into document field names.
+ * 
+ * @author Oliver Gierke
+ * @since 1.3
+ */
+public class TypeBasedAggregationOperationContext implements AggregationOperationContext {
+
+	private final Class<?> type;
+	private final MappingContext<? extends MongoPersistentEntity<?>, MongoPersistentProperty> mappingContext;
+	private final QueryMapper mapper;
+
+	/**
+	 * Creates a new {@link TypeBasedAggregationOperationContext} for the given type, {@link MappingContext} and
+	 * {@link QueryMapper}.
+	 * 
+	 * @param type must not be {@literal null}.
+	 * @param mappingContext must not be {@literal null}.
+	 * @param mapper must not be {@literal null}.
+	 */
+	public TypeBasedAggregationOperationContext(Class<?> type,
+			MappingContext<? extends MongoPersistentEntity<?>, MongoPersistentProperty> mappingContext, QueryMapper mapper) {
+
+		Assert.notNull(type, "Type must not be null!");
+		Assert.notNull(mappingContext, "MappingContext must not be null!");
+		Assert.notNull(mapper, "QueryMapper must not be null!");
+
+		this.type = type;
+		this.mappingContext = mappingContext;
+		this.mapper = mapper;
+	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperationContext#getMappedObject(com.mongodb.DBObject)
+	 */
+	@Override
+	public DBObject getMappedObject(DBObject dbObject) {
+		return mapper.getMappedObject(dbObject, mappingContext.getPersistentEntity(type));
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperationContext#getReference(org.springframework.data.mongodb.core.aggregation.Field)
+	 */
+	@Override
+	public FieldReference getReference(Field field) {
+
+		PropertyPath.from(field.getTarget(), type);
+		return getReferenceFor(field);
+	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperationContext#getReference(java.lang.String)
+	 */
+	@Override
+	public FieldReference getReference(String name) {
+		return getReferenceFor(field(name));
+	}
+
+	private FieldReference getReferenceFor(Field field) {
+
+		PersistentPropertyPath<MongoPersistentProperty> propertyPath = mappingContext.getPersistentPropertyPath(
+				field.getTarget(), type);
+		Field mappedField = field(propertyPath.getLeafProperty().getName(),
+				propertyPath.toDotPath(MongoPersistentProperty.PropertyToFieldNameConverter.INSTANCE));
+
+		return new FieldReference(new ExposedField(mappedField, true));
+	}
+}

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/TypedAggregation.java

@@ -0,0 +1,51 @@
+/*
+ * Copyright 2013 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.mongodb.core.aggregation;
+
+import org.springframework.util.Assert;
+
+/**
+ * A {@code TypedAggregation} is a special {@link Aggregation} that holds information of the input aggregation type.
+ * 
+ * @author Thomas Darimont
+ * @author Oliver Gierke
+ */
+public class TypedAggregation<I> extends Aggregation {
+
+	private final Class<I> inputType;
+
+	/**
+	 * Creates a new {@link TypedAggregation} from the given {@link AggregationOperation}s.
+	 * 
+	 * @param operations must not be {@literal null} or empty.
+	 */
+	public TypedAggregation(Class<I> inputType, AggregationOperation... operations) {
+
+		super(operations);
+
+		Assert.notNull(inputType, "Input type must not be null!");
+		this.inputType = inputType;
+	}
+
+	/**
+	 * Returns the input type for the {@link Aggregation}.
+	 * 
+	 * @return the inputType will never be {@literal null}.
+	 */
+	public Class<I> getInputType() {
+		return inputType;
+	}
+}

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/UnwindOperation.java

@@ -0,0 +1,55 @@
+/*
+ * Copyright 2013 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.mongodb.core.aggregation;
+
+import org.springframework.data.mongodb.core.aggregation.ExposedFields.ExposedField;
+import org.springframework.util.Assert;
+
+import com.mongodb.BasicDBObject;
+import com.mongodb.DBObject;
+
+/**
+ * Encapsulates the aggregation framework {@code $unwind}-operation.
+ * 
+ * @see http://docs.mongodb.org/manual/reference/aggregation/unwind/#pipe._S_unwind
+ * @author Thomas Darimont
+ * @author Oliver Gierke
+ * @since 1.3
+ */
+public class UnwindOperation implements AggregationOperation {
+
+	private final ExposedField field;
+
+	/**
+	 * Creates a new {@link UnwindOperation} for the given {@link Field}.
+	 * 
+	 * @param field must not be {@literal null}.
+	 */
+	public UnwindOperation(Field field) {
+
+		Assert.notNull(field);
+		this.field = new ExposedField(field, true);
+	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperation#toDBObject(org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)
+	 */
+	@Override
+	public DBObject toDBObject(AggregationOperationContext context) {
+		return new BasicDBObject("$unwind", context.getReference(field).toString());
+	}
+}

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/package-info.java

@@ -0,0 +1,5 @@
+/**
+ * Support for the MongoDB aggregation framework.
+ * @since 1.3
+ */
+package org.springframework.data.mongodb.core.aggregation;

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/CustomConversions.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2011-2013 the original author or authors.
+ * Copyright 2011-2014 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -17,12 +17,14 @@ package org.springframework.data.mongodb.core.convert;
 
 import java.util.ArrayList;
 import java.util.Arrays;
-import java.util.HashMap;
+import java.util.Collections;
 import java.util.HashSet;
+import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Locale;
-import java.util.Map;
 import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -39,6 +41,7 @@ import org.springframework.data.convert.WritingConverter;
 import org.springframework.data.mapping.model.SimpleTypeHolder;
 import org.springframework.data.mongodb.core.convert.MongoConverters.BigDecimalToStringConverter;
 import org.springframework.data.mongodb.core.convert.MongoConverters.BigIntegerToStringConverter;
+import org.springframework.data.mongodb.core.convert.MongoConverters.DBObjectToStringConverter;
 import org.springframework.data.mongodb.core.convert.MongoConverters.StringToBigDecimalConverter;
 import org.springframework.data.mongodb.core.convert.MongoConverters.StringToBigIntegerConverter;
 import org.springframework.data.mongodb.core.convert.MongoConverters.StringToURLConverter;
@@ -54,6 +57,7 @@ import org.springframework.util.Assert;
  * .
  * 
  * @author Oliver Gierke
+ * @author Thomas Darimont
  */
 public class CustomConversions {
 
@@ -65,7 +69,7 @@ public class CustomConversions {
 	private final Set<ConvertiblePair> writingPairs;
 	private final Set<Class<?>> customSimpleTypes;
 	private final SimpleTypeHolder simpleTypeHolder;
-	private final Map<Class<?>, HashMap<Class<?>, CacheValue>> cache;
+	private final ConcurrentMap<ConvertiblePair, CacheValue> customReadTargetTypes;
 
 	private final List<Object> converters;
 
@@ -85,26 +89,33 @@ public class CustomConversions {
 
 		Assert.notNull(converters);
 
-		this.readingPairs = new HashSet<ConvertiblePair>();
-		this.writingPairs = new HashSet<ConvertiblePair>();
+		this.readingPairs = new LinkedHashSet<ConvertiblePair>();
+		this.writingPairs = new LinkedHashSet<ConvertiblePair>();
 		this.customSimpleTypes = new HashSet<Class<?>>();
-		this.cache = new HashMap<Class<?>, HashMap<Class<?>, CacheValue>>();
+		this.customReadTargetTypes = new ConcurrentHashMap<GenericConverter.ConvertiblePair, CacheValue>();
 
-		this.converters = new ArrayList<Object>();
-		this.converters.add(CustomToStringConverter.INSTANCE);
-		this.converters.add(BigDecimalToStringConverter.INSTANCE);
-		this.converters.add(StringToBigDecimalConverter.INSTANCE);
-		this.converters.add(BigIntegerToStringConverter.INSTANCE);
-		this.converters.add(StringToBigIntegerConverter.INSTANCE);
-		this.converters.add(URLToStringConverter.INSTANCE);
-		this.converters.add(StringToURLConverter.INSTANCE);
-		this.converters.addAll(JodaTimeConverters.getConvertersToRegister());
-		this.converters.addAll(converters);
+		List<Object> toRegister = new ArrayList<Object>();
 
-		for (Object c : this.converters) {
+		toRegister.addAll(converters);
+		toRegister.add(CustomToStringConverter.INSTANCE);
+		toRegister.add(BigDecimalToStringConverter.INSTANCE);
+		toRegister.add(StringToBigDecimalConverter.INSTANCE);
+		toRegister.add(BigIntegerToStringConverter.INSTANCE);
+		toRegister.add(StringToBigIntegerConverter.INSTANCE);
+		toRegister.add(URLToStringConverter.INSTANCE);
+		toRegister.add(StringToURLConverter.INSTANCE);
+		toRegister.add(DBObjectToStringConverter.INSTANCE);
+		toRegister.addAll(JodaTimeConverters.getConvertersToRegister());
+
+		// Add user provided converters to make sure they can override the defaults
+
+		for (Object c : toRegister) {
 			registerConversion(c);
 		}
 
+		Collections.reverse(toRegister);
+
+		this.converters = Collections.unmodifiableList(toRegister);
 		this.simpleTypeHolder = new SimpleTypeHolder(customSimpleTypes, MongoSimpleTypes.HOLDER);
 	}
 
@@ -192,25 +203,25 @@ public class CustomConversions {
 	 * 
 	 * @param pair
 	 */
-	private void register(ConverterRegistration context) {
+	private void register(ConverterRegistration converterRegistration) {
 
-		ConvertiblePair pair = context.getConvertiblePair();
+		ConvertiblePair pair = converterRegistration.getConvertiblePair();
 
-		if (context.isReading()) {
+		if (converterRegistration.isReading()) {
 
 			readingPairs.add(pair);
 
-			if (LOG.isWarnEnabled() && !context.isSimpleSourceType()) {
+			if (LOG.isWarnEnabled() && !converterRegistration.isSimpleSourceType()) {
 				LOG.warn(String.format(READ_CONVERTER_NOT_SIMPLE, pair.getSourceType(), pair.getTargetType()));
 			}
 		}
 
-		if (context.isWriting()) {
+		if (converterRegistration.isWriting()) {
 
 			writingPairs.add(pair);
 			customSimpleTypes.add(pair.getSourceType());
 
-			if (LOG.isWarnEnabled() && !context.isSimpleTargetType()) {
+			if (LOG.isWarnEnabled() && !converterRegistration.isSimpleTargetType()) {
 				LOG.warn(String.format(WRITE_CONVERTER_NOT_SIMPLE, pair.getSourceType(), pair.getTargetType()));
 			}
 		}
@@ -220,11 +231,11 @@ public class CustomConversions {
 	 * Returns the target type to convert to in case we have a custom conversion registered to convert the given source
 	 * type into a Mongo native one.
 	 * 
-	 * @param source must not be {@literal null}
+	 * @param sourceType must not be {@literal null}
 	 * @return
 	 */
-	public Class<?> getCustomWriteTarget(Class<?> source) {
-		return getCustomWriteTarget(source, null);
+	public Class<?> getCustomWriteTarget(Class<?> sourceType) {
+		return getCustomWriteTarget(sourceType, null);
 	}
 
 	/**
@@ -232,71 +243,78 @@ public class CustomConversions {
 	 * oth the given expected type though. If {@code expectedTargetType} is {@literal null} we will simply return the
 	 * first target type matching or {@literal null} if no conversion can be found.
 	 * 
-	 * @param source must not be {@literal null}
-	 * @param expectedTargetType
+	 * @param sourceType must not be {@literal null}
+	 * @param requestedTargetType
 	 * @return
 	 */
-	public Class<?> getCustomWriteTarget(Class<?> source, Class<?> expectedTargetType) {
-		Assert.notNull(source);
-		return getCustomTarget(source, expectedTargetType, writingPairs);
+	public Class<?> getCustomWriteTarget(Class<?> sourceType, Class<?> requestedTargetType) {
+
+		Assert.notNull(sourceType);
+
+		return getCustomTarget(sourceType, requestedTargetType, writingPairs);
 	}
 
 	/**
 	 * Returns whether we have a custom conversion registered to write into a Mongo native type. The returned type might
-	 * be a subclass oth the given expected type though.
+	 * be a subclass of the given expected type though.
 	 * 
-	 * @param source must not be {@literal null}
+	 * @param sourceType must not be {@literal null}
 	 * @return
 	 */
-	public boolean hasCustomWriteTarget(Class<?> source) {
-		return hasCustomWriteTarget(source, null);
+	public boolean hasCustomWriteTarget(Class<?> sourceType) {
+
+		Assert.notNull(sourceType);
+		return hasCustomWriteTarget(sourceType, null);
 	}
 
 	/**
 	 * Returns whether we have a custom conversion registered to write an object of the given source type into an object
 	 * of the given Mongo native target type.
 	 * 
-	 * @param source must not be {@literal null}.
-	 * @param expectedTargetType
+	 * @param sourceType must not be {@literal null}.
+	 * @param requestedTargetType
 	 * @return
 	 */
-	public boolean hasCustomWriteTarget(Class<?> source, Class<?> expectedTargetType) {
-		return getCustomWriteTarget(source, expectedTargetType) != null;
+	public boolean hasCustomWriteTarget(Class<?> sourceType, Class<?> requestedTargetType) {
+
+		Assert.notNull(sourceType);
+		return getCustomWriteTarget(sourceType, requestedTargetType) != null;
 	}
 
 	/**
 	 * Returns whether we have a custom conversion registered to read the given source into the given target type.
 	 * 
-	 * @param source must not be {@literal null}
-	 * @param expectedTargetType must not be {@literal null}
+	 * @param sourceType must not be {@literal null}
+	 * @param requestedTargetType must not be {@literal null}
 	 * @return
 	 */
-	public boolean hasCustomReadTarget(Class<?> source, Class<?> expectedTargetType) {
+	public boolean hasCustomReadTarget(Class<?> sourceType, Class<?> requestedTargetType) {
 
-		Assert.notNull(source);
-		Assert.notNull(expectedTargetType);
+		Assert.notNull(sourceType);
+		Assert.notNull(requestedTargetType);
 
-		return getCustomReadTarget(source, expectedTargetType) != null;
+		return getCustomReadTarget(sourceType, requestedTargetType) != null;
 	}
 
 	/**
 	 * Inspects the given {@link ConvertiblePair} for ones that have a source compatible type as source. Additionally
-	 * checks assignabilty of the target type if one is given.
+	 * checks assignability of the target type if one is given.
 	 * 
-	 * @param source must not be {@literal null}
-	 * @param expectedTargetType
-	 * @param pairs must not be {@literal null}
+	 * @param sourceType must not be {@literal null}.
+	 * @param requestedTargetType can be {@literal null}.
+	 * @param pairs must not be {@literal null}.
 	 * @return
 	 */
-	private static Class<?> getCustomTarget(Class<?> source, Class<?> expectedTargetType, Iterable<ConvertiblePair> pairs) {
+	private static Class<?> getCustomTarget(Class<?> sourceType, Class<?> requestedTargetType,
+			Iterable<ConvertiblePair> pairs) {
 
-		Assert.notNull(source);
+		Assert.notNull(sourceType);
 		Assert.notNull(pairs);
 
 		for (ConvertiblePair typePair : pairs) {
-			if (typePair.getSourceType().isAssignableFrom(source)) {
+			if (typePair.getSourceType().isAssignableFrom(sourceType)) {
 				Class<?> targetType = typePair.getTargetType();
-				if (expectedTargetType == null || targetType.isAssignableFrom(expectedTargetType)) {
+				if (requestedTargetType == null || targetType.isAssignableFrom(requestedTargetType)) {
 					return targetType;
 				}
 			}
@@ -305,27 +323,33 @@ public class CustomConversions {
 		return null;
 	}
 
-	private Class<?> getCustomReadTarget(Class<?> source, Class<?> expectedTargetType) {
+	/**
+	 * Returns the actual target type for the given {@code sourceType} and {@code requestedTargetType}. Note that the
+	 * returned {@link Class} could be an assignable type to the given {@code requestedTargetType}.
+	 * 
+	 * @param sourceType must not be {@literal null}.
+	 * @param requestedTargetType can be {@literal null}.
+	 * @return
+	 */
+	private Class<?> getCustomReadTarget(Class<?> sourceType, Class<?> requestedTargetType) {
 
-		Class<?> type = expectedTargetType == null ? PlaceholderType.class : expectedTargetType;
+		Assert.notNull(sourceType);
 
-		Map<Class<?>, CacheValue> map;
-		CacheValue toReturn;
-
-		if ((map = cache.get(source)) == null || (toReturn = map.get(type)) == null) {
-
-			Class<?> target = getCustomTarget(source, type, readingPairs);
-
-			if (cache.get(source) == null) {
-				cache.put(source, new HashMap<Class<?>, CacheValue>());
-			}
-
-			Map<Class<?>, CacheValue> value = cache.get(source);
-			toReturn = target == null ? CacheValue.NULL : new CacheValue(target);
-			value.put(type, toReturn);
+		if (requestedTargetType == null) {
+			return null;
 		}
 
-		return toReturn.clazz;
+		ConvertiblePair lookupKey = new ConvertiblePair(sourceType, requestedTargetType);
+		CacheValue readTargetTypeValue = customReadTargetTypes.get(lookupKey);
+
+		if (readTargetTypeValue != null) {
+			return readTargetTypeValue.getType();
+		}
+
+		readTargetTypeValue = CacheValue.of(getCustomTarget(sourceType, requestedTargetType, readingPairs));
+		CacheValue cacheValue = customReadTargetTypes.putIfAbsent(lookupKey, readTargetTypeValue);
+
+		return cacheValue != null ? cacheValue.getType() : readTargetTypeValue.getType();
 	}
 
 	@WritingConverter
@@ -334,8 +358,10 @@ public class CustomConversions {
 		INSTANCE;
 
 		public Set<ConvertiblePair> getConvertibleTypes() {
+
 			ConvertiblePair localeToString = new ConvertiblePair(Locale.class, String.class);
 			ConvertiblePair booleanToString = new ConvertiblePair(Character.class, String.class);
+
 			return new HashSet<ConvertiblePair>(Arrays.asList(localeToString, booleanToString));
 		}
 
@@ -344,29 +370,29 @@ public class CustomConversions {
 		}
 	}
 
-	/**
-	 * Placeholder type to allow registering not-found values in the converter cache.
-	 * 
-	 * @author Patryk Wasik
-	 * @author Oliver Gierke
-	 */
-	private static class PlaceholderType {
-
-	}
-
 	/**
 	 * Wrapper to safely store {@literal null} values in the type cache.
 	 * 
 	 * @author Patryk Wasik
 	 * @author Oliver Gierke
+	 * @author Thomas Darimont
 	 */
 	private static class CacheValue {
 
-		public static final CacheValue NULL = new CacheValue(null);
-		private final Class<?> clazz;
+		private static final CacheValue ABSENT = new CacheValue(null);
 
-		public CacheValue(Class<?> clazz) {
-			this.clazz = clazz;
+		private final Class<?> type;
+
+		public CacheValue(Class<?> type) {
+			this.type = type;
+		}
+
+		public Class<?> getType() {
+			return type;
+		}
+
+		static CacheValue of(Class<?> type) {
+			return type == null ? ABSENT : new CacheValue(type);
 		}
 	}
 }

