DATAMONGO-2609 - Release version 3.0.4 (Neumann SR4).

Now toDocument calls toDocument on items correctly.

Original Pull Request: #883

.travis.yml

@@ -1,38 +0,0 @@
-language: java
-
-jdk:
-  - oraclejdk8
-
-before_install:
-  - mkdir -p downloads
-  - mkdir -p var/db var/log
-  - if [[ ! -d downloads/mongodb-linux-x86_64-ubuntu1604-${MONGO_VERSION} ]] ; then cd downloads && wget https://fastdl.mongodb.org/linux/mongodb-linux-x86_64-ubuntu1604-${MONGO_VERSION}.tgz && tar xzf mongodb-linux-x86_64-ubuntu1604-${MONGO_VERSION}.tgz && cd ..; fi
-  - downloads/mongodb-linux-x86_64-ubuntu1604-${MONGO_VERSION}/bin/mongod --version
-  - downloads/mongodb-linux-x86_64-ubuntu1604-${MONGO_VERSION}/bin/mongod --dbpath var/db --replSet rs0 --fork --logpath var/log/mongod.log
-  - sleep 10
-  - |-
-    downloads/mongodb-linux-x86_64-ubuntu1604-${MONGO_VERSION}/bin/mongo --eval "rs.initiate({_id: 'rs0', members:[{_id: 0, host: '127.0.0.1:27017'}]});"
-    sleep 15
-
-env:
-  matrix:
-    - MONGO_VERSION=4.1.10
-    - MONGO_VERSION=4.0.4
-    - MONGO_VERSION=3.6.12
-    - MONGO_VERSION=3.4.20
-  global:
-    - PROFILE=ci
-
-addons:
-  apt:
-    packages:
-      - oracle-java8-installer
-
-sudo: false
-
-cache:
-  directories:
-    - $HOME/.m2
-    - downloads
-
-script: "mvn clean dependency:list test -P${PROFILE} -Dsort"

Jenkinsfile

@@ -3,7 +3,7 @@ pipeline {
 
 	triggers {
 		pollSCM 'H/10 * * * *'
-		upstream(upstreamProjects: "spring-data-commons/master", threshold: hudson.model.Result.SUCCESS)
+		upstream(upstreamProjects: "spring-data-commons/2.3.x", threshold: hudson.model.Result.SUCCESS)
 	}
 
 	options {
@@ -30,51 +30,51 @@ pipeline {
 						}
 					}
 				}
-				stage('Publish JDK 8 + MongoDB 4.1') {
+				stage('Publish JDK 8 + MongoDB 4.2') {
 					when {
-						changeset "ci/openjdk8-mongodb-4.1/**"
+						changeset "ci/openjdk8-mongodb-4.2/**"
 					}
 					agent { label 'data' }
 					options { timeout(time: 30, unit: 'MINUTES') }
 
 					steps {
 						script {
-							def image = docker.build("springci/spring-data-openjdk8-with-mongodb-4.1", "ci/openjdk8-mongodb-4.1/")
+							def image = docker.build("springci/spring-data-openjdk8-with-mongodb-4.2.0", "ci/openjdk8-mongodb-4.2/")
 							docker.withRegistry('', 'hub.docker.com-springbuildmaster') {
 								image.push()
 							}
 						}
 					}
 				}
-				stage('Publish JDK 8 + MongoDB 4.2') {
-                	when {
-                		changeset "ci/openjdk8-mongodb-4.2/**"
-                	}
-                	agent { label 'data' }
-                	options { timeout(time: 30, unit: 'MINUTES') }
+				stage('Publish JDK 14 + MongoDB 4.2') {
+					when {
+						changeset "ci/openjdk14-mongodb-4.2/**"
+					}
+					agent { label 'data' }
+					options { timeout(time: 30, unit: 'MINUTES') }
 
-                	steps {
-                		script {
-                			def image = docker.build("springci/spring-data-openjdk8-with-mongodb-4.2", "ci/openjdk8-mongodb-4.2/")
-                			docker.withRegistry('', 'hub.docker.com-springbuildmaster') {
-                				image.push()
-                			}
-                		}
-                	}
-                }
+					steps {
+						script {
+							def image = docker.build("springci/spring-data-openjdk14-with-mongodb-4.2.0", "ci/openjdk14-mongodb-4.2/")
+							docker.withRegistry('', 'hub.docker.com-springbuildmaster') {
+								image.push()
+							}
+						}
+					}
+				}
 			}
 		}
 
-		stage("test: baseline") {
+		stage("test: baseline (jdk8)") {
 			when {
 				anyOf {
-					branch 'master'
+					branch '3.0.x'
 					not { triggeredBy 'UpstreamCause' }
 				}
 			}
 			agent {
 				docker {
-					image 'springci/spring-data-openjdk8-with-mongodb-4.2:latest'
+					image 'springci/spring-data-openjdk8-with-mongodb-4.2.0:latest'
 					label 'data'
 					args '-v $HOME:/tmp/jenkins-home'
 				}
@@ -83,23 +83,23 @@ pipeline {
 			steps {
 				sh 'rm -rf ?'
 				sh 'mkdir -p /tmp/mongodb/db /tmp/mongodb/log'
-				sh 'mongod --dbpath /tmp/mongodb/db --replSet rs0 --fork --logpath /tmp/mongodb/log/mongod.log &'
+				sh 'mongod --setParameter transactionLifetimeLimitSeconds=90 --setParameter maxTransactionLockRequestTimeoutMillis=10000 --dbpath /tmp/mongodb/db --replSet rs0 --fork --logpath /tmp/mongodb/log/mongod.log &'
 				sh 'sleep 10'
 				sh 'mongo --eval "rs.initiate({_id: \'rs0\', members:[{_id: 0, host: \'127.0.0.1:27017\'}]});"'
 				sh 'sleep 15'
-				sh 'MAVEN_OPTS="-Duser.name=jenkins -Duser.home=/tmp/jenkins-home" ./mvnw clean dependency:list test -Dsort -U -B'
+				sh 'MAVEN_OPTS="-Duser.name=jenkins -Duser.home=/tmp/jenkins-home" ./mvnw clean dependency:list test -Duser.name=jenkins -Dsort -U -B'
 			}
 		}
 
 		stage("Test other configurations") {
 			when {
 				anyOf {
-					branch 'master'
+					branch '3.0.x'
 					not { triggeredBy 'UpstreamCause' }
 				}
 			}
 			parallel {
-				stage("test: mongodb 4.0") {
+				stage("test: mongodb 4.0 (jdk8)") {
 					agent {
 						docker {
 							image 'springci/spring-data-openjdk8-with-mongodb-4.0:latest'
@@ -111,17 +111,18 @@ pipeline {
 					steps {
 						sh 'rm -rf ?'
 						sh 'mkdir -p /tmp/mongodb/db /tmp/mongodb/log'
-						sh 'mongod --dbpath /tmp/mongodb/db --replSet rs0 --fork --logpath /tmp/mongodb/log/mongod.log &'
+						sh 'mongod --setParameter transactionLifetimeLimitSeconds=90 --setParameter maxTransactionLockRequestTimeoutMillis=10000 --dbpath /tmp/mongodb/db --replSet rs0 --fork --logpath /tmp/mongodb/log/mongod.log &'
 						sh 'sleep 10'
 						sh 'mongo --eval "rs.initiate({_id: \'rs0\', members:[{_id: 0, host: \'127.0.0.1:27017\'}]});"'
 						sh 'sleep 15'
-						sh 'MAVEN_OPTS="-Duser.name=jenkins -Duser.home=/tmp/jenkins-home" ./mvnw clean dependency:list test -Dsort -U -B'
+						sh 'MAVEN_OPTS="-Duser.name=jenkins -Duser.home=/tmp/jenkins-home" ./mvnw clean dependency:list test -Duser.name=jenkins -Dsort -U -B'
 					}
 				}
-				stage("test: mongodb 4.1") {
+
+				stage("test: mongodb 4.2 (jdk8)") {
 					agent {
 						docker {
-							image 'springci/spring-data-openjdk8-with-mongodb-4.1:latest'
+							image 'springci/spring-data-openjdk8-with-mongodb-4.2.0:latest'
 							label 'data'
 							args '-v $HOME:/tmp/jenkins-home'
 						}
@@ -130,11 +131,31 @@ pipeline {
 					steps {
 						sh 'rm -rf ?'
 						sh 'mkdir -p /tmp/mongodb/db /tmp/mongodb/log'
-						sh 'mongod --dbpath /tmp/mongodb/db --replSet rs0 --fork --logpath /tmp/mongodb/log/mongod.log &'
+						sh 'mongod --setParameter transactionLifetimeLimitSeconds=90 --setParameter maxTransactionLockRequestTimeoutMillis=10000 --dbpath /tmp/mongodb/db --replSet rs0 --fork --logpath /tmp/mongodb/log/mongod.log &'
 						sh 'sleep 10'
 						sh 'mongo --eval "rs.initiate({_id: \'rs0\', members:[{_id: 0, host: \'127.0.0.1:27017\'}]});"'
 						sh 'sleep 15'
-						sh 'MAVEN_OPTS="-Duser.name=jenkins -Duser.home=/tmp/jenkins-home" ./mvnw clean dependency:list test -Dsort -U -B'
+						sh 'MAVEN_OPTS="-Duser.name=jenkins -Duser.home=/tmp/jenkins-home" ./mvnw clean dependency:list test -Duser.name=jenkins -Dsort -U -B'
+					}
+				}
+
+				stage("test: baseline (jdk14)") {
+					agent {
+						docker {
+							image 'springci/spring-data-openjdk14-with-mongodb-4.2.0:latest'
+							label 'data'
+							args '-v $HOME:/tmp/jenkins-home'
+						}
+					}
+					options { timeout(time: 30, unit: 'MINUTES') }
+					steps {
+						sh 'rm -rf ?'
+						sh 'mkdir -p /tmp/mongodb/db /tmp/mongodb/log'
+						sh 'mongod --setParameter transactionLifetimeLimitSeconds=90 --setParameter maxTransactionLockRequestTimeoutMillis=10000 --dbpath /tmp/mongodb/db --replSet rs0 --fork --logpath /tmp/mongodb/log/mongod.log &'
+						sh 'sleep 10'
+						sh 'mongo --eval "rs.initiate({_id: \'rs0\', members:[{_id: 0, host: \'127.0.0.1:27017\'}]});"'
+						sh 'sleep 15'
+						sh 'MAVEN_OPTS="-Duser.name=jenkins -Duser.home=/tmp/jenkins-home" ./mvnw -Pjava11 clean dependency:list test -Duser.name=jenkins -Dsort -U -B'
 					}
 				}
 			}
@@ -143,7 +164,7 @@ pipeline {
 		stage('Release to artifactory') {
 			when {
 				anyOf {
-					branch 'master'
+					branch '3.0.x'
 					not { triggeredBy 'UpstreamCause' }
 				}
 			}
@@ -175,7 +196,7 @@ pipeline {
 
