DATAMONGO-772 - Release version 1.3.2.RELEASE.

DATAMONGO-772 - Prepare 1.3.2.RELEASE.
Updated version of SD-CMNS to 1.6.2.RELEASE.
2013-10-25 08:11:23 -07:00 · 2013-10-25 16:51:57 +02:00 · 2013-10-25 11:00:17 +02:00 · 2013-10-14 08:59:42 +02:00 · 2013-10-13 13:50:54 +02:00 · 2013-10-08 12:46:17 +02:00
204 changed files with 41758 additions and 1808 deletions
--- a/README.md
+++ b/README.md
@@ -1,150 +1,141 @@
-Spring Data MongoDB
-======================
+# 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 Spring Data MongoDB aims to provide a familiar and consistent Spring-based programming model for 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
+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
------------
+## Getting Help

-For a comprehensive treatmet of all the Spring Data MongoDB features, please refer to the The [User Guide](http://static.springsource.org/spring-data/data-mongodb/docs/current/reference/html/) 
+For a comprehensive treatment of all the Spring Data MongoDB features, please refer to:

-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://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). 

 If you are new to Spring as well as to Spring Data, look for information about [Spring projects](http://www.springsource.org/projects). 


-Quick Start
-----------
+## Quick Start

-## MongoDB
+### Maven configuration

-For those in a hurry:
+Add the Maven dependency:

+```xml
+<dependency>
+  <groupId>org.springframework.data</groupId>
+  <artifactId>spring-data-mongodb</artifactId>
+  <version>1.3.2.RELEASE</version>
+</dependency>
+```

-* Download the jar through Maven:
+If you'd rather like the latest snapshots of the upcoming major version, use our Maven snapshot repository and declare the appropriate dependency version.

-          <dependency>
-            <groupId>org.springframework.data</groupId>
-            <artifactId>spring-data-mongodb</artifactId>
-            <version>1.2.0.BUILD-SNAPSHOT</version>
-          </dependency> 
+```xml
+<dependency>
+  <groupId>org.springframework.data</groupId>
+  <artifactId>spring-data-mongodb</artifactId>
+  <version>1.4.0.BUILD-SNAPSHOT</version>
+</dependency>

-
-          <repository>
-            <id>spring-maven-snapshot</id>
-            <snapshots><enabled>true</enabled></snapshots>
-            <name>Springframework Maven SNAPSHOT Repository</name>
-            <url>http://maven.springframework.org/snapshot</url>
-          </repository> 
+<repository>
+  <id>spring-libs-snapshot</id>
+  <name>Spring Snapshot Repository</name>
+  <url>http://repo.springsource.org/libs-snapshot</url>
+</repository>
+```

 ### MongoTemplate
-MongoTemplate is the central support class for Mongo database operations.  It provides
+
+MongoTemplate is the central support class for Mongo database operations. It provides:

 * Basic POJO mapping support to and from BSON
-* Connection Affinity callback
+* 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).

-Future plans are to support optional logging and/or exception throwing based on WriteResult return value, common map-reduce operations, GridFS operations.  A simple API for partial document updates is also planned.
+### Spring Data repositories

-### Easy Data Repository generation
+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.  

-To simplify the creation of Data Repositories a generic Repository interface and default implementation is provided.  Furthermore, Spring will automatically create a Repository implementation 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:

-The Repository interface is
+```java
+public interface PersonRepository extends CrudRepository<Person, Long> {

-        public interface Repository<T, ID extends Serializable> { 
+  List<Person> findByLastname(String lastname);

-          T save(T entity);
+  List<Person> findByFirstnameLike(String firstname);
+}
+```

-          List<T> save(Iterable<? extends T> entities);
+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.

-          T findById(ID id);
+You can have Spring automatically create a proxy for the interface by using the following JavaConfig:

-          boolean exists(ID id);
+```java
+@Configuration
+@EnableMongoRepositories
+class ApplicationConfig extends AbstractMongoConfiguration {

-          List<T> findAll();
+  @Override
+  public Mongo mongo() throws Exception {
+    return new Mongo();
+  }

-          Long count();
+  @Override
+  protected String getDatabaseName() {
+    return "springdata";
+  }
+}
+```

-          void delete(T entity);
+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:

-          void delete(Iterable<? extends T> entities);
+```xml
+<bean id="template" class="org.springframework.data.document.mongodb.MongoTemplate">
+  <constructor-arg>
+    <bean class="com.mongodb.Mongo">
+       <constructor-arg value="localhost" />
+       <constructor-arg value="27017" />
+    </bean>
+  </constructor-arg>
+  <constructor-arg value="database" />
+</bean>

-          void deleteAll();
-        }
+<mongo:repositories base-package="com.acme.repository" />
+```

+This will find the repository interface and register a proxy object in the container. You can use it as shown below:

-The MongoRepository extends Repository and will in future add more Mongo specific methods.
+```java
+@Service
+public class MyService {

-    public interface MongoRepository<T, ID extends Serializable> extends
-        Repository<T, ID> {
-    }
+  private final PersonRepository repository;

-SimpleMongoRepository is the out of the box implementation of the MongoRepository you can use for basid CRUD operations.  
+  @Autowired
+  public MyService(PersonRepository repository) {
+    this.repository = repository;
+  }

-To go beyond basic CRUD, extend the MongoRepository interface and supply your own finder methods that follow simple naming conventions such that they can be easily converted into queries.  
+  public void doWork() {

-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 regular expression is shown below
+     repository.deleteAll();

-    public interface PersonRepository extends MongoRepository<Person, Long> {
+     Person person = new Person();
+     person.setFirstname("Oliver");
+     person.setLastname("Gierke");
+     person = repository.save(person);

-      List<Person> findByLastname(String lastname);
+     List<Person> lastNameResults = repository.findByLastname("Gierke");
+     List<Person> firstNameResults = repository.findByFirstnameLike("Oli*");
+ }
+}
+```

-      List<Person> findByFirstnameLike(String firstname);
-    }
-
-You can have Spring automatically generate the implemention as shown below
-
-        <bean id="template" class="org.springframework.data.document.mongodb.MongoTemplate">
-                <constructor-arg>
-                        <bean class="com.mongodb.Mongo">
-                                <constructor-arg value="localhost" />
-                                <constructor-arg value="27017" />
-                        </bean>
-                </constructor-arg>
-                <constructor-arg value="database" />
-                <property name="defaultCollectionName" value="springdata" />
-        </bean>
-
-        <bean class="org.springframework.data.document.mongodb.repository.MongoRepositoryFactoryBean">
-                <property name="template" ref="template" />
-                <property name="repositoryInterface" value="org.springframework.data.document.mongodb.repository.PersonRepository" />
-        </bean>
-
-This will register an object in the container named PersonRepository.  You can use it as shown below
-
-     @Service
-     public class MyService {
-
-        @Autowired
-        PersonRepository repository;
-
-
-        public void doWork() {
-
-           repository.deleteAll();
-
-           Person person = new Person();
-           person.setFirstname("Oliver");
-           person.setLastname("Gierke");
-           person = repository.save(person);
-
-           List<Person> lastNameResults = repository.findByLastname("Gierke");
-
-           List<Person> firstNameResults = repository.findByFirstnameLike("Oli*");
-
-       }
-    }
-
-
-Contributing to Spring Data
---------------------------
+## Contributing to Spring Data

 Here are some ways for you to get involved in the community:

--- a/etc/formatting.xml
+++ b/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"/>
--- a/pom.xml
+++ b/pom.xml
@@ -5,7 +5,7 @@
 	
 	<groupId>org.springframework.data</groupId>
 	<artifactId>spring-data-mongodb-parent</artifactId>
-	<version>1.2.0.RELEASE</version>
+	<version>1.3.2.RELEASE</version>
 	<packaging>pom</packaging>

 	<name>Spring Data MongoDB</name>
@@ -15,7 +15,7 @@
 	<parent>
 		<groupId>org.springframework.data.build</groupId>
 		<artifactId>spring-data-parent</artifactId>
-		<version>1.0.0.RELEASE</version>
+		<version>1.2.0.RELEASE</version>
 		<relativePath>../spring-data-build/parent/pom.xml</relativePath>
 	</parent>
 	
@@ -26,11 +26,10 @@
 		<module>spring-data-mongodb-distribution</module>
 	</modules>

-
 	<properties>
 		<project.type>multi</project.type>
-		<dist.name>spring-data-mongodb</dist.name>
-		<springdata.commons>1.5.0.RELEASE</springdata.commons>
+		<dist.id>spring-data-mongodb</dist.id>
+		<springdata.commons>1.6.2.RELEASE</springdata.commons>
 		<mongo>2.10.1</mongo>
 	</properties>
 	
@@ -38,9 +37,9 @@
 		<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 Inc.</organization>
+			<organizationUrl>http://www.gopivotal.com</organizationUrl>
 			<roles>
 				<role>Project Lean</role>
 			</roles>
@@ -49,9 +48,9 @@
 		<developer>
 			<id>trisberg</id>
 			<name>Thomas Risberg</name>
-			<email>trisberg at vmware.com</email>
-			<organization>SpringSource</organization>
-			<organizationUrl>http://www.springsource.com</organizationUrl>
+			<email>trisberg at gopivotal.com</email>
+			<organization>Pivotal Inc.</organization>
+			<organizationUrl>http://www.gopivotal.com</organizationUrl>
 			<roles>
 				<role>Developer</role>
 			</roles>
@@ -60,9 +59,9 @@
 		<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 Inc.</organization>
+			<organizationUrl>http://www.gopivotal.com</organizationUrl>
 			<roles>
 				<role>Developer</role>
 			</roles>
@@ -71,14 +70,25 @@
 		<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 Inc.</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 Inc.</organization>
+			<organizationUrl>http://www.gopivotal.com</organizationUrl>
+			<roles>
+				<role>Developer</role>
+			</roles>
+			<timezone>+1</timezone>
+		</developer>
 	</developers>

 	<dependencies>
@@ -89,5 +99,12 @@
 			<version>${mongo}</version>
 		</dependency>
 	</dependencies>
+	
+	<repositories>
+		<repository>
+			<id>spring-lib-release</id>
+			<url>http://repo.springsource.org/libs-release-local</url>
+		</repository>
+	</repositories>

 </project>
--- a/spring-data-mongodb-cross-store/pom.xml
+++ b/spring-data-mongodb-cross-store/pom.xml
@@ -6,7 +6,7 @@
 	<parent>
 		<groupId>org.springframework.data</groupId>
 		<artifactId>spring-data-mongodb-parent</artifactId>
-		<version>1.2.0.RELEASE</version>
+		<version>1.3.2.RELEASE</version>
 		<relativePath>../pom.xml</relativePath>
 	</parent>
 	
@@ -52,7 +52,7 @@
 		<dependency>
 			<groupId>org.springframework.data</groupId>
 			<artifactId>spring-data-mongodb</artifactId>
-			<version>1.2.0.RELEASE</version>
+			<version>1.3.2.RELEASE</version>
 		</dependency>

 		<dependency>
--- a/spring-data-mongodb-cross-store/src/main/java/org/springframework/data/mongodb/crossstore/MongoChangeSetPersister.java
+++ b/spring-data-mongodb-cross-store/src/main/java/org/springframework/data/mongodb/crossstore/MongoChangeSetPersister.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.
@@ -34,6 +34,10 @@ import com.mongodb.DBCollection;
 import com.mongodb.DBObject;
 import com.mongodb.MongoException;

+/**
+ * @author Thomas Risberg
+ * @author Oliver Gierke
+ */
 public class MongoChangeSetPersister implements ChangeSetPersister<Object> {

 	private static final String ENTITY_CLASS = "_entity_class";
@@ -58,6 +62,10 @@ public class MongoChangeSetPersister implements ChangeSetPersister<Object> {
 		this.entityManagerFactory = entityManagerFactory;
 	}

+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.crossstore.ChangeSetPersister#getPersistentState(java.lang.Class, java.lang.Object, org.springframework.data.crossstore.ChangeSet)
+	 */
 	public void getPersistentState(Class<? extends ChangeSetBacked> entityClass, Object id, final ChangeSet changeSet)
 			throws DataAccessException, NotFoundException {

@@ -100,6 +108,10 @@ public class MongoChangeSetPersister implements ChangeSetPersister<Object> {
 		});
 	}

+	/*
+	 * (non-Javadoc)
+	 * @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) {
@@ -109,6 +121,10 @@ public class MongoChangeSetPersister implements ChangeSetPersister<Object> {
 		return o;
 	}

+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.crossstore.ChangeSetPersister#persistState(org.springframework.data.crossstore.ChangeSetBacked, org.springframework.data.crossstore.ChangeSet)
+	 */
 	public Object persistState(ChangeSetBacked entity, ChangeSet cs) throws DataAccessException {
 		if (cs == null) {
 			log.debug("Flush: changeset was null, nothing to flush.");
@@ -169,8 +185,13 @@ public class MongoChangeSetPersister implements ChangeSetPersister<Object> {
 		return 0L;
 	}

+	/**
+	 * Returns the collection the given entity type shall be persisted to.
+	 * 
+	 * @param entityClass must not be {@literal null}.
+	 * @return
+	 */
 	private String getCollectionNameForEntity(Class<? extends ChangeSetBacked> entityClass) {
-		return ClassUtils.getQualifiedName(entityClass);
+		return mongoTemplate.getCollectionName(entityClass);
 	}
-
 }
--- a/spring-data-mongodb-cross-store/src/main/java/org/springframework/data/mongodb/crossstore/package-info.java
+++ b/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;
+
--- a/spring-data-mongodb-cross-store/src/test/java/org/springframework/data/mongodb/crossstore/CrossStoreMongoTests.java
+++ b/spring-data-mongodb-cross-store/src/test/java/org/springframework/data/mongodb/crossstore/CrossStoreMongoTests.java
@@ -36,9 +36,14 @@ import org.springframework.transaction.annotation.Transactional;
 import org.springframework.transaction.support.TransactionCallback;
 import org.springframework.transaction.support.TransactionTemplate;

-import com.mongodb.DBCollection;
 import com.mongodb.DBObject;

+/**
+ * Integration tests for MongoDB cross-store persistence (mainly {@link MongoChangeSetPersister}).
+ * 
+ * @author Thomas Risberg
+ * @author Oliver Gierke
+ */
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration("classpath:/META-INF/spring/applicationContext.xml")
 public class CrossStoreMongoTests {
@@ -58,7 +63,7 @@ public class CrossStoreMongoTests {

 		txTemplate = new TransactionTemplate(transactionManager);

-		clearData(Person.class.getName());
+		clearData(Person.class);

 		Address address = new Address(12, "MAin St.", "Boston", "MA", "02101");

@@ -91,11 +96,10 @@ public class CrossStoreMongoTests {
 		});
 	}

-	private void clearData(String collectionName) {
-		DBCollection col = this.mongoTemplate.getCollection(collectionName);
-		if (col != null) {
-			this.mongoTemplate.dropCollection(collectionName);
-		}
+	private void clearData(Class<?> domainType) {
+
+		String collectionName = mongoTemplate.getCollectionName(domainType);
+		mongoTemplate.dropCollection(collectionName);
 	}

 	@Test
@@ -183,7 +187,7 @@ public class CrossStoreMongoTests {

 		boolean weFound3 = false;

-		for (DBObject dbo : this.mongoTemplate.getCollection(Person.class.getName()).find()) {
+		for (DBObject dbo : this.mongoTemplate.getCollection(mongoTemplate.getCollectionName(Person.class)).find()) {
 			Assert.assertTrue(!dbo.get("_entity_id").equals(2L));
 			if (dbo.get("_entity_id").equals(3L)) {
 				weFound3 = true;
--- a/spring-data-mongodb-distribution/pom.xml
+++ b/spring-data-mongodb-distribution/pom.xml
@@ -13,13 +13,12 @@
 	<parent>
 		<groupId>org.springframework.data</groupId>
 		<artifactId>spring-data-mongodb-parent</artifactId>
-		<version>1.2.0.RELEASE</version>
+		<version>1.3.2.RELEASE</version>
 		<relativePath>../pom.xml</relativePath>
 	</parent>
 	
 	<properties>
 		<project.root>${basedir}/..</project.root>
-		<dist.id>spring-data-mongodb</dist.id>
 		<dist.key>SDMONGO</dist.key>
 	</properties>

--- a/spring-data-mongodb-log4j/README.md
+++ b/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" : {
--- a/spring-data-mongodb-log4j/pom.xml
+++ b/spring-data-mongodb-log4j/pom.xml
@@ -5,7 +5,7 @@
 	<parent>
 		<groupId>org.springframework.data</groupId>
 		<artifactId>spring-data-mongodb-parent</artifactId>
-		<version>1.2.0.RELEASE</version>
+		<version>1.3.2.RELEASE</version>
 		<relativePath>../pom.xml</relativePath>
 	</parent>

--- a/spring-data-mongodb-log4j/src/main/java/org/springframework/data/mongodb/log4j/MongoLog4jAppender.java
+++ b/spring-data-mongodb-log4j/src/main/java/org/springframework/data/mongodb/log4j/MongoLog4jAppender.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,
@@ -13,7 +13,6 @@
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
-
 package org.springframework.data.mongodb.log4j;

 import java.net.UnknownHostException;
@@ -21,188 +20,207 @@ import java.util.Arrays;
 import java.util.Calendar;
 import java.util.Map;

-import com.mongodb.BasicDBList;
-import com.mongodb.BasicDBObject;
-import com.mongodb.DB;
-import com.mongodb.Mongo;
-import com.mongodb.WriteConcern;
 import org.apache.log4j.AppenderSkeleton;
 import org.apache.log4j.Level;
 import org.apache.log4j.MDC;
 import org.apache.log4j.PatternLayout;
 import org.apache.log4j.spi.LoggingEvent;

+import com.mongodb.BasicDBList;
+import com.mongodb.BasicDBObject;
+import com.mongodb.DB;
+import com.mongodb.Mongo;
+import com.mongodb.WriteConcern;
+
 /**
- * @author Jon Brisbin <jbrisbin@vmware.com>
+ * Log4j appender writing log entries into a MongoDB instance.
+ * 
+ * @author Jon Brisbin
+ * @author Oliver Gierke
 */
 public class MongoLog4jAppender extends AppenderSkeleton {