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/DBObjectAccessor.java

@@ -0,0 +1,123 @@
+/*
+ * Copyright 2013 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.mongodb.core.convert;
+
+import java.util.Arrays;
+import java.util.Iterator;
+import java.util.Map;
+
+import org.springframework.data.mongodb.core.mapping.MongoPersistentProperty;
+import org.springframework.util.Assert;
+
+import com.mongodb.BasicDBObject;
+import com.mongodb.DBObject;
+
+/**
+ * Wrapper value object for a {@link BasicDBObject} to be able to access raw values by {@link MongoPersistentProperty}
+ * references. The accessors will transparently resolve nested document values that a {@link MongoPersistentProperty}
+ * might refer to through a path expression in field names.
+ * 
+ * @author Oliver Gierke
+ */
+class DBObjectAccessor {
+
+	private final DBObject dbObject;
+
+	/**
+	 * Creates a new {@link DBObjectAccessor} for the given {@link DBObject}.
+	 * 
+	 * @param dbObject must be a {@link BasicDBObject} effectively, must not be {@literal null}.
+	 */
+	public DBObjectAccessor(DBObject dbObject) {
+
+		Assert.notNull(dbObject, "DBObject must not be null!");
+		Assert.isInstanceOf(BasicDBObject.class, dbObject, "Given DBObject must be a BasicDBObject!");
+
+		this.dbObject = dbObject;
+	}
+
+	/**
+	 * Puts the given value into the backing {@link DBObject} based on the coordinates defined through the given
+	 * {@link MongoPersistentProperty}. By default this will be the plain field name. But field names might also consist
+	 * of path traversals so we might need to create intermediate {@link BasicDBObject}s.
+	 * 
+	 * @param prop must not be {@literal null}.
+	 * @param value
+	 */
+	public void put(MongoPersistentProperty prop, Object value) {
+
+		Assert.notNull(prop, "MongoPersistentProperty must not be null!");
+		String fieldName = prop.getFieldName();
+
+		Iterator<String> parts = Arrays.asList(fieldName.split("\\.")).iterator();
+		DBObject dbObject = this.dbObject;
+
+		while (parts.hasNext()) {
+
+			String part = parts.next();
+
+			if (parts.hasNext()) {
+				BasicDBObject nestedDbObject = new BasicDBObject();
+				dbObject.put(part, nestedDbObject);
+				dbObject = nestedDbObject;
+			} else {
+				dbObject.put(part, value);
+			}
+		}
+	}
+
+	/**
+	 * Returns the value the given {@link MongoPersistentProperty} refers to. By default this will be a direct field but
+	 * the method will also transparently resolve nested values the {@link MongoPersistentProperty} might refer to through
+	 * a path expression in the field name metadata.
+	 * 
+	 * @param property must not be {@literal null}.
+	 * @return
+	 */
+	@SuppressWarnings("unchecked")
+	public Object get(MongoPersistentProperty property) {
+
+		String fieldName = property.getFieldName();
+		Iterator<String> parts = Arrays.asList(fieldName.split("\\.")).iterator();
+		Map<Object, Object> source = this.dbObject.toMap();
+		Object result = null;
+
+		while (source != null && parts.hasNext()) {
+
+			result = source.get(parts.next());
+
+			if (parts.hasNext()) {
+				source = getAsMap(result);
+			}
+		}
+
+		return result;
+	}
+
+	@SuppressWarnings("unchecked")
+	private Map<Object, Object> getAsMap(Object source) {
+
+		if (source instanceof BasicDBObject) {
+			return ((DBObject) source).toMap();
+		}
+
+		if (source instanceof Map) {
+			return (Map<Object, Object>) source;
+		}
+
+		return null;
+	}
+}

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/DBObjectPropertyAccessor.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012 the original author or authors.
+ * Copyright 2012-2014 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -31,18 +31,30 @@ import com.mongodb.DBObject;
  */
 class DBObjectPropertyAccessor extends MapAccessor {
 
-	static MapAccessor INSTANCE = new DBObjectPropertyAccessor();
+	static final MapAccessor INSTANCE = new DBObjectPropertyAccessor();
 
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.context.expression.MapAccessor#getSpecificTargetClasses()
+	 */
 	@Override
 	public Class<?>[] getSpecificTargetClasses() {
 		return new Class[] { DBObject.class };
 	}
 
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.context.expression.MapAccessor#canRead(org.springframework.expression.EvaluationContext, java.lang.Object, java.lang.String)
+	 */
 	@Override
 	public boolean canRead(EvaluationContext context, Object target, String name) {
 		return true;
 	}
 
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.context.expression.MapAccessor#read(org.springframework.expression.EvaluationContext, java.lang.Object, java.lang.String)
+	 */
 	@Override
 	@SuppressWarnings("unchecked")
 	public TypedValue read(EvaluationContext context, Object target, String name) {
@@ -52,4 +64,4 @@ class DBObjectPropertyAccessor extends MapAccessor {
 		Object value = source.get(name);
 		return value == null ? TypedValue.NULL : new TypedValue(value);
 	}
-}
+}

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/DbRefResolver.java

@@ -0,0 +1,55 @@
+/*
+ * Copyright 2013-2014 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.mongodb.core.convert;
+
+import org.springframework.data.mongodb.core.mapping.MongoPersistentEntity;
+import org.springframework.data.mongodb.core.mapping.MongoPersistentProperty;
+
+import com.mongodb.DBRef;
+
+/**
+ * Used to resolve associations annotated with {@link org.springframework.data.mongodb.core.mapping.DBRef}.
+ * 
+ * @author Thomas Darimont
+ * @author Oliver Gierke
+ * @since 1.4
+ */
+public interface DbRefResolver {
+
+	/**
+	 * Resolves the given {@link DBRef} into an object of the given {@link MongoPersistentProperty}'s type. The method
+	 * might return a proxy object for the {@link DBRef} or resolve it immediately. In both cases the
+	 * {@link DbRefResolverCallback} will be used to obtain the actual backing object.
+	 * 
+	 * @param property will never be {@literal null}.
+	 * @param dbref the {@link DBRef} to resolve.
+	 * @param callback will never be {@literal null}.
+	 * @return
+	 */
+	Object resolveDbRef(MongoPersistentProperty property, DBRef dbref, DbRefResolverCallback callback);
+
+	/**
+	 * Creates a {@link DBRef} instance for the given {@link org.springframework.data.mongodb.core.mapping.DBRef}
+	 * annotation, {@link MongoPersistentEntity} and id.
+	 * 
+	 * @param annotation will never be {@literal null}.
+	 * @param entity will never be {@literal null}.
+	 * @param id will never be {@literal null}.
+	 * @return
+	 */
+	DBRef createDbRef(org.springframework.data.mongodb.core.mapping.DBRef annotation, MongoPersistentEntity<?> entity,
+			Object id);
+}

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/DbRefResolverCallback.java

@@ -0,0 +1,35 @@
+/*
+ * Copyright 2013 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.mongodb.core.convert;
+
+import org.springframework.data.mongodb.core.mapping.MongoPersistentProperty;
+
+/**
+ * Callback interface to be used in conjunction with {@link DbRefResolver}.
+ * 
+ * @author Thomas Darimont
+ * @author Oliver Gierke
+ */
+public interface DbRefResolverCallback {
+
+	/**
+	 * Resolve the final object for the given {@link MongoPersistentProperty}.
+	 * 
+	 * @param property will never be {@literal null}.
+	 * @return
+	 */
+	Object resolve(MongoPersistentProperty property);
+}

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/DefaultDbRefResolver.java

@@ -0,0 +1,479 @@
+/*
+ * Copyright 2013-2014 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.mongodb.core.convert;
+
+import static org.springframework.util.ReflectionUtils.*;
+
+import java.io.IOException;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
+import java.io.Serializable;
+import java.lang.reflect.Method;
+
+import org.aopalliance.intercept.MethodInterceptor;
+import org.aopalliance.intercept.MethodInvocation;
+import org.objenesis.Objenesis;
+import org.objenesis.ObjenesisStd;
+import org.springframework.aop.framework.ProxyFactory;
+import org.springframework.beans.BeanUtils;
+import org.springframework.cglib.proxy.Callback;
+import org.springframework.cglib.proxy.Enhancer;
+import org.springframework.cglib.proxy.Factory;
+import org.springframework.cglib.proxy.MethodProxy;
+import org.springframework.dao.DataAccessException;
+import org.springframework.dao.support.PersistenceExceptionTranslator;
+import org.springframework.data.mongodb.LazyLoadingException;
+import org.springframework.data.mongodb.MongoDbFactory;
+import org.springframework.data.mongodb.core.mapping.MongoPersistentEntity;
+import org.springframework.data.mongodb.core.mapping.MongoPersistentProperty;
+import org.springframework.util.Assert;
+import org.springframework.util.ClassUtils;
+import org.springframework.util.ReflectionUtils;
+import org.springframework.util.StringUtils;
+
+import com.mongodb.DB;
+import com.mongodb.DBRef;
+
+/**
+ * A {@link DbRefResolver} that resolves {@link org.springframework.data.mongodb.core.mapping.DBRef}s by delegating to a
+ * {@link DbRefResolverCallback} than is able to generate lazy loading proxies.
+ * 
+ * @author Thomas Darimont
+ * @author Oliver Gierke
+ * @since 1.4
+ */
+public class DefaultDbRefResolver implements DbRefResolver {
+
+	private static final boolean OBJENESIS_PRESENT = ClassUtils.isPresent("org.objenesis.Objenesis", null);
+
+	private final MongoDbFactory mongoDbFactory;
+	private final PersistenceExceptionTranslator exceptionTranslator;
+
+	/**
+	 * Creates a new {@link DefaultDbRefResolver} with the given {@link MongoDbFactory}.
+	 * 
+	 * @param mongoDbFactory must not be {@literal null}.
+	 */
+	public DefaultDbRefResolver(MongoDbFactory mongoDbFactory) {
+
+		Assert.notNull(mongoDbFactory, "MongoDbFactory translator must not be null!");
+
+		this.mongoDbFactory = mongoDbFactory;
+		this.exceptionTranslator = mongoDbFactory.getExceptionTranslator();
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.convert.DbRefResolver#resolveDbRef(org.springframework.data.mongodb.core.mapping.MongoPersistentProperty, org.springframework.data.mongodb.core.convert.DbRefResolverCallback)
+	 */
+	@Override
+	public Object resolveDbRef(MongoPersistentProperty property, DBRef dbref, DbRefResolverCallback callback) {
+
+		Assert.notNull(property, "Property must not be null!");
+		Assert.notNull(callback, "Callback must not be null!");
+
+		if (isLazyDbRef(property)) {
+			return createLazyLoadingProxy(property, dbref, callback);
+		}
+
+		return callback.resolve(property);
+	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.convert.DbRefResolver#created(org.springframework.data.mongodb.core.mapping.MongoPersistentProperty, org.springframework.data.mongodb.core.mapping.MongoPersistentEntity, java.lang.Object)
+	 */
+	@Override
+	public DBRef createDbRef(org.springframework.data.mongodb.core.mapping.DBRef annotation,
+			MongoPersistentEntity<?> entity, Object id) {
+
+		DB db = mongoDbFactory.getDb();
+		db = annotation != null && StringUtils.hasText(annotation.db()) ? mongoDbFactory.getDb(annotation.db()) : db;
+
+		return new DBRef(db, entity.getCollection(), id);
+	}
+
+	/**
+	 * Creates a proxy for the given {@link MongoPersistentProperty} using the given {@link DbRefResolverCallback} to
+	 * eventually resolve the value of the property.
+	 * 
+	 * @param property must not be {@literal null}.
+	 * @param dbref can be {@literal null}.
+	 * @param callback must not be {@literal null}.
+	 * @return
+	 */
+	private Object createLazyLoadingProxy(MongoPersistentProperty property, DBRef dbref, DbRefResolverCallback callback) {
+
+		ProxyFactory proxyFactory = new ProxyFactory();
+		Class<?> propertyType = property.getType();
+
+		for (Class<?> type : propertyType.getInterfaces()) {
+			proxyFactory.addInterface(type);
+		}
+
+		LazyLoadingInterceptor interceptor = new LazyLoadingInterceptor(property, dbref, exceptionTranslator, callback);
+
+		proxyFactory.addInterface(LazyLoadingProxy.class);
+
+		if (propertyType.isInterface()) {
+			proxyFactory.addInterface(propertyType);
+			proxyFactory.addAdvice(interceptor);
+			return proxyFactory.getProxy();
+		}
+
+		proxyFactory.setProxyTargetClass(true);
+		proxyFactory.setTargetClass(propertyType);
+
+		if (!OBJENESIS_PRESENT) {
+			proxyFactory.addAdvice(interceptor);
+			return proxyFactory.getProxy();
+		}
+
+		return ObjenesisProxyEnhancer.enhanceAndGet(proxyFactory, propertyType, interceptor);
+	}
+
+	/**
+	 * Returns whether the property shall be resolved lazily.
+	 * 
+	 * @param property must not be {@literal null}.
+	 * @return
+	 */
+	private boolean isLazyDbRef(MongoPersistentProperty property) {
+		return property.getDBRef() != null && property.getDBRef().lazy();
+	}
+
+	/**
+	 * A {@link MethodInterceptor} that is used within a lazy loading proxy. The property resolving is delegated to a
+	 * {@link DbRefResolverCallback}. The resolving process is triggered by a method invocation on the proxy and is
+	 * guaranteed to be performed only once.
+	 * 
+	 * @author Thomas Darimont
+	 * @author Oliver Gierke
+	 */
+	static class LazyLoadingInterceptor implements MethodInterceptor, org.springframework.cglib.proxy.MethodInterceptor,
+			Serializable {
+
+		private static final Method INITIALIZE_METHOD, TO_DBREF_METHOD;
+
+		private final DbRefResolverCallback callback;
+		private final MongoPersistentProperty property;
+		private final PersistenceExceptionTranslator exceptionTranslator;
+
+		private volatile boolean resolved;
+		private Object result;
+		private DBRef dbref;
+
+		static {
+			try {
+				INITIALIZE_METHOD = LazyLoadingProxy.class.getMethod("initialize");
+				TO_DBREF_METHOD = LazyLoadingProxy.class.getMethod("toDBRef");
+			} catch (Exception e) {
+				throw new RuntimeException(e);
+			}
+		}
+
+		/**
+		 * Creates a new {@link LazyLoadingInterceptor} for the given {@link MongoPersistentProperty},
+		 * {@link PersistenceExceptionTranslator} and {@link DbRefResolverCallback}.
+		 * 
+		 * @param property must not be {@literal null}.
+		 * @param dbref can be {@literal null}.
+		 * @param callback must not be {@literal null}.
+		 */
+		public LazyLoadingInterceptor(MongoPersistentProperty property, DBRef dbref,
+				PersistenceExceptionTranslator exceptionTranslator, DbRefResolverCallback callback) {
+
+			Assert.notNull(property, "Property must not be null!");
+			Assert.notNull(exceptionTranslator, "Exception translator must not be null!");
+			Assert.notNull(callback, "Callback must not be null!");
+
+			this.dbref = dbref;
+			this.callback = callback;
+			this.exceptionTranslator = exceptionTranslator;
+			this.property = property;
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see org.aopalliance.intercept.MethodInterceptor#invoke(org.aopalliance.intercept.MethodInvocation)
+		 */
+		@Override
+		public Object invoke(MethodInvocation invocation) throws Throwable {
+			return intercept(invocation.getThis(), invocation.getMethod(), invocation.getArguments(), null);
+		}
+
+		/* 
+		 * (non-Javadoc)
+		 * @see org.springframework.cglib.proxy.MethodInterceptor#intercept(java.lang.Object, java.lang.reflect.Method, java.lang.Object[], org.springframework.cglib.proxy.MethodProxy)
+		 */
+		@Override
+		public Object intercept(Object obj, Method method, Object[] args, MethodProxy proxy) throws Throwable {
+
+			if (INITIALIZE_METHOD.equals(method)) {
+				return ensureResolved();
+			}
+
+			if (TO_DBREF_METHOD.equals(method)) {
+				return this.dbref;
+			}
+
+			if (isObjectMethod(method) && Object.class.equals(method.getDeclaringClass())) {
+
+				if (ReflectionUtils.isToStringMethod(method)) {
+					return proxyToString(proxy);
+				}
+
+				if (ReflectionUtils.isEqualsMethod(method)) {
+					return proxyEquals(proxy, args[0]);
+				}
+
+				if (ReflectionUtils.isHashCodeMethod(method)) {
+					return proxyHashCode(proxy);
+				}
+			}
+
+			Object target = ensureResolved();
+
+			if (target == null) {
+				return null;
+			}
+
+			return method.invoke(target, args);
+		}
+
+		/**
+		 * Returns a to string representation for the given {@code proxy}.
+		 * 
+		 * @param proxy
+		 * @return
+		 */
+		private String proxyToString(Object proxy) {
+
+			StringBuilder description = new StringBuilder();
+			if (dbref != null) {
+				description.append(dbref.getRef());
+				description.append(":");
+				description.append(dbref.getId());
+			} else {
+				description.append(System.identityHashCode(proxy));
+			}
+			description.append("$").append(LazyLoadingProxy.class.getSimpleName());
+
+			return description.toString();
+		}
+
+		/**
+		 * Returns the hashcode for the given {@code proxy}.
+		 * 
+		 * @param proxy
+		 * @return
+		 */
+		private int proxyHashCode(Object proxy) {
+			return proxyToString(proxy).hashCode();
+		}
+
+		/**
+		 * Performs an equality check for the given {@code proxy}.
+		 * 
+		 * @param proxy
+		 * @param that
+		 * @return
+		 */
+		private boolean proxyEquals(Object proxy, Object that) {
+
+			if (!(that instanceof LazyLoadingProxy)) {
+				return false;
+			}
+
+			if (that == proxy) {
+				return true;
+			}
+
+			return proxyToString(proxy).equals(that.toString());
+		}
+
+		/**
+		 * Will trigger the resolution if the proxy is not resolved already or return a previously resolved result.
+		 * 
+		 * @return
+		 */
+		private Object ensureResolved() {
+
+			if (!resolved) {
+				this.result = resolve();
+				this.resolved = true;
+			}
+
+			return this.result;
+		}
+
+		/**
+		 * Callback method for serialization.
+		 * 
+		 * @param out
+		 * @throws IOException
+		 */
+		private void writeObject(ObjectOutputStream out) throws IOException {
+
+			ensureResolved();
+			out.writeObject(this.result);
+		}
+
+		/**
+		 * Callback method for deserialization.
+		 * 
+		 * @param in
+		 * @throws IOException
+		 */
+		private void readObject(ObjectInputStream in) throws IOException {
+
+			try {
+				this.resolved = true;
+				this.result = in.readObject();
+			} catch (ClassNotFoundException e) {
+				throw new LazyLoadingException("Could not deserialize result", e);
+			}
+		}
+
+		/**
+		 * Resolves the proxy into its backing object.
+		 * 
+		 * @return
+		 */
+		private synchronized Object resolve() {
+
+			if (!resolved) {
+
+				try {
+
+					return callback.resolve(property);
+
+				} catch (RuntimeException ex) {
+
+					DataAccessException translatedException = this.exceptionTranslator.translateExceptionIfPossible(ex);
+					throw new LazyLoadingException("Unable to lazily resolve DBRef!", translatedException);
+				}
+			}
+
+			return result;
+		}
+	}
+
+	/**
+	 * Static class to accommodate optional dependency on Objenesis.
+	 * 
+	 * @author Oliver Gierke
+	 * @author Thomas Darimont
+	 * @since 1.4
+	 */
+	private static class ObjenesisProxyEnhancer {
+
+		private static final boolean IS_SPRING_4_OR_BETTER = ClassUtils.isPresent(
+				"org.springframework.core.DefaultParameterNameDiscoverer", null);
+
+		private static final InstanceCreatorStrategy INSTANCE_CREATOR;
+
+		static {
+
+			if (IS_SPRING_4_OR_BETTER) {
+				INSTANCE_CREATOR = new Spring4ObjenesisInstanceCreatorStrategy();
+			} else {
+				INSTANCE_CREATOR = new DefaultObjenesisInstanceCreatorStrategy();
+			}
+		}
+
+		public static Object enhanceAndGet(ProxyFactory proxyFactory, Class<?> type,
+				org.springframework.cglib.proxy.MethodInterceptor interceptor) {
+
+			Enhancer enhancer = new Enhancer();
+			enhancer.setSuperclass(type);
+			enhancer.setCallbackType(org.springframework.cglib.proxy.MethodInterceptor.class);
+			enhancer.setInterfaces(new Class[] { LazyLoadingProxy.class });
+
+			Factory factory = (Factory) INSTANCE_CREATOR.newInstance(enhancer.createClass());
+			factory.setCallbacks(new Callback[] { interceptor });
+			return factory;
+		}
+
+		/**
+		 * Strategy for constructing new instances of a given {@link Class}.
+		 * 
+		 * @author Thomas Darimont
+		 */
+		interface InstanceCreatorStrategy {
+			Object newInstance(Class<?> clazz);
+		}
+
+		/**
+		 * An {@link InstanceCreatorStrategy} that uses Objenesis from the classpath.
+		 * 
+		 * @author Thomas Darimont
+		 */
+		private static class DefaultObjenesisInstanceCreatorStrategy implements InstanceCreatorStrategy {
+
+			private static final Objenesis OBJENESIS = new ObjenesisStd(true);
+
+			/*
+			 * (non-Javadoc)
+			 * @see org.springframework.data.mongodb.core.convert.DefaultDbRefResolver.ObjenesisProxyEnhancer.InstanceCreatorStrategy#newInstance(java.lang.Class)
+			 */
+			@Override
+			public Object newInstance(Class<?> clazz) {
+				return OBJENESIS.newInstance(clazz);
+			}
+		}
+
+		/**
+		 * An {@link InstanceCreatorStrategy} that uses a repackaged version of Objenesis from Spring 4.
+		 * 
+		 * @author Thomas Darimont
+		 */
+		private static class Spring4ObjenesisInstanceCreatorStrategy implements InstanceCreatorStrategy {
+
+			private static final String SPRING4_OBJENESIS_CLASS_NAME = "org.springframework.objenesis.ObjenesisStd";
+			private static final Object OBJENESIS;
+			private static final Method NEW_INSTANCE_METHOD;
+
+			static {
+
+				try {
+					Class<?> objenesisClass = ClassUtils.forName(SPRING4_OBJENESIS_CLASS_NAME,
+							ObjenesisProxyEnhancer.class.getClassLoader());
+
+					OBJENESIS = BeanUtils.instantiateClass(objenesisClass.getConstructor(boolean.class), true);
+					NEW_INSTANCE_METHOD = objenesisClass.getMethod("newInstance", Class.class);
+
+				} catch (Exception e) {
+					throw new RuntimeException("Could not setup Objenesis infrastructure with Spring 4 ", e);
+				}
+			}
+
+			/*
+			 * (non-Javadoc)
+			 * @see org.springframework.data.mongodb.core.convert.DefaultDbRefResolver.ObjenesisProxyEnhancer.InstanceCreatorStrategy#newInstance(java.lang.Class)
+			 */
+			@Override
+			public Object newInstance(Class<?> clazz) {
+
+				try {
+					return NEW_INSTANCE_METHOD.invoke(OBJENESIS, clazz);
+				} catch (Exception e) {
+					throw new RuntimeException("Could not created instance for " + clazz, e);
+				}
+			}
+		}
+	}
+}