 		stage('Publish documentation') {
 			when {
-				branch 'master'
+				branch '3.0.x'
 			}
 			agent {
 				docker {

README.adoc

@@ -50,12 +50,7 @@ public class MyService {
 
 @Configuration
 @EnableMongoRepositories
-class ApplicationConfig extends AbstractMongoConfiguration {
-
-  @Override
-  public MongoClient mongoClient() {
-    return new MongoClient();
-  }
+class ApplicationConfig extends AbstractMongoClientConfiguration {
 
   @Override
   protected String getDatabaseName() {
@@ -94,6 +89,143 @@ If you'd rather like the latest snapshots of the upcoming major version, use our
 </repository>
 ----
 
+== Upgrading from 2.x
+
+The 4.0 MongoDB Java Driver does no longer support certain features that have already been deprecated in one of the last minor versions.
+Some of the changes affect the initial setup configuration as well as compile/runtime features. We summarized the most typical changes one might encounter.
+
+=== XML Namespace
+
+.Changed XML Namespace Elements and Attributes:
+|===
+Element / Attribute | 2.x | 3.x
+
+| `<mongo:mongo-client />`
+| Used to create a `com.mongodb.MongoClient`
+| Now exposes a `com.mongodb.client.MongoClient`
+
+| `<mongo:mongo-client replica-set="..." />`
+| Was a comma delimited list of replica set members (host/port)
+| Now defines the replica set name. +
+Use `<mongo:client-settings cluster-hosts="..." />` instead
+
+| `<mongo:db-factory writeConcern="..." />`
+| NONE, NORMAL, SAFE, FSYNC_SAFE, REPLICAS_SAFE, MAJORITY
+| W1, W2, W3, UNAKNOWLEDGED, AKNOWLEDGED, JOURNALED, MAJORITY
+|===
+
+.Removed XML Namespace Elements and Attributes:
+|===
+Element / Attribute | Replacement in 3.x | Comment
+
+| `<mongo:db-factory mongo-ref="..." />`
+| `<mongo:db-factory mongo-client-ref="..." />`
+| Referencing a `com.mongodb.client.MongoClient`.
+
+| `<mongo:mongo-client credentials="..." />`
+| `<mongo:mongo-client credential="..." />`
+| Single authentication data instead of list.
+
+| `<mongo:client-options />`
+| `<mongo:client-settings />`
+| See `com.mongodb.MongoClientSettings` for details.
+|===
+
+.New XML Namespace Elements and Attributes:
+|===
+Element | Comment
+
+| `<mongo:db-factory mongo-client-ref="..." />`
+| Replacement for `<mongo:db-factory mongo-ref="..." />`
+
+| `<mongo:db-factory connection-string="..." />`
+| Replacement for `uri` and `client-uri`.
+
+| `<mongo:mongo-client connection-string="..." />`
+| Replacement for `uri` and `client-uri`.
+
+| `<mongo:client-settings />`
+| Namespace element for `com.mongodb.MongoClientSettings`.
+
+|===
+
+=== Java Configuration
+
+.Java API changes
+|===
+Type | Comment
+
+| `MongoClientFactoryBean`
+| Creates `com.mongodb.client.MongoClient` instead of `com.mongodb.MongoClient` +
+Uses `MongoClientSettings` instead of `MongoClientOptions`.
+
+| `MongoDataIntegrityViolationException`
+| Uses `WriteConcernResult` instead of `WriteResult`.
+
+| `BulkOperationException`
+| Uses `MongoBulkWriteException` and `com.mongodb.bulk.BulkWriteError` instead of `BulkWriteException` and `com.mongodb.BulkWriteError`
+
+| `ReactiveMongoClientFactoryBean`
+| Uses `com.mongodb.MongoClientSettings` instead of `com.mongodb.async.client.MongoClientSettings`
+
+| `ReactiveMongoClientSettingsFactoryBean`
+| Now produces `com.mongodb.MongoClientSettings` instead of `com.mongodb.async.client.MongoClientSettings`
+|===
+
+.Removed Java API:
+|===
+2.x | Replacement in 3.x | Comment
+
+| `MongoClientOptionsFactoryBean`
+| `MongoClientSettingsFactoryBean`
+| Creating a `com.mongodb.MongoClientSettings`.
+
+| `AbstractMongoConfiguration`
+| `AbstractMongoClientConfiguration` +
+(Available since 2.1)
+| Using `com.mongodb.client.MongoClient`.
+
+| `MongoDbFactory#getLegacyDb()`
+| -
+| -
+
+| `SimpleMongoDbFactory`
+| `SimpleMongoClientDbFactory` +
+(Available since 2.1)
+|
+
+| `MapReduceOptions#getOutputType()`
+| `MapReduceOptions#getMapReduceAction()`
+| Returns `MapReduceAction` instead of `MapReduceCommand.OutputType`.
+
+| `Meta\|Query` maxScan & snapshot
+|
+|
+|===
+
+=== Other Changes
+
+==== UUID Types
+
+The MongoDB UUID representation can now be configured with different formats.
+This has to be done via `MongoClientSettings` as shown in the snippet below.
+
+.UUID Codec Configuration
+====
+[source,java]
+----
+static class Config extends AbstractMongoClientConfiguration {
+
+    @Override
+    public void configureClientSettings(MongoClientSettings.Builder builder) {
+        builder.uuidRepresentation(UuidRepresentation.STANDARD);
+    }
+
+    // ...
+}
+----
+====
+
 == Getting Help
 
 Having trouble with Spring Data? We’d love to help!

ci/openjdk11-mongodb-4.2/Dockerfile

@@ -0,0 +1,15 @@
+FROM adoptopenjdk/openjdk11:latest
+
+ENV TZ=Etc/UTC
+ENV DEBIAN_FRONTEND=noninteractive
+
+RUN set -eux; \
+	apt-get update && apt-get install -y apt-transport-https apt-utils gnupg2 ; \
+	apt-key adv --keyserver hkps://keyserver.ubuntu.com:443 --recv e162f504a20cdf15827f718d4b7c549a058f8b6b ; \
+	echo "deb [ arch=amd64 ] https://repo.mongodb.org/apt/ubuntu bionic/mongodb-org/4.2 multiverse" | tee /etc/apt/sources.list.d/mongodb-org-4.2.list; \
+	echo ${TZ} > /etc/timezone;
+
+RUN apt-get update ; \
+	apt-get install -y mongodb-org=4.2.0 mongodb-org-server=4.2.0 mongodb-org-shell=4.2.0 mongodb-org-mongos=4.2.0 mongodb-org-tools=4.2.0 ; \
+	apt-get clean; \
+	rm -rf /var/lib/apt/lists/*;

ci/openjdk14-mongodb-4.2/Dockerfile

@@ -0,0 +1,15 @@
+FROM adoptopenjdk/openjdk14:latest
+
+ENV TZ=Etc/UTC
+ENV DEBIAN_FRONTEND=noninteractive
+
+RUN set -eux; \
+	apt-get update && apt-get install -y apt-transport-https apt-utils gnupg2 ; \
+	apt-key adv --keyserver hkps://keyserver.ubuntu.com:443 --recv e162f504a20cdf15827f718d4b7c549a058f8b6b ; \
+	echo "deb [ arch=amd64 ] https://repo.mongodb.org/apt/ubuntu bionic/mongodb-org/4.2 multiverse" | tee /etc/apt/sources.list.d/mongodb-org-4.2.list; \
+	echo ${TZ} > /etc/timezone;
+
+RUN apt-get update ; \
+	apt-get install -y mongodb-org=4.2.0 mongodb-org-server=4.2.0 mongodb-org-shell=4.2.0 mongodb-org-mongos=4.2.0 mongodb-org-tools=4.2.0 ; \
+	apt-get clean; \
+	rm -rf /var/lib/apt/lists/*;

ci/openjdk8-mongodb-4.0/Dockerfile

@@ -1,14 +1,15 @@
 FROM adoptopenjdk/openjdk8:latest
 
-RUN apt-get update && apt-get install -y apt-transport-https apt-utils gnupg2
+ENV TZ=Etc/UTC
+ENV DEBIAN_FRONTEND=noninteractive
 