-  public static final String LEVEL = "level";
-  public static final String NAME = "name";
-  public static final String APP_ID = "applicationId";
-  public static final String TIMESTAMP = "timestamp";
-  public static final String PROPERTIES = "properties";
-  public static final String TRACEBACK = "traceback";
-  public static final String MESSAGE = "message";
-  public static final String YEAR = "year";
-  public static final String MONTH = "month";
-  public static final String DAY = "day";
-  public static final String HOUR = "hour";
+	public static final String LEVEL = "level";
+	public static final String NAME = "name";
+	public static final String APP_ID = "applicationId";
+	public static final String TIMESTAMP = "timestamp";
+	public static final String PROPERTIES = "properties";
+	public static final String TRACEBACK = "traceback";
+	public static final String MESSAGE = "message";
+	public static final String YEAR = "year";
+	public static final String MONTH = "month";
+	public static final String DAY = "day";
+	public static final String HOUR = "hour";

-  protected String host = "localhost";
-  protected int port = 27017;
-  protected String database = "logs";
-  protected String collectionPattern = "%c";
-  protected PatternLayout collectionLayout = new PatternLayout(collectionPattern);
-  protected String applicationId = System.getProperty("APPLICATION_ID", null);
-  protected WriteConcern warnOrHigherWriteConcern = WriteConcern.SAFE;
-  protected WriteConcern infoOrLowerWriteConcern = WriteConcern.NORMAL;
-  protected Mongo mongo;
-  protected DB db;
+	protected String host = "localhost";
+	protected int port = 27017;
+	protected String database = "logs";
+	protected String collectionPattern = "%c";
+	protected PatternLayout collectionLayout = new PatternLayout(collectionPattern);
+	protected String applicationId = System.getProperty("APPLICATION_ID", null);
+	protected WriteConcern warnOrHigherWriteConcern = WriteConcern.SAFE;
+	protected WriteConcern infoOrLowerWriteConcern = WriteConcern.NORMAL;
+	protected Mongo mongo;
+	protected DB db;

-  public MongoLog4jAppender() {
-  }
+	public MongoLog4jAppender() {
+	}

-  public MongoLog4jAppender(boolean isActive) {
-    super(isActive);
-  }
+	public MongoLog4jAppender(boolean isActive) {
+		super(isActive);
+	}

-  public String getHost() {
-    return host;
-  }
+	public String getHost() {
+		return host;
+	}

-  public void setHost(String host) {
-    this.host = host;
-  }
+	public void setHost(String host) {
+		this.host = host;
+	}

-  public int getPort() {
-    return port;
-  }
+	public int getPort() {
+		return port;
+	}

-  public void setPort(int port) {
-    this.port = port;
-  }
+	public void setPort(int port) {
+		this.port = port;
+	}

-  public String getDatabase() {
-    return database;
-  }
+	public String getDatabase() {
+		return database;
+	}

-  public void setDatabase(String database) {
-    this.database = database;
-  }
+	public void setDatabase(String database) {
+		this.database = database;
+	}

-  public String getCollectionPattern() {
-    return collectionPattern;
-  }
+	public String getCollectionPattern() {
+		return collectionPattern;
+	}

-  public void setCollectionPattern(String collectionPattern) {
-    this.collectionPattern = collectionPattern;
-    this.collectionLayout = new PatternLayout(collectionPattern);
-  }
+	public void setCollectionPattern(String collectionPattern) {
+		this.collectionPattern = collectionPattern;
+		this.collectionLayout = new PatternLayout(collectionPattern);
+	}

-  public String getApplicationId() {
-    return applicationId;
-  }
+	public String getApplicationId() {
+		return applicationId;
+	}

-  public void setApplicationId(String applicationId) {
-    this.applicationId = applicationId;
-  }
+	public void setApplicationId(String applicationId) {
+		this.applicationId = applicationId;
+	}

-  public void setWarnOrHigherWriteConcern(String wc) {
-    this.warnOrHigherWriteConcern = WriteConcern.valueOf(wc);
-  }
+	public void setWarnOrHigherWriteConcern(String wc) {
+		this.warnOrHigherWriteConcern = WriteConcern.valueOf(wc);
+	}

-  public String getWarnOrHigherWriteConcern() {
-    return warnOrHigherWriteConcern.toString();
-  }
+	public String getWarnOrHigherWriteConcern() {
+		return warnOrHigherWriteConcern.toString();
+	}

-  public String getInfoOrLowerWriteConcern() {
-    return infoOrLowerWriteConcern.toString();
-  }
+	public String getInfoOrLowerWriteConcern() {
+		return infoOrLowerWriteConcern.toString();
+	}

-  public void setInfoOrLowerWriteConcern(String wc) {
-    this.infoOrLowerWriteConcern = WriteConcern.valueOf(wc);
-  }
+	public void setInfoOrLowerWriteConcern(String wc) {
+		this.infoOrLowerWriteConcern = WriteConcern.valueOf(wc);
+	}

-  protected void connectToMongo() throws UnknownHostException {
-    this.mongo = new Mongo(host, port);
-    this.db = mongo.getDB(database);
-  }
+	protected void connectToMongo() throws UnknownHostException {
+		this.mongo = new Mongo(host, port);
+		this.db = mongo.getDB(database);
+	}

-  @SuppressWarnings({"unchecked"})
-  @Override
-  protected void append(final LoggingEvent event) {
-    if (null == db) {
-      try {
-        connectToMongo();
-      } catch (UnknownHostException e) {
-        throw new RuntimeException(e.getMessage(), e);
-      }
-    }
+	/*
+	 * (non-Javadoc)
+	 * @see org.apache.log4j.AppenderSkeleton#append(org.apache.log4j.spi.LoggingEvent)
+	 */
+	@Override
+	@SuppressWarnings({ "unchecked" })
+	protected void append(final LoggingEvent event) {
+		if (null == db) {
+			try {
+				connectToMongo();
+			} catch (UnknownHostException e) {
+				throw new RuntimeException(e.getMessage(), e);
+			}
+		}

-    BasicDBObject dbo = new BasicDBObject();
-    if (null != applicationId) {
-      dbo.put(APP_ID, applicationId);
-      MDC.put(APP_ID, applicationId);
-    }
-    dbo.put(NAME, event.getLogger().getName());
-    dbo.put(LEVEL, event.getLevel().toString());
-    Calendar tstamp = Calendar.getInstance();
-    tstamp.setTimeInMillis(event.getTimeStamp());
-    dbo.put(TIMESTAMP, tstamp.getTime());
+		BasicDBObject dbo = new BasicDBObject();
+		if (null != applicationId) {
+			dbo.put(APP_ID, applicationId);
+			MDC.put(APP_ID, applicationId);
+		}
+		dbo.put(NAME, event.getLogger().getName());
+		dbo.put(LEVEL, event.getLevel().toString());
+		Calendar tstamp = Calendar.getInstance();
+		tstamp.setTimeInMillis(event.getTimeStamp());
+		dbo.put(TIMESTAMP, tstamp.getTime());

-    // Copy properties into document
-    Map<Object, Object> props = event.getProperties();
-    if (null != props && props.size() > 0) {
-      BasicDBObject propsDbo = new BasicDBObject();
-      for (Map.Entry<Object, Object> entry : props.entrySet()) {
-        propsDbo.put(entry.getKey().toString(), entry.getValue().toString());
-      }
-      dbo.put(PROPERTIES, propsDbo);
-    }
+		// Copy properties into document
+		Map<Object, Object> props = event.getProperties();
+		if (null != props && props.size() > 0) {
+			BasicDBObject propsDbo = new BasicDBObject();
+			for (Map.Entry<Object, Object> entry : props.entrySet()) {
+				propsDbo.put(entry.getKey().toString(), entry.getValue().toString());
+			}
+			dbo.put(PROPERTIES, propsDbo);
+		}

-    // Copy traceback info (if there is any) into the document
-    String[] traceback = event.getThrowableStrRep();
-    if (null != traceback && traceback.length > 0) {
-      BasicDBList tbDbo = new BasicDBList();
-      tbDbo.addAll(Arrays.asList(traceback));
-      dbo.put(TRACEBACK, tbDbo);
-    }
+		// Copy traceback info (if there is any) into the document
+		String[] traceback = event.getThrowableStrRep();
+		if (null != traceback && traceback.length > 0) {
+			BasicDBList tbDbo = new BasicDBList();
+			tbDbo.addAll(Arrays.asList(traceback));
+			dbo.put(TRACEBACK, tbDbo);
+		}

-    // Put the rendered message into the document
-    dbo.put(MESSAGE, event.getRenderedMessage());
+		// Put the rendered message into the document
+		dbo.put(MESSAGE, event.getRenderedMessage());

-    // Insert the document
-    Calendar now = Calendar.getInstance();
-    MDC.put(YEAR, now.get(Calendar.YEAR));
-    MDC.put(MONTH, String.format("%1$02d", now.get(Calendar.MONTH) + 1));
-    MDC.put(DAY, String.format("%1$02d", now.get(Calendar.DAY_OF_MONTH)));
-    MDC.put(HOUR, String.format("%1$02d", now.get(Calendar.HOUR_OF_DAY)));
+		// Insert the document
+		Calendar now = Calendar.getInstance();
+		MDC.put(YEAR, now.get(Calendar.YEAR));
+		MDC.put(MONTH, String.format("%1$02d", now.get(Calendar.MONTH) + 1));
+		MDC.put(DAY, String.format("%1$02d", now.get(Calendar.DAY_OF_MONTH)));
+		MDC.put(HOUR, String.format("%1$02d", now.get(Calendar.HOUR_OF_DAY)));

-    String coll = collectionLayout.format(event);
+		String coll = collectionLayout.format(event);

-    MDC.remove(YEAR);
-    MDC.remove(MONTH);
-    MDC.remove(DAY);
-    MDC.remove(HOUR);
-    if (null != applicationId) {
-      MDC.remove(APP_ID);
-    }
+		MDC.remove(YEAR);
+		MDC.remove(MONTH);
+		MDC.remove(DAY);
+		MDC.remove(HOUR);
+		if (null != applicationId) {
+			MDC.remove(APP_ID);
+		}

-    WriteConcern wc;
-    if (event.getLevel().isGreaterOrEqual(Level.WARN)) {
-      wc = warnOrHigherWriteConcern;
-    } else {
-      wc = infoOrLowerWriteConcern;
-    }
-    db.getCollection(coll).insert(dbo, wc);
-  }
+		WriteConcern wc;
+		if (event.getLevel().isGreaterOrEqual(Level.WARN)) {
+			wc = warnOrHigherWriteConcern;
+		} else {
+			wc = infoOrLowerWriteConcern;
+		}
+		db.getCollection(coll).insert(dbo, wc);
+	}

-  public void close() {
-    mongo.close();
-  }
+	/*
+	 * (non-Javadoc)
+	 * @see org.apache.log4j.AppenderSkeleton#close()
+	 */
+	public void close() {

-  public boolean requiresLayout() {
-    return true;
-  }
+		if (mongo != null) {
+			mongo.close();
+		}
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.apache.log4j.AppenderSkeleton#requiresLayout()
+	 */
+	public boolean requiresLayout() {
+		return true;
+	}
 }
--- a/spring-data-mongodb-log4j/src/main/java/org/springframework/data/mongodb/log4j/package-info.java
+++ b/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;
+
--- a/spring-data-mongodb-log4j/src/test/java/org/springframework/data/mongodb/log4j/AppenderTest.java
+++ b/spring-data-mongodb-log4j/src/test/java/org/springframework/data/mongodb/log4j/AppenderTest.java
@@ -1,75 +0,0 @@
-/*
- * Copyright (c) 2011 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.
- * 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.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 {
-
-  private static final String NAME = AppenderTest.class.getName();
-  private Logger log = Logger.getLogger(NAME);
-  private Mongo mongo;
-  private DB db;
-  private 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);
-    }
-  }
-
-  @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));
-
-  }
-
-  @Test
-  public void testProperties() {
-    MDC.put("property", "one");
-    log.debug("DEBUG message");
-  }
-
-}
--- a/spring-data-mongodb-log4j/src/test/java/org/springframework/data/mongodb/log4j/MongoLog4jAppenderIntegrationTests.java
+++ b/spring-data-mongodb-log4j/src/test/java/org/springframework/data/mongodb/log4j/MongoLog4jAppenderIntegrationTests.java
@@ -0,0 +1,77 @@
+/*
+ * 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.log4j;
+
+import static org.hamcrest.Matchers.*;
+import static org.junit.Assert.*;
+
+import java.util.Calendar;
+
+import org.apache.log4j.Logger;
+import org.apache.log4j.MDC;
+import org.junit.Before;
+import org.junit.Test;
+
+import com.mongodb.DB;
+import com.mongodb.DBCursor;
+import com.mongodb.Mongo;
+
+/**
+ * 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() 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));
+	}
+
+	@Test
+	public void testProperties() {
+
+		MDC.put("property", "one");
+		log.debug("DEBUG message");
+	}
+}
--- a/spring-data-mongodb-log4j/src/test/java/org/springframework/data/mongodb/log4j/MongoLog4jAppenderUnitTests.java
+++ b/spring-data-mongodb-log4j/src/test/java/org/springframework/data/mongodb/log4j/MongoLog4jAppenderUnitTests.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.log4j;
+
+import org.junit.Test;
+
+/**
+ * Unit tests for {@link MongoLog4jAppender}.
+ * 
+ * @author Oliver Gierke
+ */
+public class MongoLog4jAppenderUnitTests {
+
+	/**
+	 * @see DATAMONGO-641
+	 */
+	@Test
+	public void closesWithoutMongoInstancePresent() {
+		new MongoLog4jAppender().close();
+	}
+}
--- a/spring-data-mongodb-log4j/src/test/resources/log4j.properties
+++ b/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
--- a/spring-data-mongodb/Spring
+++ b/spring-data-mongodb/Spring
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
-<context version="7.0.3.1152">
+<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"/>
@@ -10,6 +10,7 @@
                    <element name="**.config.**" type="WeakTypePattern"/>
                </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"/>
            </element>
@@ -93,6 +94,12 @@
                    <dependency type="AllowedDependency" toName="Project|spring-data-mongodb::Layer|Core::Subsystem|Query"/>
                </element>
            </element>
+            <element name="API" type="Subsystem">
+                <element name="Assignment" type="TypeFilter">
+                    <element name="org.springframework.data.mongodb.*" type="IncludeTypePattern"/>
+                </element>
+                <stereotype name="Public"/>
+            </element>
        </architecture>
        <workspace>
            <element name="src/main/java" type="JavaRootDirectory">
--- a/spring-data-mongodb/pom.xml
+++ b/spring-data-mongodb/pom.xml
@@ -11,7 +11,7 @@
 	<parent>
 		<groupId>org.springframework.data</groupId>
 		<artifactId>spring-data-mongodb-parent</artifactId>
-		<version>1.2.0.RELEASE</version>
+		<version>1.3.2.RELEASE</version>
 		<relativePath>../pom.xml</relativePath>
 	</parent>

@@ -141,8 +141,8 @@

 			<plugin>
 				<groupId>com.mysema.maven</groupId>
-				<artifactId>maven-apt-plugin</artifactId>
-				<version>1.0.4</version>
+				<artifactId>apt-maven-plugin</artifactId>
+				<version>1.0.8</version>
 				<dependencies>
 					<dependency>
 						<groupId>com.mysema.querydsl</groupId>
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/config/AbstractMongoConfiguration.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/config/AbstractMongoConfiguration.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.
@@ -32,6 +32,7 @@ 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.MappingMongoConverter;
+import org.springframework.data.mongodb.core.mapping.CamelCaseAbbreviatingFieldNamingStrategy;
 import org.springframework.data.mongodb.core.mapping.Document;
 import org.springframework.data.mongodb.core.mapping.MongoMappingContext;
 import org.springframework.data.support.CachingIsNewStrategyFactory;
@@ -58,12 +59,12 @@ public abstract class AbstractMongoConfiguration {
 	protected abstract String getDatabaseName();

 	/**
-	 * Return the {@link Mongo} instance to connect to.
+	 * 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}.
 	 * 
 	 * @return
 	 * @throws Exception
 	 */
-	@Bean
 	public abstract Mongo mongo() throws Exception;

 	/**
@@ -134,7 +135,10 @@ public abstract class AbstractMongoConfiguration {
 		MongoMappingContext mappingContext = new MongoMappingContext();
 		mappingContext.setInitialEntitySet(getInitialEntitySet());
 		mappingContext.setSimpleTypeHolder(customConversions().getSimpleTypeHolder());
-		mappingContext.initialize();
+
+		if (abbreviateFieldNames()) {
+			mappingContext.setFieldNamingStrategy(new CamelCaseAbbreviatingFieldNamingStrategy());
+		}

 		return mappingContext;
 	}
@@ -205,4 +209,15 @@ public abstract class AbstractMongoConfiguration {

 		return initialEntitySet;
 	}
+
+	/**
+	 * Configures whether to abbreviate field names for domain objects by configuring a
+	 * {@link CamelCaseAbbreviatingFieldNamingStrategy} on the {@link MongoMappingContext} instance created. For advanced
+	 * customization needs, consider overriding {@link #mappingMongoConverter()}.
+	 * 
+	 * @return
+	 */
+	protected boolean abbreviateFieldNames() {
+		return false;
+	}
 }
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/config/BeanNames.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/config/BeanNames.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,
@@ -13,11 +13,14 @@
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
-
 package org.springframework.data.mongodb.config;

 /**
- * @author Jon Brisbin <jbrisbin@vmware.com>
+ * Constants to declare bean names used by the namespace configuration.
+ * 
+ * @author Jon Brisbin
+ * @author Oliver Gierke
+ * @author Martin Baumgartner
 */
 public abstract class BeanNames {