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/DefaultMongoTypeMapper.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2011 the original author or authors.
+ * Copyright 2011-2013 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -18,16 +18,19 @@ package org.springframework.data.mongodb.core.convert;
 import java.util.Arrays;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 
-import org.springframework.data.convert.SimpleTypeInformationMapper;
 import org.springframework.data.convert.DefaultTypeMapper;
+import org.springframework.data.convert.SimpleTypeInformationMapper;
 import org.springframework.data.convert.TypeAliasAccessor;
 import org.springframework.data.convert.TypeInformationMapper;
 import org.springframework.data.mapping.PersistentEntity;
 import org.springframework.data.mapping.context.MappingContext;
 import org.springframework.data.util.ClassTypeInformation;
 import org.springframework.data.util.TypeInformation;
+
 import com.mongodb.BasicDBList;
+import com.mongodb.BasicDBObject;
 import com.mongodb.DBObject;
 
 /**
@@ -37,33 +40,43 @@ import com.mongodb.DBObject;
  * respectively.
  * 
  * @author Oliver Gierke
+ * @author Thomas Darimont
  */
 public class DefaultMongoTypeMapper extends DefaultTypeMapper<DBObject> implements MongoTypeMapper {
 
 	public static final String DEFAULT_TYPE_KEY = "_class";
-	@SuppressWarnings("rawtypes")
+	@SuppressWarnings("rawtypes")//
 	private static final TypeInformation<List> LIST_TYPE_INFO = ClassTypeInformation.from(List.class);
-	@SuppressWarnings("rawtypes")
+	@SuppressWarnings("rawtypes")//
 	private static final TypeInformation<Map> MAP_TYPE_INFO = ClassTypeInformation.from(Map.class);
-	private String typeKey = DEFAULT_TYPE_KEY;
+
+	private final TypeAliasAccessor<DBObject> accessor;
+	private final String typeKey;
 
 	public DefaultMongoTypeMapper() {
-		this(DEFAULT_TYPE_KEY, Arrays.asList(SimpleTypeInformationMapper.INSTANCE));
+		this(DEFAULT_TYPE_KEY);
 	}
 
 	public DefaultMongoTypeMapper(String typeKey) {
-		super(new DBObjectTypeAliasAccessor(typeKey));
-		this.typeKey = typeKey;
+		this(typeKey, Arrays.asList(SimpleTypeInformationMapper.INSTANCE));
 	}
 
 	public DefaultMongoTypeMapper(String typeKey, MappingContext<? extends PersistentEntity<?, ?>, ?> mappingContext) {
-		super(new DBObjectTypeAliasAccessor(typeKey), mappingContext, Arrays.asList(SimpleTypeInformationMapper.INSTANCE));
-		this.typeKey = typeKey;
+		this(typeKey, new DBObjectTypeAliasAccessor(typeKey), mappingContext, Arrays
+				.asList(SimpleTypeInformationMapper.INSTANCE));
 	}
 
 	public DefaultMongoTypeMapper(String typeKey, List<? extends TypeInformationMapper> mappers) {
-		super(new DBObjectTypeAliasAccessor(typeKey), mappers);
+		this(typeKey, new DBObjectTypeAliasAccessor(typeKey), null, mappers);
+	}
+
+	private DefaultMongoTypeMapper(String typeKey, TypeAliasAccessor<DBObject> accessor,
+			MappingContext<? extends PersistentEntity<?, ?>, ?> mappingContext, List<? extends TypeInformationMapper> mappers) {
+
+		super(accessor, mappingContext, mappers);
+
 		this.typeKey = typeKey;
+		this.accessor = accessor;
 	}
 
 	/*
@@ -74,6 +87,31 @@ public class DefaultMongoTypeMapper extends DefaultTypeMapper<DBObject> implemen
 		return typeKey == null ? false : typeKey.equals(key);
 	}
 
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.convert.MongoTypeMapper#writeTypeRestrictions(java.util.Set)
+	 */
+	@Override
+	public void writeTypeRestrictions(DBObject result, Set<Class<?>> restrictedTypes) {
+
+		if (restrictedTypes == null || restrictedTypes.isEmpty()) {
+			return;
+		}
+
+		BasicDBList restrictedMappedTypes = new BasicDBList();
+
+		for (Class<?> restrictedType : restrictedTypes) {
+
+			Object typeAlias = getAliasFor(ClassTypeInformation.from(restrictedType));
+
+			if (typeAlias != null) {
+				restrictedMappedTypes.add(typeAlias);
+			}
+		}
+
+		accessor.writeTypeTo(result, new BasicDBObject("$in", restrictedMappedTypes));
+	}
+
 	/* (non-Javadoc)
 	 * @see org.springframework.data.convert.DefaultTypeMapper#getFallbackTypeFor(java.lang.Object)
 	 */
@@ -83,6 +121,7 @@ public class DefaultMongoTypeMapper extends DefaultTypeMapper<DBObject> implemen
 	}
 
 	/**
+	 * {@link TypeAliasAccessor} to store aliases in a {@link DBObject}.
 	 * 
 	 * @author Oliver Gierke
 	 */

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/LazyLoadingProxy.java

@@ -0,0 +1,45 @@
+/*
+ * Copyright 2014 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.mongodb.core.convert;
+
+import org.springframework.data.mongodb.core.convert.DefaultDbRefResolver.LazyLoadingInterceptor;
+
+import com.mongodb.DBRef;
+
+/**
+ * Allows direct interaction with the underlying {@link LazyLoadingInterceptor}.
+ * 
+ * @author Thomas Darimont
+ * @since 1.5
+ */
+public interface LazyLoadingProxy {
+
+	/**
+	 * Initializes the proxy and returns the wrapped value.
+	 * 
+	 * @return
+	 * @since 1.5
+	 */
+	Object initialize();
+
+	/**
+	 * Returns the {@link DBRef} represented by this {@link LazyLoadingProxy}, may be null.
+	 * 
+	 * @return
+	 * @since 1.5
+	 */
+	DBRef toDBRef();
+}

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/MappingMongoConverter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2011-2013 by the original author(s).
+ * Copyright 2011-2014 by the original author(s).
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -19,6 +19,8 @@ import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
+import java.util.EnumMap;
+import java.util.EnumSet;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
@@ -57,11 +59,9 @@ import org.springframework.data.util.TypeInformation;
 import org.springframework.expression.spel.standard.SpelExpressionParser;
 import org.springframework.util.Assert;
 import org.springframework.util.CollectionUtils;
-import org.springframework.util.StringUtils;
 
 import com.mongodb.BasicDBList;
 import com.mongodb.BasicDBObject;
-import com.mongodb.DB;
 import com.mongodb.DBObject;
 import com.mongodb.DBRef;
 
@@ -72,15 +72,17 @@ import com.mongodb.DBRef;
  * @author Oliver Gierke
  * @author Jon Brisbin
  * @author Patrik Wasik
+ * @author Thomas Darimont
+ * @author Christoph Strobl
  */
 public class MappingMongoConverter extends AbstractMongoConverter implements ApplicationContextAware {
 
-	protected static final Logger log = LoggerFactory.getLogger(MappingMongoConverter.class);
+	protected static final Logger LOGGER = LoggerFactory.getLogger(MappingMongoConverter.class);
 
 	protected final MappingContext<? extends MongoPersistentEntity<?>, MongoPersistentProperty> mappingContext;
 	protected final SpelExpressionParser spelExpressionParser = new SpelExpressionParser();
-	protected final MongoDbFactory mongoDbFactory;
 	protected final QueryMapper idMapper;
+	protected final DbRefResolver dbRefResolver;
 	protected ApplicationContext applicationContext;
 	protected boolean useFieldAccessOnly = true;
 	protected MongoTypeMapper typeMapper;
@@ -89,21 +91,21 @@ public class MappingMongoConverter extends AbstractMongoConverter implements App
 	private SpELContext spELContext;
 
 	/**
-	 * Creates a new {@link MappingMongoConverter} given the new {@link MongoDbFactory} and {@link MappingContext}.
+	 * Creates a new {@link MappingMongoConverter} given the new {@link DbRefResolver} and {@link MappingContext}.
 	 * 
 	 * @param mongoDbFactory must not be {@literal null}.
 	 * @param mappingContext must not be {@literal null}.
 	 */
 	@SuppressWarnings("deprecation")
-	public MappingMongoConverter(MongoDbFactory mongoDbFactory,
+	public MappingMongoConverter(DbRefResolver dbRefResolver,
 			MappingContext<? extends MongoPersistentEntity<?>, MongoPersistentProperty> mappingContext) {
 
 		super(ConversionServiceFactory.createDefaultConversionService());
 
-		Assert.notNull(mongoDbFactory);
-		Assert.notNull(mappingContext);
+		Assert.notNull(dbRefResolver, "DbRefResolver must not be null!");
+		Assert.notNull(mappingContext, "MappingContext must not be null!");
 
-		this.mongoDbFactory = mongoDbFactory;
+		this.dbRefResolver = dbRefResolver;
 		this.mappingContext = mappingContext;
 		this.typeMapper = new DefaultMongoTypeMapper(DefaultMongoTypeMapper.DEFAULT_TYPE_KEY, mappingContext);
 		this.idMapper = new QueryMapper(this);
@@ -111,6 +113,19 @@ public class MappingMongoConverter extends AbstractMongoConverter implements App
 		this.spELContext = new SpELContext(DBObjectPropertyAccessor.INSTANCE);
 	}
 
+	/**
+	 * Creates a new {@link MappingMongoConverter} given the new {@link MongoDbFactory} and {@link MappingContext}.
+	 * 
+	 * @deprecated use the constructor taking a {@link DbRefResolver} instead.
+	 * @param mongoDbFactory must not be {@literal null}.
+	 * @param mappingContext must not be {@literal null}.
+	 */
+	@Deprecated
+	public MappingMongoConverter(MongoDbFactory mongoDbFactory,
+			MappingContext<? extends MongoPersistentEntity<?>, MongoPersistentProperty> mappingContext) {
+		this(new DefaultDbRefResolver(mongoDbFactory), mappingContext);
+	}
+
 	/**
 	 * Configures the {@link MongoTypeMapper} to be used to add type information to {@link DBObject}s created by the
 	 * converter and how to lookup type information from {@link DBObject}s when reading them. Uses a
@@ -124,6 +139,15 @@ public class MappingMongoConverter extends AbstractMongoConverter implements App
 				mappingContext) : typeMapper;
 	}
 
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.convert.MongoConverter#getTypeMapper()
+	 */
+	@Override
+	public MongoTypeMapper getTypeMapper() {
+		return this.typeMapper;
+	}
+
 	/**
 	 * Configure the characters dots potentially contained in a {@link Map} shall be replaced with. By default we don't do
 	 * any translation but rather reject a {@link Map} with keys containing dots causing the conversion for the entire
@@ -224,7 +248,7 @@ public class MappingMongoConverter extends AbstractMongoConverter implements App
 				parent);
 	}
 
-	private <S extends Object> S read(final MongoPersistentEntity<S> entity, final DBObject dbo, Object parent) {
+	private <S extends Object> S read(final MongoPersistentEntity<S> entity, final DBObject dbo, final Object parent) {
 
 		final DefaultSpELExpressionEvaluator evaluator = new DefaultSpELExpressionEvaluator(dbo, spELContext);
 
@@ -251,11 +275,20 @@ public class MappingMongoConverter extends AbstractMongoConverter implements App
 		// Handle associations
 		entity.doWithAssociations(new AssociationHandler<MongoPersistentProperty>() {
 			public void doWithAssociation(Association<MongoPersistentProperty> association) {
-				MongoPersistentProperty inverseProp = association.getInverse();
-				Object obj = getValueInternal(inverseProp, dbo, evaluator, result);
 
-				wrapper.setProperty(inverseProp, obj);
+				MongoPersistentProperty property = association.getInverse();
 
+				Object value = dbo.get(property.getName());
+				DBRef dbref = value instanceof DBRef ? (DBRef) value : null;
+				Object obj = dbRefResolver.resolveDbRef(property, dbref, new DbRefResolverCallback() {
+
+					@Override
+					public Object resolve(MongoPersistentProperty property) {
+						return getValueInternal(property, dbo, evaluator, parent);
+					}
+				});
+
+				wrapper.setProperty(property, obj);
 			}
 		});
 
@@ -275,7 +308,12 @@ public class MappingMongoConverter extends AbstractMongoConverter implements App
 			Assert.isTrue(annotation != null, "The referenced property has to be mapped with @DBRef!");
 		}
 
-		return createDBRef(object, annotation);
+		// @see DATAMONGO-913
+		if (object instanceof LazyLoadingProxy) {
+			return ((LazyLoadingProxy) object).toDBRef();
+		}
+
+		return createDBRef(object, referingProperty);
 	}
 
 	/**
@@ -356,8 +394,7 @@ public class MappingMongoConverter extends AbstractMongoConverter implements App
 			try {
 				Object id = wrapper.getProperty(idProperty, Object.class, fieldAccessOnly);
 				dbo.put("_id", idMapper.convertId(id));
-			} catch (ConversionException ignored) {
-			}
+			} catch (ConversionException ignored) {}
 		}
 
 		// Write the properties
@@ -373,10 +410,11 @@ public class MappingMongoConverter extends AbstractMongoConverter implements App
 				Object propertyObj = wrapper.getProperty(prop, prop.getType(), fieldAccessOnly);
 
 				if (null != propertyObj) {
+
 					if (!conversions.isSimpleType(propertyObj.getClass())) {
 						writePropertyInternal(propertyObj, dbo, prop);
 					} else {
-						writeSimpleInternal(propertyObj, dbo, prop.getFieldName());
+						writeSimpleInternal(propertyObj, dbo, prop);
 					}
 				}
 			}
@@ -401,46 +439,68 @@ public class MappingMongoConverter extends AbstractMongoConverter implements App
 			return;
 		}
 
-		String name = prop.getFieldName();
+		DBObjectAccessor accessor = new DBObjectAccessor(dbo);
+
 		TypeInformation<?> valueType = ClassTypeInformation.from(obj.getClass());
 		TypeInformation<?> type = prop.getTypeInformation();
 
 		if (valueType.isCollectionLike()) {
 			DBObject collectionInternal = createCollection(asCollection(obj), prop);
-			dbo.put(name, collectionInternal);
+			accessor.put(prop, collectionInternal);
 			return;
 		}
 
 		if (valueType.isMap()) {
 			DBObject mapDbObj = createMap((Map<Object, Object>) obj, prop);
-			dbo.put(name, mapDbObj);
+			accessor.put(prop, mapDbObj);
 			return;
 		}
 
 		if (prop.isDbReference()) {
-			DBRef dbRefObj = createDBRef(obj, prop.getDBRef());
+
+			DBRef dbRefObj = null;
+
+			/*
+			 * If we already have a LazyLoadingProxy, we use it's cached DBRef value instead of 
+			 * unnecessarily initializing it only to convert it to a DBRef a few instructions later.
+			 */
+			if (obj instanceof LazyLoadingProxy) {
+				dbRefObj = ((LazyLoadingProxy) obj).toDBRef();
+			}
+
+			dbRefObj = dbRefObj != null ? dbRefObj : createDBRef(obj, prop);
+
 			if (null != dbRefObj) {
-				dbo.put(name, dbRefObj);
+				accessor.put(prop, dbRefObj);
 				return;
 			}
 		}
 
+		/*
+		 * If we have a LazyLoadingProxy we make sure it is initialized first.
+		 */
+		if (obj instanceof LazyLoadingProxy) {
+			obj = ((LazyLoadingProxy) obj).initialize();
+		}
+
 		// Lookup potential custom target type
 		Class<?> basicTargetType = conversions.getCustomWriteTarget(obj.getClass(), null);
 
 		if (basicTargetType != null) {
-			dbo.put(name, conversionService.convert(obj, basicTargetType));
+			accessor.put(prop, conversionService.convert(obj, basicTargetType));
 			return;
 		}
 
-		BasicDBObject propDbObj = new BasicDBObject();
+		Object existingValue = accessor.get(prop);
+		BasicDBObject propDbObj = existingValue instanceof BasicDBObject ? (BasicDBObject) existingValue
+				: new BasicDBObject();
 		addCustomTypeKeyIfNecessary(type, obj, propDbObj);
 
 		MongoPersistentEntity<?> entity = isSubtype(prop.getType(), obj.getClass()) ? mappingContext
 				.getPersistentEntity(obj.getClass()) : mappingContext.getPersistentEntity(type);
 
 		writeInternal(obj, propDbObj, entity);
-		dbo.put(name, propDbObj);
+		accessor.put(prop, propDbObj);
 	}
 
 	private boolean isSubtype(Class<?> left, Class<?> right) {
@@ -485,7 +545,7 @@ public class MappingMongoConverter extends AbstractMongoConverter implements App
 				continue;
 			}
 