-RUN apt-key adv --keyserver hkps://keyserver.ubuntu.com:443 --recv 9DA31620334BD75D9DCB49F368818C72E52529D4
+RUN RUN set -eux; \
+	apt-get update && apt-get install -y apt-transport-https apt-utils gnupg2 ; \
+	apt-key adv --keyserver hkps://keyserver.ubuntu.com:443 --recv 9DA31620334BD75D9DCB49F368818C72E52529D4 ; \
+	echo "deb [ arch=amd64 ] https://repo.mongodb.org/apt/ubuntu bionic/mongodb-org/4.0 multiverse" | tee /etc/apt/sources.list.d/mongodb-org-4.0.list; \
+	echo ${TZ} > /etc/timezone;
 
-RUN echo "deb [ arch=amd64 ] https://repo.mongodb.org/apt/ubuntu bionic/mongodb-org/4.0 multiverse" | tee /etc/apt/sources.list.d/mongodb-org-4.0.list
-
-RUN apt-get update
-
-RUN apt-get install -y mongodb-org=4.0.9 mongodb-org-server=4.0.9 mongodb-org-shell=4.0.9 mongodb-org-mongos=4.0.9 mongodb-org-tools=4.0.9
-
-RUN apt-get clean \
- && rm -rf /var/lib/apt/lists/*
+RUN apt-get update ; \
+	apt-get install -y mongodb-org=4.0.14 mongodb-org-server=4.0.14 mongodb-org-shell=4.0.14 mongodb-org-mongos=4.0.14 mongodb-org-tools=4.0.14 ; \
+	apt-get clean; \
+	rm -rf /var/lib/apt/lists/*;

ci/openjdk8-mongodb-4.1/Dockerfile

@@ -1,14 +0,0 @@
-FROM adoptopenjdk/openjdk8:latest
-
-RUN apt-get update && apt-get install -y apt-transport-https apt-utils gnupg2
-
-RUN apt-key adv --keyserver hkps://keyserver.ubuntu.com:443 --recv 4B7C549A058F8B6B
-
-RUN echo "deb [ arch=amd64 ] https://repo.mongodb.org/apt/ubuntu bionic/mongodb-org/4.1 multiverse" | tee /etc/apt/sources.list.d/mongodb-org-4.1.list
-
-RUN apt-get update
-
-RUN apt-get install -y mongodb-org-unstable=4.1.13 mongodb-org-unstable-server=4.1.13 mongodb-org-unstable-shell=4.1.13 mongodb-org-unstable-mongos=4.1.13 mongodb-org-unstable-tools=4.1.13
-
-RUN apt-get clean \
- && rm -rf /var/lib/apt/lists/*

ci/openjdk8-mongodb-4.2/Dockerfile

@@ -1,14 +1,15 @@
 FROM adoptopenjdk/openjdk8:latest
 
-RUN apt-get update && apt-get install -y apt-transport-https apt-utils gnupg2
+ENV TZ=Etc/UTC
+ENV DEBIAN_FRONTEND=noninteractive
 
-RUN apt-key adv --keyserver hkps://keyserver.ubuntu.com:443 --recv e162f504a20cdf15827f718d4b7c549a058f8b6b
+RUN set -eux; \
+	apt-get update && apt-get install -y apt-transport-https apt-utils gnupg2 ; \
+	apt-key adv --keyserver hkps://keyserver.ubuntu.com:443 --recv e162f504a20cdf15827f718d4b7c549a058f8b6b ; \
+	echo "deb [ arch=amd64 ] https://repo.mongodb.org/apt/ubuntu bionic/mongodb-org/4.2 multiverse" | tee /etc/apt/sources.list.d/mongodb-org-4.2.list; \
+	echo ${TZ} > /etc/timezone;
 
-RUN echo "deb [ arch=amd64 ] https://repo.mongodb.org/apt/ubuntu bionic/mongodb-org/4.2 multiverse" | tee /etc/apt/sources.list.d/mongodb-org-4.2.list
-
-RUN apt-get update
-
-RUN apt-get install -y mongodb-org=4.2.0 mongodb-org-server=4.2.0 mongodb-org-shell=4.2.0 mongodb-org-mongos=4.2.0 mongodb-org-tools=4.2.0
-
-RUN apt-get clean \
- && rm -rf /var/lib/apt/lists/*
+RUN apt-get update ; \
+	apt-get install -y mongodb-org=4.2.0 mongodb-org-server=4.2.0 mongodb-org-shell=4.2.0 mongodb-org-mongos=4.2.0 mongodb-org-tools=4.2.0 ; \
+	apt-get clean; \
+	rm -rf /var/lib/apt/lists/*;

pom.xml

@@ -5,7 +5,7 @@
 
 	<groupId>org.springframework.data</groupId>
 	<artifactId>spring-data-mongodb-parent</artifactId>
-	<version>3.0.0.M2</version>
+	<version>3.0.4.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>2.3.0.M2</version>
+		<version>2.3.4.RELEASE</version>
 	</parent>
 
 	<modules>
@@ -26,9 +26,9 @@
 	<properties>
 		<project.type>multi</project.type>
 		<dist.id>spring-data-mongodb</dist.id>
-		<springdata.commons>2.3.0.M2</springdata.commons>
-		<mongo>3.12.0</mongo>
-		<mongo.reactivestreams>1.13.0</mongo.reactivestreams>
+		<springdata.commons>2.3.4.RELEASE</springdata.commons>
+		<mongo>4.0.5</mongo>
+		<mongo.reactivestreams>${mongo}</mongo.reactivestreams>
 		<jmh.version>1.19</jmh.version>
 	</properties>
 
@@ -127,15 +127,25 @@
 		<!-- MongoDB -->
 		<dependency>
 			<groupId>org.mongodb</groupId>
-			<artifactId>mongo-java-driver</artifactId>
+			<artifactId>mongodb-driver-core</artifactId>
 			<version>${mongo}</version>
 		</dependency>
 	</dependencies>
 
 	<repositories>
 		<repository>
-			<id>spring-libs-milestone</id>
-			<url>https://repo.spring.io/libs-milestone</url>
+			<id>spring-libs-release</id>
+			<url>https://repo.spring.io/libs-release</url>
+		</repository>
+		<repository>
+			<id>sonatype-libs-snapshot</id>
+			<url>https://oss.sonatype.org/content/repositories/snapshots</url>
+			<releases>
+        <enabled>false</enabled>
+      </releases>
+			<snapshots>
+        <enabled>true</enabled>
+      </snapshots>
 		</repository>
 	</repositories>
 

spring-data-mongodb-benchmarks/pom.xml

@@ -7,7 +7,7 @@
 	<parent>
 		<groupId>org.springframework.data</groupId>
 		<artifactId>spring-data-mongodb-parent</artifactId>
-		<version>3.0.0.M2</version>
+		<version>3.0.4.RELEASE</version>
 		<relativePath>../pom.xml</relativePath>
 	</parent>
 

spring-data-mongodb-distribution/pom.xml

@@ -14,7 +14,7 @@
 	<parent>
 		<groupId>org.springframework.data</groupId>
 		<artifactId>spring-data-mongodb-parent</artifactId>
-		<version>3.0.0.M2</version>
+		<version>3.0.4.RELEASE</version>
 		<relativePath>../pom.xml</relativePath>
 	</parent>
 

spring-data-mongodb/pom.xml

@@ -11,7 +11,7 @@
 	<parent>
 		<groupId>org.springframework.data</groupId>
 		<artifactId>spring-data-mongodb-parent</artifactId>
-		<version>3.0.0.M2</version>
+		<version>3.0.4.RELEASE</version>
 		<relativePath>../pom.xml</relativePath>
 	</parent>
 
@@ -65,6 +65,12 @@
 			<artifactId>querydsl-mongodb</artifactId>
 			<version>${querydsl}</version>
 			<optional>true</optional>
+			<exclusions>
+				<exclusion>
+					<groupId>org.mongodb</groupId>
+					<artifactId>mongo-java-driver</artifactId>
+				</exclusion>
+			</exclusions>
 		</dependency>
 
 		<dependency>
@@ -82,28 +88,19 @@
 		</dependency>
 
 		<!-- reactive -->
+
 		<dependency>
 			<groupId>org.mongodb</groupId>
-			<artifactId>mongodb-driver-reactivestreams</artifactId>
-			<version>${mongo.reactivestreams}</version>
+			<artifactId>mongodb-driver-sync</artifactId>
+			<version>${mongo}</version>
 			<optional>true</optional>
 		</dependency>
 