@@ -28,4 +31,6 @@ public abstract class BeanNames {
 	static final String VALIDATING_EVENT_LISTENER = "validatingMongoEventListener";
 	static final String IS_NEW_STRATEGY_FACTORY = "isNewStrategyFactory";
 	static final String DEFAULT_CONVERTER_BEAN_NAME = "mappingConverter";
+	static final String MONGO_TEMPLATE = "mongoTemplate";
+	static final String GRID_FS_TEMPLATE = "gridFsTemplate";
 }
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/config/GridFsTemplateParser.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/config/GridFsTemplateParser.java
@@ -0,0 +1,78 @@
+/*
+ * 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 org.springframework.beans.factory.BeanDefinitionStoreException;
+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.xml.AbstractBeanDefinitionParser;
+import org.springframework.beans.factory.xml.BeanDefinitionParser;
+import org.springframework.beans.factory.xml.ParserContext;
+import org.springframework.data.config.BeanComponentDefinitionBuilder;
+import org.springframework.data.mongodb.gridfs.GridFsTemplate;
+import org.springframework.util.StringUtils;
+import org.w3c.dom.Element;
+
+/**
+ * {@link BeanDefinitionParser} to parse {@code gridFsTemplate} elements into {@link BeanDefinition}s.
+ * 
+ * @author Martin Baumgartner
+ */
+class GridFsTemplateParser extends AbstractBeanDefinitionParser {
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.beans.factory.xml.AbstractBeanDefinitionParser#resolveId(org.w3c.dom.Element, org.springframework.beans.factory.support.AbstractBeanDefinition, org.springframework.beans.factory.xml.ParserContext)
+	 */
+	@Override
+	protected String resolveId(Element element, AbstractBeanDefinition definition, ParserContext parserContext)
+			throws BeanDefinitionStoreException {
+
+		String id = super.resolveId(element, definition, parserContext);
+		return StringUtils.hasText(id) ? id : BeanNames.GRID_FS_TEMPLATE;
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.beans.factory.xml.AbstractBeanDefinitionParser#parseInternal(org.w3c.dom.Element, org.springframework.beans.factory.xml.ParserContext)
+	 */
+	@Override
+	protected AbstractBeanDefinition parseInternal(Element element, ParserContext parserContext) {
+
+		BeanComponentDefinitionBuilder helper = new BeanComponentDefinitionBuilder(element, parserContext);
+
+		String converterRef = element.getAttribute("converter-ref");
+		String dbFactoryRef = element.getAttribute("db-factory-ref");
+
+		BeanDefinitionBuilder gridFsTemplateBuilder = BeanDefinitionBuilder.genericBeanDefinition(GridFsTemplate.class);
+
+		if (StringUtils.hasText(dbFactoryRef)) {
+			gridFsTemplateBuilder.addConstructorArgReference(dbFactoryRef);
+		} else {
+			gridFsTemplateBuilder.addConstructorArgReference(BeanNames.DB_FACTORY);
+		}
+
+		if (StringUtils.hasText(converterRef)) {
+			gridFsTemplateBuilder.addConstructorArgReference(converterRef);
+		} else {
+			gridFsTemplateBuilder.addConstructorArgReference(BeanNames.DEFAULT_CONVERTER_BEAN_NAME);
+		}
+
+		return (AbstractBeanDefinition) helper.getComponentIdButFallback(gridFsTemplateBuilder, BeanNames.GRID_FS_TEMPLATE)
+				.getBeanDefinition();
+	}
+}
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/config/MappingMongoConverterParser.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/config/MappingMongoConverterParser.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.
@@ -54,6 +54,7 @@ import org.springframework.data.mapping.context.MappingContextIsNewStrategyFacto
 import org.springframework.data.mongodb.core.convert.CustomConversions;
 import org.springframework.data.mongodb.core.convert.MappingMongoConverter;
 import org.springframework.data.mongodb.core.index.MongoPersistentEntityIndexCreator;
+import org.springframework.data.mongodb.core.mapping.CamelCaseAbbreviatingFieldNamingStrategy;
 import org.springframework.data.mongodb.core.mapping.Document;
 import org.springframework.data.mongodb.core.mapping.MongoMappingContext;
 import org.springframework.data.mongodb.core.mapping.event.ValidatingMongoEventListener;
@@ -69,6 +70,7 @@ import org.w3c.dom.Element;
 * @author Jon Brisbin
 * @author Oliver Gierke
 * @author Maciej Walkowiak
+ * @author Thomas Darimont
 */
 public class MappingMongoConverterParser implements BeanDefinitionParser {

@@ -104,6 +106,11 @@ 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);
 		}
@@ -118,6 +125,7 @@ public class MappingMongoConverterParser implements BeanDefinitionParser {
 					.genericBeanDefinition(MongoPersistentEntityIndexCreator.class);
 			indexHelperBuilder.addConstructorArgReference(ctxRef);
 			indexHelperBuilder.addConstructorArgReference(dbFactoryRef);
+			indexHelperBuilder.addDependsOn(ctxRef);

 			parserContext.registerBeanComponent(new BeanComponentDefinition(indexHelperBuilder.getBeanDefinition(),
 					INDEX_HELPER));
@@ -200,6 +208,12 @@ public class MappingMongoConverterParser implements BeanDefinitionParser {
 			mappingContextBuilder.addPropertyValue("simpleTypeHolder", simpleTypesDefinition);
 		}

+		String abbreviateFieldNames = element.getAttribute("abbreviate-field-names");
+		if ("true".equals(abbreviateFieldNames)) {
+			mappingContextBuilder.addPropertyValue("fieldNamingStrategy", new RootBeanDefinition(
+					CamelCaseAbbreviatingFieldNamingStrategy.class));
+		}
+
 		ctxRef = converterId + "." + MAPPING_CONTEXT;

 		parserContext.registerBeanComponent(componentDefinitionBuilder.getComponent(mappingContextBuilder, ctxRef));
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/config/MongoNamespaceHandler.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/config/MongoNamespaceHandler.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.
@@ -24,6 +24,7 @@ import org.springframework.data.repository.config.RepositoryConfigurationExtensi
 * {@link org.springframework.beans.factory.xml.NamespaceHandler} for Mongo DB configuration.
 * 
 * @author Oliver Gierke
+ * @author Martin Baumgartner
 */
 public class MongoNamespaceHandler extends NamespaceHandlerSupport {

@@ -42,5 +43,7 @@ public class MongoNamespaceHandler extends NamespaceHandlerSupport {
 		registerBeanDefinitionParser("db-factory", new MongoDbFactoryParser());
 		registerBeanDefinitionParser("jmx", new MongoJmxParser());
 		registerBeanDefinitionParser("auditing", new MongoAuditingBeanDefinitionParser());
+		registerBeanDefinitionParser("template", new MongoTemplateParser());
+		registerBeanDefinitionParser("gridFsTemplate", new GridFsTemplateParser());
 	}
 }
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/config/MongoTemplateParser.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/config/MongoTemplateParser.java
@@ -0,0 +1,86 @@
+/*
+ * 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.config;
+
+import static org.springframework.data.config.ParsingUtils.*;
+import static org.springframework.data.mongodb.config.MongoParsingUtils.*;
+
+import org.springframework.beans.factory.BeanDefinitionStoreException;
+import org.springframework.beans.factory.config.BeanDefinition;
+import org.springframework.beans.factory.parsing.BeanComponentDefinition;
+import org.springframework.beans.factory.support.AbstractBeanDefinition;
+import org.springframework.beans.factory.support.BeanDefinitionBuilder;
+import org.springframework.beans.factory.xml.AbstractBeanDefinitionParser;
+import org.springframework.beans.factory.xml.BeanDefinitionParser;
+import org.springframework.beans.factory.xml.ParserContext;
+import org.springframework.data.config.BeanComponentDefinitionBuilder;
+import org.springframework.data.mongodb.core.MongoTemplate;
+import org.springframework.util.StringUtils;
+import org.w3c.dom.Element;
+
+/**
+ * {@link BeanDefinitionParser} to parse {@code template} elements into {@link BeanDefinition}s.
+ * 
+ * @author Martin Baumgartner
+ */
+class MongoTemplateParser extends AbstractBeanDefinitionParser {
+
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.beans.factory.xml.AbstractBeanDefinitionParser#resolveId(org.w3c.dom.Element, org.springframework.beans.factory.support.AbstractBeanDefinition, org.springframework.beans.factory.xml.ParserContext)
+	 */
+	@Override
+	protected String resolveId(Element element, AbstractBeanDefinition definition, ParserContext parserContext)
+			throws BeanDefinitionStoreException {
+
+		String id = super.resolveId(element, definition, parserContext);
+		return StringUtils.hasText(id) ? id : BeanNames.MONGO_TEMPLATE;
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.beans.factory.xml.AbstractBeanDefinitionParser#parseInternal(org.w3c.dom.Element, org.springframework.beans.factory.xml.ParserContext)
+	 */
+	@Override
+	protected AbstractBeanDefinition parseInternal(Element element, ParserContext parserContext) {
+
+		BeanComponentDefinitionBuilder helper = new BeanComponentDefinitionBuilder(element, parserContext);
+
+		String converterRef = element.getAttribute("converter-ref");
+		String dbFactoryRef = element.getAttribute("db-factory-ref");
+
+		BeanDefinitionBuilder mongoTemplateBuilder = BeanDefinitionBuilder.genericBeanDefinition(MongoTemplate.class);
+		setPropertyValue(mongoTemplateBuilder, element, "write-concern", "writeConcern");
+
+		if (StringUtils.hasText(dbFactoryRef)) {
+			mongoTemplateBuilder.addConstructorArgReference(dbFactoryRef);
+		} else {
+			mongoTemplateBuilder.addConstructorArgReference(BeanNames.DB_FACTORY);
+		}
+
+		if (StringUtils.hasText(converterRef)) {
+			mongoTemplateBuilder.addConstructorArgReference(converterRef);
+		}
+
+		BeanDefinitionBuilder writeConcernPropertyEditorBuilder = getWriteConcernPropertyEditorBuilder();
+
+		BeanComponentDefinition component = helper.getComponent(writeConcernPropertyEditorBuilder);
+		parserContext.registerBeanComponent(component);
+
+		return (AbstractBeanDefinition) helper.getComponentIdButFallback(mongoTemplateBuilder, BeanNames.MONGO_TEMPLATE)
+				.getBeanDefinition();
+	}
+}
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/config/ServerAddressPropertyEditor.java
+++ b/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.
@@ -31,6 +31,7 @@ import com.mongodb.ServerAddress;
 * 
 * @author Mark Pollack
 * @author Oliver Gierke
+ * @author Thomas Darimont
 */
 public class ServerAddressPropertyEditor extends PropertyEditorSupport {

@@ -43,6 +44,11 @@ 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);

--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/DefaultIndexOperations.java
+++ b/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));
+							}
 						}
 					}

--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MongoDataIntegrityViolationException.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MongoDataIntegrityViolationException.java
@@ -0,0 +1,71 @@
+/*
+ * 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;
+
+import org.springframework.dao.DataIntegrityViolationException;
+import org.springframework.util.Assert;
+
+import com.mongodb.WriteResult;
+
+/**
+ * Mongo-specific {@link DataIntegrityViolationException}.
+ * 
+ * @author Oliver Gierke
+ */
+public class MongoDataIntegrityViolationException extends DataIntegrityViolationException {
+
+	private static final long serialVersionUID = -186980521176764046L;
+
+	private final WriteResult writeResult;
+	private final MongoActionOperation actionOperation;
+
+	/**
+	 * Creates a new {@link MongoDataIntegrityViolationException} using the given message and {@link WriteResult}.
+	 * 
+	 * @param message the exception message
+	 * @param writeResult the {@link WriteResult} that causes the exception, must not be {@literal null}.
+	 * @param actionOperation the {@link MongoActionOperation} that caused the exception, must not be {@literal null}.
+	 */
+	public MongoDataIntegrityViolationException(String message, WriteResult writeResult,
+			MongoActionOperation actionOperation) {
+
+		super(message);
+
+		Assert.notNull(writeResult, "WriteResult must not be null!");
+		Assert.notNull(actionOperation, "MongoActionOperation must not be null!");
+
+		this.writeResult = writeResult;
+		this.actionOperation = actionOperation;
+	}
+
+	/**
+	 * Returns the {@link WriteResult} that caused the exception.
+	 * 
+	 * @return the writeResult
+	 */
+	public WriteResult getWriteResult() {
+		return writeResult;
+	}
+
+	/**
+	 * Returns the {@link MongoActionOperation} in which the current exception occured.
+	 * 
+	 * @return the actionOperation
+	 */
+	public MongoActionOperation getActionOperation() {
+		return actionOperation;
+	}
+}
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MongoDbUtils.java
+++ b/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 +26,13 @@ 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
 * @since 1.0
 */
 public abstract class MongoDbUtils {
@@ -131,8 +130,11 @@ 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);
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MongoFactoryBean.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MongoFactoryBean.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2012 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.
@@ -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) {
@@ -117,6 +148,7 @@ public class MongoFactoryBean implements FactoryBean<Mongo>, InitializingBean, D
 	 * (non-Javadoc)
 	 * @see org.springframework.beans.factory.InitializingBean#afterPropertiesSet()
 	 */
+	@SuppressWarnings("deprecation")
 	public void afterPropertiesSet() throws Exception {

 		Mongo mongo;
@@ -126,15 +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);
 		}
@@ -146,6 +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()
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MongoOperations.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MongoOperations.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.
@@ -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}.
@@ -408,16 +464,21 @@ public interface MongoOperations {
 	 *          specification
 	 * @param entityClass the parameterized type of the returned list.
 	 * @param collectionName name of the collection to retrieve the objects from
-	 * 
 	 * @return the converted object
 	 */
 	<T> T findOne(Query query, Class<T> entityClass, String collectionName);

+	boolean exists(Query query, String collectionName);
+
+	boolean exists(Query query, Class<?> entityClass);
+
+	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}.
@@ -433,7 +494,7 @@ 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}.
@@ -442,7 +503,6 @@ public interface MongoOperations {
 	 *          specification
 	 * @param entityClass the parameterized type of the returned list.
 	 * @param collectionName name of the collection to retrieve the objects from
-	 * 
 	 * @return the List of converted objects
 	 */
 	<T> List<T> find(Query query, Class<T> entityClass, String collectionName);
@@ -464,7 +524,6 @@ public interface MongoOperations {
 	 * @param id the id of the document to return
 	 * @param entityClass the type to convert the document to
 	 * @param collectionName the collection to query for the document
-	 * 
 	 * @param <T>
 	 * @return
 	 */
@@ -501,7 +560,7 @@ 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}.
@@ -510,7 +569,6 @@ public interface MongoOperations {
 	 *          specification
 	 * @param entityClass the parameterized type of the returned list.
 	 * @param collectionName name of the collection to retrieve the objects from
-	 * 
 	 * @return the converted object
 	 */
 	<T> T findAndRemove(Query query, Class<T> entityClass, String collectionName);
@@ -555,7 +613,7 @@ 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.
 	 * 
@@ -593,7 +651,7 @@ 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
@@ -610,7 +668,7 @@ 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
@@ -646,6 +704,18 @@ 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.
@@ -670,6 +740,19 @@ 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.
@@ -694,6 +777,19 @@ 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.
 	 * 
@@ -713,11 +809,12 @@ public interface MongoOperations {
 	 * 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 <T>
 	 * @param query
 	 * @param entityClass
 	 */
-	<T> void remove(Query query, Class<T> entityClass);
+	void remove(Query query, Class<?> entityClass);
+
+	void remove(Query query, Class<?> entityClass, String collectionName);

 	/**
 	 * Remove all documents from the specified collection that match the provided query document criteria. There is no
@@ -734,4 +831,4 @@ public interface MongoOperations {
 	 * @return
 	 */
 	MongoConverter getConverter();
-}
+}
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MongoTemplate.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MongoTemplate.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2012 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.
@@ -44,7 +44,6 @@ import org.springframework.core.convert.ConversionService;
 import org.springframework.core.io.Resource;
 import org.springframework.core.io.ResourceLoader;
 import org.springframework.dao.DataAccessException;
-import org.springframework.dao.DataIntegrityViolationException;
 import org.springframework.dao.InvalidDataAccessApiUsageException;
 import org.springframework.dao.OptimisticLockingFailureException;
 import org.springframework.data.authentication.UserCredentials;
@@ -54,10 +53,17 @@ 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.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;
@@ -69,9 +75,11 @@ import org.springframework.data.mongodb.core.mapping.MongoPersistentEntity;
 import org.springframework.data.mongodb.core.mapping.MongoPersistentProperty;
 import org.springframework.data.mongodb.core.mapping.MongoSimpleTypes;
 import org.springframework.data.mongodb.core.mapping.event.AfterConvertEvent;
+import org.springframework.data.mongodb.core.mapping.event.AfterDeleteEvent;
 import org.springframework.data.mongodb.core.mapping.event.AfterLoadEvent;
 import org.springframework.data.mongodb.core.mapping.event.AfterSaveEvent;
 import org.springframework.data.mongodb.core.mapping.event.BeforeConvertEvent;
+import org.springframework.data.mongodb.core.mapping.event.BeforeDeleteEvent;
 import org.springframework.data.mongodb.core.mapping.event.BeforeSaveEvent;
 import org.springframework.data.mongodb.core.mapping.event.MongoMappingEvent;
 import org.springframework.data.mongodb.core.mapreduce.GroupBy;
@@ -112,6 +120,10 @@ 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
 */
 public class MongoTemplate implements MongoOperations, ApplicationContextAware {

@@ -134,7 +146,8 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware {
 	private final MappingContext<? extends MongoPersistentEntity<?>, MongoPersistentProperty> mappingContext;
 	private final MongoDbFactory mongoDbFactory;
 	private final MongoExceptionTranslator exceptionTranslator = new MongoExceptionTranslator();
-	private final QueryMapper mapper;
+	private final QueryMapper queryMapper;
+	private final UpdateMapper updateMapper;

 	private WriteConcern writeConcern;
 	private WriteConcernResolver writeConcernResolver = DefaultWriteConcernResolver.INSTANCE;
@@ -187,7 +200,8 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware {

 		this.mongoDbFactory = mongoDbFactory;
 		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();
@@ -480,6 +494,24 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware {
 		}
 	}

+	public boolean exists(Query query, Class<?> entityClass) {
+		return exists(query, entityClass, determineCollectionName(entityClass));
+	}
+
+	public boolean exists(Query query, String collectionName) {
+		return exists(query, null, collectionName);
+	}
+
+	public boolean exists(Query query, Class<?> entityClass, String collectionName) {
+
+		if (query == null) {
+			throw new InvalidDataAccessApiUsageException("Query passed in to exist can't be null");
+		}
+
+		DBObject mappedQuery = queryMapper.getMappedObject(query.getQueryObject(), getPersistentEntity(entityClass));
+		return execute(collectionName, new FindCallback(mappedQuery)).hasNext();
+	}
+
 	// Find methods that take a Query to express the query and that return a List of objects.

 	public <T> List<T> find(Query query, Class<T> entityClass) {
@@ -534,8 +566,26 @@ 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");
@@ -585,7 +635,7 @@ 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>() {
@@ -650,10 +700,9 @@ 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());
@@ -662,12 +711,33 @@ 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());

-		if (mongoPersistentEntity == null || mongoPersistentEntity.hasVersionProperty()) {
-			BeanWrapper<PersistentEntity<Object, ?>, Object> wrapper = BeanWrapper.create(entity, null);
+		if (mongoPersistentEntity != null && mongoPersistentEntity.hasVersionProperty()) {
+			BeanWrapper<PersistentEntity<Object, ?>, Object> wrapper = BeanWrapper.create(entity,
+					this.mongoConverter.getConversionService());
 			wrapper.setProperty(mongoPersistentEntity.getVersionProperty(), 0);
 		}
 	}
@@ -770,8 +840,7 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware {

 		// Fresh instance -> initialize version property
 		if (version == null) {
-			beanWrapper.setProperty(versionProperty, 0);
-			doSave(collectionName, objectToSave, this.mongoConverter);
+			doInsert(collectionName, objectToSave, this.mongoConverter);
 		} else {

 			assertUpdateableIdIfNotSet(objectToSave);
@@ -792,29 +861,18 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware {
 			maybeEmitEvent(new BeforeSaveEvent<T>(objectToSave, dbObject));
 			Update update = Update.fromDBObject(dbObject, ID_FIELD);

-			updateFirst(query, update, objectToSave.getClass());
+			doUpdate(collectionName, query, update, objectToSave.getClass(), false, false);
 			maybeEmitEvent(new AfterSaveEvent<T>(objectToSave, dbObject));
 		}
 	}

-	@SuppressWarnings("unchecked")
 	protected <T> void doSave(String collectionName, T objectToSave, MongoWriter<T> writer) {

 		assertUpdateableIdIfNotSet(objectToSave);

-		DBObject dbDoc = new BasicDBObject();
-
 		maybeEmitEvent(new BeforeConvertEvent<T>(objectToSave));

-		if (!(objectToSave instanceof String)) {
-			writer.write(objectToSave, dbDoc);
-		} else {
-			try {
-				objectToSave = (T) 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());
@@ -898,6 +956,10 @@ 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);
 	}
@@ -906,6 +968,10 @@ 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);
 	}
@@ -914,6 +980,10 @@ 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) {

@@ -922,10 +992,10 @@ 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(),
+				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: "
@@ -941,7 +1011,7 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware {
 				if (entity != null && entity.hasVersionProperty() && !multi) {
 					if (writeResult.getN() == 0) {
 						throw new OptimisticLockingFailureException("Optimistic lock exception on saving entity: "
-								+ updateObj.toMap().toString());
+								+ updateObj.toMap().toString() + " to collection " + collectionName);
 					}
 				}

@@ -981,11 +1051,12 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware {

 		Assert.notNull(object);

-		MongoPersistentEntity<?> entity = mappingContext.getPersistentEntity(object.getClass());
+		Class<?> objectType = object.getClass();
+		MongoPersistentEntity<?> entity = mappingContext.getPersistentEntity(objectType);
 		MongoPersistentProperty idProp = entity == null ? null : entity.getIdProperty();

 		if (idProp == null) {
-			throw new MappingException("No id property found for object of type " + entity.getType().getName());
+			throw new MappingException("No id property found for object of type " + objectType);
 		}

 		ConversionService service = mongoConverter.getConversionService();
@@ -1014,24 +1085,35 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware {
 		}
 	}

-	public <T> void remove(Query query, Class<T> entityClass) {
-		Assert.notNull(query);
-		doRemove(determineCollectionName(entityClass), query, entityClass);
+	public void remove(Query query, String collectionName) {
+		remove(query, null, collectionName);
+	}
+
+	public void remove(Query query, Class<?> entityClass) {
+		remove(query, entityClass, determineCollectionName(entityClass));
+	}
+
+	public void remove(Query query, Class<?> entityClass, String collectionName) {
+		doRemove(collectionName, query, entityClass);
 	}

 	protected <T> void doRemove(final String collectionName, final Query query, final Class<T> entityClass) {

 		if (query == null) {
-			throw new InvalidDataAccessApiUsageException("Query passed in to remove can't be null");
+			throw new InvalidDataAccessApiUsageException("Query passed in to remove can't be null!");
 		}

+		Assert.hasText(collectionName, "Collection name must not be null or empty!");
+
 		final DBObject queryObject = query.getQueryObject();
 		final MongoPersistentEntity<?> entity = getPersistentEntity(entityClass);

 		execute(collectionName, new CollectionCallback<Void>() {
 			public Void doInCollection(DBCollection collection) throws MongoException, DataAccessException {

-				DBObject dboq = mapper.getMappedObject(queryObject, entity);
+				maybeEmitEvent(new BeforeDeleteEvent<T>(queryObject, entityClass));
+
+				DBObject dboq = queryMapper.getMappedObject(queryObject, entity);

 				MongoAction mongoAction = new MongoAction(writeConcern, MongoActionOperation.REMOVE, collectionName,
 						entityClass, null, queryObject);
@@ -1044,15 +1126,14 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware {
 				WriteResult wr = writeConcernToUse == null ? collection.remove(dboq) : collection.remove(dboq,
 						writeConcernToUse);
 				handleAnyWriteResultErrors(wr, dboq, MongoActionOperation.REMOVE);
+
+				maybeEmitEvent(new AfterDeleteEvent<T>(queryObject, entityClass));
+
 				return null;
 			}
 		});
 	}

-	public void remove(final Query query, String collectionName) {
-		doRemove(collectionName, query, null);
-	}
-
 	public <T> List<T> findAll(Class<T> entityClass) {
 		return executeFindMultiInternal(new FindCallback(null), null, new ReadDbObjectCallback<T>(mongoConverter,
 				entityClass), determineCollectionName(entityClass));
@@ -1127,7 +1208,7 @@ 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
@@ -1176,6 +1257,64 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware {

 	}

+	@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) {

 		String func = function;
@@ -1284,57 +1423,28 @@ 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);
 	}

 	/**
@@ -1348,14 +1458,43 @@ 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) {
@@ -1393,7 +1532,7 @@ 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);
 	}

@@ -1408,19 +1547,15 @@ 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)));
-		}
-
-		DBObject mappedQuery = mapper.getMappedObject(query, entity);
+		DBObject mappedUpdate = queryMapper.getMappedObject(update.getUpdateObject(), entity);
+		DBObject mappedQuery = queryMapper.getMappedObject(query, 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);
 	}

@@ -1647,7 +1782,7 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware {
 		}

 		if (writeResultChecking == WriteResultChecking.EXCEPTION) {
-			throw new DataIntegrityViolationException(message);
+			throw new MongoDataIntegrityViolationException(message, writeResult, operation);
 		} else {
 			LOGGER.error(message);
 			return;
@@ -1845,6 +1980,35 @@ 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;
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/Aggregation.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/Aggregation.java
@@ -0,0 +1,286 @@
+/*
+ * 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 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(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, 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());
+			}
+		}
+
+		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));
+		}
+	}
+}
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/AggregationOperation.java
+++ b/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);
+}
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/AggregationOperationContext.java
+++ b/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);
+}
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/AggregationResults.java
+++ b/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;
+	}
+}
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/ExposedFields.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/ExposedFields.java
@@ -0,0 +1,385 @@
+/*
+ * 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.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 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();
+		}
+
+		/**
+		 * Returns whether the field can be referred to using the given name.
+		 * 
+		 * @param input
+		 * @return
+		 */
+		public boolean canBeReferredToBy(String input) {
+			return getTarget().equals(input);
+		}
+
+		/*
+		 * (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 $} prefix.
+		 * 
+		 * @return
+		 */
+		public String getRaw() {
+			String target = field.getTarget();
+			return field.synthetic ? target : String.format("%s.%s", Fields.UNDERSCORE_ID, target);
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see java.lang.Object#toString()
+		 */
+		@Override
+		public String toString() {
+			return String.format("$%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();
+		}
+	}
+}
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/ExposedFieldsAggregationOperationContext.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/ExposedFieldsAggregationOperationContext.java
@@ -0,0 +1,80 @@
+/*
+ * 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.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;
+
+	/**
+	 * Creates a new {@link ExposedFieldsAggregationOperationContext} from the given {@link ExposedFields}.
+	 * 
+	 * @param exposedFields must not be {@literal null}.
+	 */
+	public ExposedFieldsAggregationOperationContext(ExposedFields exposedFields) {
+
+		Assert.notNull(exposedFields, "ExposedFields must not be null!");
+		this.exposedFields = exposedFields;
+	}
+
+	/* 
+	 * (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 getReference(field.getTarget());
+	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperationContext#getReference(java.lang.String)
+	 */
+	@Override
+	public FieldReference getReference(String name) {
+
+		ExposedField field = exposedFields.getField(name);
+
+		if (field != null) {
+			return new FieldReference(field);
+		}
+
+		throw new IllegalArgumentException(String.format("Invalid reference '%s'!", name));
+	}
+}
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/Field.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/Field.java
@@ -0,0 +1,39 @@
+/*
+ * 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();
+}
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/Fields.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/Fields.java
@@ -0,0 +1,271 @@
+/*
+ * 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.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 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 String UNDERSCORE_ID = "_id";
+	public static 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) {
+
+			Assert.hasText(name, "AggregationField name must not be null or empty!");
+
+			if (target == null && name.contains(".")) {
+				this.name = name.substring(name.indexOf(".") + 1);
+				this.target = name;
+			} else {
+				this.name = name;
+				this.target = target;
+			}
+		}
+
+		/*
+		 * (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 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;
+		}
+	}
+}
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/FieldsExposingAggregationOperation.java
+++ b/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();
+}
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/GeoNearOperation.java
+++ b/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()));
+	}
+}
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/GroupOperation.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/GroupOperation.java
@@ -0,0 +1,375 @@
+/*
+ * 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.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 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 + "]";
+		}
+	}
+}
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/LimitOperation.java
+++ b/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);
+	}
+}
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/MatchOperation.java
+++ b/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()));
+	}
+}
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/ProjectionOperation.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/ProjectionOperation.java
@@ -0,0 +1,661 @@
+/*
+ * 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.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.ExposedFields.FieldReference;
+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);
+	}
+
+	/**
+	 * 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);
+	}
+
+	/**
+	 * Builder for {@link ProjectionOperation}s on a field.
+	 * 
+	 * @author Oliver Gierke
+	 * @author Thomas Darimont
+	 */
+	public static class ProjectionOperationBuilder implements AggregationOperation {
+
+		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) {
+
+			Assert.hasText(name, "Field name must not be null or empty!");
+			Assert.notNull(operation, "ProjectionOperation must not be null!");
+
+			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
+		 */
+		public ProjectionOperation as(String alias) {
+
+			if (previousProjection != null) {
+				return this.operation.andReplaceLastOneWith(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 must not be 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 must not be 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 must not be 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 must not be 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, "Number must not be 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 must not be 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 must not be 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 must not be 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
+					FieldReference reference = context.getReference(field.getTarget());
+
+					if (field.getName().equals(field.getTarget())) {
+
+						// render field as included
+						return 1;
+					}
+
+					// render field reference
+					return reference.toString();
+				} 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);
+	}
+
+}
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/SkipOperation.java
+++ b/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);
+	}
+}
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/SortOperation.java
+++ b/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);
+	}
+}
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/TypeBasedAggregationOperationContext.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/TypeBasedAggregationOperationContext.java
@@ -0,0 +1,102 @@
+/*
+ * 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) {
+		PropertyPath path = PropertyPath.from(name, type);
+
+		PersistentPropertyPath<MongoPersistentProperty> propertyPath = mappingContext.getPersistentPropertyPath(path);
+
+		return getReferenceFor(field(path.getLeafProperty().getSegment(),
+				propertyPath.toDotPath(MongoPersistentProperty.PropertyToFieldNameConverter.INSTANCE)));
+	}
+
+	private FieldReference getReferenceFor(Field field) {
+		return new FieldReference(new ExposedField(field, true));
+	}
+}
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/TypedAggregation.java
+++ b/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;
+	}
+}
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/UnwindOperation.java
+++ b/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());
+	}
+}
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/package-info.java
+++ b/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;
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/CustomConversions.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/CustomConversions.java
@@ -17,9 +17,11 @@ package org.springframework.data.mongodb.core.convert;

 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Locale;
+import java.util.Map;
 import java.util.Set;

 import org.slf4j.Logger;
@@ -37,6 +39,7 @@ 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;
@@ -63,6 +66,7 @@ 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 List<Object> converters;

@@ -85,6 +89,7 @@ public class CustomConversions {
 		this.readingPairs = new HashSet<ConvertiblePair>();
 		this.writingPairs = new HashSet<ConvertiblePair>();
 		this.customSimpleTypes = new HashSet<Class<?>>();
+		this.cache = new HashMap<Class<?>, HashMap<Class<?>, CacheValue>>();

 		this.converters = new ArrayList<Object>();
 		this.converters.add(CustomToStringConverter.INSTANCE);
@@ -94,6 +99,7 @@ public class CustomConversions {
 		this.converters.add(StringToBigIntegerConverter.INSTANCE);
 		this.converters.add(URLToStringConverter.INSTANCE);
 		this.converters.add(StringToURLConverter.INSTANCE);
+		this.converters.add(DBObjectToStringConverter.INSTANCE);
 		this.converters.addAll(JodaTimeConverters.getConvertersToRegister());
 		this.converters.addAll(converters);

@@ -268,9 +274,11 @@ public class CustomConversions {
 	 * @return
 	 */
 	public boolean hasCustomReadTarget(Class<?> source, Class<?> expectedTargetType) {
+
 		Assert.notNull(source);
 		Assert.notNull(expectedTargetType);
-		return getCustomTarget(source, expectedTargetType, readingPairs) != null;
+
+		return getCustomReadTarget(source, expectedTargetType) != null;
 	}

 	/**
@@ -299,8 +307,32 @@ public class CustomConversions {
 		return null;
 	}

+	private Class<?> getCustomReadTarget(Class<?> source, Class<?> expectedTargetType) {
+
+		Class<?> type = expectedTargetType == null ? PlaceholderType.class : expectedTargetType;
+
+		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);
+		}
+
+		return toReturn.clazz;
+	}
+
 	@WritingConverter
 	private enum CustomToStringConverter implements GenericConverter {
+
 		INSTANCE;

 		public Set<ConvertiblePair> getConvertibleTypes() {
@@ -313,4 +345,30 @@ public class CustomConversions {
 			return source.toString();
 		}
 	}
+
+	/**
+	 * 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
+	 */
+	private static class CacheValue {
+
+		public static final CacheValue NULL = new CacheValue(null);
+		private final Class<?> clazz;
+
+		public CacheValue(Class<?> clazz) {
+			this.clazz = clazz;
+		}
+	}
 }
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/DefaultMongoTypeMapper.java
+++ b/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
 	 */
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/MappingMongoConverter.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/MappingMongoConverter.java
@@ -71,6 +71,8 @@ import com.mongodb.DBRef;
 * 
 * @author Oliver Gierke
 * @author Jon Brisbin
+ * @author Patrik Wasik
+ * @author Thomas Darimont
 */
 public class MappingMongoConverter extends AbstractMongoConverter implements ApplicationContextAware {

@@ -123,6 +125,15 @@ 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
@@ -238,10 +249,7 @@ public class MappingMongoConverter extends AbstractMongoConverter implements App
 		entity.doWithProperties(new PropertyHandler<MongoPersistentProperty>() {
 			public void doWithPersistentProperty(MongoPersistentProperty prop) {

-				boolean isConstructorProperty = entity.isConstructorArgument(prop);
-				boolean hasValueForProperty = dbo.containsField(prop.getFieldName());
-
-				if (!hasValueForProperty || isConstructorProperty) {
+				if (!dbo.containsField(prop.getFieldName()) || entity.isConstructorArgument(prop)) {
 					return;
 				}

@@ -358,8 +366,7 @@ 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
@@ -414,8 +421,7 @@ public class MappingMongoConverter extends AbstractMongoConverter implements App
 		}

 		if (valueType.isMap()) {
-			BasicDBObject mapDbObj = new BasicDBObject();
-			writeMapInternal((Map<Object, Object>) obj, mapDbObj, type);
+			DBObject mapDbObj = createMap((Map<Object, Object>) obj, prop);
 			dbo.put(name, mapDbObj);
 			return;
 		}
@@ -495,6 +501,42 @@ public class MappingMongoConverter extends AbstractMongoConverter implements App
 		return dbList;
 	}

+	/**
+	 * Writes the given {@link Map} using the given {@link MongoPersistentProperty} information.
+	 * 
+	 * @param map must not {@literal null}.
+	 * @param property must not be {@literal null}.
+	 * @return
+	 */
+	protected DBObject createMap(Map<Object, Object> map, MongoPersistentProperty property) {
+
+		Assert.notNull(map, "Given map must not be null!");
+		Assert.notNull(property, "PersistentProperty must not be null!");
+
+		if (!property.isDbReference()) {
+			return writeMapInternal(map, new BasicDBObject(), property.getTypeInformation());
+		}
+
+		BasicDBObject dbObject = new BasicDBObject();
+
+		for (Map.Entry<Object, Object> entry : map.entrySet()) {
+
+			Object key = entry.getKey();
+			Object value = entry.getValue();
+
+			if (conversions.isSimpleType(key.getClass())) {
+
+				String simpleKey = potentiallyEscapeMapKey(key.toString());
+				dbObject.put(simpleKey, value != null ? createDBRef(value, property.getDBRef()) : null);
+
+			} else {
+				throw new MappingException("Cannot use a complex object as a key value.");
+			}
+		}
+
+		return dbObject;
+	}
+
 	/**
 	 * Populates the given {@link BasicDBList} with values from the given {@link Collection}.
 	 * 
@@ -832,7 +874,7 @@ public class MappingMongoConverter extends AbstractMongoConverter implements App
 			return conversionService.convert(obj, target);
 		}

-		if (null != obj && conversions.isSimpleType(obj.getClass())) {
+		if (conversions.isSimpleType(obj.getClass())) {
 			// Doesn't need conversion
 			return getPotentiallyConvertedSimpleWrite(obj);
 		}
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/MongoConverter.java
+++ b/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();
 }
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/MongoConverters.java
+++ b/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();
+		}
+	}
 }
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/MongoTypeMapper.java
+++ b/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);
 }
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/QueryMapper.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/QueryMapper.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.
@@ -18,6 +18,7 @@ package org.springframework.data.mongodb.core.convert;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
+import java.util.Set;

 import org.bson.types.ObjectId;
 import org.springframework.core.convert.ConversionException;
@@ -29,6 +30,7 @@ import org.springframework.data.mapping.context.MappingContext;
 import org.springframework.data.mapping.context.PersistentPropertyPath;
 import org.springframework.data.mongodb.core.mapping.MongoPersistentEntity;
 import org.springframework.data.mongodb.core.mapping.MongoPersistentProperty;
+import org.springframework.data.mongodb.core.query.Query;
 import org.springframework.util.Assert;

 import com.mongodb.BasicDBList;
@@ -41,11 +43,11 @@ import com.mongodb.DBRef;
 * 
 * @author Jon Brisbin
 * @author Oliver Gierke
+ * @author Patryk Wasik
 */
 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;
@@ -73,9 +75,10 @@ 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);
 		}