-			DBRef dbRef = createDBRef(element, property.getDBRef());
+			DBRef dbRef = createDBRef(element, property);
 			dbList.add(dbRef);
 		}
 
@@ -518,7 +578,7 @@ public class MappingMongoConverter extends AbstractMongoConverter implements App
 			if (conversions.isSimpleType(key.getClass())) {
 
 				String simpleKey = potentiallyEscapeMapKey(key.toString());
-				dbObject.put(simpleKey, value != null ? createDBRef(value, property.getDBRef()) : null);
+				dbObject.put(simpleKey, value != null ? createDBRef(value, property) : null);
 
 			} else {
 				throw new MappingException("Cannot use a complex object as a key value.");
@@ -638,7 +698,7 @@ public class MappingMongoConverter extends AbstractMongoConverter implements App
 	 */
 	protected void addCustomTypeKeyIfNecessary(TypeInformation<?> type, Object value, DBObject dbObject) {
 
-		TypeInformation<?> actualType = type != null ? type.getActualType() : type;
+		TypeInformation<?> actualType = type != null ? type.getActualType() : null;
 		Class<?> reference = actualType == null ? Object.class : actualType.getType();
 
 		boolean notTheSameClass = !value.getClass().equals(reference);
@@ -658,6 +718,11 @@ public class MappingMongoConverter extends AbstractMongoConverter implements App
 		dbObject.put(key, getPotentiallyConvertedSimpleWrite(value));
 	}
 
+	private void writeSimpleInternal(Object value, DBObject dbObject, MongoPersistentProperty property) {
+		DBObjectAccessor accessor = new DBObjectAccessor(dbObject);
+		accessor.put(property, getPotentiallyConvertedSimpleWrite(value));
+	}
+
 	/**
 	 * Checks whether we have a custom conversion registered for the given value into an arbitrary simple Mongo type.
 	 * Returns the converted value if so. If not, we perform special enum handling or simply return the value as is.
@@ -706,7 +771,7 @@ public class MappingMongoConverter extends AbstractMongoConverter implements App
 		return target.isAssignableFrom(value.getClass()) ? value : conversionService.convert(value, target);
 	}
 
-	protected DBRef createDBRef(Object target, org.springframework.data.mongodb.core.mapping.DBRef dbref) {
+	protected DBRef createDBRef(Object target, MongoPersistentProperty property) {
 
 		Assert.notNull(target);
 
@@ -715,6 +780,7 @@ public class MappingMongoConverter extends AbstractMongoConverter implements App
 		}
 
 		MongoPersistentEntity<?> targetEntity = mappingContext.getPersistentEntity(target.getClass());
+		targetEntity = targetEntity == null ? targetEntity = mappingContext.getPersistentEntity(property) : targetEntity;
 
 		if (null == targetEntity) {
 			throw new MappingException("No mapping metadata found for " + target.getClass());
@@ -726,17 +792,21 @@ public class MappingMongoConverter extends AbstractMongoConverter implements App
 			throw new MappingException("No id property found on class " + targetEntity.getType());
 		}
 
-		BeanWrapper<MongoPersistentEntity<Object>, Object> wrapper = BeanWrapper.create(target, conversionService);
-		Object id = wrapper.getProperty(idProperty, Object.class, useFieldAccessOnly);
+		Object id = null;
+
+		if (target.getClass().equals(idProperty.getType())) {
+			id = target;
+		} else {
+			BeanWrapper<MongoPersistentEntity<Object>, Object> wrapper = BeanWrapper.create(target, conversionService);
+			id = wrapper.getProperty(idProperty, Object.class, useFieldAccessOnly);
+		}
 
 		if (null == id) {
 			throw new MappingException("Cannot create a reference to an object with a NULL id.");
 		}
 
-		DB db = mongoDbFactory.getDb();
-		db = dbref != null && StringUtils.hasText(dbref.db()) ? mongoDbFactory.getDb(dbref.db()) : db;
-
-		return new DBRef(db, targetEntity.getCollection(), idMapper.convertId(id));
+		return dbRefResolver.createDbRef(property == null ? null : property.getDBRef(), targetEntity,
+				idMapper.convertId(id));
 	}
 
 	protected Object getValueInternal(MongoPersistentProperty prop, DBObject dbo, SpELExpressionEvaluator eval,
@@ -753,7 +823,7 @@ public class MappingMongoConverter extends AbstractMongoConverter implements App
 	 * @param sourceValue must not be {@literal null}.
 	 * @return the converted {@link Collection} or array, will never be {@literal null}.
 	 */
-	@SuppressWarnings("unchecked")
+	@SuppressWarnings({ "unchecked", "null" })
 	private Object readCollectionOrArray(TypeInformation<?> targetType, BasicDBList sourceValue, Object parent) {
 
 		Assert.notNull(targetType);
@@ -766,17 +836,26 @@ public class MappingMongoConverter extends AbstractMongoConverter implements App
 
 		collectionType = Collection.class.isAssignableFrom(collectionType) ? collectionType : List.class;
 
-		Collection<Object> items = targetType.getType().isArray() ? new ArrayList<Object>() : CollectionFactory
-				.createCollection(collectionType, sourceValue.size());
 		TypeInformation<?> componentType = targetType.getComponentType();
 		Class<?> rawComponentType = componentType == null ? null : componentType.getType();
 
+		Collection<Object> items;
+
+		if (targetType.getType().isArray()) {
+			items = new ArrayList<Object>();
+		} else if (EnumSet.class.isAssignableFrom(collectionType)) {
+			Assert.notNull(rawComponentType, "Component type must not be null for enum sets!");
+			items = EnumSet.noneOf(rawComponentType.asSubclass(Enum.class));
+		} else {
+			items = CollectionFactory.createCollection(collectionType, sourceValue.size());
+		}
+
 		for (int i = 0; i < sourceValue.size(); i++) {
 
 			Object dbObjItem = sourceValue.get(i);
 
 			if (dbObjItem instanceof DBRef) {
-				items.add(DBRef.class.equals(rawComponentType) ? dbObjItem : read(componentType, ((DBRef) dbObjItem).fetch(),
+				items.add(DBRef.class.equals(rawComponentType) ? dbObjItem : read(componentType, readRef((DBRef) dbObjItem),
 						parent));
 			} else if (dbObjItem instanceof DBObject) {
 				items.add(read(componentType, (DBObject) dbObjItem, parent));
@@ -795,36 +874,48 @@ public class MappingMongoConverter extends AbstractMongoConverter implements App
 	 * @param dbObject
 	 * @return
 	 */
-	@SuppressWarnings("unchecked")
+	@SuppressWarnings({ "unchecked", "null", "rawtypes" })
 	protected Map<Object, Object> readMap(TypeInformation<?> type, DBObject dbObject, Object parent) {
 
 		Assert.notNull(dbObject);
 
 		Class<?> mapType = typeMapper.readType(dbObject, type).getType();
-		Map<Object, Object> map = CollectionFactory.createMap(mapType, dbObject.keySet().size());
+
+		TypeInformation<?> keyType = type.getComponentType();
+		Class<?> rawKeyType = keyType == null ? null : keyType.getType();
+
+		TypeInformation<?> valueType = type.getMapValueType();
+		Class<?> rawValueType = valueType == null ? null : valueType.getType();
+
+		Map<Object, Object> map;
+
+		if (EnumMap.class.isAssignableFrom(mapType)) {
+			Assert.notNull(keyType, "Key type must nut be null for enum maps!");
+			map = new EnumMap(rawKeyType.asSubclass(Enum.class));
+		} else {
+			map = CollectionFactory.createMap(mapType, dbObject.keySet().size());
+		}
+
 		Map<String, Object> sourceMap = dbObject.toMap();
 
 		for (Entry<String, Object> entry : sourceMap.entrySet()) {
+
 			if (typeMapper.isTypeKey(entry.getKey())) {
 				continue;
 			}
 
 			Object key = potentiallyUnescapeMapKey(entry.getKey());
 
-			TypeInformation<?> keyTypeInformation = type.getComponentType();
-			if (keyTypeInformation != null) {
-				Class<?> keyType = keyTypeInformation.getType();
-				key = conversionService.convert(key, keyType);
+			if (rawKeyType != null) {
+				key = conversionService.convert(key, rawKeyType);
 			}
 
 			Object value = entry.getValue();
-			TypeInformation<?> valueType = type.getMapValueType();
-			Class<?> rawValueType = valueType == null ? null : valueType.getType();
 
 			if (value instanceof DBObject) {
 				map.put(key, read(valueType, (DBObject) value, parent));
 			} else if (value instanceof DBRef) {
-				map.put(key, DBRef.class.equals(rawValueType) ? value : read(valueType, ((DBRef) value).fetch()));
+				map.put(key, DBRef.class.equals(rawValueType) ? value : read(valueType, readRef((DBRef) value)));
 			} else {
 				Class<?> valueClass = valueType == null ? null : valueType.getType();
 				map.put(key, getPotentiallyConvertedSimpleRead(value, valueClass));
@@ -870,15 +961,17 @@ public class MappingMongoConverter extends AbstractMongoConverter implements App
 			return getPotentiallyConvertedSimpleWrite(obj);
 		}
 
+		TypeInformation<?> typeHint = typeInformation == null ? ClassTypeInformation.OBJECT : typeInformation;
+
 		if (obj instanceof BasicDBList) {
-			return maybeConvertList((BasicDBList) obj);
+			return maybeConvertList((BasicDBList) obj, typeHint);
 		}
 
 		if (obj instanceof DBObject) {
 			DBObject newValueDbo = new BasicDBObject();
 			for (String vk : ((DBObject) obj).keySet()) {
 				Object o = ((DBObject) obj).get(vk);
-				newValueDbo.put(vk, convertToMongoType(o));
+				newValueDbo.put(vk, convertToMongoType(o, typeHint));
 			}
 			return newValueDbo;
 		}
@@ -886,17 +979,17 @@ public class MappingMongoConverter extends AbstractMongoConverter implements App
 		if (obj instanceof Map) {
 			DBObject result = new BasicDBObject();
 			for (Map.Entry<Object, Object> entry : ((Map<Object, Object>) obj).entrySet()) {
-				result.put(entry.getKey().toString(), convertToMongoType(entry.getValue()));
+				result.put(entry.getKey().toString(), convertToMongoType(entry.getValue(), typeHint));
 			}
 			return result;
 		}
 
 		if (obj.getClass().isArray()) {
-			return maybeConvertList(Arrays.asList((Object[]) obj));
+			return maybeConvertList(Arrays.asList((Object[]) obj), typeHint);
 		}
 
 		if (obj instanceof Collection) {
-			return maybeConvertList((Collection<?>) obj);
+			return maybeConvertList((Collection<?>) obj, typeHint);
 		}
 
 		DBObject newDbo = new BasicDBObject();
@@ -909,11 +1002,13 @@ public class MappingMongoConverter extends AbstractMongoConverter implements App
 		return !obj.getClass().equals(typeInformation.getType()) ? newDbo : removeTypeInfoRecursively(newDbo);
 	}
 
-	public BasicDBList maybeConvertList(Iterable<?> source) {
+	public BasicDBList maybeConvertList(Iterable<?> source, TypeInformation<?> typeInformation) {
+
 		BasicDBList newDbl = new BasicDBList();
 		for (Object element : source) {
-			newDbl.add(convertToMongoType(element));
+			newDbl.add(convertToMongoType(element, typeInformation));
 		}
+
 		return newDbl;
 	}
 
@@ -956,7 +1051,7 @@ public class MappingMongoConverter extends AbstractMongoConverter implements App
 
 	private class MongoDbPropertyValueProvider implements PropertyValueProvider<MongoPersistentProperty> {
 
-		private final DBObject source;
+		private final DBObjectAccessor source;
 		private final SpELExpressionEvaluator evaluator;
 		private final Object parent;
 
@@ -969,7 +1064,7 @@ public class MappingMongoConverter extends AbstractMongoConverter implements App
 			Assert.notNull(source);
 			Assert.notNull(evaluator);
 
-			this.source = source;
+			this.source = new DBObjectAccessor(source);
 			this.evaluator = evaluator;
 			this.parent = parent;
 		}
@@ -981,7 +1076,7 @@ public class MappingMongoConverter extends AbstractMongoConverter implements App
 		public <T> T getPropertyValue(MongoPersistentProperty property) {
 
 			String expression = property.getSpelExpression();
-			Object value = expression != null ? evaluator.evaluate(expression) : source.get(property.getFieldName());
+			Object value = expression != null ? evaluator.evaluate(expression) : source.get(property);
 
 			if (value == null) {
 				return null;
@@ -1034,7 +1129,7 @@ public class MappingMongoConverter extends AbstractMongoConverter implements App
 		if (conversions.hasCustomReadTarget(value.getClass(), rawType)) {
 			return (T) conversionService.convert(value, rawType);
 		} else if (value instanceof DBRef) {
-			return (T) (rawType.equals(DBRef.class) ? value : read(type, ((DBRef) value).fetch(), parent));
+			return (T) (rawType.equals(DBRef.class) ? value : read(type, readRef((DBRef) value), parent));
 		} else if (value instanceof BasicDBList) {
 			return (T) readCollectionOrArray(type, (BasicDBList) value, parent);
 		} else if (value instanceof DBObject) {
@@ -1043,4 +1138,14 @@ public class MappingMongoConverter extends AbstractMongoConverter implements App
 			return (T) getPotentiallyConvertedSimpleRead(value, rawType);
 		}
 	}
+
+	/**
+	 * Performs the fetch operation for the given {@link DBRef}.
+	 * 
+	 * @param ref
+	 * @return
+	 */
+	DBObject readRef(DBRef ref) {
+		return ref.fetch();
+	}
 }

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/MongoConverter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2011 the original author or authors.
+ * Copyright 2010-2013 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -17,6 +17,7 @@ package org.springframework.data.mongodb.core.convert;
 
 import org.springframework.data.convert.EntityConverter;
 import org.springframework.data.convert.EntityReader;
+import org.springframework.data.convert.TypeMapper;
 import org.springframework.data.mongodb.core.mapping.MongoPersistentEntity;
 import org.springframework.data.mongodb.core.mapping.MongoPersistentProperty;
 
@@ -26,9 +27,17 @@ import com.mongodb.DBObject;
  * Central Mongo specific converter interface which combines {@link MongoWriter} and {@link MongoReader}.
  * 
  * @author Oliver Gierke
+ * @author Thomas Darimont
  */
 public interface MongoConverter extends
 		EntityConverter<MongoPersistentEntity<?>, MongoPersistentProperty, Object, DBObject>, MongoWriter<Object>,
 		EntityReader<Object, DBObject> {
 
+	/**
+	 * Returns thw {@link TypeMapper} being used to write type information into {@link DBObject}s created with that
+	 * converter.
+	 * 
+	 * @return will never be {@literal null}.
+	 */
+	MongoTypeMapper getTypeMapper();
 }

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/MongoConverters.java

@@ -24,8 +24,11 @@ import org.bson.types.ObjectId;
 import org.springframework.core.convert.ConversionFailedException;
 import org.springframework.core.convert.TypeDescriptor;
 import org.springframework.core.convert.converter.Converter;
+import org.springframework.data.convert.ReadingConverter;
 import org.springframework.util.StringUtils;
 
+import com.mongodb.DBObject;
+
 /**
  * Wrapper class to contain useful converters for the usage with Mongo.
  * 
@@ -147,4 +150,15 @@ abstract class MongoConverters {
 			}
 		}
 	}
+
+	@ReadingConverter
+	public static enum DBObjectToStringConverter implements Converter<DBObject, String> {
+
+		INSTANCE;
+
+		@Override
+		public String convert(DBObject source) {
+			return source == null ? null : source.toString();
+		}
+	}
 }

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/MongoTypeMapper.java

@@ -15,6 +15,8 @@
  */
 package org.springframework.data.mongodb.core.convert;
 
+import java.util.Set;
+
 import org.springframework.data.convert.TypeMapper;
 
 import com.mongodb.DBObject;
@@ -32,4 +34,14 @@ public interface MongoTypeMapper extends TypeMapper<DBObject> {
 	 * @return
 	 */
 	boolean isTypeKey(String key);
+
+	/**
+	 * Writes type restrictions to the given {@link DBObject}. This usually results in an {@code $in}-clause to be
+	 * generated that restricts the type-key (e.g. {@code _class}) to be in the set of type aliases for the given
+	 * {@code restrictedTypes}.
+	 * 
+	 * @param result must not be {@literal null}
+	 * @param restrictedTypes must not be {@literal null}
+	 */
+	void writeTypeRestrictions(DBObject result, Set<Class<?>> restrictedTypes);
 }

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/QueryMapper.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2011-2013 the original author or authors.
+ * Copyright 2011-2014 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -17,18 +17,27 @@ package org.springframework.data.mongodb.core.convert;
 
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collections;
+import java.util.Iterator;
 import java.util.List;
+import java.util.Map.Entry;
+import java.util.Set;
 
 import org.bson.types.ObjectId;
 import org.springframework.core.convert.ConversionException;
 import org.springframework.core.convert.ConversionService;
+import org.springframework.core.convert.converter.Converter;
+import org.springframework.data.mapping.Association;
 import org.springframework.data.mapping.PersistentEntity;
 import org.springframework.data.mapping.PropertyPath;
 import org.springframework.data.mapping.PropertyReferenceException;
 import org.springframework.data.mapping.context.MappingContext;
 import org.springframework.data.mapping.context.PersistentPropertyPath;
+import org.springframework.data.mapping.model.MappingException;
 import org.springframework.data.mongodb.core.mapping.MongoPersistentEntity;
 import org.springframework.data.mongodb.core.mapping.MongoPersistentProperty;
+import org.springframework.data.mongodb.core.mapping.MongoPersistentProperty.PropertyToFieldNameConverter;
+import org.springframework.data.mongodb.core.query.Query;
 import org.springframework.util.Assert;
 
 import com.mongodb.BasicDBList;
@@ -42,11 +51,12 @@ import com.mongodb.DBRef;
  * @author Jon Brisbin
  * @author Oliver Gierke
  * @author Patryk Wasik
+ * @author Thomas Darimont
+ * @author Christoph Strobl
  */
 public class QueryMapper {
 
 	private static final List<String> DEFAULT_ID_NAMES = Arrays.asList("id", "_id");
-	private static final String N_OR_PATTERN = "\\$.*or";
 
 	private final ConversionService conversionService;
 	private final MongoConverter converter;
@@ -74,9 +84,10 @@ public class QueryMapper {
 	 * @param entity can be {@literal null}.
 	 * @return
 	 */
+	@SuppressWarnings("deprecation")
 	public DBObject getMappedObject(DBObject query, MongoPersistentEntity<?> entity) {
 
-		if (Keyword.isKeyword(query)) {
+		if (isNestedKeyword(query)) {
 			return getMappedKeyword(new Keyword(query), entity);
 		}
 