 		<dependency>
 			<groupId>org.mongodb</groupId>
-			<artifactId>mongodb-driver-async</artifactId>
-			<version>${mongo}</version>
+			<artifactId>mongodb-driver-reactivestreams</artifactId>
+			<version>${mongo.reactivestreams}</version>
 			<optional>true</optional>
-			<exclusions>
-				<exclusion>
-					<groupId>org.mongodb</groupId>
-					<artifactId>mongodb-driver-core</artifactId>
-				</exclusion>
-				<exclusion>
-					<groupId>org.mongodb</groupId>
-					<artifactId>bson</artifactId>
-				</exclusion>
-			</exclusions>
 		</dependency>
 
 		<dependency>
@@ -253,6 +250,13 @@
 			<scope>test</scope>
 		</dependency>
 
+		<dependency>
+			<groupId>org.junit-pioneer</groupId>
+			<artifactId>junit-pioneer</artifactId>
+			<version>0.5.3</version>
+			<scope>test</scope>
+		</dependency>
+
 		<dependency>
 			<groupId>javax.transaction</groupId>
 			<artifactId>jta</artifactId>
@@ -340,12 +344,6 @@
 						<java.util.logging.config.file>src/test/resources/logging.properties</java.util.logging.config.file>
 						<reactor.trace.cancel>true</reactor.trace.cancel>
 					</systemPropertyVariables>
-					<properties>
-						<property>
-							<name>listener</name>
-							<value>org.springframework.data.mongodb.test.util.CleanMongoDBJunitRunListener</value>
-						</property>
-					</properties>
 				</configuration>
 			</plugin>
 

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

@@ -19,9 +19,9 @@ import java.util.List;
 
 import org.springframework.dao.DataAccessException;
 
-import com.mongodb.BulkWriteError;
-import com.mongodb.BulkWriteException;
-import com.mongodb.BulkWriteResult;
+import com.mongodb.MongoBulkWriteException;
+import com.mongodb.bulk.BulkWriteError;
+import com.mongodb.bulk.BulkWriteResult;
 
 /**
  * Is thrown when errors occur during bulk operations.
@@ -38,12 +38,12 @@ public class BulkOperationException extends DataAccessException {
 	private final BulkWriteResult result;
 
 	/**
-	 * Creates a new {@link BulkOperationException} with the given message and source {@link BulkWriteException}.
+	 * Creates a new {@link BulkOperationException} with the given message and source {@link MongoBulkWriteException}.
 	 *
 	 * @param message must not be {@literal null}.
 	 * @param source must not be {@literal null}.
 	 */
-	public BulkOperationException(String message, BulkWriteException source) {
+	public BulkOperationException(String message, MongoBulkWriteException source) {
 
 		super(message, source);
 

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

@@ -25,8 +25,10 @@ public class LazyLoadingException extends UncategorizedDataAccessException {
 	private static final long serialVersionUID = -7089224903873220037L;
 
 	/**
-	 * @param msg
-	 * @param cause
+	 * Constructor for LazyLoadingException.
+	 *
+	 * @param msg the detail message.
+	 * @param cause the exception thrown by underlying data access API.
 	 */
 	public LazyLoadingException(String msg, Throwable cause) {
 		super(msg, cause);

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

@@ -0,0 +1,112 @@
+/*
+ * Copyright 2011-2019 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
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.mongodb;
+
+import org.bson.codecs.configuration.CodecRegistry;
+import org.springframework.dao.DataAccessException;
+import org.springframework.dao.support.PersistenceExceptionTranslator;
+import org.springframework.data.mongodb.core.MongoExceptionTranslator;
+
+import com.mongodb.ClientSessionOptions;
+import com.mongodb.client.ClientSession;
+import com.mongodb.client.MongoDatabase;
+
+/**
+ * Interface for factories creating {@link MongoDatabase} instances.
+ *
+ * @author Mark Pollack
+ * @author Thomas Darimont
+ * @author Christoph Strobl
+ * @since 3.0
+ */
+public interface MongoDatabaseFactory extends CodecRegistryProvider, MongoSessionProvider {
+
+	/**
+	 * Obtain a {@link MongoDatabase} from the underlying factory.
+	 *
+	 * @return never {@literal null}.
+	 * @throws DataAccessException
+	 */
+	MongoDatabase getMongoDatabase() throws DataAccessException;
+
+	/**
+	 * Obtain a {@link MongoDatabase} instance to access the database with the given name.
+	 *
+	 * @param dbName must not be {@literal null}.
+	 * @return never {@literal null}.
+	 * @throws DataAccessException
+	 */
+	MongoDatabase getMongoDatabase(String dbName) throws DataAccessException;
+
+	/**
+	 * Exposes a shared {@link MongoExceptionTranslator}.
+	 *
+	 * @return will never be {@literal null}.
+	 */
+	PersistenceExceptionTranslator getExceptionTranslator();
+
+	/**
+	 * Get the underlying {@link CodecRegistry} used by the MongoDB Java driver.
+	 *
+	 * @return never {@literal null}.
+	 */
+	@Override
+	default CodecRegistry getCodecRegistry() {
+		return getMongoDatabase().getCodecRegistry();
+	}
+
+	/**
+	 * Obtain a {@link ClientSession} for given ClientSessionOptions.
+	 *
+	 * @param options must not be {@literal null}.
+	 * @return never {@literal null}.
+	 * @since 2.1
+	 */
+	ClientSession getSession(ClientSessionOptions options);
+
+	/**
+	 * Obtain a {@link ClientSession} bound instance of {@link MongoDatabaseFactory} returning {@link MongoDatabase}
+	 * instances that are aware and bound to a new session with given {@link ClientSessionOptions options}.
+	 *
+	 * @param options must not be {@literal null}.
+	 * @return never {@literal null}.
+	 * @since 2.1
+	 */
+	default MongoDatabaseFactory withSession(ClientSessionOptions options) {
+		return withSession(getSession(options));
+	}
+
+	/**
+	 * Obtain a {@link ClientSession} bound instance of {@link MongoDatabaseFactory} returning {@link MongoDatabase}
+	 * instances that are aware and bound to the given session.
+	 *
+	 * @param session must not be {@literal null}.
+	 * @return never {@literal null}.
+	 * @since 2.1
+	 */
+	MongoDatabaseFactory withSession(ClientSession session);
+
+	/**
+	 * Returns if the given {@link MongoDatabaseFactory} is bound to a {@link ClientSession} that has an
+	 * {@link ClientSession#hasActiveTransaction() active transaction}.
+	 *
+	 * @return {@literal true} if there's an active transaction, {@literal false} otherwise.
+	 * @since 2.1.3
+	 */
+	default boolean isTransactionActive() {
+		return false;
+	}
+}

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

@@ -27,7 +27,7 @@ import com.mongodb.client.ClientSession;
 import com.mongodb.client.MongoDatabase;
 
 /**
- * Helper class for managing a {@link MongoDatabase} instances via {@link MongoDbFactory}. Used for obtaining
+ * Helper class for managing a {@link MongoDatabase} instances via {@link MongoDatabaseFactory}. Used for obtaining
  * {@link ClientSession session bound} resources, such as {@link MongoDatabase} and
  * {@link com.mongodb.client.MongoCollection} suitable for transactional usage.
  * <p />
@@ -41,93 +41,94 @@ import com.mongodb.client.MongoDatabase;
 public class MongoDatabaseUtils {
 
 	/**
-	 * Obtain the default {@link MongoDatabase database} form the given {@link MongoDbFactory factory} using
+	 * Obtain the default {@link MongoDatabase database} form the given {@link MongoDatabaseFactory factory} using
 	 * {@link SessionSynchronization#ON_ACTUAL_TRANSACTION native session synchronization}.
 	 * <p />
 	 * Registers a {@link MongoSessionSynchronization MongoDB specific transaction synchronization} within the current
 	 * {@link Thread} if {@link TransactionSynchronizationManager#isSynchronizationActive() synchronization is active}.
 	 *
-	 * @param factory the {@link MongoDbFactory} to get the {@link MongoDatabase} from.
+	 * @param factory the {@link MongoDatabaseFactory} to get the {@link MongoDatabase} from.
 	 * @return the {@link MongoDatabase} that is potentially associated with a transactional {@link ClientSession}.
 	 */
-	public static MongoDatabase getDatabase(MongoDbFactory factory) {
+	public static MongoDatabase getDatabase(MongoDatabaseFactory factory) {
 		return doGetMongoDatabase(null, factory, SessionSynchronization.ON_ACTUAL_TRANSACTION);
 	}
 