@@ -83,11 +86,32 @@ public class QueryMapper {

 		for (String key : query.keySet()) {

-			MongoPersistentProperty targetProperty = getTargetProperty(key, entity);
-			String newKey = determineKey(key, entity);
-			Object value = query.get(key);
+			// TODO: remove one once QueryMapper can work with Query instances directly
+			if (Query.isRestrictedTypeKey(key)) {

-			result.put(newKey, getMappedValue(value, targetProperty, newKey));
+				@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 = entity == null ? new Field(key) : new MetadataBackedField(key, entity, mappingContext);
+
+			Object rawValue = query.get(key);
+			String newKey = field.getMappedKey();
+
+			if (isNestedKeyword(rawValue) && !field.isIdField()) {
+				Keyword keyword = new Keyword((DBObject) rawValue);
+				result.put(newKey, getMappedKeyword(field, keyword));
+			} else {
+				result.put(newKey, getMappedValue(field, rawValue));
+			}
 		}

 		return result;
@@ -96,63 +120,62 @@ public class QueryMapper {
 	/**
 	 * 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) {
+	private 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(condition instanceof DBObject ? 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, MongoPersistentProperty property) {
+	private DBObject getMappedKeyword(Field property, Keyword keyword) {

-		if (property.isAssociation()) {
-			convertAssociation(keyword.value, property);
-		}
+		boolean needsAssociationConversion = property.isAssociation() && !keyword.isExists();
+		Object value = keyword.getValue();

-		return new BasicDBObject(keyword.key, getMappedValue(keyword.value, property, keyword.key));
+		Object convertedValue = needsAssociationConversion ? convertAssociation(value, property.getProperty())
+				: 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, MongoPersistentProperty property, String newKey) {
+	private Object getMappedValue(Field documentField, Object value) {

-		if (property == null) {
-			return convertSimpleOrDBObject(source, null);
-		}
+		if (documentField.isIdField()) {

-		if (property.isIdProperty() || "_id".equals(newKey)) {
-
-			if (source instanceof DBObject) {
-				DBObject valueDbo = (DBObject) source;
+			if (value instanceof DBObject) {
+				DBObject valueDbo = (DBObject) value;
 				if (valueDbo.containsField("$in") || valueDbo.containsField("$nin")) {
 					String inKey = valueDbo.containsField("$in") ? "$in" : "$nin";
 					List<Object> ids = new ArrayList<Object>();
@@ -163,63 +186,25 @@ public class QueryMapper {
 				} else if (valueDbo.containsField("$ne")) {
 					valueDbo.put("$ne", convertId(valueDbo.get("$ne")));
 				} else {
-					return getMappedObject((DBObject) source, null);
+					return getMappedObject((DBObject) value, null);
 				}

 				return valueDbo;

 			} else {
-				return convertId(source);
+				return convertId(value);
 			}
 		}

-		if (property.isAssociation()) {
-			return Keyword.isKeyword(source) ? getMappedKeyword(new Keyword(source), property) : convertAssociation(source,
-					property);
+		if (isNestedKeyword(value)) {
+			return getMappedKeyword(new Keyword((DBObject) value), null);
 		}

-		return convertSimpleOrDBObject(source, mappingContext.getPersistentEntity(property));
-	}
-
-	private MongoPersistentProperty getTargetProperty(String key, MongoPersistentEntity<?> entity) {
-
-		if (isIdKey(key, entity)) {
-			return entity.getIdProperty();
+		if (documentField.isAssociation()) {
+			return convertAssociation(value, documentField.getProperty());
 		}

-		PersistentPropertyPath<MongoPersistentProperty> path = getPath(key, entity);
-		return path == null ? null : path.getLeafProperty();
-	}
-
-	private PersistentPropertyPath<MongoPersistentProperty> getPath(String key, MongoPersistentEntity<?> entity) {
-
-		if (entity == null) {
-			return null;
-		}
-
-		try {
-			PropertyPath path = PropertyPath.from(key, entity.getTypeInformation());
-			return mappingContext.getPersistentPropertyPath(path);
-		} catch (PropertyReferenceException e) {
-			return null;
-		}
-	}
-
-	/**
-	 * Returns the translated key assuming the given one is a propert (path) reference.
-	 * 
-	 * @param key the source key
-	 * @param entity the base entity
-	 * @return the translated key
-	 */
-	private String determineKey(String key, MongoPersistentEntity<?> entity) {
-
-		if (entity == null && DEFAULT_ID_NAMES.contains(key)) {
-			return "_id";
-		}
-
-		PersistentPropertyPath<MongoPersistentProperty> path = getPath(key, entity);
-		return path == null ? key : path.toDotPath(MongoPersistentProperty.PropertyToFieldNameConverter.INSTANCE);
+		return convertSimpleOrDBObject(value, documentField.getPropertyEntity());
 	}

 	/**
@@ -232,18 +217,30 @@ public class QueryMapper {
 	private Object convertSimpleOrDBObject(Object source, MongoPersistentEntity<?> entity) {

 		if (source instanceof BasicDBList) {
-			return converter.convertToMongoType(source);
+			return delegateConvertToMongoType(source, entity);
 		}

 		if (source instanceof DBObject) {
 			return getMappedObject((DBObject) source, entity);
 		}

+		return delegateConvertToMongoType(source, entity);
+	}
+
+	/**
+	 * 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);
 	}

 	/**
-	 * Converts the given source assuming it's actually an association to anoter object.
+	 * Converts the given source assuming it's actually an association to another object.
 	 * 
 	 * @param source
 	 * @param property
@@ -263,31 +260,19 @@ public class QueryMapper {
 			return result;
 		}

+		if (property.isMap()) {
+			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));
+			}
+			return result;
+		}
+
 		return source == null || source instanceof DBRef ? source : converter.toDBRef(source, property);
 	}

-	/**
-	 * Returns whether the given key will be considered an id key.
-	 * 
-	 * @param key
-	 * @param entity
-	 * @return
-	 */
-	private boolean isIdKey(String key, MongoPersistentEntity<?> entity) {
-
-		if (entity == null) {
-			return false;
-		}
-
-		MongoPersistentProperty idProperty = entity.getIdProperty();
-
-		if (idProperty != null) {
-			return idProperty.getName().equals(key) || idProperty.getFieldName().equals(key);
-		}
-
-		return DEFAULT_ID_NAMES.contains(key);
-	}
-
 	/**
 	 * Converts the given raw id value into either {@link ObjectId} or {@link String}.
 	 * 
@@ -302,7 +287,40 @@ 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("$");
 	}

 	/**
@@ -312,36 +330,237 @@ public class QueryMapper {
 	 */
 	private 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);
+		}
+
+		public boolean hasIterableValue() {
+			return value instanceof Iterable;
+		}
+
+		public String getKey() {
+			return key;
+		}
+
+		@SuppressWarnings("unchecked")
+		public <T> T getValue() {
+			return (T) value;
+		}
+	}
+
+	/**
+	 * Value object to represent a field and its meta-information.
+	 * 
+	 * @author Oliver Gierke
+	 */
+	private static class Field {
+
+		private static final String ID_KEY = "_id";
+
+		protected final String name;
+
+		/**
+		 * Creates a new {@link DocumentField} without meta-information but the given name.
+		 * 
+		 * @param name must not be {@literal null} or empty.
+		 */
+		public Field(String name) {
+
+			Assert.hasText(name, "Name must not be null!");
+			this.name = name;
+		}
+
+		/**
+		 * Returns a new {@link DocumentField} with the given name.
+		 * 
+		 * @param name must not be {@literal null} or empty.
+		 * @return
+		 */
+		public Field with(String name) {
+			return new Field(name);
+		}
+
+		/**
+		 * Returns whether the current field is the id field.
+		 * 
+		 * @return
+		 */
+		public boolean isIdField() {
+			return ID_KEY.equals(name);
+		}
+
+		/**
+		 * Returns the underlying {@link MongoPersistentProperty} backing the field.
+		 * 
+		 * @return
+		 */
+		public MongoPersistentProperty getProperty() {
+			return null;
+		}
+
+		/**
+		 * Returns the {@link MongoPersistentEntity} that field is conatined in.
+		 * 
+		 * @return
+		 */
+		public MongoPersistentEntity<?> getPropertyEntity() {
+			return null;
+		}
+
+		/**
+		 * Returns whether the field represents an association.
+		 * 
+		 * @return
+		 */
+		public boolean isAssociation() {
+			return false;
+		}
+
+		/**
+		 * Returns the key to be used in the mapped document eventually.
+		 * 
+		 * @return
+		 */
+		public String getMappedKey() {
+			return isIdField() ? ID_KEY : name;
+		}
+	}
+
+	/**
+	 * Extension of {@link DocumentField} to be backed with mapping metadata.
+	 * 
+	 * @author Oliver Gierke
+	 */
+	private static class MetadataBackedField extends Field {
+
+		private final MongoPersistentEntity<?> entity;
+		private final MappingContext<? extends MongoPersistentEntity<?>, MongoPersistentProperty> mappingContext;
+		private final MongoPersistentProperty property;
+
+		/**
+		 * Creates a new {@link MetadataBackedField} with the given name, {@link MongoPersistentEntity} and
+		 * {@link MappingContext}.
+		 * 
+		 * @param name must not be {@literal null} or empty.
+		 * @param entity must not be {@literal null}.
+		 * @param context must not be {@literal null}.
+		 */
+		public MetadataBackedField(String name, MongoPersistentEntity<?> entity,
+				MappingContext<? extends MongoPersistentEntity<?>, MongoPersistentProperty> context) {
+
+			super(name);
+
+			Assert.notNull(entity, "MongoPersistentEntity must not be null!");
+
+			this.entity = entity;
+			this.mappingContext = context;
+
+			PersistentPropertyPath<MongoPersistentProperty> path = getPath(name);
+			this.property = path == null ? null : path.getLeafProperty();
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.core.convert.QueryMapper.Field#with(java.lang.String)
+		 */
+		@Override
+		public MetadataBackedField with(String name) {
+			return new MetadataBackedField(name, entity, mappingContext);
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.core.convert.QueryMapper.Field#isIdKey()
+		 */
+		@Override
+		public boolean isIdField() {
+
+			MongoPersistentProperty idProperty = entity.getIdProperty();
+
+			if (idProperty != null) {
+				return idProperty.getName().equals(name) || idProperty.getFieldName().equals(name);
 			}

-			DBObject dbObject = (DBObject) value;
-			return dbObject.keySet().size() == 1 && dbObject.keySet().iterator().next().startsWith("$");
+			return DEFAULT_ID_NAMES.contains(name);
+		}
+
+		/* 
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.core.convert.QueryMapper.Field#getProperty()
+		 */
+		@Override
+		public MongoPersistentProperty getProperty() {
+			return property;
+		}
+
+		/* 
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.core.convert.QueryMapper.Field#getEntity()
+		 */
+		@Override
+		public MongoPersistentEntity<?> getPropertyEntity() {
+			MongoPersistentProperty property = getProperty();
+			return property == null ? null : mappingContext.getPersistentEntity(property);
+		}
+
+		/* 
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.core.convert.QueryMapper.Field#isAssociation()
+		 */
+		@Override
+		public boolean isAssociation() {
+
+			MongoPersistentProperty property = getProperty();
+			return property == null ? false : property.isAssociation();
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.core.convert.QueryMapper.Field#getTargetKey()
+		 */
+		@Override
+		public String getMappedKey() {
+
+			PersistentPropertyPath<MongoPersistentProperty> path = getPath(name);
+			return path == null ? name : path.toDotPath(MongoPersistentProperty.PropertyToFieldNameConverter.INSTANCE);
+		}
+
+		private PersistentPropertyPath<MongoPersistentProperty> getPath(String name) {
+
+			try {
+				PropertyPath path = PropertyPath.from(name, entity.getTypeInformation());
+				return mappingContext.getPersistentPropertyPath(path);
+			} catch (PropertyReferenceException e) {
+				return null;
+			}
 		}
 	}
 }
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/UpdateMapper.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/UpdateMapper.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.convert;
+
+import org.springframework.data.mongodb.core.mapping.MongoPersistentEntity;
+
+/**
+ * A subclass of {@link QueryMapper} that retains type information on the mongo types.
+ * 
+ * @author Thomas Darimont
+ */
+public class UpdateMapper extends QueryMapper {
+
+	private final MongoWriter<?> 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());
+	}
+}
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/package-info.java
+++ b/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;
+
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/geo/GeoResults.java
+++ b/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;
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/geo/package-info.java
+++ b/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;
+
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/index/CompoundIndex.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/index/CompoundIndex.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.
@@ -26,6 +26,8 @@ import java.lang.annotation.Target;
 * 
 * @author Jon Brisbin
 * @author Oliver Gierke
+ * @author Philipp Schneider
+ * @author Johno Crawford
 */
@Target({ ElementType.TYPE })
@Documented
@@ -69,4 +71,20 @@ public @interface CompoundIndex {
 	 * @return
 	 */
 	String collection() default "";
+
+	/**
+	 * If {@literal true} the index will be created in the background.
+	 * 
+	 * @see http://docs.mongodb.org/manual/core/indexes/#background-construction
+	 * @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;
 }
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/index/Index.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/index/Index.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.
@@ -18,18 +18,20 @@ package org.springframework.data.mongodb.core.index;
 import java.util.LinkedHashMap;
 import java.util.Map;

+import org.springframework.data.domain.Sort.Direction;
 import org.springframework.data.mongodb.core.query.Order;

 import com.mongodb.BasicDBObject;
 import com.mongodb.DBObject;

+@SuppressWarnings("deprecation")
 public class Index implements IndexDefinition {

 	public enum Duplicates {
 		RETAIN, DROP
 	}

-	private final Map<String, Order> fieldSpec = new LinkedHashMap<String, Order>();
+	private final Map<String, Direction> fieldSpec = new LinkedHashMap<String, Direction>();

 	private String name;

@@ -42,12 +44,37 @@ public class Index implements IndexDefinition {
 	public Index() {
 	}

-	public Index(String key, Order order) {
-		fieldSpec.put(key, order);
+	public Index(String key, Direction direction) {
+		fieldSpec.put(key, direction);
 	}

+	/**
+	 * Creates a new {@link Indexed} on the given key and {@link Order}.
+	 * 
+	 * @deprecated use {@link #Index(String, Direction)} instead.
+	 * @param key must not be {@literal null} or empty.
+	 * @param order must not be {@literal null}.
+	 */
+	@Deprecated
+	public Index(String key, Order order) {
+		this(key, order.toDirection());
+	}
+
+	/**
+	 * Adds the given field to the index.
+	 * 
+	 * @deprecated use {@link #on(String, Direction)} instead.
+	 * @param key must not be {@literal null} or empty.
+	 * @param order must not be {@literal null}.
+	 * @return
+	 */
+	@Deprecated
 	public Index on(String key, Order order) {
-		fieldSpec.put(key, order);
+		return on(key, order.toDirection());
+	}
+
+	public Index on(String key, Direction direction) {
+		fieldSpec.put(key, direction);
 		return this;
 	}

@@ -76,7 +103,7 @@ public class Index implements IndexDefinition {
 	public DBObject getIndexKeys() {
 		DBObject dbo = new BasicDBObject();
 		for (String k : fieldSpec.keySet()) {
-			dbo.put(k, (fieldSpec.get(k).equals(Order.ASCENDING) ? 1 : -1));
+			dbo.put(k, fieldSpec.get(k).equals(Direction.ASC) ? 1 : -1);
 		}
 		return dbo;
 	}
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/index/IndexField.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/index/IndexField.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2012 the original author or authors.
+ * Copyright 2012-2013 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 +15,7 @@
 */
 package org.springframework.data.mongodb.core.index;

+import org.springframework.data.domain.Sort.Direction;
 import org.springframework.data.mongodb.core.query.Order;
 import org.springframework.util.Assert;
 import org.springframework.util.ObjectUtils;
@@ -24,30 +25,38 @@ import org.springframework.util.ObjectUtils;
 * 
 * @author Oliver Gierke
 */
+@SuppressWarnings("deprecation")
 public final class IndexField {

 	private final String key;
-	private final Order order;
+	private final Direction direction;
 	private final boolean isGeo;

-	private IndexField(String key, Order order, boolean isGeo) {
+	private IndexField(String key, Direction direction, boolean isGeo) {

 		Assert.hasText(key);
-		Assert.isTrue(order != null ^ isGeo);
+		Assert.isTrue(direction != null ^ isGeo);

 		this.key = key;
-		this.order = order;
+		this.direction = direction;
 		this.isGeo = isGeo;
 	}

 	/**
 	 * Creates a default {@link IndexField} with the given key and {@link Order}.
 	 * 
+	 * @deprecated use {@link #create(String, Direction)}.
 	 * @param key must not be {@literal null} or emtpy.
-	 * @param order must not be {@literal null}.
+	 * @param direction must not be {@literal null}.
 	 * @return
 	 */
+	@Deprecated
 	public static IndexField create(String key, Order order) {
+		Assert.notNull(order);
+		return new IndexField(key, order.toDirection(), false);
+	}
+
+	public static IndexField create(String key, Direction order) {
 		Assert.notNull(order);
 		return new IndexField(key, order, false);
 	}
@@ -70,12 +79,23 @@ public final class IndexField {
 	}

 	/**
-	 * Returns the order of the {@link IndexField} or {@literal null} in case we have a geo index field.
+	 * Returns the direction of the {@link IndexField} or {@literal null} in case we have a geo index field.
 	 * 
-	 * @return the order
+	 * @deprecated use {@link #getDirection()} instead.
+	 * @return the direction
 	 */
+	@Deprecated
 	public Order getOrder() {
-		return order;
+		return Direction.ASC.equals(direction) ? Order.ASCENDING : Order.DESCENDING;
+	}
+
+	/**
+	 * Returns the direction of the {@link IndexField} or {@literal null} in case we have a geo index field.
+	 * 
+	 * @return the direction
+	 */
+	public Direction getDirection() {
+		return direction;
 	}

 	/**
@@ -104,7 +124,8 @@ public final class IndexField {

 		IndexField that = (IndexField) obj;

-		return this.key.equals(that.key) && ObjectUtils.nullSafeEquals(this.order, that.order) && this.isGeo == that.isGeo;
+		return this.key.equals(that.key) && ObjectUtils.nullSafeEquals(this.direction, that.direction)
+				&& this.isGeo == that.isGeo;
 	}