@@ -84,95 +95,186 @@ public class QueryMapper {
 
 		for (String key : query.keySet()) {
 
-			Field field = entity == null ? new Field(key) : new MetadataBackedField(key, entity, mappingContext);
-			result.put(field.getMappedKey(), getMappedValue(query.get(key), field));
+			// TODO: remove one once QueryMapper can work with Query instances directly
+			if (Query.isRestrictedTypeKey(key)) {
+
+				@SuppressWarnings("unchecked")
+				Set<Class<?>> restrictedTypes = (Set<Class<?>>) query.get(key);
+				this.converter.getTypeMapper().writeTypeRestrictions(result, restrictedTypes);
+
+				continue;
+			}
+
+			if (isKeyword(key)) {
+				result.putAll(getMappedKeyword(new Keyword(query, key), entity));
+				continue;
+			}
+
+			Field field = createPropertyField(entity, key, mappingContext);
+			Entry<String, Object> entry = getMappedObjectForField(field, query.get(key));
+
+			result.put(entry.getKey(), entry.getValue());
 		}
 
 		return result;
 	}
 
+	/**
+	 * Extracts the mapped object value for given field out of rawValue taking nested {@link Keyword}s into account
+	 * 
+	 * @param field
+	 * @param rawValue
+	 * @return
+	 */
+	protected Entry<String, Object> getMappedObjectForField(Field field, Object rawValue) {
+
+		String key = field.getMappedKey();
+		Object value;
+
+		if (isNestedKeyword(rawValue) && !field.isIdField()) {
+			Keyword keyword = new Keyword((DBObject) rawValue);
+			value = getMappedKeyword(field, keyword);
+		} else {
+			value = getMappedValue(field, rawValue);
+		}
+
+		return createMapEntry(key, value);
+	}
+
+	/**
+	 * @param entity
+	 * @param key
+	 * @param mappingContext
+	 * @return
+	 */
+	protected Field createPropertyField(MongoPersistentEntity<?> entity, String key,
+			MappingContext<? extends MongoPersistentEntity<?>, MongoPersistentProperty> mappingContext) {
+		return entity == null ? new Field(key) : new MetadataBackedField(key, entity, mappingContext);
+	}
+
 	/**
 	 * Returns the given {@link DBObject} representing a keyword by mapping the keyword's value.
 	 * 
-	 * @param query the {@link DBObject} representing a keyword (e.g. {@code $ne : … } )
+	 * @param keyword the {@link DBObject} representing a keyword (e.g. {@code $ne : … } )
 	 * @param entity
 	 * @return
 	 */
-	private DBObject getMappedKeyword(Keyword query, MongoPersistentEntity<?> entity) {
+	protected DBObject getMappedKeyword(Keyword keyword, MongoPersistentEntity<?> entity) {
 
 		// $or/$nor
-		if (query.key.matches(N_OR_PATTERN)) {
+		if (keyword.isOrOrNor() || keyword.hasIterableValue()) {
 
-			Iterable<?> conditions = (Iterable<?>) query.value;
+			Iterable<?> conditions = keyword.getValue();
 			BasicDBList newConditions = new BasicDBList();
 
 			for (Object condition : conditions) {
-				newConditions.add(getMappedObject((DBObject) condition, entity));
+				newConditions.add(isDBObject(condition) ? getMappedObject((DBObject) condition, entity)
+						: convertSimpleOrDBObject(condition, entity));
 			}
 
-			return new BasicDBObject(query.key, newConditions);
+			return new BasicDBObject(keyword.getKey(), newConditions);
 		}
 
-		return new BasicDBObject(query.key, convertSimpleOrDBObject(query.value, entity));
+		return new BasicDBObject(keyword.getKey(), convertSimpleOrDBObject(keyword.getValue(), entity));
 	}
 
 	/**
 	 * Returns the mapped keyword considered defining a criteria for the given property.
 	 * 
-	 * @param keyword
 	 * @param property
+	 * @param keyword
 	 * @return
 	 */
-	public DBObject getMappedKeyword(Keyword keyword, Field property) {
+	protected DBObject getMappedKeyword(Field property, Keyword keyword) {
 
-		if (property.isAssociation()) {
-			convertAssociation(keyword.value, property.getProperty());
-		}
+		boolean needsAssociationConversion = property.isAssociation() && !keyword.isExists();
+		Object value = keyword.getValue();
 
-		return new BasicDBObject(keyword.key, getMappedValue(keyword.value, property.with(keyword.key)));
+		Object convertedValue = needsAssociationConversion ? convertAssociation(value, property) : getMappedValue(
+				property.with(keyword.getKey()), value);
+
+		return new BasicDBObject(keyword.key, convertedValue);
 	}
 
 	/**
 	 * Returns the mapped value for the given source object assuming it's a value for the given
 	 * {@link MongoPersistentProperty}.
 	 * 
-	 * @param source the source object to be mapped
+	 * @param value the source object to be mapped
 	 * @param property the property the value is a value for
 	 * @param newKey the key the value will be bound to eventually
 	 * @return
 	 */
-	private Object getMappedValue(Object source, Field key) {
+	protected Object getMappedValue(Field documentField, Object value) {
 
-		if (key.isIdField()) {
+		if (documentField.isIdField()) {
+
+			if (isDBObject(value)) {
+				DBObject valueDbo = (DBObject) value;
+				DBObject resultDbo = new BasicDBObject(valueDbo.toMap());
 
-			if (source instanceof DBObject) {
-				DBObject valueDbo = (DBObject) source;
 				if (valueDbo.containsField("$in") || valueDbo.containsField("$nin")) {
 					String inKey = valueDbo.containsField("$in") ? "$in" : "$nin";
 					List<Object> ids = new ArrayList<Object>();
 					for (Object id : (Iterable<?>) valueDbo.get(inKey)) {
 						ids.add(convertId(id));
 					}
-					valueDbo.put(inKey, ids.toArray(new Object[ids.size()]));
+					resultDbo.put(inKey, ids.toArray(new Object[ids.size()]));
 				} else if (valueDbo.containsField("$ne")) {
-					valueDbo.put("$ne", convertId(valueDbo.get("$ne")));
+					resultDbo.put("$ne", convertId(valueDbo.get("$ne")));
 				} else {
-					return getMappedObject((DBObject) source, null);
+					return getMappedObject(resultDbo, null);
 				}
 
-				return valueDbo;
+				return resultDbo;
 
 			} else {
-				return convertId(source);
+				return convertId(value);
 			}
 		}
 
-		if (key.isAssociation()) {
-			return Keyword.isKeyword(source) ? getMappedKeyword(new Keyword(source), key) : convertAssociation(source,
-					key.getProperty());
+		if (isNestedKeyword(value)) {
+			return getMappedKeyword(new Keyword((DBObject) value), null);
 		}
 
-		return convertSimpleOrDBObject(source, key.getPropertyEntity());
+		if (isAssociationConversionNecessary(documentField, value)) {
+			return convertAssociation(value, documentField);
+		}
+
+		return convertSimpleOrDBObject(value, documentField.getPropertyEntity());
+	}
+
+	/**
+	 * Returns whether the given {@link Field} represents an association reference that together with the given value
+	 * requires conversion to a {@link org.springframework.data.mongodb.core.mapping.DBRef} object. We check whether the
+	 * type of the given value is compatible with the type of the given document field in order to deal with potential
+	 * query field exclusions, since MongoDB uses the {@code int} {@literal 0} as an indicator for an excluded field.
+	 * 
+	 * @param documentField must not be {@literal null}.
+	 * @param value
+	 * @return
+	 */
+	protected boolean isAssociationConversionNecessary(Field documentField, Object value) {
+
+		Assert.notNull(documentField, "Document field must not be null!");
+
+		if (value == null) {
+			return false;
+		}
+
+		if (!documentField.isAssociation()) {
+			return false;
+		}
+
+		Class<? extends Object> type = value.getClass();
+		MongoPersistentProperty property = documentField.getProperty();
+
+		if (property.getActualType().isAssignableFrom(type)) {
+			return true;
+		}
+
+		MongoPersistentEntity<?> entity = documentField.getPropertyEntity();
+		return entity.hasIdProperty() && entity.getIdProperty().getActualType().isAssignableFrom(type);
 	}
 
 	/**
@@ -182,36 +284,52 @@ public class QueryMapper {
 	 * @param entity
 	 * @return
 	 */
-	private Object convertSimpleOrDBObject(Object source, MongoPersistentEntity<?> entity) {
+	protected Object convertSimpleOrDBObject(Object source, MongoPersistentEntity<?> entity) {
 
 		if (source instanceof BasicDBList) {
-			return converter.convertToMongoType(source);
+			return delegateConvertToMongoType(source, entity);
 		}
 
-		if (source instanceof DBObject) {
+		if (isDBObject(source)) {
 			return getMappedObject((DBObject) source, entity);
 		}
 
-		return converter.convertToMongoType(source);
+		return delegateConvertToMongoType(source, entity);
 	}
 
 	/**
-	 * Converts the given source assuming it's actually an association to anoter object.
+	 * Converts the given source Object to a mongo type with the type information of the original source type omitted.
+	 * Subclasses may overwrite this method to retain the type information of the source type on the resulting mongo type.
+	 * 
+	 * @param source
+	 * @param entity
+	 * @return the converted mongo type or null if source is null
+	 */
+	protected Object delegateConvertToMongoType(Object source, MongoPersistentEntity<?> entity) {
+		return converter.convertToMongoType(source, entity == null ? null : entity.getTypeInformation());
+	}
+
+	protected Object convertAssociation(Object source, Field field) {
+		return convertAssociation(source, field.getProperty());
+	}
+
+	/**
+	 * Converts the given source assuming it's actually an association to another object.
 	 * 
 	 * @param source
 	 * @param property
 	 * @return
 	 */
-	private Object convertAssociation(Object source, MongoPersistentProperty property) {
+	protected Object convertAssociation(Object source, MongoPersistentProperty property) {
 
-		if (property == null || !property.isAssociation()) {
+		if (property == null || source == null || source instanceof DBRef || source instanceof DBObject) {
 			return source;
 		}
 
 		if (source instanceof Iterable) {
 			BasicDBList result = new BasicDBList();
 			for (Object element : (Iterable<?>) source) {
-				result.add(element instanceof DBRef ? element : converter.toDBRef(element, property));
+				result.add(createDbRefFor(element, property));
 			}
 			return result;
 		}
@@ -220,13 +338,55 @@ public class QueryMapper {
 			BasicDBObject result = new BasicDBObject();
 			DBObject dbObject = (DBObject) source;
 			for (String key : dbObject.keySet()) {
-				Object o = dbObject.get(key);
-				result.put(key, o instanceof DBRef ? o : converter.toDBRef(o, property));
+				result.put(key, createDbRefFor(dbObject.get(key), property));
 			}
 			return result;
 		}
 
-		return source == null || source instanceof DBRef ? source : converter.toDBRef(source, property);
+		return createDbRefFor(source, property);
+	}
+
+	/**
+	 * Checks whether the given value is a {@link DBObject}.
+	 * 
+	 * @param value can be {@literal null}.
+	 * @return
+	 */
+	protected final boolean isDBObject(Object value) {
+		return value instanceof DBObject;
+	}
+
+	/**
+	 * Creates a new {@link Entry} for the given {@link Field} with the given value.
+	 * 
+	 * @param field must not be {@literal null}.
+	 * @param value can be {@literal null}.
+	 * @return
+	 */
+	protected final Entry<String, Object> createMapEntry(Field field, Object value) {
+		return createMapEntry(field.getMappedKey(), value);
+	}
+
+	/**
+	 * Creates a new {@link Entry} with the given key and value.
+	 * 
+	 * @param key must not be {@literal null} or empty.
+	 * @param value can be {@literal null}
+	 * @return
+	 */
+	private Entry<String, Object> createMapEntry(String key, Object value) {
+
+		Assert.hasText(key, "Key must not be null or empty!");
+		return Collections.singletonMap(key, value).entrySet().iterator().next();
+	}
+
+	private DBRef createDbRefFor(Object source, MongoPersistentProperty property) {
+
+		if (source instanceof DBRef) {
+			return (DBRef) source;
+		}
+
+		return converter.toDBRef(source, property);
 	}
 
 	/**
@@ -243,7 +403,40 @@ public class QueryMapper {
 			// Ignore
 		}
 
-		return converter.convertToMongoType(id);
+		return delegateConvertToMongoType(id, null);
+	}
+
+	/**
+	 * Returns whether the given {@link Object} is a keyword, i.e. if it's a {@link DBObject} with a keyword key.
+	 * 
+	 * @param candidate
+	 * @return
+	 */
+	protected boolean isNestedKeyword(Object candidate) {
+
+		if (!(candidate instanceof BasicDBObject)) {
+			return false;
+		}
+
+		BasicDBObject dbObject = (BasicDBObject) candidate;
+		Set<String> keys = dbObject.keySet();
+
+		if (keys.size() != 1) {
+			return false;
+		}
+
+		return isKeyword(keys.iterator().next().toString());
+	}
+
+	/**
+	 * Returns whether the given {@link String} is a MongoDB keyword. The default implementation will check against the
+	 * set of registered keywords returned by {@link #getKeywords()}.
+	 * 
+	 * @param candidate
+	 * @return
+	 */
+	protected boolean isKeyword(String candidate) {
+		return candidate.startsWith("$");
 	}
 
 	/**
@@ -251,38 +444,51 @@ public class QueryMapper {
 	 * 
 	 * @author Oliver Gierke
 	 */
-	private static class Keyword {
+	static class Keyword {
 
-		String key;
-		Object value;
+		private static final String N_OR_PATTERN = "\\$.*or";
 
-		Keyword(Object source) {
+		private final String key;
+		private final Object value;
 
-			Assert.isInstanceOf(DBObject.class, source);
+		public Keyword(DBObject source, String key) {
+			this.key = key;
+			this.value = source.get(key);
+		}
 
-			DBObject value = (DBObject) source;
+		public Keyword(DBObject dbObject) {
 
-			Assert.isTrue(value.keySet().size() == 1, "Keyword must have a single key only!");
+			Set<String> keys = dbObject.keySet();
+			Assert.isTrue(keys.size() == 1, "Can only use a single value DBObject!");
 
-			this.key = value.keySet().iterator().next();
-			this.value = value.get(key);
+			this.key = keys.iterator().next();
+			this.value = dbObject.get(key);
 		}
 
 		/**
-		 * Returns whether the given value actually represents a keyword. If this returns {@literal true} it's safe to call
-		 * the constructor.
+		 * Returns whether the current keyword is the {@code $exists} keyword.
 		 * 
-		 * @param value
 		 * @return
 		 */
-		static boolean isKeyword(Object value) {
+		public boolean isExists() {
+			return "$exists".equalsIgnoreCase(key);
+		}
 
-			if (!(value instanceof DBObject)) {
-				return false;
-			}
+		public boolean isOrOrNor() {
+			return key.matches(N_OR_PATTERN);
+		}
 
-			DBObject dbObject = (DBObject) value;
-			return dbObject.keySet().size() == 1 && dbObject.keySet().iterator().next().startsWith("$");
+		public boolean hasIterableValue() {
+			return value instanceof Iterable;
+		}
+
+		public String getKey() {
+			return key;
+		}
+
+		@SuppressWarnings("unchecked")
+		public <T> T getValue() {
+			return (T) value;
 		}
 	}
 
@@ -291,14 +497,14 @@ public class QueryMapper {
 	 * 
 	 * @author Oliver Gierke
 	 */
-	private static class Field {
+	protected static class Field {
 
 		private static final String ID_KEY = "_id";
 
 		protected final String name;
 
 		/**
-		 * Creates a new {@link Field} without meta-information but the given name.
+		 * Creates a new {@link DocumentField} without meta-information but the given name.
 		 * 
 		 * @param name must not be {@literal null} or empty.
 		 */
@@ -309,7 +515,7 @@ public class QueryMapper {
 		}
 
 		/**
-		 * Returns a new {@link Field} with the given name.
+		 * Returns a new {@link DocumentField} with the given name.
 		 * 
 		 * @param name must not be {@literal null} or empty.
 		 * @return
@@ -328,7 +534,9 @@ public class QueryMapper {
 		}
 
 		/**
-		 * Returns the underlying {@link MongoPersistentProperty} backing the field.
+		 * Returns the underlying {@link MongoPersistentProperty} backing the field. For path traversals this will be the
+		 * property that represents the value to handle. This means it'll be the leaf property for plain paths or the
+		 * association property in case we refer to an association somewhere in the path.
 		 * 
 		 * @return
 		 */
@@ -362,18 +570,36 @@ public class QueryMapper {
 		public String getMappedKey() {
 			return isIdField() ? ID_KEY : name;
 		}
+
+		/**
+		 * Returns whether the field references an association in case it refers to a nested field.
+		 * 
+		 * @return
+		 */
+		public boolean containsAssociation() {
+			return false;
+		}
+
+		public Association<MongoPersistentProperty> getAssociation() {
+			return null;
+		}
 	}
 
 	/**
-	 * Extension of {@link Field} to be backed with mapping metadata.
+	 * Extension of {@link DocumentField} to be backed with mapping metadata.
 	 * 
 	 * @author Oliver Gierke
+	 * @author Thomas Darimont
 	 */
-	private static class MetadataBackedField extends Field {
+	protected static class MetadataBackedField extends Field {
+
+		private static final String INVALID_ASSOCIATION_REFERENCE = "Invalid path reference %s! Associations can only be pointed to directly or via their id property!";
 
 		private final MongoPersistentEntity<?> entity;
 		private final MappingContext<? extends MongoPersistentEntity<?>, MongoPersistentProperty> mappingContext;
 		private final MongoPersistentProperty property;
+		private final PersistentPropertyPath<MongoPersistentProperty> path;
+		private final Association<MongoPersistentProperty> association;
 
 		/**
 		 * Creates a new {@link MetadataBackedField} with the given name, {@link MongoPersistentEntity} and
@@ -385,6 +611,21 @@ public class QueryMapper {
 		 */
 		public MetadataBackedField(String name, MongoPersistentEntity<?> entity,
 				MappingContext<? extends MongoPersistentEntity<?>, MongoPersistentProperty> context) {
+			this(name, entity, context, null);
+		}
+
+		/**
+		 * Creates a new {@link MetadataBackedField} with the given name, {@link MongoPersistentEntity} and
+		 * {@link MappingContext} with the given {@link MongoPersistentProperty}.
+		 * 
+		 * @param name must not be {@literal null} or empty.
+		 * @param entity must not be {@literal null}.
+		 * @param context must not be {@literal null}.
+		 * @param property may be {@literal null}.
+		 */
+		public MetadataBackedField(String name, MongoPersistentEntity<?> entity,
+				MappingContext<? extends MongoPersistentEntity<?>, MongoPersistentProperty> context,
+				MongoPersistentProperty property) {
 
 			super(name);
 
@@ -393,8 +634,9 @@ public class QueryMapper {
 			this.entity = entity;
 			this.mappingContext = context;
 
-			PersistentPropertyPath<MongoPersistentProperty> path = getPath(name);
-			this.property = path == null ? null : path.getLeafProperty();
+			this.path = getPath(name);
+			this.property = path == null ? property : path.getLeafProperty();
+			this.association = findAssociation();
 		}
 
 		/*
@@ -403,7 +645,7 @@ public class QueryMapper {
 		 */
 		@Override
 		public MetadataBackedField with(String name) {
-			return new MetadataBackedField(name, entity, mappingContext);
+			return new MetadataBackedField(name, entity, mappingContext, property);
 		}
 
 		/*
@@ -428,7 +670,7 @@ public class QueryMapper {
 		 */
 		@Override
 		public MongoPersistentProperty getProperty() {
-			return property;
+			return association == null ? property : association.getInverse();
 		}
 
 		/* 
@@ -447,9 +689,34 @@ public class QueryMapper {
 		 */
 		@Override
 		public boolean isAssociation() {
+			return association != null;
+		}
 
-			MongoPersistentProperty property = getProperty();
-			return property == null ? false : property.isAssociation();
+		/* 
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.core.convert.QueryMapper.Field#getAssociation()
+		 */
+		@Override
+		public Association<MongoPersistentProperty> getAssociation() {
+			return association;
+		}
+
+		/**
+		 * Finds the association property in the {@link PersistentPropertyPath}.
+		 * 
+		 * @return
+		 */
+		private final Association<MongoPersistentProperty> findAssociation() {
+
+			if (this.path != null) {
+				for (MongoPersistentProperty p : this.path) {
+					if (p.isAssociation()) {
+						return p.getAssociation();
+					}
+				}
+			}
+
+			return null;
 		}
 
 		/*
@@ -458,19 +725,57 @@ public class QueryMapper {
 		 */
 		@Override
 		public String getMappedKey() {
-
-			PersistentPropertyPath<MongoPersistentProperty> path = getPath(name);
-			return path == null ? name : path.toDotPath(MongoPersistentProperty.PropertyToFieldNameConverter.INSTANCE);
+			return path == null ? name : path.toDotPath(getPropertyConverter());
 		}
 