 	/**
-	 * Obtain the default {@link MongoDatabase database} form the given {@link MongoDbFactory factory}.
+	 * Obtain the default {@link MongoDatabase database} form the given {@link MongoDatabaseFactory factory}.
 	 * <p />
 	 * Registers a {@link MongoSessionSynchronization MongoDB specific transaction synchronization} within the current
 	 * {@link Thread} if {@link TransactionSynchronizationManager#isSynchronizationActive() synchronization is active}.
 	 *
-	 * @param factory the {@link MongoDbFactory} to get the {@link MongoDatabase} from.
+	 * @param factory the {@link MongoDatabaseFactory} to get the {@link MongoDatabase} from.
 	 * @param sessionSynchronization the synchronization to use. Must not be {@literal null}.
 	 * @return the {@link MongoDatabase} that is potentially associated with a transactional {@link ClientSession}.
 	 */
-	public static MongoDatabase getDatabase(MongoDbFactory factory, SessionSynchronization sessionSynchronization) {
+	public static MongoDatabase getDatabase(MongoDatabaseFactory factory, SessionSynchronization sessionSynchronization) {
 		return doGetMongoDatabase(null, factory, sessionSynchronization);
 	}
 
 	/**
-	 * Obtain the {@link MongoDatabase database} with given name form the given {@link MongoDbFactory factory} using
+	 * Obtain the {@link MongoDatabase database} with given name form the given {@link MongoDatabaseFactory factory} using
 	 * {@link SessionSynchronization#ON_ACTUAL_TRANSACTION native session synchronization}.
 	 * <p />
 	 * Registers a {@link MongoSessionSynchronization MongoDB specific transaction synchronization} within the current
 	 * {@link Thread} if {@link TransactionSynchronizationManager#isSynchronizationActive() synchronization is active}.
 	 *
 	 * @param dbName the name of the {@link MongoDatabase} to get.
-	 * @param factory the {@link MongoDbFactory} to get the {@link MongoDatabase} from.
+	 * @param factory the {@link MongoDatabaseFactory} to get the {@link MongoDatabase} from.
 	 * @return the {@link MongoDatabase} that is potentially associated with a transactional {@link ClientSession}.
 	 */
-	public static MongoDatabase getDatabase(String dbName, MongoDbFactory factory) {
+	public static MongoDatabase getDatabase(@Nullable String dbName, MongoDatabaseFactory factory) {
 		return doGetMongoDatabase(dbName, factory, SessionSynchronization.ON_ACTUAL_TRANSACTION);
 	}
 
 	/**
-	 * Obtain the {@link MongoDatabase database} with given name form the given {@link MongoDbFactory factory}.
+	 * Obtain the {@link MongoDatabase database} with given name form the given {@link MongoDatabaseFactory factory}.
 	 * <p />
 	 * Registers a {@link MongoSessionSynchronization MongoDB specific transaction synchronization} within the current
 	 * {@link Thread} if {@link TransactionSynchronizationManager#isSynchronizationActive() synchronization is active}.
-	 * 
+	 *
 	 * @param dbName the name of the {@link MongoDatabase} to get.
-	 * @param factory the {@link MongoDbFactory} to get the {@link MongoDatabase} from.
+	 * @param factory the {@link MongoDatabaseFactory} to get the {@link MongoDatabase} from.
 	 * @param sessionSynchronization the synchronization to use. Must not be {@literal null}.
 	 * @return the {@link MongoDatabase} that is potentially associated with a transactional {@link ClientSession}.
 	 */
-	public static MongoDatabase getDatabase(String dbName, MongoDbFactory factory,
+	public static MongoDatabase getDatabase(@Nullable String dbName, MongoDatabaseFactory factory,
 			SessionSynchronization sessionSynchronization) {
 		return doGetMongoDatabase(dbName, factory, sessionSynchronization);
 	}
 
-	private static MongoDatabase doGetMongoDatabase(@Nullable String dbName, MongoDbFactory factory,
+	private static MongoDatabase doGetMongoDatabase(@Nullable String dbName, MongoDatabaseFactory factory,
 			SessionSynchronization sessionSynchronization) {
 
 		Assert.notNull(factory, "Factory must not be null!");
 
 		if (!TransactionSynchronizationManager.isSynchronizationActive()) {
-			return StringUtils.hasText(dbName) ? factory.getDb(dbName) : factory.getDb();
+			return StringUtils.hasText(dbName) ? factory.getMongoDatabase(dbName) : factory.getMongoDatabase();
 		}
 
 		ClientSession session = doGetSession(factory, sessionSynchronization);
 
 		if (session == null) {
-			return StringUtils.hasText(dbName) ? factory.getDb(dbName) : factory.getDb();
+			return StringUtils.hasText(dbName) ? factory.getMongoDatabase(dbName) : factory.getMongoDatabase();
 		}
 
-		MongoDbFactory factoryToUse = factory.withSession(session);
-		return StringUtils.hasText(dbName) ? factoryToUse.getDb(dbName) : factoryToUse.getDb();
+		MongoDatabaseFactory factoryToUse = factory.withSession(session);
+		return StringUtils.hasText(dbName) ? factoryToUse.getMongoDatabase(dbName) : factoryToUse.getMongoDatabase();
 	}
 
 	/**
-	 * Check if the {@link MongoDbFactory} is actually bound to a {@link ClientSession} that has an active transaction, or
-	 * if a {@link TransactionSynchronization} has been registered for the {@link MongoDbFactory resource} and if the
-	 * associated {@link ClientSession} has an {@link ClientSession#hasActiveTransaction() active transaction}.
+	 * Check if the {@link MongoDatabaseFactory} is actually bound to a {@link ClientSession} that has an active
+	 * transaction, or if a {@link TransactionSynchronization} has been registered for the {@link MongoDatabaseFactory
+	 * resource} and if the associated {@link ClientSession} has an {@link ClientSession#hasActiveTransaction() active
+	 * transaction}.
 	 *
 	 * @param dbFactory the resource to check transactions for. Must not be {@literal null}.
 	 * @return {@literal true} if the factory has an ongoing transaction.
 	 * @since 2.1.3
 	 */
-	public static boolean isTransactionActive(MongoDbFactory dbFactory) {
+	public static boolean isTransactionActive(MongoDatabaseFactory dbFactory) {
 
 		if (dbFactory.isTransactionActive()) {
 			return true;
@@ -138,7 +139,8 @@ public class MongoDatabaseUtils {
 	}
 
 	@Nullable
-	private static ClientSession doGetSession(MongoDbFactory dbFactory, SessionSynchronization sessionSynchronization) {
+	private static ClientSession doGetSession(MongoDatabaseFactory dbFactory,
+			SessionSynchronization sessionSynchronization) {
 
 		MongoResourceHolder resourceHolder = (MongoResourceHolder) TransactionSynchronizationManager.getResource(dbFactory);
 
@@ -169,7 +171,7 @@ public class MongoDatabaseUtils {
 		return resourceHolder.getSession();
 	}
 
-	private static ClientSession createClientSession(MongoDbFactory dbFactory) {
+	private static ClientSession createClientSession(MongoDatabaseFactory dbFactory) {
 		return dbFactory.getSession(ClientSessionOptions.builder().causallyConsistent(true).build());
 	}
 
@@ -184,7 +186,7 @@ public class MongoDatabaseUtils {
 
 		private final MongoResourceHolder resourceHolder;
 
-		MongoSessionSynchronization(MongoResourceHolder resourceHolder, MongoDbFactory dbFactory) {
+		MongoSessionSynchronization(MongoResourceHolder resourceHolder, MongoDatabaseFactory dbFactory) {
 
 			super(resourceHolder, dbFactory);
 			this.resourceHolder = resourceHolder;

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

@@ -15,14 +15,8 @@
  */
 package org.springframework.data.mongodb;
 
-import org.bson.codecs.configuration.CodecRegistry;
 import org.springframework.dao.DataAccessException;
-import org.springframework.dao.support.PersistenceExceptionTranslator;
-import org.springframework.data.mongodb.core.MongoExceptionTranslator;
 
-import com.mongodb.ClientSessionOptions;
-import com.mongodb.DB;
-import com.mongodb.client.ClientSession;
 import com.mongodb.client.MongoDatabase;
 
 /**
@@ -31,92 +25,33 @@ import com.mongodb.client.MongoDatabase;
  * @author Mark Pollack
  * @author Thomas Darimont
  * @author Christoph Strobl
+ * @deprecated since 3.0, use {@link MongoDatabaseFactory} instead.
  */
-public interface MongoDbFactory extends CodecRegistryProvider, MongoSessionProvider {
+@Deprecated
+public interface MongoDbFactory extends MongoDatabaseFactory {
 
 	/**
 	 * Creates a default {@link MongoDatabase} instance.
 	 *
-	 * @return
+	 * @return never {@literal null}.
 	 * @throws DataAccessException
-	 */
-	MongoDatabase getDb() throws DataAccessException;
-
-	/**
-	 * Creates a {@link DB} instance to access the database with the given name.
-	 *
-	 * @param dbName must not be {@literal null} or empty.
-	 * @return
-	 * @throws DataAccessException
-	 */
-	MongoDatabase getDb(String dbName) throws DataAccessException;
-
-	/**
-	 * Exposes a shared {@link MongoExceptionTranslator}.
-	 *
-	 * @return will never be {@literal null}.
-	 */
-	PersistenceExceptionTranslator getExceptionTranslator();
-
-	/**
-	 * Get the legacy database entry point. Please consider {@link #getDb()} instead.
-	 *
-	 * @return
-	 * @deprecated since 2.1, use {@link #getDb()}. This method will be removed with a future version as it works only
-	 *             with the legacy MongoDB driver.
+	 * @deprecated since 3.0. Use {@link #getMongoDatabase()} instead.
 	 */
 	@Deprecated
-	DB getLegacyDb();
-
-	/**
-	 * Get the underlying {@link CodecRegistry} used by the MongoDB Java driver.
-	 *
-	 * @return never {@literal null}.
-	 */
-	@Override
-	default CodecRegistry getCodecRegistry() {
-		return getDb().getCodecRegistry();
+	default MongoDatabase getDb() throws DataAccessException {
+		return getMongoDatabase();
 	}
 