 	/* 
@@ -116,7 +137,7 @@ public final class IndexField {

 		int result = 17;
 		result += 31 * ObjectUtils.nullSafeHashCode(key);
-		result += 31 * ObjectUtils.nullSafeHashCode(order);
+		result += 31 * ObjectUtils.nullSafeHashCode(direction);
 		result += 31 * ObjectUtils.nullSafeHashCode(isGeo);
 		return result;
 	}
@@ -127,6 +148,6 @@ public final class IndexField {
 	 */
 	@Override
 	public String toString() {
-		return String.format("IndexField [ key: %s, order: %s, isGeo: %s]", key, order, isGeo);
+		return String.format("IndexField [ key: %s, direction: %s, isGeo: %s]", key, direction, isGeo);
 	}
 }
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/index/Indexed.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/index/Indexed.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,
@@ -13,7 +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 +23,10 @@ import java.lang.annotation.Target;
 /**
 * Mark a field to be indexed using MongoDB's indexing feature.
 * 
- * @author Jon Brisbin <jbrisbin@vmware.com>
+ * @author Jon Brisbin
+ * @author Oliver Gierke
+ * @author Philipp Schneider
+ * @author Johno Crawford
 */
@Target(ElementType.FIELD)
@Retention(RetentionPolicy.RUNTIME)
@@ -41,4 +43,20 @@ public @interface Indexed {
 	String name() default "";

 	String collection() default "";
+
+	/**
+	 * If {@literal true} the index will be created in the background.
+	 * 
+	 * @see http://docs.mongodb.org/manual/core/indexes/#background-construction
+	 * @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;
 }
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/index/MongoPersistentEntityIndexCreator.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/index/MongoPersistentEntityIndexCreator.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.
@@ -43,6 +43,8 @@ import com.mongodb.util.JSON;
 * 
 * @author Jon Brisbin
 * @author Oliver Gierke
+ * @author Philipp Schneider
+ * @author Johno Crawford
 */
 public class MongoPersistentEntityIndexCreator implements
 		ApplicationListener<MappingContextEvent<MongoPersistentEntity<?>, MongoPersistentProperty>> {
@@ -106,7 +108,8 @@ public class MongoPersistentEntityIndexCreator implements
 					String indexColl = StringUtils.hasText(index.collection()) ? index.collection() : entity.getCollection();
 					DBObject definition = (DBObject) JSON.parse(index.def());

-					ensureIndex(indexColl, index.name(), definition, index.unique(), index.dropDups(), index.sparse());
+					ensureIndex(indexColl, index.name(), definition, index.unique(), index.dropDups(), index.sparse(),
+							index.background(), index.expireAfterSeconds());

 					if (log.isDebugEnabled()) {
 						log.debug("Created compound index " + index);
@@ -140,7 +143,8 @@ public class MongoPersistentEntityIndexCreator implements
 						int direction = index.direction() == IndexDirection.ASCENDING ? 1 : -1;
 						DBObject definition = new BasicDBObject(persistentProperty.getFieldName(), direction);

-						ensureIndex(collection, name, definition, index.unique(), index.dropDups(), index.sparse());
+						ensureIndex(collection, name, definition, index.unique(), index.dropDups(), index.sparse(),
+								index.background(), index.expireAfterSeconds());

 						if (log.isDebugEnabled()) {
 							log.debug("Created property index " + index);
@@ -189,15 +193,22 @@ 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 dropDups, boolean sparse, boolean background, int expireAfterSeconds) {

 		DBObject opts = new BasicDBObject();
 		opts.put("name", name);
 		opts.put("dropDups", dropDups);
 		opts.put("sparse", sparse);
 		opts.put("unique", unique);
+		opts.put("background", background);
+
+		if (expireAfterSeconds != -1) {
+			opts.put("expireAfterSeconds", expireAfterSeconds);
+		}

 		mongoDbFactory.getDb().getCollection(collection).ensureIndex(indexDefinition, opts);
 	}
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/index/package-info.java
+++ b/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;
+
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapping/BasicMongoPersistentEntity.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapping/BasicMongoPersistentEntity.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.
@@ -15,20 +15,29 @@
 */
 package org.springframework.data.mongodb.core.mapping;

+import java.lang.reflect.Field;
 import java.util.Comparator;
+import java.util.HashMap;
+import java.util.Map;

 import org.springframework.beans.BeansException;
 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;
 import org.springframework.data.mapping.model.BasicPersistentEntity;
+import org.springframework.data.mapping.model.MappingException;
 import org.springframework.data.mongodb.MongoCollectionUtils;
 import org.springframework.data.util.TypeInformation;
 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;

 /**
@@ -37,10 +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 @DocumentField annotation!";
 	private final String collection;
 	private final SpelExpressionParser parser;
 	private final StandardEvaluationContext context;
@@ -89,6 +100,19 @@ public class BasicMongoPersistentEntity<T> extends BasicPersistentEntity<T, Mong
 		return expression.getValue(context, String.class);
 	}

+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mapping.model.BasicPersistentEntity#verify()
+	 */
+	@Override
+	public void verify() {
+
+		AssertFieldNameUniquenessHandler handler = new AssertFieldNameUniquenessHandler();
+
+		doWithProperties(handler);
+		doWithAssociations(handler);
+	}
+
 	/**
 	 * {@link Comparator} implementation inspecting the {@link MongoPersistentProperty}'s order.
 	 * 
@@ -115,4 +139,91 @@ public class BasicMongoPersistentEntity<T> extends BasicPersistentEntity<T, Mong
 			return o1.getFieldOrder() - o2.getFieldOrder();
 		}
 	}
+
+	/**
+	 * 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.
+	 * 
+	 * @author Oliver Gierke
+	 */
+	private static class AssertFieldNameUniquenessHandler implements PropertyHandler<MongoPersistentProperty>,
+			AssociationHandler<MongoPersistentProperty> {
+
+		private final Map<String, MongoPersistentProperty> properties = new HashMap<String, MongoPersistentProperty>();
+
+		public void doWithPersistentProperty(MongoPersistentProperty persistentProperty) {
+			assertUniqueness(persistentProperty);
+		}
+
+		public void doWithAssociation(Association<MongoPersistentProperty> association) {
+			assertUniqueness(association.getInverse());
+		}
+
+		private void assertUniqueness(MongoPersistentProperty property) {
+
+			String fieldName = property.getFieldName();
+			MongoPersistentProperty existingProperty = properties.get(fieldName);
+
+			if (existingProperty != null) {
+				throw new MappingException(String.format(AMBIGUOUS_FIELD_MAPPING, property.toString(),
+						existingProperty.toString(), fieldName));
+			}
+
+			properties.put(fieldName, property);
+		}
+	}
 }
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapping/BasicMongoPersistentProperty.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapping/BasicMongoPersistentProperty.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.
@@ -24,8 +24,10 @@ 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;
 import org.springframework.data.mapping.model.SimpleTypeHolder;
 import org.springframework.util.ReflectionUtils;
 import org.springframework.util.StringUtils;
@@ -37,6 +39,7 @@ import com.mongodb.DBObject;
 * 
 * @author Oliver Gierke
 * @author Patryk Wasik
+ * @author Thomas Darimont
 */
 public class BasicMongoPersistentProperty extends AnnotationBasedPersistentProperty<MongoPersistentProperty> implements
 		MongoPersistentProperty {
@@ -60,6 +63,8 @@ public class BasicMongoPersistentProperty extends AnnotationBasedPersistentPrope
 		CAUSE_FIELD = ReflectionUtils.findField(Throwable.class, "cause");
 	}

+	private final FieldNamingStrategy fieldNamingStrategy;
+
 	/**
 	 * Creates a new {@link BasicMongoPersistentProperty}.
 	 * 
@@ -67,10 +72,14 @@ public class BasicMongoPersistentProperty extends AnnotationBasedPersistentPrope
 	 * @param propertyDescriptor
 	 * @param owner
 	 * @param simpleTypeHolder
+	 * @param fieldNamingStrategy
 	 */
 	public BasicMongoPersistentProperty(Field field, PropertyDescriptor propertyDescriptor,
-			MongoPersistentEntity<?> owner, SimpleTypeHolder simpleTypeHolder) {
+			MongoPersistentEntity<?> owner, SimpleTypeHolder simpleTypeHolder, FieldNamingStrategy fieldNamingStrategy) {
+
 		super(field, propertyDescriptor, owner, simpleTypeHolder);
+		this.fieldNamingStrategy = fieldNamingStrategy == null ? PropertyNameFieldNamingStrategy.INSTANCE
+				: fieldNamingStrategy;

 		if (isIdProperty() && getFieldName() != ID_FIELD_NAME) {
 			LOG.warn("Customizing field name for id property not allowed! Custom name will not be considered!");
@@ -102,6 +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}.
 	 * 
@@ -110,12 +128,34 @@ 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 = getField().getAnnotation(
-				org.springframework.data.mongodb.core.mapping.Field.class);
-		return annotation != null && StringUtils.hasText(annotation.value()) ? annotation.value() : field.getName();
+		org.springframework.data.mongodb.core.mapping.Field annotation = findAnnotation(org.springframework.data.mongodb.core.mapping.Field.class);
+
+		if (annotation != null && StringUtils.hasText(annotation.value())) {
+			return annotation.value();
+		}
+
+		String fieldName = fieldNamingStrategy.getFieldName(this);
+
+		if (!StringUtils.hasText(fieldName)) {
+			throw new MappingException(String.format("Invalid (null or empty) field name returned for property %s by %s!",
+					this, fieldNamingStrategy.getClass()));
+		}
+
+		return fieldName;
 	}

 	/*
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapping/CachingMongoPersistentProperty.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapping/CachingMongoPersistentProperty.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.
@@ -38,10 +38,11 @@ public class CachingMongoPersistentProperty extends BasicMongoPersistentProperty
 	 * @param propertyDescriptor
 	 * @param owner
 	 * @param simpleTypeHolder
+	 * @param fieldNamingStrategy
 	 */
 	public CachingMongoPersistentProperty(Field field, PropertyDescriptor propertyDescriptor,
-			MongoPersistentEntity<?> owner, SimpleTypeHolder simpleTypeHolder) {
-		super(field, propertyDescriptor, owner, simpleTypeHolder);
+			MongoPersistentEntity<?> owner, SimpleTypeHolder simpleTypeHolder, FieldNamingStrategy fieldNamingStrategy) {
+		super(field, propertyDescriptor, owner, simpleTypeHolder, fieldNamingStrategy);
 	}

 	/*
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapping/CamelCaseAbbreviatingFieldNamingStrategy.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapping/CamelCaseAbbreviatingFieldNamingStrategy.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.mapping;
+
+import java.util.Locale;
+
+/**
+ * {@link FieldNamingStrategy} that abbreviates field names by using the very first letter of the camel case parts of
+ * the {@link MongoPersistentProperty}'s name.
+ * 
+ * @since 1.3
+ * @author Oliver Gierke
+ */
+public class CamelCaseAbbreviatingFieldNamingStrategy implements FieldNamingStrategy {
+
+	private static final String CAMEL_CASE_PATTERN = "(?<!(^|[A-Z]))(?=[A-Z])|(?<!^)(?=[A-Z][a-z])";
+
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.mapping.FieldNamingStrategy#getFieldName(org.springframework.data.mongodb.core.mapping.MongoPersistentProperty)
+	 */
+	public String getFieldName(MongoPersistentProperty property) {
+
+		String[] parts = property.getName().split(CAMEL_CASE_PATTERN);
+		StringBuilder builder = new StringBuilder();
+
+		for (String part : parts) {
+			builder.append(part.substring(0, 1).toLowerCase(Locale.US));
+		}
+
+		return builder.toString();
+	}
+}
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapping/FieldNamingStrategy.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapping/FieldNamingStrategy.java
@@ -0,0 +1,36 @@
+/*
+ * 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.mapping;
+
+/**
+ * SPI interface to determine how to name document fields in cases the field name is not manually defined.
+ * 
+ * @see DocumentField
+ * @see PropertyNameFieldNamingStrategy
+ * @see CamelCaseAbbreviatingFieldNamingStrategy
+ * @since 1.3
+ * @author Oliver Gierke
+ */
+public interface FieldNamingStrategy {
+
+	/**
+	 * Returns the field name to be used for the given {@link MongoPersistentProperty}.
+	 * 
+	 * @param property must not be {@literal null} or empty;
+	 * @return
+	 */
+	String getFieldName(MongoPersistentProperty property);
+}
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapping/MongoMappingContext.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapping/MongoMappingContext.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.
@@ -17,6 +17,7 @@ package org.springframework.data.mongodb.core.mapping;

 import java.beans.PropertyDescriptor;
 import java.lang.reflect.Field;
+import java.util.AbstractMap;

 import org.springframework.beans.BeansException;
 import org.springframework.context.ApplicationContext;
@@ -36,6 +37,9 @@ import org.springframework.data.util.TypeInformation;
 public class MongoMappingContext extends AbstractMappingContext<BasicMongoPersistentEntity<?>, MongoPersistentProperty>
 		implements ApplicationContextAware {

+	private static final FieldNamingStrategy DEFAULT_NAMING_STRATEGY = PropertyNameFieldNamingStrategy.INSTANCE;
+
+	private FieldNamingStrategy fieldNamingStrategy = DEFAULT_NAMING_STRATEGY;
 	private ApplicationContext context;

 	/**
@@ -45,13 +49,24 @@ public class MongoMappingContext extends AbstractMappingContext<BasicMongoPersis
 		setSimpleTypeHolder(MongoSimpleTypes.HOLDER);
 	}

+	/**
+	 * Configures the {@link FieldNamingStrategy} to be used to determine the field name if no manual mapping is applied.
+	 * Defaults to a strategy using the plain property name.
+	 * 
+	 * @param fieldNamingStrategy the {@link FieldNamingStrategy} to be used to determine the field name if no manual
+	 *          mapping is applied.
+	 */
+	public void setFieldNamingStrategy(FieldNamingStrategy fieldNamingStrategy) {
+		this.fieldNamingStrategy = fieldNamingStrategy == null ? DEFAULT_NAMING_STRATEGY : fieldNamingStrategy;
+	}
+
 	/*
 	 * (non-Javadoc)
 	 * @see org.springframework.data.mapping.context.AbstractMappingContext#shouldCreatePersistentEntityFor(org.springframework.data.util.TypeInformation)
 	 */
 	@Override
 	protected boolean shouldCreatePersistentEntityFor(TypeInformation<?> type) {
-		return !MongoSimpleTypes.HOLDER.isSimpleType(type.getType());
+		return !MongoSimpleTypes.HOLDER.isSimpleType(type.getType()) && !AbstractMap.class.isAssignableFrom(type.getType());
 	}

 	/*
@@ -61,7 +76,7 @@ public class MongoMappingContext extends AbstractMappingContext<BasicMongoPersis
 	@Override
 	public MongoPersistentProperty createPersistentProperty(Field field, PropertyDescriptor descriptor,
 			BasicMongoPersistentEntity<?> owner, SimpleTypeHolder simpleTypeHolder) {
-		return new CachingMongoPersistentProperty(field, descriptor, owner, simpleTypeHolder);
+		return new CachingMongoPersistentProperty(field, descriptor, owner, simpleTypeHolder, fieldNamingStrategy);
 	}