-		private PersistentPropertyPath<MongoPersistentProperty> getPath(String name) {
+		protected PersistentPropertyPath<MongoPersistentProperty> getPath() {
+			return path;
+		}
+
+		/**
+		 * Returns the {@link PersistentPropertyPath} for the given <code>pathExpression</code>.
+		 * 
+		 * @param pathExpression
+		 * @return
+		 */
+		private PersistentPropertyPath<MongoPersistentProperty> getPath(String pathExpression) {
 
 			try {
-				PropertyPath path = PropertyPath.from(name, entity.getTypeInformation());
-				return mappingContext.getPersistentPropertyPath(path);
+
+				PropertyPath path = PropertyPath.from(pathExpression, entity.getTypeInformation());
+				PersistentPropertyPath<MongoPersistentProperty> propertyPath = mappingContext.getPersistentPropertyPath(path);
+
+				Iterator<MongoPersistentProperty> iterator = propertyPath.iterator();
+				boolean associationDetected = false;
+
+				while (iterator.hasNext()) {
+
+					MongoPersistentProperty property = iterator.next();
+
+					if (property.isAssociation()) {
+						associationDetected = true;
+						continue;
+					}
+
+					if (associationDetected && !property.isIdProperty()) {
+						throw new MappingException(String.format(INVALID_ASSOCIATION_REFERENCE, pathExpression));
+					}
+				}
+
+				return propertyPath;
 			} catch (PropertyReferenceException e) {
 				return null;
 			}
 		}
+
+		/**
+		 * Return the {@link Converter} to be used to created the mapped key. Default implementation will use
+		 * {@link PropertyToFieldNameConverter}.
+		 * 
+		 * @return
+		 */
+		protected Converter<MongoPersistentProperty, String> getPropertyConverter() {
+			return PropertyToFieldNameConverter.INSTANCE;
+		}
 	}
 }

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/UpdateMapper.java

@@ -0,0 +1,275 @@
+/*
+ * Copyright 2013-2014 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.mongodb.core.convert;
+
+import java.util.Arrays;
+import java.util.Iterator;
+import java.util.Map.Entry;
+
+import org.springframework.core.convert.converter.Converter;
+import org.springframework.data.mapping.Association;
+import org.springframework.data.mapping.context.MappingContext;
+import org.springframework.data.mongodb.core.mapping.MongoPersistentEntity;
+import org.springframework.data.mongodb.core.mapping.MongoPersistentProperty;
+import org.springframework.data.mongodb.core.mapping.MongoPersistentProperty.PropertyToFieldNameConverter;
+import org.springframework.data.mongodb.core.query.Query;
+import org.springframework.data.mongodb.core.query.Update.Modifier;
+import org.springframework.data.mongodb.core.query.Update.Modifiers;
+import org.springframework.data.util.ClassTypeInformation;
+import org.springframework.util.Assert;
+
+import com.mongodb.BasicDBObject;
+import com.mongodb.DBObject;
+
+/**
+ * A subclass of {@link QueryMapper} that retains type information on the mongo types.
+ * 
+ * @author Thomas Darimont
+ * @author Oliver Gierke
+ * @author Christoph Strobl
+ */
+public class UpdateMapper extends QueryMapper {
+
+	private final MongoConverter converter;
+
+	/**
+	 * Creates a new {@link UpdateMapper} using the given {@link MongoConverter}.
+	 * 
+	 * @param converter must not be {@literal null}.
+	 */
+	public UpdateMapper(MongoConverter converter) {
+
+		super(converter);
+		this.converter = converter;
+	}
+
+	/**
+	 * Converts the given source object to a mongo type retaining the original type information of the source type on the
+	 * mongo type.
+	 * 
+	 * @see org.springframework.data.mongodb.core.convert.QueryMapper#delegateConvertToMongoType(java.lang.Object,
+	 *      org.springframework.data.mongodb.core.mapping.MongoPersistentEntity)
+	 */
+	@Override
+	protected Object delegateConvertToMongoType(Object source, MongoPersistentEntity<?> entity) {
+		return entity == null ? super.delegateConvertToMongoType(source, null) : converter.convertToMongoType(source,
+				entity.getTypeInformation());
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.convert.QueryMapper#getMappedObjectForField(org.springframework.data.mongodb.core.convert.QueryMapper.Field, java.lang.Object)
+	 */
+	@Override
+	protected Entry<String, Object> getMappedObjectForField(Field field, Object rawValue) {
+
+		if (isDBObject(rawValue)) {
+			return createMapEntry(field, convertSimpleOrDBObject(rawValue, field.getPropertyEntity()));
+		}
+
+		if (isQuery(rawValue)) {
+			return createMapEntry(field,
+					super.getMappedObject(((Query) rawValue).getQueryObject(), field.getPropertyEntity()));
+		}
+
+		if (isUpdateModifier(rawValue)) {
+			return getMappedUpdateModifier(field, rawValue);
+		}
+
+		return super.getMappedObjectForField(field, getMappedValue(field, rawValue));
+	}
+
+	private Entry<String, Object> getMappedUpdateModifier(Field field, Object rawValue) {
+		Object value = null;
+
+		if (rawValue instanceof Modifier) {
+
+			value = getMappedValue((Modifier) rawValue);
+
+		} else if (rawValue instanceof Modifiers) {
+
+			DBObject modificationOperations = new BasicDBObject();
+
+			for (Modifier modifier : ((Modifiers) rawValue).getModifiers()) {
+				modificationOperations.putAll(getMappedValue(modifier).toMap());
+			}
+
+			value = modificationOperations;
+		} else {
+			throw new IllegalArgumentException(String.format("Unable to map value of type '%s'!", rawValue.getClass()));
+		}
+
+		return createMapEntry(field, value);
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.convert.QueryMapper#isAssociationConversionNecessary(org.springframework.data.mongodb.core.convert.QueryMapper.Field, java.lang.Object)
+	 */
+	@Override
+	protected boolean isAssociationConversionNecessary(Field documentField, Object value) {
+		return super.isAssociationConversionNecessary(documentField, value) || documentField.containsAssociation();
+	}
+
+	private boolean isUpdateModifier(Object value) {
+		return value instanceof Modifier || value instanceof Modifiers;
+	}
+
+	private boolean isQuery(Object value) {
+		return value instanceof Query;
+	}
+
+	private DBObject getMappedValue(Modifier modifier) {
+
+		Object value = converter.convertToMongoType(modifier.getValue(), ClassTypeInformation.OBJECT);
+		return new BasicDBObject(modifier.getKey(), value);
+	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.convert.QueryMapper#createPropertyField(org.springframework.data.mongodb.core.mapping.MongoPersistentEntity, java.lang.String, org.springframework.data.mapping.context.MappingContext)
+	 */
+	@Override
+	protected Field createPropertyField(MongoPersistentEntity<?> entity, String key,
+			MappingContext<? extends MongoPersistentEntity<?>, MongoPersistentProperty> mappingContext) {
+
+		return entity == null ? super.createPropertyField(entity, key, mappingContext) : //
+				new MetadataBackedUpdateField(entity, key, mappingContext);
+	}
+
+	/**
+	 * {@link MetadataBackedField} that handles {@literal $} paths inside a field key. We clean up an update key
+	 * containing a {@literal $} before handing it to the super class to make sure property lookups and transformations
+	 * continue to work as expected. We provide a custom property converter to re-applied the cleaned up {@literal $}s
+	 * when constructing the mapped key.
+	 * 
+	 * @author Thomas Darimont
+	 * @author Oliver Gierke
+	 */
+	private static class MetadataBackedUpdateField extends MetadataBackedField {
+
+		private final String key;
+
+		/**
+		 * Creates a new {@link MetadataBackedField} with the given {@link MongoPersistentEntity}, key and
+		 * {@link MappingContext}. We clean up the key before handing it up to the super class to make sure it continues to
+		 * work as expected.
+		 * 
+		 * @param entity must not be {@literal null}.
+		 * @param key must not be {@literal null} or empty.
+		 * @param mappingContext must not be {@literal null}.
+		 */
+		public MetadataBackedUpdateField(MongoPersistentEntity<?> entity, String key,
+				MappingContext<? extends MongoPersistentEntity<?>, MongoPersistentProperty> mappingContext) {
+
+			super(key.replaceAll("\\.\\$", ""), entity, mappingContext);
+			this.key = key;
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.core.convert.QueryMapper.MetadataBackedField#getMappedKey()
+		 */
+		@Override
+		public String getMappedKey() {
+			return this.getPath() == null ? key : super.getMappedKey();
+		}
+
+		/* 
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.core.convert.QueryMapper.MetadataBackedField#getPropertyConverter()
+		 */
+		@Override
+		protected Converter<MongoPersistentProperty, String> getPropertyConverter() {
+			return isAssociation() ? new AssociationConverter(getAssociation()) : new UpdatePropertyConverter(key);
+		}
+
+		/**
+		 * Converter to skip all properties after an association property was rendered.
+		 * 
+		 * @author Oliver Gierke
+		 */
+		private static class AssociationConverter implements Converter<MongoPersistentProperty, String> {
+
+			private final MongoPersistentProperty property;
+			private boolean associationFound;
+
+			/**
+			 * Creates a new {@link AssociationConverter} for the given {@link Association}.
+			 * 
+			 * @param association must not be {@literal null}.
+			 */
+			public AssociationConverter(Association<MongoPersistentProperty> association) {
+
+				Assert.notNull(association, "Association must not be null!");
+				this.property = association.getInverse();
+			}
+
+			/* 
+			 * (non-Javadoc)
+			 * @see org.springframework.core.convert.converter.Converter#convert(java.lang.Object)
+			 */
+			@Override
+			public String convert(MongoPersistentProperty source) {
+
+				if (associationFound) {
+					return null;
+				}
+
+				if (property.equals(source)) {
+					associationFound = true;
+				}
+
+				return source.getFieldName();
+			}
+		}
+
+		/**
+		 * Special {@link Converter} for {@link MongoPersistentProperty} instances that will concatenate the {@literal $}
+		 * contained in the source update key.
+		 * 
+		 * @author Oliver Gierke
+		 */
+		private static class UpdatePropertyConverter implements Converter<MongoPersistentProperty, String> {
+
+			private final Iterator<String> iterator;
+
+			/**
+			 * Creates a new {@link UpdatePropertyConverter} with the given update key.
+			 * 
+			 * @param updateKey must not be {@literal null} or empty.
+			 */
+			public UpdatePropertyConverter(String updateKey) {
+
+				Assert.hasText(updateKey, "Update key must not be null or empty!");
+
+				this.iterator = Arrays.asList(updateKey.split("\\.")).iterator();
+				this.iterator.next();
+			}
+
+			/* 
+			 * (non-Javadoc)
+			 * @see org.springframework.core.convert.converter.Converter#convert(java.lang.Object)
+			 */
+			@Override
+			public String convert(MongoPersistentProperty property) {
+
+				String mappedName = PropertyToFieldNameConverter.INSTANCE.convert(property);
+				return iterator.hasNext() && iterator.next().equals("$") ? String.format("%s.$", mappedName) : mappedName;
+			}
+		}
+	}
+}

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/package-info.java

@@ -0,0 +1,5 @@
+/**
+ * Spring Data MongoDB specific converter infrastructure.
+ */
+package org.springframework.data.mongodb.core.convert;
+

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/geo/GeoResults.java

@@ -131,7 +131,7 @@ public class GeoResults<T> implements Iterable<GeoResult<T>> {
 	private static Distance calculateAverageDistance(List<? extends GeoResult<?>> results, Metric metric) {
 
 		if (results.isEmpty()) {
-			return new Distance(0, null);
+			return new Distance(0, metric);
 		}
 
 		double averageDistance = 0;

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/geo/Point.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2011 the original author or authors.
+ * Copyright 2010-2014 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -30,10 +30,8 @@ import org.springframework.util.Assert;
  */
 public class Point {
 
-	@Field(order = 10)
-	private final double x;
-	@Field(order = 20)
-	private final double y;
+	@Field(order = 10) private final double x;
+	@Field(order = 20) private final double y;
 
 	@PersistenceConstructor
 	public Point(double x, double y) {
@@ -69,9 +67,9 @@ public class Point {
 		int result = 1;
 		long temp;
 		temp = Double.doubleToLongBits(x);
-		result = prime * result + (int) (temp ^ (temp >>> 32));
+		result = prime * result + (int) (temp ^ temp >>> 32);
 		temp = Double.doubleToLongBits(y);
-		result = prime * result + (int) (temp ^ (temp >>> 32));
+		result = prime * result + (int) (temp ^ temp >>> 32);
 		return result;
 	}
 
@@ -98,6 +96,6 @@ public class Point {
 
 	@Override
 	public String toString() {
-		return String.format("Point [latitude=%f, longitude=%f]", x, y);
+		return String.format("Point [x=%f, y=%f]", x, y);
 	}
 }

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/geo/package-info.java

@@ -0,0 +1,5 @@
+/**
+ * Support for MongoDB geo-spatial queries.
+ */
+package org.springframework.data.mongodb.core.geo;
+

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/index/CompoundIndex.java

@@ -27,6 +27,7 @@ import java.lang.annotation.Target;
  * @author Jon Brisbin
  * @author Oliver Gierke
  * @author Philipp Schneider
+ * @author Johno Crawford
  */
 @Target({ ElementType.TYPE })
 @Documented
@@ -50,10 +51,24 @@ public @interface CompoundIndex {
 	@Deprecated
 	IndexDirection direction() default IndexDirection.ASCENDING;
 
+	/**
+	 * @see http://docs.mongodb.org/manual/core/index-unique/
+	 * @return
+	 */
 	boolean unique() default false;
 
+	/**
+	 * If set to true index will skip over any document that is missing the indexed field.
+	 * 
+	 * @see http://docs.mongodb.org/manual/core/index-sparse/
+	 * @return
+	 */
 	boolean sparse() default false;
 
+	/**
+	 * @see http://docs.mongodb.org/manual/core/index-creation/#index-creation-duplicate-dropping
+	 * @return
+	 */
 	boolean dropDups() default false;
 
 	/**
@@ -78,4 +93,12 @@ public @interface CompoundIndex {
 	 * @return
 	 */
 	boolean background() default false;
+
+	/**
+	 * Configures the number of seconds after which the collection should expire. Defaults to -1 for no expiry.
+	 * 
+	 * @see http://docs.mongodb.org/manual/tutorial/expire-data/
+	 * @return
+	 */
+	int expireAfterSeconds() default -1;
 }

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/index/GeoSpatialIndexType.java

@@ -0,0 +1,41 @@
+/*
+ * Copyright 2013 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.mongodb.core.index;
+
+/**
+ * Geoposatial index type.
+ * 
+ * @author Laurent Canet
+ * @author Oliver Gierke
+ * @since 1.4
+ */
+public enum GeoSpatialIndexType {
+
+	/**
+	 * Simple 2-Dimensional index for legacy-format points.
+	 */
+	GEO_2D,
+
+	/**
+	 * 2D Index for GeoJSON-formatted data over a sphere. Only available in Mongo 2.4.
+	 */
+	GEO_2DSPHERE,
+
+	/**
+	 * An haystack index for grouping results over small results.
+	 */
+	GEO_HAYSTACK
+}

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/index/GeoSpatialIndexed.java

@@ -1,11 +1,11 @@
 /*
- * Copyright (c) 2011 by the original author(s).
+ * Copyright 2010-2013 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
- *     http://www.apache.org/licenses/LICENSE-2.0
+ *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
@@ -13,7 +13,6 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-
 package org.springframework.data.mongodb.core.index;
 
 import java.lang.annotation.ElementType;
@@ -24,7 +23,8 @@ import java.lang.annotation.Target;
 /**
  * Mark a field to be indexed using MongoDB's geospatial indexing feature.
  * 
- * @author Jon Brisbin <jbrisbin@vmware.com>
+ * @author Jon Brisbin
+ * @author Laurent Canet
  */
 @Target(ElementType.FIELD)
 @Retention(RetentionPolicy.RUNTIME)
@@ -65,4 +65,27 @@ public @interface GeoSpatialIndexed {
 	 */
 	int bits() default 26;
 
+	/**
+	 * The type of the geospatial index. Default is {@link GeoSpatialIndexType#GEO_2D}
+	 * 
+	 * @since 1.4
+	 * @return
+	 */
+	GeoSpatialIndexType type() default GeoSpatialIndexType.GEO_2D;
+
+	/**
+	 * The bucket size for {@link GeoSpatialIndexType#GEO_HAYSTACK} indexes, in coordinate units.
+	 * 
+	 * @since 1.4
+	 * @return
+	 */
+	double bucketSize() default 1.0;
+
+	/**
+	 * The name of the additional field to use for {@link GeoSpatialIndexType#GEO_HAYSTACK} indexes
+	 * 
+	 * @since 1.4
+	 * @return
+	 */
+	String additionalField() default "";
 }

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/index/GeospatialIndex.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2011 the original author or authors.
+ * Copyright 2010-2013 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,6 +16,7 @@
 package org.springframework.data.mongodb.core.index;
 
 import org.springframework.util.Assert;
+import org.springframework.util.StringUtils;
 
 import com.mongodb.BasicDBObject;
 import com.mongodb.DBObject;
@@ -25,14 +26,18 @@ import com.mongodb.DBObject;
  * 
  * @author Jon Brisbin
  * @author Oliver Gierke
+ * @author Laurent Canet
  */
 public class GeospatialIndex implements IndexDefinition {
 
 	private final String field;
 	private String name;
-	private Integer min = null;
-	private Integer max = null;
-	private Integer bits = null;
+	private Integer min;
+	private Integer max;
+	private Integer bits;
+	private GeoSpatialIndexType type = GeoSpatialIndexType.GEO_2D;
+	private Double bucketSize = 1.0;
+	private String additionalField;
 
 	/**
 	 * Creates a new {@link GeospatialIndex} for the given field.
@@ -40,52 +45,146 @@ public class GeospatialIndex implements IndexDefinition {
 	 * @param field must not be empty or {@literal null}.
 	 */
 	public GeospatialIndex(String field) {
-		Assert.hasText(field);
+
+		Assert.hasText(field, "Field must have text!");
+
 		this.field = field;
 	}
 
+	/**
+	 * @param name must not be {@literal null} or empty.
+	 * @return
+	 */
 	public GeospatialIndex named(String name) {
+
+		Assert.hasText(name, "Name must have text!");
+
 		this.name = name;
 		return this;
 	}
 
+	/**
+	 * @param min
+	 * @return
+	 */
 	public GeospatialIndex withMin(int min) {
 		this.min = Integer.valueOf(min);
 		return this;
 	}
 
+	/**
+	 * @param max
+	 * @return
+	 */
 	public GeospatialIndex withMax(int max) {
 		this.max = Integer.valueOf(max);
 		return this;
 	}
 
+	/**
+	 * @param bits
+	 * @return
+	 */
 	public GeospatialIndex withBits(int bits) {
 		this.bits = Integer.valueOf(bits);
 		return this;
 	}
 