 	/**
-	 * Obtain a {@link ClientSession} for given ClientSessionOptions.
+	 * Obtain a {@link MongoDatabase} instance to access the database with the given name.
 	 *
-	 * @param options must not be {@literal null}.
+	 * @param dbName must not be {@literal null} or empty.
 	 * @return never {@literal null}.
-	 * @since 2.1
+	 * @throws DataAccessException
+	 * @deprecated since 3.0. Use {@link #getMongoDatabase(String)} instead.
 	 */
-	ClientSession getSession(ClientSessionOptions options);
-
-	/**
-	 * Obtain a {@link ClientSession} bound instance of {@link MongoDbFactory} returning {@link MongoDatabase} instances
-	 * that are aware and bound to a new session with given {@link ClientSessionOptions options}.
-	 *
-	 * @param options must not be {@literal null}.
-	 * @return never {@literal null}.
-	 * @since 2.1
-	 */
-	default MongoDbFactory withSession(ClientSessionOptions options) {
-		return withSession(getSession(options));
-	}
-
-	/**
-	 * Obtain a {@link ClientSession} bound instance of {@link MongoDbFactory} returning {@link MongoDatabase} instances
-	 * that are aware and bound to the given session.
-	 *
-	 * @param session must not be {@literal null}.
-	 * @return never {@literal null}.
-	 * @since 2.1
-	 */
-	MongoDbFactory withSession(ClientSession session);
-
-	/**
-	 * Returns if the given {@link MongoDbFactory} is bound to a {@link ClientSession} that has an
-	 * {@link ClientSession#hasActiveTransaction() active transaction}.
-	 *
-	 * @return {@literal true} if there's an active transaction, {@literal false} otherwise.
-	 * @since 2.1.3
-	 */
-	default boolean isTransactionActive() {
-		return false;
+	@Deprecated
+	default MongoDatabase getDb(String dbName) throws DataAccessException {
+		return getMongoDatabase(dbName);
 	}
 }

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

@@ -36,15 +36,15 @@ import com.mongodb.client.ClientSession;
 class MongoResourceHolder extends ResourceHolderSupport {
 
 	private @Nullable ClientSession session;
-	private MongoDbFactory dbFactory;
+	private MongoDatabaseFactory dbFactory;
 
 	/**
 	 * Create a new {@link MongoResourceHolder} for a given {@link ClientSession session}.
 	 *
 	 * @param session the associated {@link ClientSession}. Can be {@literal null}.
-	 * @param dbFactory the associated {@link MongoDbFactory}. must not be {@literal null}.
+	 * @param dbFactory the associated {@link MongoDatabaseFactory}. must not be {@literal null}.
 	 */
-	MongoResourceHolder(@Nullable ClientSession session, MongoDbFactory dbFactory) {
+	MongoResourceHolder(@Nullable ClientSession session, MongoDatabaseFactory dbFactory) {
 
 		this.session = session;
 		this.dbFactory = dbFactory;
@@ -75,9 +75,9 @@ class MongoResourceHolder extends ResourceHolderSupport {
 	}
 
 	/**
-	 * @return the associated {@link MongoDbFactory}.
+	 * @return the associated {@link MongoDatabaseFactory}.
 	 */
-	public MongoDbFactory getDbFactory() {
+	public MongoDatabaseFactory getDbFactory() {
 		return dbFactory;
 	}
 

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

@@ -36,17 +36,18 @@ import com.mongodb.client.ClientSession;
 
 /**
  * A {@link org.springframework.transaction.PlatformTransactionManager} implementation that manages
- * {@link ClientSession} based transactions for a single {@link MongoDbFactory}.
+ * {@link ClientSession} based transactions for a single {@link MongoDatabaseFactory}.
  * <p />
- * Binds a {@link ClientSession} from the specified {@link MongoDbFactory} to the thread.
+ * Binds a {@link ClientSession} from the specified {@link MongoDatabaseFactory} to the thread.
  * <p />
  * {@link TransactionDefinition#isReadOnly() Readonly} transactions operate on a {@link ClientSession} and enable causal
  * consistency, and also {@link ClientSession#startTransaction() start}, {@link ClientSession#commitTransaction()
  * commit} or {@link ClientSession#abortTransaction() abort} a transaction.
  * <p />
  * Application code is required to retrieve the {@link com.mongodb.client.MongoDatabase} via
- * {@link MongoDatabaseUtils#getDatabase(MongoDbFactory)} instead of a standard {@link MongoDbFactory#getDb()} call.
- * Spring classes such as {@link org.springframework.data.mongodb.core.MongoTemplate} use this strategy implicitly.
+ * {@link MongoDatabaseUtils#getDatabase(MongoDatabaseFactory)} instead of a standard
+ * {@link MongoDatabaseFactory#getMongoDatabase()} call. Spring classes such as
+ * {@link org.springframework.data.mongodb.core.MongoTemplate} use this strategy implicitly.
  * <p />
  * By default failure of a {@literal commit} operation raises a {@link TransactionSystemException}. One may override
  * {@link #doCommit(MongoTransactionObject)} to implement the
@@ -58,46 +59,46 @@ import com.mongodb.client.ClientSession;
  * @currentRead Shadow's Edge - Brent Weeks
  * @since 2.1
  * @see <a href="https://www.mongodb.com/transactions">MongoDB Transaction Documentation</a>
- * @see MongoDatabaseUtils#getDatabase(MongoDbFactory, SessionSynchronization)
+ * @see MongoDatabaseUtils#getDatabase(MongoDatabaseFactory, SessionSynchronization)
  */
 public class MongoTransactionManager extends AbstractPlatformTransactionManager
 		implements ResourceTransactionManager, InitializingBean {
 
-	private @Nullable MongoDbFactory dbFactory;
+	private @Nullable MongoDatabaseFactory dbFactory;
 	private @Nullable TransactionOptions options;
 
 	/**
 	 * Create a new {@link MongoTransactionManager} for bean-style usage.
 	 * <p />
-	 * <strong>Note:</strong>The {@link MongoDbFactory db factory} has to be {@link #setDbFactory(MongoDbFactory) set}
-	 * before using the instance. Use this constructor to prepare a {@link MongoTransactionManager} via a
-	 * {@link org.springframework.beans.factory.BeanFactory}.
+	 * <strong>Note:</strong>The {@link MongoDatabaseFactory db factory} has to be
+	 * {@link #setDbFactory(MongoDatabaseFactory) set} before using the instance. Use this constructor to prepare a
+	 * {@link MongoTransactionManager} via a {@link org.springframework.beans.factory.BeanFactory}.
 	 * <p />
 	 * Optionally it is possible to set default {@link TransactionOptions transaction options} defining
 	 * {@link com.mongodb.ReadConcern} and {@link com.mongodb.WriteConcern}.
 	 *
-	 * @see #setDbFactory(MongoDbFactory)
+	 * @see #setDbFactory(MongoDatabaseFactory)
 	 * @see #setTransactionSynchronization(int)
 	 */
 	public MongoTransactionManager() {}
 
 	/**
-	 * Create a new {@link MongoTransactionManager} obtaining sessions from the given {@link MongoDbFactory}.
+	 * Create a new {@link MongoTransactionManager} obtaining sessions from the given {@link MongoDatabaseFactory}.
 	 *
 	 * @param dbFactory must not be {@literal null}.
 	 */
-	public MongoTransactionManager(MongoDbFactory dbFactory) {
+	public MongoTransactionManager(MongoDatabaseFactory dbFactory) {
 		this(dbFactory, null);
 	}
 
 	/**
-	 * Create a new {@link MongoTransactionManager} obtaining sessions from the given {@link MongoDbFactory} applying the
-	 * given {@link TransactionOptions options}, if present, when starting a new transaction.
+	 * Create a new {@link MongoTransactionManager} obtaining sessions from the given {@link MongoDatabaseFactory}
+	 * applying the given {@link TransactionOptions options}, if present, when starting a new transaction.
 	 *
 	 * @param dbFactory must not be {@literal null}.
 	 * @param options can be {@literal null}.
 	 */
-	public MongoTransactionManager(MongoDbFactory dbFactory, @Nullable TransactionOptions options) {
+	public MongoTransactionManager(MongoDatabaseFactory dbFactory, @Nullable TransactionOptions options) {
 
 		Assert.notNull(dbFactory, "DbFactory must not be null!");
 
@@ -295,11 +296,11 @@ public class MongoTransactionManager extends AbstractPlatformTransactionManager
 	}
 
 	/**
-	 * Set the {@link MongoDbFactory} that this instance should manage transactions for.
+	 * Set the {@link MongoDatabaseFactory} that this instance should manage transactions for.
 	 *
 	 * @param dbFactory must not be {@literal null}.
 	 */
-	public void setDbFactory(MongoDbFactory dbFactory) {
+	public void setDbFactory(MongoDatabaseFactory dbFactory) {
 