 	/*
@@ -86,8 +101,6 @@ public class MongoMappingContext extends AbstractMappingContext<BasicMongoPersis
 	 */
 	@Override
 	public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
-
 		this.context = applicationContext;
-		super.setApplicationContext(applicationContext);
 	}
 }
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapping/MongoPersistentProperty.java
+++ b/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.
 	 * 
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapping/PropertyNameFieldNamingStrategy.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapping/PropertyNameFieldNamingStrategy.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.mapping;
+
+/**
+ * {@link FieldNamingStrategy} simply using the {@link MongoPersistentProperty}'s name.
+ * 
+ * @since 1.3
+ * @author Oliver Gierke
+ */
+public enum PropertyNameFieldNamingStrategy implements FieldNamingStrategy {
+
+	INSTANCE;
+
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.mapping.FieldNamingStrategy#getFieldName(org.springframework.data.mongodb.core.mapping.MongoPersistentProperty)
+	 */
+	public String getFieldName(MongoPersistentProperty property) {
+		return property.getName();
+	}
+}
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapping/SimpleMongoMappingContext.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapping/SimpleMongoMappingContext.java
@@ -1,167 +0,0 @@
-/*
- * Copyright 2012-2012 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.mapping;
-
-import java.beans.PropertyDescriptor;
-import java.lang.reflect.Field;
-import java.util.Arrays;
-import java.util.List;
-
-import org.springframework.data.mapping.Association;
-import org.springframework.data.mapping.context.AbstractMappingContext;
-import org.springframework.data.mapping.model.AbstractPersistentProperty;
-import org.springframework.data.mapping.model.BasicPersistentEntity;
-import org.springframework.data.mapping.model.SimpleTypeHolder;
-import org.springframework.data.mongodb.MongoCollectionUtils;
-import org.springframework.data.util.TypeInformation;
-
-/**
- * @deprecated use {@link MongoMappingContext} instead.
- * @author Oliver Gierke
- */
-@Deprecated
-public class SimpleMongoMappingContext extends
-		AbstractMappingContext<SimpleMongoMappingContext.SimpleMongoPersistentEntity<?>, MongoPersistentProperty> {
-
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mapping.context.AbstractMappingContext#createPersistentEntity(org.springframework.data.util.TypeInformation)
-	 */
-	@Override
-	protected <T> SimpleMongoPersistentEntity<T> createPersistentEntity(TypeInformation<T> typeInformation) {
-		return new SimpleMongoPersistentEntity<T>(typeInformation);
-	}
-
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mapping.context.AbstractMappingContext#createPersistentProperty(java.lang.reflect.Field, java.beans.PropertyDescriptor, org.springframework.data.mapping.model.MutablePersistentEntity, org.springframework.data.mapping.model.SimpleTypeHolder)
-	 */
-	@Override
-	protected SimplePersistentProperty createPersistentProperty(Field field, PropertyDescriptor descriptor,
-			SimpleMongoPersistentEntity<?> owner, SimpleTypeHolder simpleTypeHolder) {
-		return new SimplePersistentProperty(field, descriptor, owner, simpleTypeHolder);
-	}
-
-	static class SimplePersistentProperty extends AbstractPersistentProperty<MongoPersistentProperty> implements
-			MongoPersistentProperty {
-
-		private static final List<String> ID_FIELD_NAMES = Arrays.asList("id", "_id");
-
-		/**
-		 * Creates a new {@link SimplePersistentProperty}.
-		 * 
-		 * @param field
-		 * @param propertyDescriptor
-		 * @param information
-		 */
-		public SimplePersistentProperty(Field field, PropertyDescriptor propertyDescriptor, MongoPersistentEntity<?> owner,
-				SimpleTypeHolder simpleTypeHolder) {
-			super(field, propertyDescriptor, owner, simpleTypeHolder);
-		}
-
-		/* (non-Javadoc)
-		 * @see org.springframework.data.mapping.BasicPersistentProperty#isIdProperty()
-		 */
-		public boolean isIdProperty() {
-			return ID_FIELD_NAMES.contains(field.getName());
-		}
-
-		/* (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.core.mapping.MongoPersistentProperty#getKey()
-		 */
-		public String getFieldName() {
-			return isIdProperty() ? "_id" : getName();
-		}
-
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.core.mapping.MongoPersistentProperty#getFieldOrder()
-		 */
-		public int getFieldOrder() {
-			return Integer.MAX_VALUE;
-		}
-
-		/* (non-Javadoc)
-		 * @see org.springframework.data.mapping.AbstractPersistentProperty#createAssociation()
-		 */
-		@Override
-		protected Association<MongoPersistentProperty> createAssociation() {
-			return new Association<MongoPersistentProperty>(this, null);
-		}
-
-		/* (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.core.mapping.MongoPersistentProperty#isDbReference()
-		 */
-		public boolean isDbReference() {
-			return false;
-		}
-
-		/* (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.core.mapping.MongoPersistentProperty#getDBRef()
-		 */
-		public DBRef getDBRef() {
-			return null;
-		}
-
-		/* (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.core.mapping.MongoPersistentProperty#isVersion()
-		 */
-		public boolean isVersionProperty() {
-			return false;
-		}
-
-		/* 
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.mapping.MongoPersistentProperty#usePropertyAccess()
-		 */
-		public boolean usePropertyAccess() {
-			return false;
-		}
-	}
-
-	static class SimpleMongoPersistentEntity<T> extends BasicPersistentEntity<T, MongoPersistentProperty> implements
-			MongoPersistentEntity<T> {
-
-		/**
-		 * @param information
-		 */
-		public SimpleMongoPersistentEntity(TypeInformation<T> information) {
-			super(information);
-		}
-
-		/* (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.core.mapping.MongoPersistentEntity#getCollection()
-		 */
-		public String getCollection() {
-			return MongoCollectionUtils.getPreferredCollectionName(getType());
-		}
-
-		/* (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.core.mapping.MongoPersistentEntity#getVersionProperty()
-		 */
-		public MongoPersistentProperty getVersionProperty() {
-			return null;
-		}
-
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.core.mapping.MongoPersistentEntity#hasVersionProperty()
-		 */
-		public boolean hasVersionProperty() {
-			return false;
-		}
-	}
-}
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapping/event/AbstractDeleteEvent.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapping/event/AbstractDeleteEvent.java
@@ -0,0 +1,50 @@
+/*
+ * Copyright 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.
+ * 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.mapping.event;
+
+import com.mongodb.DBObject;
+
+/**
+ * Base class for delete events.
+ * 
+ * @author Martin Baumgartner
+ */
+public abstract class AbstractDeleteEvent<T> extends MongoMappingEvent<DBObject> {
+
+	private static final long serialVersionUID = 1L;
+	private final Class<T> type;
+
+	/**
+	 * Creates a new {@link AbstractDeleteEvent} for the given {@link DBObject} and type.
+	 * 
+	 * @param dbo must not be {@literal null}.
+	 * @param type , possibly be {@literal null}.
+	 */
+	public AbstractDeleteEvent(DBObject dbo, Class<T> type) {
+
+		super(dbo, dbo);
+		this.type = type;
+	}
+
+	/**
+	 * Returns the type for which the {@link AbstractDeleteEvent} shall be invoked for.
+	 * 
+	 * @return
+	 */
+	public Class<T> getType() {
+		return type;
+	}
+}
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapping/event/AbstractMongoEventListener.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapping/event/AbstractMongoEventListener.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2011 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.
@@ -27,6 +27,7 @@ import com.mongodb.DBObject;
 * 
 * @author Jon Brisbin
 * @author Oliver Gierke
+ * @author Martin Baumgartner
 */
 public abstract class AbstractMongoEventListener<E> implements ApplicationListener<MongoMappingEvent<?>> {

@@ -45,6 +46,7 @@ public abstract class AbstractMongoEventListener<E> implements ApplicationListen
 	 * (non-Javadoc)
 	 * @see org.springframework.context.ApplicationListener#onApplicationEvent(org.springframework.context.ApplicationEvent)
 	 */
+	@SuppressWarnings("rawtypes")
 	public void onApplicationEvent(MongoMappingEvent<?> event) {

 		if (event instanceof AfterLoadEvent) {
@@ -57,6 +59,22 @@ public abstract class AbstractMongoEventListener<E> implements ApplicationListen
 			return;
 		}

+		if (event instanceof AbstractDeleteEvent) {
+
+			Class<?> eventDomainType = ((AbstractDeleteEvent) event).getType();
+
+			if (eventDomainType != null && domainClass.isAssignableFrom(eventDomainType)) {
+				if (event instanceof BeforeDeleteEvent) {
+					onBeforeDelete(event.getDBObject());
+				}
+				if (event instanceof AfterDeleteEvent) {
+					onAfterDelete(event.getDBObject());
+				}
+			}
+
+			return;
+		}
+
 		@SuppressWarnings("unchecked")
 		E source = (E) event.getSource();

@@ -78,31 +96,43 @@ public abstract class AbstractMongoEventListener<E> implements ApplicationListen

 	public void onBeforeConvert(E source) {
 		if (LOG.isDebugEnabled()) {
-			LOG.debug("onBeforeConvert(" + source + ")");
+			LOG.debug("onBeforeConvert({})", source);
 		}
 	}

 	public void onBeforeSave(E source, DBObject dbo) {
 		if (LOG.isDebugEnabled()) {
-			LOG.debug("onBeforeSave(" + source + ", " + dbo + ")");
+			LOG.debug("onBeforeSave({}, {})", source, dbo);
 		}
 	}

 	public void onAfterSave(E source, DBObject dbo) {
 		if (LOG.isDebugEnabled()) {
-			LOG.debug("onAfterSave(" + source + ", " + dbo + ")");
+			LOG.debug("onAfterSave({}, {})", source, dbo);
 		}
 	}

 	public void onAfterLoad(DBObject dbo) {
 		if (LOG.isDebugEnabled()) {
-			LOG.debug("onAfterLoad(" + dbo + ")");
+			LOG.debug("onAfterLoad({})", dbo);
 		}
 	}

 	public void onAfterConvert(DBObject dbo, E source) {
 		if (LOG.isDebugEnabled()) {
-			LOG.debug("onAfterConvert(" + dbo + "," + source + ")");
+			LOG.debug("onAfterConvert({}, {})", dbo, source);
+		}
+	}
+
+	public void onAfterDelete(DBObject dbo) {
+		if (LOG.isDebugEnabled()) {
+			LOG.debug("onAfterConvert({})", dbo);
+		}
+	}
+
+	public void onBeforeDelete(DBObject dbo) {
+		if (LOG.isDebugEnabled()) {
+			LOG.debug("onAfterConvert({})", dbo);
 		}
 	}
 }
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapping/event/AfterDeleteEvent.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapping/event/AfterDeleteEvent.java
@@ -0,0 +1,39 @@
+/*
+ * Copyright 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.
+ * 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.mapping.event;
+
+import com.mongodb.DBObject;
+
+/**
+ * Event being thrown after a single or a set of documents has/have been deleted. The {@link DBObject} held in the event
+ * will be the query document <em>after</am> it has been mapped onto the domain type handled.
+ * 
+ * @author Martin Baumgartner
+ */
+public class AfterDeleteEvent<T> extends AbstractDeleteEvent<T> {
+
+	private static final long serialVersionUID = 1L;
+
+	/**
+	 * Creates a new {@link AfterDeleteEvent} for the given {@link DBObject} and type.
+	 * 
+	 * @param dbo must not be {@literal null}.
+	 * @param type can be {@literal null}.
+	 */
+	public AfterDeleteEvent(DBObject dbo, Class<T> type) {
+		super(dbo, type);
+	}
+}
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapping/event/BeforeDeleteEvent.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapping/event/BeforeDeleteEvent.java
@@ -0,0 +1,39 @@
+/*
+ * Copyright 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.
+ * 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.mapping.event;
+
+import com.mongodb.DBObject;
+
+/**
+ * Event being thrown before a document is deleted. The {@link DBObject} held in the event will represent the query
+ * document <em>before</em> being mapped based on the domain class handled.
+ * 
+ * @author Martin Baumgartner
+ */
+public class BeforeDeleteEvent<T> extends AbstractDeleteEvent<T> {
+
+	private static final long serialVersionUID = -2627547705679734497L;
+
+	/**
+	 * Creates a new {@link BeforeDeleteEvent} for the given {@link DBObject} and type.
+	 * 
+	 * @param dbo must not be {@literal null}.
+	 * @param type can be {@literal null}.
+	 */
+	public BeforeDeleteEvent(DBObject dbo, Class<T> type) {
+		super(dbo, type);
+	}
+}
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapping/event/LoggingEventListener.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapping/event/LoggingEventListener.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.
@@ -17,15 +17,19 @@ package org.springframework.data.mongodb.core.mapping.event;

 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
+import org.springframework.context.ApplicationListener;

 import com.mongodb.DBObject;

 /**
- * @author Jon Brisbin <jbrisbin@vmware.com>
+ * {@link ApplicationListener} for Mongo mapping events logging the events.
+ * 
+ * @author Jon Brisbin
+ * @author Martin Baumgartner
 */
 public class LoggingEventListener extends AbstractMongoEventListener<Object> {

-	private static final Logger log = LoggerFactory.getLogger(LoggingEventListener.class);
+	private static final Logger LOGGER = LoggerFactory.getLogger(LoggingEventListener.class);

 	/*
 	 * (non-Javadoc)
@@ -33,7 +37,7 @@ public class LoggingEventListener extends AbstractMongoEventListener<Object> {
 	 */
 	@Override
 	public void onBeforeConvert(Object source) {
-		log.info("onBeforeConvert: " + source);
+		LOGGER.info("onBeforeConvert: {}", source);
 	}

 	/*
@@ -42,10 +46,7 @@ public class LoggingEventListener extends AbstractMongoEventListener<Object> {
 	 */
 	@Override
 	public void onBeforeSave(Object source, DBObject dbo) {
-		try {
-			log.info("onBeforeSave: " + source + ", " + dbo);
-		} catch (Throwable ignored) {
-		}
+		LOGGER.info("onBeforeSave: {}, {}", source, dbo);
 	}

 	/*
@@ -54,7 +55,7 @@ public class LoggingEventListener extends AbstractMongoEventListener<Object> {
 	 */
 	@Override
 	public void onAfterSave(Object source, DBObject dbo) {
-		log.info("onAfterSave: " + source + ", " + dbo);
+		LOGGER.info("onAfterSave: {}, {}", source, dbo);
 	}

 	/*
@@ -63,7 +64,7 @@ public class LoggingEventListener extends AbstractMongoEventListener<Object> {
 	 */
 	@Override
 	public void onAfterLoad(DBObject dbo) {
-		log.info("onAfterLoad: " + dbo);
+		LOGGER.info("onAfterLoad: {}", dbo);
 	}

 	/*
@@ -72,6 +73,24 @@ public class LoggingEventListener extends AbstractMongoEventListener<Object> {
 	 */
 	@Override
 	public void onAfterConvert(DBObject dbo, Object source) {
-		log.info("onAfterConvert: " + dbo + ", " + source);
+		LOGGER.info("onAfterConvert: {}, {}", dbo, source);
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.mapping.event.AbstractMongoEventListener#onAfterDelete(com.mongodb.DBObject)
+	 */
+	@Override
+	public void onAfterDelete(DBObject dbo) {
+		LOGGER.info("onAfterDelete: {}", dbo);
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.mapping.event.AbstractMongoEventListener#onBeforeDelete(com.mongodb.DBObject)
+	 */
+	@Override
+	public void onBeforeDelete(DBObject dbo) {
+		LOGGER.info("onBeforeDelete: {}", dbo);
 	}
 }
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapping/event/package-info.java
+++ b/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;
+
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapping/package-info.java
+++ b/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;
+
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapreduce/package-info.java
+++ b/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;
+
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/query/Criteria.java
+++ b/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 2010-2013 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.
@@ -39,6 +39,10 @@ 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
 */
 public class Criteria implements CriteriaDefinition {

@@ -396,34 +400,54 @@ 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;
 	}

@@ -468,6 +492,7 @@ public class Criteria implements CriteriaDefinition {
 				}
 			}
 		}
+
 		DBObject queryCriteria = new BasicDBObject();
 		if (isValue != NOT_SET) {
 			queryCriteria.put(this.key, this.isValue);
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/query/Field.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/query/Field.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.
@@ -17,15 +17,26 @@ package org.springframework.data.mongodb.core.query;

 import java.util.HashMap;
 import java.util.Map;
+import java.util.Map.Entry;
+
+import org.springframework.util.Assert;
+import org.springframework.util.ObjectUtils;

 import com.mongodb.BasicDBObject;
 import com.mongodb.DBObject;

+/**
+ * @author Thomas Risberg
+ * @author Oliver Gierke
+ * @author Patryk Wasik
+ */
 public class Field {

-	private Map<String, Integer> criteria = new HashMap<String, Integer>();
-
-	private Map<String, Object> slices = new HashMap<String, Object>();
+	private final Map<String, Integer> criteria = new HashMap<String, Integer>();
+	private final Map<String, Object> slices = new HashMap<String, Object>();
+	private final Map<String, Criteria> elemMatchs = new HashMap<String, Criteria>();
+	private String postionKey;
+	private int positionValue;

 	public Field include(String key) {
 		criteria.put(key, Integer.valueOf(1));
@@ -47,14 +58,104 @@ public class Field {
 		return this;
 	}

+	public Field elemMatch(String key, Criteria elemMatchCriteria) {
+		elemMatchs.put(key, elemMatchCriteria);
+		return this;
+	}
+
+	/**
+	 * The array field must appear in the query. Only one positional {@code $} operator can appear in the projection and
+	 * only one array field can appear in the query.
+	 * 
+	 * @param field query array field, must not be {@literal null} or empty.
+	 * @param value
+	 * @return
+	 */
+	public Field position(String field, int value) {
+
+		Assert.hasText(field, "DocumentField must not be null or empty!");
+
+		postionKey = field;
+		positionValue = value;
+
+		return this;
+	}
+
 	public DBObject getFieldsObject() {
+
 		DBObject dbo = new BasicDBObject();
+
 		for (String k : criteria.keySet()) {
-			dbo.put(k, (criteria.get(k)));
+			dbo.put(k, criteria.get(k));
 		}
+
 		for (String k : slices.keySet()) {
-			dbo.put(k, new BasicDBObject("$slice", (slices.get(k))));
+			dbo.put(k, new BasicDBObject("$slice", slices.get(k)));
 		}
+
+		for (Entry<String, Criteria> entry : elemMatchs.entrySet()) {
+			DBObject dbObject = new BasicDBObject("$elemMatch", entry.getValue().getCriteriaObject());
+			dbo.put(entry.getKey(), dbObject);
+		}
+
+		if (postionKey != null) {
+			dbo.put(postionKey + ".$", positionValue);
+		}
+
 		return dbo;
 	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see java.lang.Object#equals(java.lang.Object)
+	 */
+	@Override
+	public boolean equals(Object object) {
+
+		if (this == object) {
+			return true;
+		}
+
+		if (!(object instanceof Field)) {
+			return false;
+		}
+
+		Field that = (Field) object;
+
+		if (!this.criteria.equals(that.criteria)) {
+			return false;
+		}
+
+		if (!this.slices.equals(that.slices)) {
+			return false;
+		}
+
+		if (!this.elemMatchs.equals(that.elemMatchs)) {
+			return false;
+		}
+
+		boolean samePositionKey = this.postionKey == null ? that.postionKey == null : this.postionKey
+				.equals(that.postionKey);
+		boolean samePositionValue = this.positionValue == that.positionValue;
+
+		return samePositionKey && samePositionValue;
+	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see java.lang.Object#hashCode()
+	 */
+	@Override
+	public int hashCode() {
+
+		int result = 17;
+
+		result += 31 * ObjectUtils.nullSafeHashCode(this.criteria);
+		result += 31 * ObjectUtils.nullSafeHashCode(this.elemMatchs);
+		result += 31 * ObjectUtils.nullSafeHashCode(this.slices);
+		result += 31 * ObjectUtils.nullSafeHashCode(this.postionKey);
+		result += 31 * ObjectUtils.nullSafeHashCode(this.positionValue);
+
+		return result;
+	}
 }
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/query/NearQuery.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/query/NearQuery.java
@@ -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;
@@ -29,6 +30,7 @@ import com.mongodb.DBObject;
 * Builder class to build near-queries.
 * 
 * @author Oliver Gierke
+ * @author Thomas Darimont
 */
 public class NearQuery {

@@ -38,6 +40,7 @@ public class NearQuery {
 	private Metric metric;
 	private boolean spherical;
 	private Integer num;
+	private Integer skip;

 	/**
 	 * Creates a new {@link NearQuery}.
@@ -116,7 +119,7 @@ public class NearQuery {
 	}

 	/**
-	 * Configures the number of results to return.
+	 * Configures the maximum number of results to return.
 	 * 
 	 * @param num
 	 * @return
@@ -126,6 +129,29 @@ 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
+	 * @return
+	 */
+	public NearQuery with(Pageable pageable) {
+		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.
@@ -290,9 +316,18 @@ public class NearQuery {
 	 */
 	public NearQuery query(Query query) {
 		this.query = query;
+		this.skip = query.getSkip();
+		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}.
 	 * 
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/query/Order.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/query/Order.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.
@@ -15,11 +15,31 @@
 */
 package org.springframework.data.mongodb.core.query;