+	/**
+	 * @param type must not be {@literal null}.
+	 * @return
+	 */
+	public GeospatialIndex typed(GeoSpatialIndexType type) {
+
+		Assert.notNull(type, "Type must not be null!");
+
+		this.type = type;
+		return this;
+	}
+
+	/**
+	 * @param bucketSize
+	 * @return
+	 */
+	public GeospatialIndex withBucketSize(double bucketSize) {
+		this.bucketSize = bucketSize;
+		return this;
+	}
+
+	/**
+	 * @param fieldName.
+	 * @return
+	 */
+	public GeospatialIndex withAdditionalField(String fieldName) {
+		this.additionalField = fieldName;
+		return this;
+	}
+
 	public DBObject getIndexKeys() {
+
 		DBObject dbo = new BasicDBObject();
-		dbo.put(field, "2d");
+
+		switch (type) {
+
+			case GEO_2D:
+				dbo.put(field, "2d");
+				break;
+
+			case GEO_2DSPHERE:
+				dbo.put(field, "2dsphere");
+				break;
+
+			case GEO_HAYSTACK:
+				dbo.put(field, "geoHaystack");
+				if (!StringUtils.hasText(additionalField)) {
+					throw new IllegalArgumentException("When defining geoHaystack index, an additionnal field must be defined");
+				}
+				dbo.put(additionalField, 1);
+				break;
+
+			default:
+				throw new IllegalArgumentException("Unsupported geospatial index " + type);
+		}
+
 		return dbo;
 	}
 
 	public DBObject getIndexOptions() {
-		if (name == null && min == null && max == null) {
+
+		if (name == null && min == null && max == null && bucketSize == null) {
 			return null;
 		}
+
 		DBObject dbo = new BasicDBObject();
 		if (name != null) {
 			dbo.put("name", name);
 		}
-		if (min != null) {
-			dbo.put("min", min);
-		}
-		if (max != null) {
-			dbo.put("max", max);
-		}
-		if (bits != null) {
-			dbo.put("bits", bits);
+
+		switch (type) {
+
+			case GEO_2D:
+
+				if (min != null) {
+					dbo.put("min", min);
+				}
+				if (max != null) {
+					dbo.put("max", max);
+				}
+				if (bits != null) {
+					dbo.put("bits", bits);
+				}
+				break;
+
+			case GEO_2DSPHERE:
+
+				break;
+
+			case GEO_HAYSTACK:
+
+				if (bucketSize != null) {
+					dbo.put("bucketSize", bucketSize);
+				}
+				break;
 		}
 		return dbo;
 	}

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/index/Index.java

@@ -41,8 +41,7 @@ public class Index implements IndexDefinition {
 
 	private boolean sparse = false;
 
-	public Index() {
-	}
+	public Index() {}
 
 	public Index(String key, Direction direction) {
 		fieldSpec.put(key, direction);
@@ -83,16 +82,33 @@ public class Index implements IndexDefinition {
 		return this;
 	}
 
+	/**
+	 * Reject all documents that contain a duplicate value for the indexed field.
+	 * 
+	 * @see http://docs.mongodb.org/manual/core/index-unique/
+	 * @return
+	 */
 	public Index unique() {
 		this.unique = true;
 		return this;
 	}
 
+	/**
+	 * Skip over any document that is missing the indexed field.
+	 * 
+	 * @see http://docs.mongodb.org/manual/core/index-sparse/
+	 * @return
+	 */
 	public Index sparse() {
 		this.sparse = true;
 		return this;
 	}
 
+	/**
+	 * @see http://docs.mongodb.org/manual/core/index-creation/#index-creation-duplicate-dropping
+	 * @param duplicates
+	 * @return
+	 */
 	public Index unique(Duplicates duplicates) {
 		if (duplicates == Duplicates.DROP) {
 			this.dropDuplicates = true;

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/index/Indexed.java

@@ -26,21 +26,48 @@ import java.lang.annotation.Target;
  * @author Jon Brisbin
  * @author Oliver Gierke
  * @author Philipp Schneider
+ * @author Johno Crawford
  */
 @Target(ElementType.FIELD)
 @Retention(RetentionPolicy.RUNTIME)
 public @interface Indexed {
 
+	/**
+	 * If set to true reject all documents that contain a duplicate value for the indexed field.
+	 * 
+	 * @see http://docs.mongodb.org/manual/core/index-unique/
+	 * @return
+	 */
 	boolean unique() default false;
 
 	IndexDirection direction() default IndexDirection.ASCENDING;
 
+	/**
+	 * If set to true index will skip over any document that is missing the indexed field.
+	 * 
+	 * @see http://docs.mongodb.org/manual/core/index-sparse/
+	 * @return
+	 */
 	boolean sparse() default false;
 
+	/**
+	 * @see http://docs.mongodb.org/manual/core/index-creation/#index-creation-duplicate-dropping
+	 * @return
+	 */
 	boolean dropDups() default false;
 
+	/**
+	 * Index name.
+	 * 
+	 * @return
+	 */
 	String name() default "";
 
+	/**
+	 * Colleciton name for index to be created on.
+	 * 
+	 * @return
+	 */
 	String collection() default "";
 
 	/**
@@ -50,4 +77,12 @@ public @interface Indexed {
 	 * @return
 	 */
 	boolean background() default false;
+
+	/**
+	 * Configures the number of seconds after which the collection should expire. Defaults to -1 for no expiry.
+	 * 
+	 * @see http://docs.mongodb.org/manual/tutorial/expire-data/
+	 * @return
+	 */
+	int expireAfterSeconds() default -1;
 }

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/index/MongoPersistentEntityIndexCreator.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2011-2013 the original author or authors.
+ * Copyright 2011-2014 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -44,11 +44,13 @@ import com.mongodb.util.JSON;
  * @author Jon Brisbin
  * @author Oliver Gierke
  * @author Philipp Schneider
+ * @author Johno Crawford
+ * @author Laurent Canet
  */
 public class MongoPersistentEntityIndexCreator implements
 		ApplicationListener<MappingContextEvent<MongoPersistentEntity<?>, MongoPersistentProperty>> {
 
-	private static final Logger log = LoggerFactory.getLogger(MongoPersistentEntityIndexCreator.class);
+	private static final Logger LOGGER = LoggerFactory.getLogger(MongoPersistentEntityIndexCreator.class);
 
 	private final Map<Class<?>, Boolean> classesSeen = new ConcurrentHashMap<Class<?>, Boolean>();
 	private final MongoDbFactory mongoDbFactory;
@@ -95,8 +97,8 @@ public class MongoPersistentEntityIndexCreator implements
 	protected void checkForIndexes(final MongoPersistentEntity<?> entity) {
 		final Class<?> type = entity.getType();
 		if (!classesSeen.containsKey(type)) {
-			if (log.isDebugEnabled()) {
-				log.debug("Analyzing class " + type + " for index information.");
+			if (LOGGER.isDebugEnabled()) {
+				LOGGER.debug("Analyzing class " + type + " for index information.");
 			}
 
 			// Make sure indexes get created
@@ -108,10 +110,10 @@ public class MongoPersistentEntityIndexCreator implements
 					DBObject definition = (DBObject) JSON.parse(index.def());
 
 					ensureIndex(indexColl, index.name(), definition, index.unique(), index.dropDups(), index.sparse(),
-							index.background());
+							index.background(), index.expireAfterSeconds());
 
-					if (log.isDebugEnabled()) {
-						log.debug("Created compound index " + index);
+					if (LOGGER.isDebugEnabled()) {
+						LOGGER.debug("Created compound index " + index);
 					}
 				}
 			}
@@ -131,8 +133,8 @@ public class MongoPersistentEntityIndexCreator implements
 						} else {
 							if (!name.equals(field.getName()) && index.unique() && !index.sparse()) {
 								// Names don't match, and sparse is not true. This situation will generate an error on the server.
-								if (log.isWarnEnabled()) {
-									log.warn("The index name " + name + " doesn't match this property name: " + field.getName()
+								if (LOGGER.isWarnEnabled()) {
+									LOGGER.warn("The index name " + name + " doesn't match this property name: " + field.getName()
 											+ ". Setting sparse=true on this index will prevent errors when inserting documents.");
 								}
 							}
@@ -143,10 +145,10 @@ public class MongoPersistentEntityIndexCreator implements
 						DBObject definition = new BasicDBObject(persistentProperty.getFieldName(), direction);
 
 						ensureIndex(collection, name, definition, index.unique(), index.dropDups(), index.sparse(),
-								index.background());
+								index.background(), index.expireAfterSeconds());
 
-						if (log.isDebugEnabled()) {
-							log.debug("Created property index " + index);
+						if (LOGGER.isDebugEnabled()) {
+							LOGGER.debug("Created property index " + index);
 						}
 
 					} else if (field.isAnnotationPresent(GeoSpatialIndexed.class)) {
@@ -156,13 +158,15 @@ public class MongoPersistentEntityIndexCreator implements
 						GeospatialIndex indexObject = new GeospatialIndex(persistentProperty.getFieldName());
 						indexObject.withMin(index.min()).withMax(index.max());
 						indexObject.named(StringUtils.hasText(index.name()) ? index.name() : field.getName());
+						indexObject.typed(index.type()).withBucketSize(index.bucketSize())
+								.withAdditionalField(index.additionalField());
 
 						String collection = StringUtils.hasText(index.collection()) ? index.collection() : entity.getCollection();
 						mongoDbFactory.getDb().getCollection(collection)
 								.ensureIndex(indexObject.getIndexKeys(), indexObject.getIndexOptions());
 
-						if (log.isDebugEnabled()) {
-							log.debug(String.format("Created %s for entity %s in collection %s! ", indexObject, entity.getType(),
+						if (LOGGER.isDebugEnabled()) {
+							LOGGER.debug(String.format("Created %s for entity %s in collection %s! ", indexObject, entity.getType(),
 									collection));
 						}
 					}
@@ -192,9 +196,11 @@ public class MongoPersistentEntityIndexCreator implements
 	 * @param unique whether it shall be a unique index
 	 * @param dropDups whether to drop duplicates
 	 * @param sparse sparse or not
+	 * @param background whether the index will be created in the background
+	 * @param expireAfterSeconds the time to live for documents in the collection
 	 */
 	protected void ensureIndex(String collection, String name, DBObject indexDefinition, boolean unique,
-			boolean dropDups, boolean sparse, boolean background) {
+			boolean dropDups, boolean sparse, boolean background, int expireAfterSeconds) {
 
 		DBObject opts = new BasicDBObject();
 		opts.put("name", name);
@@ -203,6 +209,10 @@ public class MongoPersistentEntityIndexCreator implements
 		opts.put("unique", unique);
 		opts.put("background", background);
 
+		if (expireAfterSeconds != -1) {
+			opts.put("expireAfterSeconds", expireAfterSeconds);
+		}
+
 		mongoDbFactory.getDb().getCollection(collection).ensureIndex(indexDefinition, opts);
 	}
 }

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/index/package-info.java

@@ -0,0 +1,5 @@
+/**
+ * Support for MongoDB document indexing.
+ */
+package org.springframework.data.mongodb.core.index;
+

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapping/BasicMongoPersistentEntity.java

@@ -15,6 +15,7 @@
  */
 package org.springframework.data.mongodb.core.mapping;
 
+import java.lang.reflect.Field;
 import java.util.Comparator;
 import java.util.HashMap;
 import java.util.Map;
@@ -24,6 +25,7 @@ import org.springframework.context.ApplicationContext;
 import org.springframework.context.ApplicationContextAware;
 import org.springframework.context.expression.BeanFactoryAccessor;
 import org.springframework.context.expression.BeanFactoryResolver;
+import org.springframework.data.annotation.Id;
 import org.springframework.data.mapping.Association;
 import org.springframework.data.mapping.AssociationHandler;
 import org.springframework.data.mapping.PropertyHandler;
@@ -35,6 +37,7 @@ import org.springframework.expression.Expression;
 import org.springframework.expression.ParserContext;
 import org.springframework.expression.spel.standard.SpelExpressionParser;
 import org.springframework.expression.spel.support.StandardEvaluationContext;
+import org.springframework.util.Assert;
 import org.springframework.util.StringUtils;
 
 /**
@@ -43,11 +46,12 @@ import org.springframework.util.StringUtils;
  * 
  * @author Jon Brisbin
  * @author Oliver Gierke
+ * @author Thomas Darimont
  */
 public class BasicMongoPersistentEntity<T> extends BasicPersistentEntity<T, MongoPersistentProperty> implements
 		MongoPersistentEntity<T>, ApplicationContextAware {
 
-	private static final String AMBIGUOUS_FIELD_MAPPING = "Ambiguous field mapping detected! Both %s and %s map to the same field name %s! Disambiguate using @Field annotation!";
+	private static final String AMBIGUOUS_FIELD_MAPPING = "Ambiguous field mapping detected! Both %s and %s map to the same field name %s! Disambiguate using @DocumentField annotation!";
 	private final String collection;
 	private final SpelExpressionParser parser;
 	private final StandardEvaluationContext context;
@@ -136,6 +140,60 @@ public class BasicMongoPersistentEntity<T> extends BasicPersistentEntity<T, Mong
 		}
 	}
 
+	/**
+	 * As a general note: An implicit id property has a name that matches "id" or "_id". An explicit id property is one
+	 * that is annotated with @see {@link Id}. The property id is updated according to the following rules: 1) An id
+	 * property which is defined explicitly takes precedence over an implicitly defined id property. 2) In case of any
+	 * ambiguity a @see {@link MappingException} is thrown.
+	 * 
+	 * @param property - the new id property candidate
+	 * @return
+	 */
+	@Override
+	protected MongoPersistentProperty returnPropertyIfBetterIdPropertyCandidateOrNull(MongoPersistentProperty property) {
+
+		Assert.notNull(property);
+
+		if (!property.isIdProperty()) {
+			return null;
+		}
+
+		MongoPersistentProperty currentIdProperty = getIdProperty();
+
+		boolean currentIdPropertyIsSet = currentIdProperty != null;
+		@SuppressWarnings("null")
+		boolean currentIdPropertyIsExplicit = currentIdPropertyIsSet ? currentIdProperty.isExplicitIdProperty() : false;
+		boolean newIdPropertyIsExplicit = property.isExplicitIdProperty();
+
+		if (!currentIdPropertyIsSet) {
+			return property;
+
+		}
+
+		@SuppressWarnings("null")
+		Field currentIdPropertyField = currentIdProperty.getField();
+
+		if (newIdPropertyIsExplicit && currentIdPropertyIsExplicit) {
+			throw new MappingException(String.format(
+					"Attempt to add explicit id property %s but already have an property %s registered "
+							+ "as explicit id. Check your mapping configuration!", property.getField(), currentIdPropertyField));
+
+		} else if (newIdPropertyIsExplicit && !currentIdPropertyIsExplicit) {
+			// explicit id property takes precedence over implicit id property
+			return property;
+
+		} else if (!newIdPropertyIsExplicit && currentIdPropertyIsExplicit) {
+			// no id property override - current property is explicitly defined
+
+		} else {
+			throw new MappingException(String.format(
+					"Attempt to add id property %s but already have an property %s registered "
+							+ "as id. Check your mapping configuration!", property.getField(), currentIdPropertyField));
+		}
+
+		return null;
+	}
+
 	/**
 	 * Handler to collect {@link MongoPersistentProperty} instances and check that each of them is mapped to a distinct
 	 * field name.

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapping/BasicMongoPersistentProperty.java

@@ -24,6 +24,7 @@ import java.util.Set;
 import org.bson.types.ObjectId;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
+import org.springframework.data.annotation.Id;
 import org.springframework.data.mapping.Association;
 import org.springframework.data.mapping.model.AnnotationBasedPersistentProperty;
 import org.springframework.data.mapping.model.MappingException;
@@ -38,6 +39,7 @@ import com.mongodb.DBObject;
  * 
  * @author Oliver Gierke
  * @author Patryk Wasik
+ * @author Thomas Darimont
  */
 public class BasicMongoPersistentProperty extends AnnotationBasedPersistentProperty<MongoPersistentProperty> implements
 		MongoPersistentProperty {
@@ -109,6 +111,15 @@ public class BasicMongoPersistentProperty extends AnnotationBasedPersistentPrope
 		return SUPPORTED_ID_PROPERTY_NAMES.contains(field.getName());
 	}
 
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.mapping.MongoPersistentProperty#isExplicitIdProperty()
+	 */
+	@Override
+	public boolean isExplicitIdProperty() {
+		return isAnnotationPresent(Id.class);
+	}
+
 	/**
 	 * Returns the key to be used to store the value of the property inside a Mongo {@link DBObject}.
 	 * 
@@ -117,7 +128,18 @@ public class BasicMongoPersistentProperty extends AnnotationBasedPersistentPrope
 	public String getFieldName() {
 
 		if (isIdProperty()) {
-			return ID_FIELD_NAME;
+
+			if (owner == null) {
+				return ID_FIELD_NAME;
+			}
+
+			if (owner.getIdProperty() == null) {
+				return ID_FIELD_NAME;
+			}
+
+			if (owner.isIdProperty(this)) {
+				return ID_FIELD_NAME;
+			}
 		}
 
 		org.springframework.data.mongodb.core.mapping.Field annotation = findAnnotation(org.springframework.data.mongodb.core.mapping.Field.class);

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapping/DBRef.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2011-2012 by the original author(s).
+ * Copyright 2011-2013 by the original author(s).
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -27,7 +27,8 @@ import org.springframework.data.annotation.Reference;
  * An annotation that indicates the annotated field is to be stored using a {@link com.mongodb.DBRef}.
  * 
  * @author Jon Brisbin
- * @authot Oliver Gierke
+ * @author Oliver Gierke
+ * @author Thomas Darimont
  */
 @Documented
 @Retention(RetentionPolicy.RUNTIME)
@@ -41,4 +42,11 @@ public @interface DBRef {
 	 * @return
 	 */
 	String db() default "";
+
+	/**
+	 * Controls whether the referenced entity should be loaded lazily. This defaults to {@literal false}.
+	 * 
+	 * @return
+	 */
+	boolean lazy() default false;
 }

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapping/FieldNamingStrategy.java

@@ -18,7 +18,7 @@ package org.springframework.data.mongodb.core.mapping;
 /**
  * SPI interface to determine how to name document fields in cases the field name is not manually defined.
  * 
- * @see Field
+ * @see DocumentField
  * @see PropertyNameFieldNamingStrategy
  * @see CamelCaseAbbreviatingFieldNamingStrategy
  * @since 1.3

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapping/MongoPersistentProperty.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2011-2012 the original author or authors.
+ * Copyright 2011-2013 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,6 +16,8 @@
 package org.springframework.data.mongodb.core.mapping;
 
 import org.springframework.core.convert.converter.Converter;
+import org.springframework.data.annotation.Id;
+import org.springframework.data.mapping.PersistentEntity;
 import org.springframework.data.mapping.PersistentProperty;
 
 /**
@@ -23,6 +25,7 @@ import org.springframework.data.mapping.PersistentProperty;
  * 
  * @author Oliver Gierke
  * @author Patryk Wasik
+ * @author Thomas Darimont
  */
 public interface MongoPersistentProperty extends PersistentProperty<MongoPersistentProperty> {
 
@@ -48,6 +51,14 @@ public interface MongoPersistentProperty extends PersistentProperty<MongoPersist
 	 */
 	boolean isDbReference();
 
+	/**
+	 * Returns whether the property is explicitly marked as an identifier property of the owning {@link PersistentEntity}.
+	 * A property is an explicit id property if it is annotated with @see {@link Id}.
+	 * 
+	 * @return
+	 */
+	boolean isExplicitIdProperty();
+
 	/**
 	 * Returns the {@link DBRef} if the property is a reference.
 	 * 

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapping/event/AbstractMongoEventListener.java

@@ -126,13 +126,13 @@ public abstract class AbstractMongoEventListener<E> implements ApplicationListen
 
 	public void onAfterDelete(DBObject dbo) {
 		if (LOG.isDebugEnabled()) {
-			LOG.debug("onAfterConvert({})", dbo);
+			LOG.debug("onAfterDelete({})", dbo);
 		}
 	}
 
 	public void onBeforeDelete(DBObject dbo) {
 		if (LOG.isDebugEnabled()) {
-			LOG.debug("onAfterConvert({})", dbo);
+			LOG.debug("onBeforeDelete({})", dbo);
 		}
 	}
 }

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapping/event/AuditingEventListener.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012 the original author or authors.
+ * Copyright 2012-2014 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -28,14 +28,14 @@ import org.springframework.util.Assert;
  */
 public class AuditingEventListener implements ApplicationListener<BeforeConvertEvent<Object>> {
 