 		Assert.notNull(dbFactory, "DbFactory must not be null!");
 		this.dbFactory = dbFactory;
@@ -315,12 +316,12 @@ public class MongoTransactionManager extends AbstractPlatformTransactionManager
 	}
 
 	/**
-	 * Get the {@link MongoDbFactory} that this instance manages transactions for.
+	 * Get the {@link MongoDatabaseFactory} that this instance manages transactions for.
 	 *
 	 * @return can be {@literal null}.
 	 */
 	@Nullable
-	public MongoDbFactory getDbFactory() {
+	public MongoDatabaseFactory getDbFactory() {
 		return dbFactory;
 	}
 
@@ -329,7 +330,7 @@ public class MongoTransactionManager extends AbstractPlatformTransactionManager
 	 * @see org.springframework.transaction.support.ResourceTransactionManager#getResourceFactory()
 	 */
 	@Override
-	public MongoDbFactory getResourceFactory() {
+	public MongoDatabaseFactory getResourceFactory() {
 		return getRequiredDbFactory();
 	}
 
@@ -344,7 +345,7 @@ public class MongoTransactionManager extends AbstractPlatformTransactionManager
 
 	private MongoResourceHolder newResourceHolder(TransactionDefinition definition, ClientSessionOptions options) {
 
-		MongoDbFactory dbFactory = getResourceFactory();
+		MongoDatabaseFactory dbFactory = getResourceFactory();
 
 		MongoResourceHolder resourceHolder = new MongoResourceHolder(dbFactory.getSession(options), dbFactory);
 		resourceHolder.setTimeoutIfNotDefaulted(determineTimeout(definition));
@@ -355,7 +356,7 @@ public class MongoTransactionManager extends AbstractPlatformTransactionManager
 	/**
 	 * @throws IllegalStateException if {@link #dbFactory} is {@literal null}.
 	 */
-	private MongoDbFactory getRequiredDbFactory() {
+	private MongoDatabaseFactory getRequiredDbFactory() {
 
 		Assert.state(dbFactory != null,
 				"MongoTransactionManager operates upon a MongoDbFactory. Did you forget to provide one? It's required.");

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

@@ -31,6 +31,7 @@ import com.mongodb.reactivestreams.client.MongoDatabase;
  *
  * @author Mark Paluch
  * @author Christoph Strobl
+ * @author Mathieu Ouellet
  * @since 2.0
  */
 public interface ReactiveMongoDatabaseFactory extends CodecRegistryProvider {
@@ -38,19 +39,19 @@ public interface ReactiveMongoDatabaseFactory extends CodecRegistryProvider {
 	/**
 	 * Creates a default {@link MongoDatabase} instance.
 	 *
-	 * @return
+	 * @return never {@literal null}.
 	 * @throws DataAccessException
 	 */
-	MongoDatabase getMongoDatabase() throws DataAccessException;
+	Mono<MongoDatabase> getMongoDatabase() throws DataAccessException;
 
 	/**
-	 * Creates a {@link MongoDatabase} instance to access the database with the given name.
+	 * Obtain a {@link MongoDatabase} instance to access the database with the given name.
 	 *
 	 * @param dbName must not be {@literal null} or empty.
-	 * @return
+	 * @return never {@literal null}.
 	 * @throws DataAccessException
 	 */
-	MongoDatabase getMongoDatabase(String dbName) throws DataAccessException;
+	Mono<MongoDatabase> getMongoDatabase(String dbName) throws DataAccessException;
 
 	/**
 	 * Exposes a shared {@link MongoExceptionTranslator}.
@@ -64,10 +65,7 @@ public interface ReactiveMongoDatabaseFactory extends CodecRegistryProvider {
 	 *
 	 * @return never {@literal null}.
 	 */
-	@Override
-	default CodecRegistry getCodecRegistry() {
-		return getMongoDatabase().getCodecRegistry();
-	}
+	CodecRegistry getCodecRegistry();
 
 	/**
 	 * Obtain a {@link Mono} emitting a {@link ClientSession} for given {@link ClientSessionOptions options}.

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

@@ -41,6 +41,7 @@ import com.mongodb.reactivestreams.client.MongoDatabase;
  *
  * @author Mark Paluch
  * @author Christoph Strobl
+ * @author Mathieu Ouellet
  * @since 2.2
  */
 public class ReactiveMongoDatabaseUtils {
@@ -142,14 +143,13 @@ public class ReactiveMongoDatabaseUtils {
 				.flatMap(synchronizationManager -> {
 
 					return doGetSession(synchronizationManager, factory, sessionSynchronization) //
-							.map(it -> getMongoDatabaseOrDefault(dbName, factory.withSession(it)));
-				})
-				.onErrorResume(NoTransactionException.class,
-						e -> Mono.fromSupplier(() -> getMongoDatabaseOrDefault(dbName, factory)))
-				.defaultIfEmpty(getMongoDatabaseOrDefault(dbName, factory));
+							.flatMap(it -> getMongoDatabaseOrDefault(dbName, factory.withSession(it)));
+				}) //
+				.onErrorResume(NoTransactionException.class, e -> getMongoDatabaseOrDefault(dbName, factory))
+				.switchIfEmpty(getMongoDatabaseOrDefault(dbName, factory));
 	}
 
-	private static MongoDatabase getMongoDatabaseOrDefault(@Nullable String dbName,
+	private static Mono<MongoDatabase> getMongoDatabaseOrDefault(@Nullable String dbName,
 			ReactiveMongoDatabaseFactory factory) {
 		return StringUtils.hasText(dbName) ? factory.getMongoDatabase(dbName) : factory.getMongoDatabase();
 	}

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

@@ -42,7 +42,7 @@ class ReactiveMongoResourceHolder extends ResourceHolderSupport {
 	 * Create a new {@link ReactiveMongoResourceHolder} for a given {@link ClientSession session}.
 	 *
 	 * @param session the associated {@link ClientSession}. Can be {@literal null}.
-	 * @param databaseFactory the associated {@link MongoDbFactory}. must not be {@literal null}.
+	 * @param databaseFactory the associated {@link MongoDatabaseFactory}. must not be {@literal null}.
 	 */
 	ReactiveMongoResourceHolder(@Nullable ClientSession session, ReactiveMongoDatabaseFactory databaseFactory) {
 
@@ -99,7 +99,7 @@ class ReactiveMongoResourceHolder extends ResourceHolderSupport {
 	 * If the {@link ReactiveMongoResourceHolder} is {@link #hasSession() not already associated} with a
 	 * {@link ClientSession} the given value is {@link #setSession(ClientSession) set} and returned, otherwise the current
 	 * bound session is returned.
-	 * 
+	 *
 	 * @param session
 	 * @return
 	 */

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

@@ -0,0 +1,77 @@
+/*
+ * Copyright 2020 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
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.mongodb;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.data.util.Version;
+import org.springframework.util.StringUtils;
+
+import com.mongodb.MongoDriverInformation;
+
+/**
+ * Class that exposes the SpringData MongoDB specific information like the current {@link Version} or
+ * {@link MongoDriverInformation driver information}.
+ *
+ * @author Christoph Strobl
+ * @since 3.0
+ */
+public class SpringDataMongoDB {
+
+	private static final Logger LOGGER = LoggerFactory.getLogger(SpringDataMongoDB.class);
+
+	private static final Version FALLBACK_VERSION = new Version(3);
+	private static final MongoDriverInformation DRIVER_INFORMATION = MongoDriverInformation
+			.builder(MongoDriverInformation.builder().build()).driverName("spring-data").build();
+
+	/**
+	 * Obtain the SpringData MongoDB specific driver information.
+	 *
+	 * @return never {@literal null}.
+	 */
+	public static MongoDriverInformation driverInformation() {
+		return DRIVER_INFORMATION;
+	}
+
+	/**
+	 * Fetches the "Implementation-Version" manifest attribute from the jar file.
+	 * <p />
+	 * Note that some ClassLoaders do not expose the package metadata, hence this class might not be able to determine the
+	 * version in all environments. In this case the current Major version is returned as a fallback.
+	 *
+	 * @return never {@literal null}.
+	 */
+	public static Version version() {
+
+		Package pkg = SpringDataMongoDB.class.getPackage();
+		String versionString = (pkg != null ? pkg.getImplementationVersion() : null);
+
+		if (!StringUtils.hasText(versionString)) {
+
+			LOGGER.debug("Unable to find Spring Data MongoDB version.");
+			return FALLBACK_VERSION;
+		}
+
+		try {
+			return Version.parse(versionString);
+		} catch (Exception e) {
+			LOGGER.debug("Cannot read Spring Data MongoDB version '{}'.", versionString);
+		}
+
+		return FALLBACK_VERSION;
+	}
+
+}

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

@@ -17,17 +17,22 @@ package org.springframework.data.mongodb.config;
 