+import org.springframework.data.domain.Sort.Direction;
+
 /**
 * An enum that specifies the ordering for sort or index specifications
 * 
- * @author trisberg
+ * @deprecated prefer {@link Direction}
+ * @author Thomas Risberg
+ * @author Oliver Gierke
 */
+@Deprecated
 public enum Order {
-	ASCENDING, DESCENDING
+
+	ASCENDING {
+		@Override
+		public Direction toDirection() {
+			return Direction.ASC;
+		}
+	},
+
+	DESCENDING {
+		@Override
+		public Direction toDirection() {
+			return Direction.DESC;
+		}
+	};
+
+	public abstract Direction toDirection();
 }
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/query/Query.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/query/Query.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2012 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.
@@ -19,11 +19,15 @@ import static org.springframework.data.mongodb.core.query.SerializationUtils.*;
 import static org.springframework.util.ObjectUtils.*;

 import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashSet;
 import java.util.LinkedHashMap;
 import java.util.List;
+import java.util.Set;

 import org.springframework.data.domain.Pageable;
 import org.springframework.data.domain.Sort;
+import org.springframework.data.domain.Sort.Order;
 import org.springframework.data.mongodb.InvalidMongoDbApiUsageException;
 import org.springframework.util.Assert;

@@ -33,35 +37,47 @@ import com.mongodb.DBObject;
 /**
 * @author Thomas Risberg
 * @author Oliver Gierke
+ * @author Thomas Darimont
 */
 public class Query {

+	private final static String RESTRICTED_TYPES_KEY = "_$RESTRICTED_TYPES";
+
+	private final Set<Class<?>> restrictedTypes = new HashSet<Class<?>>();
 	private LinkedHashMap<String, Criteria> criteria = new LinkedHashMap<String, Criteria>();
 	private Field fieldSpec;
-	private Sort coreSort;
-	@SuppressWarnings("deprecation")
-	private org.springframework.data.mongodb.core.query.Sort sort;
+	private Sort sort;
 	private int skip;
 	private int limit;
 	private String hint;

 	/**
-	 * Static factory method to create a Query using the provided criteria
+	 * Static factory method to create a {@link Query} using the provided {@link Criteria}.
 	 * 
-	 * @param critera
+	 * @param criteria must not be {@literal null}.
 	 * @return
 	 */
-	public static Query query(Criteria critera) {
-		return new Query(critera);
+	public static Query query(Criteria criteria) {
+		return new Query(criteria);
 	}

-	public Query() {
-	}
+	public Query() {}

+	/**
+	 * Creates a new {@link Query} using the given {@link Criteria}.
+	 * 
+	 * @param criteria must not be {@literal null}.
+	 */
 	public Query(Criteria criteria) {
 		addCriteria(criteria);
 	}

+	/**
+	 * Adds the given {@link Criteria} to the current {@link Query}.
+	 * 
+	 * @param criteria must not be {@literal null}.
+	 * @return
+	 */
 	public Query addCriteria(Criteria criteria) {
 		CriteriaDefinition existing = this.criteria.get(criteria.getKey());
 		String key = criteria.getKey();
@@ -104,21 +120,6 @@ public class Query {
 		return this;
 	}

-	/**
-	 * Returns a {@link org.springframework.data.mongodb.core.query.Sort} instance to define ordering properties.
-	 * 
-	 * @deprecated use {@link #with(Sort)} instead
-	 * @return
-	 */
-	@Deprecated
-	public org.springframework.data.mongodb.core.query.Sort sort() {
-		if (this.sort == null) {
-			this.sort = new org.springframework.data.mongodb.core.query.Sort();
-		}
-
-		return this.sort;
-	}
-
 	/**
 	 * Sets the given pagination information on the {@link Query} instance. Will transparently set {@code skip} and
 	 * {@code limit} as well as applying the {@link Sort} instance defined with the {@link Pageable}.
@@ -150,22 +151,62 @@ public class Query {
 			return this;
 		}

-		if (this.coreSort == null) {
-			this.coreSort = sort;
+		for (Order order : sort) {
+			if (order.isIgnoreCase()) {
+				throw new IllegalArgumentException(String.format("Gven sort contained an Order for %s with ignore case! "
+						+ "MongoDB does not support sorting ignoreing case currently!", order.getProperty()));
+			}
+		}
+
+		if (this.sort == null) {
+			this.sort = sort;
 		} else {
-			this.coreSort = this.coreSort.and(sort);
+			this.sort = this.sort.and(sort);
+		}
+
+		return this;
+	}
+
+	/**
+	 * @return the restrictedTypes
+	 */
+	public Set<Class<?>> getRestrictedTypes() {
+		return restrictedTypes == null ? Collections.<Class<?>> emptySet() : restrictedTypes;
+	}
+
+	/**
+	 * Restricts the query to only return documents instances that are exactly of the given types.
+	 * 
+	 * @param type may not be {@literal null}
+	 * @param additionalTypes may not be {@literal null}
+	 * @return
+	 */
+	public Query restrict(Class<?> type, Class<?>... additionalTypes) {
+
+		Assert.notNull(type, "Type must not be null!");
+		Assert.notNull(additionalTypes, "AdditionalTypes must not be null");
+
+		restrictedTypes.add(type);
+		for (Class<?> additionalType : additionalTypes) {
+			restrictedTypes.add(additionalType);
 		}

 		return this;
 	}

 	public DBObject getQueryObject() {
+
 		DBObject dbo = new BasicDBObject();
 		for (String k : criteria.keySet()) {
 			CriteriaDefinition c = criteria.get(k);
 			DBObject cl = c.getCriteriaObject();
 			dbo.putAll(cl);
 		}
+
+		if (!restrictedTypes.isEmpty()) {
+			dbo.put(RESTRICTED_TYPES_KEY, getRestrictedTypes());
+		}
+
 		return dbo;
 	}

@@ -176,25 +217,20 @@ public class Query {
 		return fieldSpec.getFieldsObject();
 	}

-	@SuppressWarnings("deprecation")
 	public DBObject getSortObject() {

-		if (this.coreSort == null && this.sort == null) {
+		if (this.sort == null && this.sort == null) {
 			return null;
 		}

 		DBObject dbo = new BasicDBObject();

-		if (this.coreSort != null) {
-			for (org.springframework.data.domain.Sort.Order order : this.coreSort) {
+		if (this.sort != null) {
+			for (org.springframework.data.domain.Sort.Order order : this.sort) {
 				dbo.put(order.getProperty(), order.isAscending() ? 1 : -1);
 			}
 		}

-		if (this.sort != null) {
-			dbo.putAll(this.sort.getSortObject());
-		}
-
 		return dbo;
 	}

@@ -269,4 +305,17 @@ public class Query {

 		return result;
 	}
+
+	/**
+	 * Returns whether the given key is the one used to hold the type restriction information.
+	 * 
+	 * @deprecated don't call this method as the restricted type handling will undergo some significant changes going
+	 *             forward.
+	 * @param key
+	 * @return
+	 */
+	@Deprecated
+	public static boolean isRestrictedTypeKey(String key) {
+		return RESTRICTED_TYPES_KEY.equals(key);
+	}
 }
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/query/Sort.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/query/Sort.java
@@ -1,56 +0,0 @@
-/*
- * Copyright 2010-2012 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.query;
-
-import java.util.LinkedHashMap;
-import java.util.Map;
-
-import com.mongodb.BasicDBObject;
-import com.mongodb.DBObject;
-
-/**
- * Helper class to define sorting criterias for a Query instance.
- * 
- * @author Thomas Risberg
- * @author Oliver Gierke
- * @deprecated use {@link org.springframework.data.domain.Sort} instead. See
- *             {@link Query#with(org.springframework.data.domain.Sort)}.
- */
-@Deprecated
-public class Sort {
-
-	private Map<String, Order> fieldSpec = new LinkedHashMap<String, Order>();
-
-	public Sort() {
-	}
-
-	public Sort(String key, Order order) {
-		fieldSpec.put(key, order);
-	}
-
-	public Sort on(String key, Order order) {
-		fieldSpec.put(key, order);
-		return this;
-	}
-
-	public DBObject getSortObject() {
-		DBObject dbo = new BasicDBObject();
-		for (String k : fieldSpec.keySet()) {
-			dbo.put(k, fieldSpec.get(k).equals(Order.ASCENDING) ? 1 : -1);
-		}
-		return dbo;
-	}
-}
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/query/Update.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/query/Update.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2012 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.
@@ -52,7 +52,10 @@ public class Update {

 	/**
 	 * Creates an {@link Update} instance from the given {@link DBObject}. Allows to explicitly exlude fields from making
-	 * it into the created {@link Update} object.
+	 * it into the created {@link Update} object. Note, that this will set attributes directly and <em>not</em> use
+	 * {@literal $set}. This means fields not given in the {@link DBObject} will be nulled when executing the update. To
+	 * create an only-updating {@link Update} instance of a {@link DBObject}, call {@link #set(String, Object)} for each
+	 * value in it.
 	 * 
 	 * @param object the source {@link DBObject} to create the update from.
 	 * @param exclude the fields to exclude.
@@ -69,7 +72,7 @@ public class Update {
 				continue;
 			}

-			update.set(key, object.get(key));
+			update.modifierOps.put(key, object.get(key));
 		}

 		return update;
@@ -160,7 +163,7 @@ public class Update {
 	 * @return
 	 */
 	public Update pop(String key, Position pos) {
-		addMultiFieldOperation("$pop", key, (pos == Position.FIRST ? -1 : 1));
+		addMultiFieldOperation("$pop", key, pos == Position.FIRST ? -1 : 1);
 		return this;
 	}

@@ -214,22 +217,23 @@ public class Update {
 		return dbo;
 	}

-	@SuppressWarnings("unchecked")
 	protected void addMultiFieldOperation(String operator, String key, Object value) {
+
 		Object existingValue = this.modifierOps.get(operator);
-		LinkedHashMap<String, Object> keyValueMap;
+		DBObject keyValueMap;
+
 		if (existingValue == null) {
-			keyValueMap = new LinkedHashMap<String, Object>();
+			keyValueMap = new BasicDBObject();
 			this.modifierOps.put(operator, keyValueMap);
 		} else {
-			if (existingValue instanceof LinkedHashMap) {
-				keyValueMap = (LinkedHashMap<String, Object>) existingValue;
+			if (existingValue instanceof BasicDBObject) {
+				keyValueMap = (BasicDBObject) existingValue;
 			} else {
 				throw new InvalidDataAccessApiUsageException("Modifier Operations should be a LinkedHashMap but was "
 						+ existingValue.getClass());
 			}
 		}
+
 		keyValueMap.put(key, value);
 	}
-
 }
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/gridfs/package-info.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/gridfs/package-info.java
@@ -0,0 +1,5 @@
+/**
+ * Support for MongoDB GridFS feature.
+ */
+package org.springframework.data.mongodb.gridfs;
+
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/monitor/ServerInfo.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/monitor/ServerInfo.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2011 the original author or authors.
+ * Copyright 2002-2013 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.
@@ -15,19 +15,20 @@
 */
 package org.springframework.data.mongodb.monitor;

-import java.net.InetAddress;
 import java.net.UnknownHostException;

-import com.mongodb.Mongo;
 import org.springframework.jmx.export.annotation.ManagedMetric;
 import org.springframework.jmx.export.annotation.ManagedOperation;
 import org.springframework.jmx.export.annotation.ManagedResource;
 import org.springframework.jmx.support.MetricType;

+import com.mongodb.Mongo;
+
 /**
 * Expose basic server information via JMX
 * 
 * @author Mark Pollack
+ * @author Thomas Darimont
 */
@ManagedResource(description = "Server Information")
 public class ServerInfo extends AbstractMonitor {
@@ -36,9 +37,20 @@ public class ServerInfo extends AbstractMonitor {
 		this.mongo = mongo;
 	}

+	/**
+	 * Returns the hostname of the used server reported by mongo.
+	 * 
+	 * @return the reported hostname can also be an IP address.
+	 * @throws UnknownHostException
+	 */
 	@ManagedOperation(description = "Server host name")
 	public String getHostName() throws UnknownHostException {
-		return InetAddress.getLocalHost().getHostName();
+
+		/* 
+		 * UnknownHostException is not necessary anymore, but clients could have
+		 * called this method in a try..catch(UnknownHostException) already
+		 */
+		return getServerStatus().getServerUsed().getHost();
 	}

 	@ManagedMetric(displayName = "Uptime Estimate")
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/package-info.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/package-info.java
@@ -0,0 +1,5 @@
+/**
+ * Spring Data's MongoDB abstraction.
+ */
+package org.springframework.data.mongodb;
+
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/Query.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/Query.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.
@@ -15,7 +15,11 @@
 */
 package org.springframework.data.mongodb.repository;

-import java.lang.annotation.*;
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;

 /**
 * Annotation to declare finder queries directly on repository methods. Both attributes allow using a placeholder
@@ -43,4 +47,12 @@ public @interface Query {
 	 * @return
 	 */
 	String fields() default "";
+
+	/**
+	 * Returns whether the query defined should be executed as count projection.
+	 * 
+	 * @since 1.3
+	 * @return
+	 */
+	boolean count() default false;
 }
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/cdi/MongoRepositoryBean.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/cdi/MongoRepositoryBean.java
@@ -53,14 +53,6 @@ public class MongoRepositoryBean<T> extends CdiRepositoryBean<T> {
 		this.operations = operations;
 	}

-	/* 
-	 * (non-Javadoc)
-	 * @see javax.enterprise.inject.spi.Bean#getScope()
-	 */
-	public Class<? extends Annotation> getScope() {
-		return operations.getScope();
-	}
-
 	/* 
 	 * (non-Javadoc)
 	 * @see org.springframework.data.repository.cdi.CdiRepositoryBean#create(javax.enterprise.context.spi.CreationalContext, java.lang.Class)
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/cdi/package-info.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/cdi/package-info.java
@@ -0,0 +1,5 @@
+/**
+ * CDI support for MongoDB specific repository implementation.
+ */
+package org.springframework.data.mongodb.repository.cdi;
+
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/config/package-info.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/config/package-info.java
@@ -0,0 +1,5 @@
+/**
+ * Support infrastructure for the configuration of MongoDB specific repositories.
+ */
+package org.springframework.data.mongodb.repository.config;
+
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/query/AbstractMongoQuery.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/query/AbstractMongoQuery.java
@@ -17,6 +17,8 @@ package org.springframework.data.mongodb.repository.query;

 import java.util.List;

+import org.springframework.core.convert.ConversionService;
+import org.springframework.core.convert.support.DefaultConversionService;
 import org.springframework.data.domain.PageImpl;
 import org.springframework.data.domain.Pageable;
 import org.springframework.data.mongodb.core.MongoOperations;
@@ -36,9 +38,12 @@ import org.springframework.util.Assert;
 * Base class for {@link RepositoryQuery} implementations for Mongo.
 * 
 * @author Oliver Gierke
+ * @author Thomas Darimont
 */
 public abstract class AbstractMongoQuery implements RepositoryQuery {

+	private static final ConversionService CONVERSION_SERVICE = new DefaultConversionService();
+
 	private final MongoQueryMethod method;
 	private final MongoOperations operations;

@@ -86,18 +91,22 @@ public abstract class AbstractMongoQuery implements RepositoryQuery {
 			return new CollectionExecution(accessor.getPageable()).execute(query);
 		} else if (method.isPageQuery()) {
 			return new PagedExecution(accessor.getPageable()).execute(query);
-		} else {
-			return new SingleEntityExecution().execute(query);
 		}
-	}

-	/**
-	 * Creates a {@link Query} instance using the given {@link ParameterAccessor}
-	 * 
-	 * @param accessor must not be {@literal null}.
-	 * @return
-	 */
-	protected abstract Query createQuery(ConvertingParameterAccessor accessor);
+		Object result = new SingleEntityExecution(isCountQuery()).execute(query);
+
+		if (result == null) {
+			return result;
+		}
+
+		Class<?> expectedReturnType = method.getReturnType().getType();
+
+		if (expectedReturnType.isAssignableFrom(result.getClass())) {
+			return result;
+		}
+
+		return CONVERSION_SERVICE.convert(result, expectedReturnType);
+	}

 	/**
 	 * Creates a {@link Query} instance using the given {@link ConvertingParameterAccessor}. Will delegate to
@@ -111,6 +120,21 @@ public abstract class AbstractMongoQuery implements RepositoryQuery {
 		return createQuery(accessor);
 	}

+	/**
+	 * Creates a {@link Query} instance using the given {@link ParameterAccessor}
+	 * 
+	 * @param accessor must not be {@literal null}.
+	 * @return
+	 */
+	protected abstract Query createQuery(ConvertingParameterAccessor accessor);
+
+	/**
+	 * Returns whether the query should get a count projection applied.
+	 * 
+	 * @return
+	 */
+	protected abstract boolean isCountQuery();
+
 	private abstract class Execution {

 		abstract Object execute(Query query);
@@ -191,6 +215,12 @@ public abstract class AbstractMongoQuery implements RepositoryQuery {
 	 */
 	class SingleEntityExecution extends Execution {

+		private final boolean countProjection;
+
+		private SingleEntityExecution(boolean countProjection) {
+			this.countProjection = countProjection;
+		}
+
 		/*
 		 * (non-Javadoc)
 		 * @see org.springframework.data.mongodb.repository.AbstractMongoQuery.Execution#execute(org.springframework.data.mongodb.core.core.query.Query)
@@ -199,7 +229,8 @@ public abstract class AbstractMongoQuery implements RepositoryQuery {
 		Object execute(Query query) {

 			MongoEntityMetadata<?> metadata = method.getEntityInformation();
-			return operations.findOne(query, metadata.getJavaType());
+			return countProjection ? operations.count(query, metadata.getJavaType()) : operations.findOne(query,
+					metadata.getJavaType());
 		}
 	}

@@ -257,6 +288,11 @@ public abstract class AbstractMongoQuery implements RepositoryQuery {
 				nearQuery.maxDistance(maxDistance).in(maxDistance.getMetric());
 			}

+			Pageable pageable = accessor.getPageable();
+			if (pageable != null) {
+				nearQuery.with(pageable);
+			}
+
 			MongoEntityMetadata<?> metadata = method.getEntityInformation();
 			return (GeoResults<Object>) operations.geoNear(nearQuery, metadata.getJavaType(), metadata.getCollectionName());
 		}
@@ -264,7 +300,13 @@ public abstract class AbstractMongoQuery implements RepositoryQuery {
 		private boolean isListOfGeoResult() {

 			TypeInformation<?> returnType = method.getReturnType();
-			return returnType.getType().equals(List.class) && GeoResult.class.equals(returnType.getComponentType());
+
+			if (!returnType.getType().equals(List.class)) {
+				return false;
+			}
+
+			TypeInformation<?> componentType = returnType.getComponentType();
+			return componentType == null ? false : GeoResult.class.equals(componentType.getType());
 		}
 	}
 }
--- a/Show More
+++ b/Show More