-	private final IsNewAwareAuditingHandler<Object> auditingHandler;
+	private final IsNewAwareAuditingHandler auditingHandler;
 
 	/**
 	 * Creates a new {@link AuditingEventListener} using the given {@link MappingContext} and {@link AuditingHandler}.
 	 * 
 	 * @param auditingHandler must not be {@literal null}.
 	 */
-	public AuditingEventListener(IsNewAwareAuditingHandler<Object> auditingHandler) {
+	public AuditingEventListener(IsNewAwareAuditingHandler auditingHandler) {
 
 		Assert.notNull(auditingHandler, "IsNewAwareAuditingHandler must not be null!");
 		this.auditingHandler = auditingHandler;

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapping/event/package-info.java

@@ -0,0 +1,5 @@
+/**
+ * Mapping event callback infrastructure for the MongoDB document-to-object mapping subsystem.
+ */
+package org.springframework.data.mongodb.core.mapping.event;
+

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapping/package-info.java

@@ -0,0 +1,5 @@
+/**
+ * Infrastructure for the MongoDB document-to-object mapping subsystem.
+ */
+package org.springframework.data.mongodb.core.mapping;
+

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapreduce/MapReduceCounts.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2012 the original author or authors.
+ * Copyright 2010-2014 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -23,7 +23,7 @@ package org.springframework.data.mongodb.core.mapreduce;
  */
 public class MapReduceCounts {
 
-	public static MapReduceCounts NONE = new MapReduceCounts(-1, -1, -1);
+	public static final MapReduceCounts NONE = new MapReduceCounts(-1, -1, -1);
 
 	private final long inputCount;
 	private final long emitCount;

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapreduce/package-info.java

@@ -0,0 +1,5 @@
+/**
+ * Support for MongoDB map-reduce operations.
+ */
+package org.springframework.data.mongodb.core.mapreduce;
+

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/query/Criteria.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2011 the original author or authors.
+ * Copyright 2010-2014 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -39,6 +39,11 @@ import com.mongodb.DBObject;
 /**
  * Central class for creating queries. It follows a fluent API style so that you can easily chain together multiple
  * criteria. Static import of the 'Criteria.where' method will improve readability.
+ * 
+ * @author Thomas Risberg
+ * @author Oliver Gierke
+ * @author Thomas Darimont
+ * @author Christoph Strobl
  */
 public class Criteria implements CriteriaDefinition {
 
@@ -48,11 +53,8 @@ public class Criteria implements CriteriaDefinition {
 	private static final Object NOT_SET = new Object();
 
 	private String key;
-
 	private List<Criteria> criteriaChain;
-
 	private LinkedHashMap<String, Object> criteria = new LinkedHashMap<String, Object>();
-
 	private Object isValue = NOT_SET;
 
 	public Criteria() {
@@ -97,13 +99,16 @@ public class Criteria implements CriteriaDefinition {
 	 * @return
 	 */
 	public Criteria is(Object o) {
-		if (isValue != NOT_SET) {
+
+		if (!isValue.equals(NOT_SET)) {
 			throw new InvalidMongoDbApiUsageException(
 					"Multiple 'is' values declared. You need to use 'and' with multiple criteria");
 		}
+
 		if (lastOperatorWasNot()) {
 			throw new InvalidMongoDbApiUsageException("Invalid query: 'not' can't be used with 'is' - use 'ne' instead.");
 		}
+
 		this.isValue = o;
 		return this;
 	}
@@ -113,8 +118,9 @@ public class Criteria implements CriteriaDefinition {
 	}
 
 	/**
-	 * Creates a criterion using the $ne operator
+	 * Creates a criterion using the {@literal $ne} operator.
 	 * 
+	 * @see http://docs.mongodb.org/manual/reference/operator/query/ne/
 	 * @param o
 	 * @return
 	 */
@@ -124,8 +130,9 @@ public class Criteria implements CriteriaDefinition {
 	}
 
 	/**
-	 * Creates a criterion using the $lt operator
+	 * Creates a criterion using the {@literal $lt} operator.
 	 * 
+	 * @see http://docs.mongodb.org/manual/reference/operator/query/lt/
 	 * @param o
 	 * @return
 	 */
@@ -135,8 +142,9 @@ public class Criteria implements CriteriaDefinition {
 	}
 
 	/**
-	 * Creates a criterion using the $lte operator
+	 * Creates a criterion using the {@literal $lte} operator.
 	 * 
+	 * @see http://docs.mongodb.org/manual/reference/operator/query/lte/
 	 * @param o
 	 * @return
 	 */
@@ -146,8 +154,9 @@ public class Criteria implements CriteriaDefinition {
 	}
 
 	/**
-	 * Creates a criterion using the $gt operator
+	 * Creates a criterion using the {@literal $gt} operator.
 	 * 
+	 * @see http://docs.mongodb.org/manual/reference/operator/query/gt/
 	 * @param o
 	 * @return
 	 */
@@ -157,8 +166,9 @@ public class Criteria implements CriteriaDefinition {
 	}
 
 	/**
-	 * Creates a criterion using the $gte operator
+	 * Creates a criterion using the {@literal $gte} operator.
 	 * 
+	 * @see http://docs.mongodb.org/manual/reference/operator/query/gte/
 	 * @param o
 	 * @return
 	 */
@@ -168,8 +178,9 @@ public class Criteria implements CriteriaDefinition {
 	}
 
 	/**
-	 * Creates a criterion using the $in operator
+	 * Creates a criterion using the {@literal $in} operator.
 	 * 
+	 * @see http://docs.mongodb.org/manual/reference/operator/query/in/
 	 * @param o the values to match against
 	 * @return
 	 */
@@ -183,8 +194,9 @@ public class Criteria implements CriteriaDefinition {
 	}
 
 	/**
-	 * Creates a criterion using the $in operator
+	 * Creates a criterion using the {@literal $in} operator.
 	 * 
+	 * @see http://docs.mongodb.org/manual/reference/operator/query/in/
 	 * @param c the collection containing the values to match against
 	 * @return
 	 */
@@ -194,8 +206,9 @@ public class Criteria implements CriteriaDefinition {
 	}
 
 	/**
-	 * Creates a criterion using the $nin operator
+	 * Creates a criterion using the {@literal $nin} operator.
 	 * 
+	 * @see http://docs.mongodb.org/manual/reference/operator/query/nin/
 	 * @param o
 	 * @return
 	 */
@@ -203,14 +216,22 @@ public class Criteria implements CriteriaDefinition {
 		return nin(Arrays.asList(o));
 	}
 
+	/**
+	 * Creates a criterion using the {@literal $nin} operator.
+	 * 
+	 * @see http://docs.mongodb.org/manual/reference/operator/query/nin/
+	 * @param o
+	 * @return
+	 */
 	public Criteria nin(Collection<?> o) {
 		criteria.put("$nin", o);
 		return this;
 	}
 
 	/**
-	 * Creates a criterion using the $mod operator
+	 * Creates a criterion using the {@literal $mod} operator.
 	 * 
+	 * @see http://docs.mongodb.org/manual/reference/operator/query/mod/
 	 * @param value
 	 * @param remainder
 	 * @return
@@ -224,8 +245,9 @@ public class Criteria implements CriteriaDefinition {
 	}
 
 	/**
-	 * Creates a criterion using the $all operator
+	 * Creates a criterion using the {@literal $all} operator.
 	 * 
+	 * @see http://docs.mongodb.org/manual/reference/operator/query/all/
 	 * @param o
 	 * @return
 	 */
@@ -233,14 +255,22 @@ public class Criteria implements CriteriaDefinition {
 		return all(Arrays.asList(o));
 	}
 
+	/**
+	 * Creates a criterion using the {@literal $all} operator.
+	 * 
+	 * @see http://docs.mongodb.org/manual/reference/operator/query/all/
+	 * @param o
+	 * @return
+	 */
 	public Criteria all(Collection<?> o) {
 		criteria.put("$all", o);
 		return this;
 	}
 
 	/**
-	 * Creates a criterion using the $size operator
+	 * Creates a criterion using the {@literal $size} operator.
 	 * 
+	 * @see http://docs.mongodb.org/manual/reference/operator/query/size/
 	 * @param s
 	 * @return
 	 */
@@ -250,8 +280,9 @@ public class Criteria implements CriteriaDefinition {
 	}
 
 	/**
-	 * Creates a criterion using the $exists operator
+	 * Creates a criterion using the {@literal $exists} operator.
 	 * 
+	 * @see http://docs.mongodb.org/manual/reference/operator/query/exists/
 	 * @param b
 	 * @return
 	 */
@@ -261,8 +292,9 @@ public class Criteria implements CriteriaDefinition {
 	}
 
 	/**
-	 * Creates a criterion using the $type operator
+	 * Creates a criterion using the {@literal $type} operator.
 	 * 
+	 * @see http://docs.mongodb.org/manual/reference/operator/query/type/
 	 * @param t
 	 * @return
 	 */
@@ -272,22 +304,31 @@ public class Criteria implements CriteriaDefinition {
 	}
 
 	/**
-	 * Creates a criterion using the $not meta operator which affects the clause directly following
+	 * Creates a criterion using the {@literal $not} meta operator which affects the clause directly following
 	 * 
+	 * @see http://docs.mongodb.org/manual/reference/operator/query/not/
 	 * @return
 	 */
 	public Criteria not() {
 		return not(null);
 	}
 
+	/**
+	 * Creates a criterion using the {@literal $not} operator.
+	 * 
+	 * @see http://docs.mongodb.org/manual/reference/operator/query/not/
+	 * @param value
+	 * @return
+	 */
 	private Criteria not(Object value) {
 		criteria.put("$not", value);
 		return this;
 	}
 
 	/**
-	 * Creates a criterion using a $regex
+	 * Creates a criterion using a {@literal $regex} operator.
 	 * 
+	 * @see http://docs.mongodb.org/manual/reference/operator/query/regex/
 	 * @param re
 	 * @return
 	 */
@@ -296,8 +337,10 @@ public class Criteria implements CriteriaDefinition {
 	}
 
 	/**
-	 * Creates a criterion using a $regex and $options
+	 * Creates a criterion using a {@literal $regex} and {@literal $options} operator.
 	 * 
+	 * @see http://docs.mongodb.org/manual/reference/operator/query/regex/
+	 * @see http://docs.mongodb.org/manual/reference/operator/query/regex/#op._S_options
 	 * @param re
 	 * @param options
 	 * @return
@@ -330,8 +373,11 @@ public class Criteria implements CriteriaDefinition {
 	}
 
 	/**
-	 * Creates a geospatial criterion using a $within $center operation. This is only available for Mongo 1.7 and higher.
+	 * Creates a geospatial criterion using a {@literal $within $centerSphere} operation. This is only available for Mongo
+	 * 1.7 and higher.
 	 * 
+	 * @see http://docs.mongodb.org/manual/reference/operator/query/geoWithin/
+	 * @see http://docs.mongodb.org/manual/reference/operator/query/centerSphere/
 	 * @param circle must not be {@literal null}
 	 * @return
 	 */
@@ -341,6 +387,13 @@ public class Criteria implements CriteriaDefinition {
 		return this;
 	}
 
+	/**
+	 * Creates a geospatial criterion using a {@literal $within} operation.
+	 * 
+	 * @see http://docs.mongodb.org/manual/reference/operator/query/geoWithin/
+	 * @param shape
+	 * @return
+	 */
 	public Criteria within(Shape shape) {
 
 		Assert.notNull(shape);
@@ -349,8 +402,9 @@ public class Criteria implements CriteriaDefinition {
 	}
 
 	/**
-	 * Creates a geospatial criterion using a $near operation
+	 * Creates a geospatial criterion using a {@literal $near} operation.
 	 * 
+	 * @see http://docs.mongodb.org/manual/reference/operator/query/near/
 	 * @param point must not be {@literal null}
 	 * @return
 	 */
@@ -361,8 +415,10 @@ public class Criteria implements CriteriaDefinition {
 	}
 
 	/**
-	 * Creates a geospatial criterion using a $nearSphere operation. This is only available for Mongo 1.7 and higher.
+	 * Creates a geospatial criterion using a {@literal $nearSphere} operation. This is only available for Mongo 1.7 and
+	 * higher.
 	 * 
+	 * @see http://docs.mongodb.org/manual/reference/operator/query/nearSphere/
 	 * @param point must not be {@literal null}
 	 * @return
 	 */
@@ -373,8 +429,9 @@ public class Criteria implements CriteriaDefinition {
 	}
 
 	/**
-	 * Creates a geospatical criterion using a $maxDistance operation, for use with $near
+	 * Creates a geospatical criterion using a {@literal $maxDistance} operation, for use with $near
 	 * 
+	 * @see http://docs.mongodb.org/manual/reference/operator/query/maxDistance/
 	 * @param maxDistance
 	 * @return
 	 */
@@ -384,8 +441,9 @@ public class Criteria implements CriteriaDefinition {
 	}
 
 	/**
-	 * Creates a criterion using the $elemMatch operator
+	 * Creates a criterion using the {@literal $elemMatch} operator
 	 * 
+	 * @see http://docs.mongodb.org/manual/reference/operator/query/elemMatch/
 	 * @param c
 	 * @return
 	 */
@@ -396,34 +454,54 @@ public class Criteria implements CriteriaDefinition {
 
 	/**
 	 * Creates an 'or' criteria using the $or operator for all of the provided criteria
+	 * <p>
+	 * Note that mongodb doesn't support an $or operator to be wrapped in a $not operator.
+	 * <p>
 	 * 
+	 * @throws IllegalArgumentException if {@link #orOperator(Criteria...)} follows a not() call directly.
 	 * @param criteria
 	 */
 	public Criteria orOperator(Criteria... criteria) {
 		BasicDBList bsonList = createCriteriaList(criteria);
-		criteriaChain.add(new Criteria("$or").is(bsonList));
-		return this;
+		return registerCriteriaChainElement(new Criteria("$or").is(bsonList));
 	}
 
 	/**
-	 * Creates a 'nor' criteria using the $nor operator for all of the provided criteria
+	 * Creates a 'nor' criteria using the $nor operator for all of the provided criteria.
+	 * <p>
+	 * Note that mongodb doesn't support an $nor operator to be wrapped in a $not operator.
+	 * <p>
 	 * 
+	 * @throws IllegalArgumentException if {@link #norOperator(Criteria...)} follows a not() call directly.
 	 * @param criteria
 	 */
 	public Criteria norOperator(Criteria... criteria) {
 		BasicDBList bsonList = createCriteriaList(criteria);
-		criteriaChain.add(new Criteria("$nor").is(bsonList));
-		return this;
+		return registerCriteriaChainElement(new Criteria("$nor").is(bsonList));
 	}
 
 	/**
-	 * Creates an 'and' criteria using the $and operator for all of the provided criteria
+	 * Creates an 'and' criteria using the $and operator for all of the provided criteria.
+	 * <p>
+	 * Note that mongodb doesn't support an $and operator to be wrapped in a $not operator.
+	 * <p>
 	 * 
+	 * @throws IllegalArgumentException if {@link #andOperator(Criteria...)} follows a not() call directly.
 	 * @param criteria
 	 */
 	public Criteria andOperator(Criteria... criteria) {
 		BasicDBList bsonList = createCriteriaList(criteria);
-		criteriaChain.add(new Criteria("$and").is(bsonList));
+		return registerCriteriaChainElement(new Criteria("$and").is(bsonList));
+	}
+
+	private Criteria registerCriteriaChainElement(Criteria criteria) {
+
+		if (lastOperatorWasNot()) {
+			throw new IllegalArgumentException("operator $not is not allowed around criteria chain element: "
+					+ criteria.getCriteriaObject());
+		} else {
+			criteriaChain.add(criteria);
+		}
 		return this;
 	}
 
@@ -451,8 +529,10 @@ public class Criteria implements CriteriaDefinition {
 	}
 
 	protected DBObject getSingleCriteriaObject() {
+
 		DBObject dbo = new BasicDBObject();
 		boolean not = false;
+
 		for (String k : this.criteria.keySet()) {
 			Object value = this.criteria.get(k);
 			if (not) {
@@ -468,13 +548,16 @@ public class Criteria implements CriteriaDefinition {
 				}
 			}
 		}
+
 		DBObject queryCriteria = new BasicDBObject();
-		if (isValue != NOT_SET) {
+
+		if (!NOT_SET.equals(isValue)) {
 			queryCriteria.put(this.key, this.isValue);
 			queryCriteria.putAll(dbo);
 		} else {
 			queryCriteria.put(this.key, dbo);
 		}
+
 		return queryCriteria;
 	}
 

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/query/Field.java

@@ -73,7 +73,7 @@ public class Field {
 	 */
 	public Field position(String field, int value) {
 
-		Assert.hasText(field, "Field must not be null or empty!");
+		Assert.hasText(field, "DocumentField must not be null or empty!");
 
 		postionKey = field;
 		positionValue = value;

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/query/NearQuery.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2011-2013 the original author or authors.
+ * Copyright 2011-2014 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -15,6 +15,7 @@
  */
 package org.springframework.data.mongodb.core.query;
 
+import org.springframework.data.domain.Pageable;
 import org.springframework.data.mongodb.core.geo.CustomMetric;
 import org.springframework.data.mongodb.core.geo.Distance;
 import org.springframework.data.mongodb.core.geo.Metric;
@@ -29,8 +30,10 @@ import com.mongodb.DBObject;
  * Builder class to build near-queries.
  * 
  * @author Oliver Gierke
+ * @author Thomas Darimont
+ * @author Christoph Strobl
  */
-public class NearQuery {
+public final class NearQuery {
 
 	private final Point point;
 	private Query query;
@@ -38,6 +41,7 @@ public class NearQuery {
 	private Metric metric;
 	private boolean spherical;
 	private Integer num;
+	private Integer skip;
 
 	/**
 	 * Creates a new {@link NearQuery}.
@@ -116,7 +120,7 @@ public class NearQuery {
 	}
 
 	/**
-	 * Configures the number of results to return.
+	 * Configures the maximum number of results to return.
 	 * 
 	 * @param num
 	 * @return
@@ -126,6 +130,31 @@ public class NearQuery {
 		return this;
 	}
 
+	/**
+	 * Configures the number of results to skip.
+	 * 
+	 * @param skip
+	 * @return
+	 */
+	public NearQuery skip(int skip) {
+		this.skip = skip;
+		return this;
+	}
+
+	/**
+	 * Configures the {@link Pageable} to use.
+	 * 
+	 * @param pageable must not be {@literal null}
+	 * @return
+	 */
+	public NearQuery with(Pageable pageable) {
+
+		Assert.notNull(pageable, "Pageable must not be 'null'.");
+		this.num = pageable.getOffset() + pageable.getPageSize();
+		this.skip = pageable.getOffset();
+		return this;
+	}
+
 	/**
 	 * Sets the max distance results shall have from the configured origin. If a {@link Metric} was set before the given
 	 * value will be interpreted as being a value in that metric. E.g.
@@ -285,14 +314,28 @@ public class NearQuery {
 	/**
 	 * Adds an actual query to the {@link NearQuery} to restrict the objects considered for the actual near operation.
 	 * 
-	 * @param query
+	 * @param query must not be {@literal null}.
 	 * @return
 	 */
 	public NearQuery query(Query query) {
+
+		Assert.notNull(query, "Cannot apply 'null' query on NearQuery.");
 		this.query = query;
+		this.skip = query.getSkip();
+
+		if (query.getLimit() != 0) {
+			this.num = query.getLimit();
+		}
 		return this;
 	}
 
+	/**
+	 * @return the number of elements to skip.
+	 */
+	public Integer getSkip() {
+		return skip;
+	}
+
 	/**
 	 * Returns the {@link DBObject} built by the {@link NearQuery}.
 	 *