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
-import org.springframework.data.mongodb.MongoDbFactory;
+import org.springframework.data.mongodb.MongoDatabaseFactory;
+import org.springframework.data.mongodb.SpringDataMongoDB;
 import org.springframework.data.mongodb.core.MongoTemplate;
-import org.springframework.data.mongodb.core.SimpleMongoClientDbFactory;
-import org.springframework.data.mongodb.core.SimpleMongoDbFactory;
+import org.springframework.data.mongodb.core.SimpleMongoClientDatabaseFactory;
 import org.springframework.data.mongodb.core.convert.DbRefResolver;
 import org.springframework.data.mongodb.core.convert.DefaultDbRefResolver;
 import org.springframework.data.mongodb.core.convert.MappingMongoConverter;
+import org.springframework.data.mongodb.core.convert.MongoCustomConversions;
 import org.springframework.data.mongodb.core.mapping.Document;
+import org.springframework.data.mongodb.core.mapping.MongoMappingContext;
 import org.springframework.lang.Nullable;
 
+import com.mongodb.MongoClientSettings;
+import com.mongodb.MongoClientSettings.Builder;
 import com.mongodb.client.MongoClient;
+import com.mongodb.client.MongoClients;
 
 /**
  * Base class for Spring Data MongoDB configuration using JavaConfig with {@link com.mongodb.client.MongoClient}.
@@ -35,40 +40,44 @@ import com.mongodb.client.MongoClient;
  * @author Christoph Strobl
  * @since 2.1
  * @see MongoConfigurationSupport
- * @see AbstractMongoConfiguration
  */
-@Configuration
+@Configuration(proxyBeanMethods = false)
 public abstract class AbstractMongoClientConfiguration extends MongoConfigurationSupport {
 
 	/**
 	 * Return the {@link MongoClient} instance to connect to. Annotate with {@link Bean} in case you want to expose a
-	 * {@link MongoClient} instance to the {@link org.springframework.context.ApplicationContext}.
+	 * {@link MongoClient} instance to the {@link org.springframework.context.ApplicationContext}. <br />
+	 * Override {@link #mongoClientSettings()} to configure connection details.
 	 *
-	 * @return
+	 * @return never {@literal null}.
+	 * @see #mongoClientSettings()
+	 * @see #configureClientSettings(Builder)
 	 */
-	public abstract MongoClient mongoClient();
+	public MongoClient mongoClient() {
+		return createMongoClient(mongoClientSettings());
+	}
 
 	/**
 	 * Creates a {@link MongoTemplate}.
 	 *
-	 * @return
+	 * @see #mongoDbFactory()
+	 * @see #mappingMongoConverter(MongoDatabaseFactory, MongoCustomConversions, MongoMappingContext)
 	 */
 	@Bean
-	public MongoTemplate mongoTemplate() throws Exception {
-		return new MongoTemplate(mongoDbFactory(), mappingMongoConverter());
+	public MongoTemplate mongoTemplate(MongoDatabaseFactory databaseFactory, MappingMongoConverter converter) {
+		return new MongoTemplate(databaseFactory, converter);
 	}
 
 	/**
-	 * Creates a {@link SimpleMongoDbFactory} to be used by the {@link MongoTemplate}. Will use the {@link MongoClient}
-	 * instance configured in {@link #mongoClient()}.
+	 * Creates a {@link org.springframework.data.mongodb.core.SimpleMongoClientDatabaseFactory} to be used by the
+	 * {@link MongoTemplate}. Will use the {@link MongoClient} instance configured in {@link #mongoClient()}.
 	 *
 	 * @see #mongoClient()
-	 * @see #mongoTemplate()
-	 * @return
+	 * @see #mongoTemplate(MongoDatabaseFactory, MappingMongoConverter)
 	 */
 	@Bean
-	public MongoDbFactory mongoDbFactory() {
-		return new SimpleMongoClientDbFactory(mongoClient(), getDatabaseName());
+	public MongoDatabaseFactory mongoDbFactory() {
+		return new SimpleMongoClientDatabaseFactory(mongoClient(), getDatabaseName());
 	}
 
 	/**
@@ -91,22 +100,32 @@ public abstract class AbstractMongoClientConfiguration extends MongoConfiguratio
 
 	/**
 	 * Creates a {@link MappingMongoConverter} using the configured {@link #mongoDbFactory()} and
-	 * {@link #mongoMappingContext()}. Will get {@link #customConversions()} applied.
+	 * {@link #mongoMappingContext(MongoCustomConversions)}. Will get {@link #customConversions()} applied.
 	 *
 	 * @see #customConversions()
-	 * @see #mongoMappingContext()
+	 * @see #mongoMappingContext(MongoCustomConversions)
 	 * @see #mongoDbFactory()
-	 * @return
-	 * @throws Exception
 	 */
 	@Bean
-	public MappingMongoConverter mappingMongoConverter() throws Exception {
+	public MappingMongoConverter mappingMongoConverter(MongoDatabaseFactory databaseFactory,
+			MongoCustomConversions customConversions, MongoMappingContext mappingContext) {
 
-		DbRefResolver dbRefResolver = new DefaultDbRefResolver(mongoDbFactory());
-		MappingMongoConverter converter = new MappingMongoConverter(dbRefResolver, mongoMappingContext());
-		converter.setCustomConversions(customConversions());
-		converter.setCodecRegistryProvider(mongoDbFactory());
+		DbRefResolver dbRefResolver = new DefaultDbRefResolver(databaseFactory);
+		MappingMongoConverter converter = new MappingMongoConverter(dbRefResolver, mappingContext);
+		converter.setCustomConversions(customConversions);
+		converter.setCodecRegistryProvider(databaseFactory);
 
 		return converter;
 	}
+
+	/**
+	 * Create the Reactive Streams {@link com.mongodb.reactivestreams.client.MongoClient} instance with given
+	 * {@link MongoClientSettings}.
+	 *
+	 * @return never {@literal null}.
+	 * @since 3.0
+	 */
+	protected MongoClient createMongoClient(MongoClientSettings settings) {
+		return MongoClients.create(settings, SpringDataMongoDB.driverInformation());
+	}
 }

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

@@ -1,121 +0,0 @@
-/*
- * Copyright 2011-2020 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
- *
- *      https://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.context.annotation.Bean;
-import org.springframework.context.annotation.Configuration;
-import org.springframework.data.mongodb.MongoDbFactory;
-import org.springframework.data.mongodb.core.MongoTemplate;
-import org.springframework.data.mongodb.core.SimpleMongoDbFactory;
-import org.springframework.data.mongodb.core.convert.DbRefResolver;
-import org.springframework.data.mongodb.core.convert.DefaultDbRefResolver;
-import org.springframework.data.mongodb.core.convert.MappingMongoConverter;
-import org.springframework.data.mongodb.core.mapping.Document;
-import org.springframework.lang.Nullable;
-
-import com.mongodb.MongoClient;
-
-/**
- * Base class for Spring Data MongoDB configuration using JavaConfig with {@link com.mongodb.MongoClient}.
- * <p />
- * <strong>INFO:</strong>In case you want to use {@link com.mongodb.client.MongoClients} for configuration please refer
- * to {@link AbstractMongoClientConfiguration}.
- *
- * @author Mark Pollack
- * @author Oliver Gierke
- * @author Thomas Darimont
- * @author Ryan Tenney
- * @author Christoph Strobl
- * @author Mark Paluch
- * @see MongoConfigurationSupport
- * @see AbstractMongoClientConfiguration
- * @deprecated since 2.2 in favor of {@link AbstractMongoClientConfiguration}.
- */
-@Configuration
-@Deprecated
-public abstract class AbstractMongoConfiguration extends MongoConfigurationSupport {
-
-	/**
-	 * Return the {@link MongoClient} instance to connect to. Annotate with {@link Bean} in case you want to expose a
-	 * {@link MongoClient} instance to the {@link org.springframework.context.ApplicationContext}.
-	 *
-	 * @return
-	 */
-	public abstract MongoClient mongoClient();
-
-	/**
-	 * Creates a {@link MongoTemplate}.
-	 *
-	 * @return
-	 */
-	@Bean
-	public MongoTemplate mongoTemplate() throws Exception {
-		return new MongoTemplate(mongoDbFactory(), mappingMongoConverter());
-	}
-
-	/**
-	 * Creates a {@link SimpleMongoDbFactory} to be used by the {@link MongoTemplate}. Will use the {@link MongoClient}
-	 * instance configured in {@link #mongoClient()}.
-	 *
-	 * @see #mongoClient()
-	 * @see #mongoTemplate()
-	 * @return
-	 */
-	@Bean
-	public MongoDbFactory mongoDbFactory() {
-		return new SimpleMongoDbFactory(mongoClient(), getDatabaseName());
-	}
-
-	/**
-	 * Return the base package to scan for mapped {@link Document}s. Will return the package name of the configuration
-	 * class' (the concrete class, not this one here) by default. So if you have a {@code com.acme.AppConfig} extending
-	 * {@link AbstractMongoConfiguration} the base package will be considered {@code com.acme} unless the method is
-	 * overridden to implement alternate behavior.
-	 *
-	 * @return the base package to scan for mapped {@link Document} classes or {@literal null} to not enable scanning for
-	 *         entities.
-	 * @deprecated use {@link #getMappingBasePackages()} instead.
-	 */
-	@Deprecated
-	@Nullable
-	protected String getMappingBasePackage() {
-
-		Package mappingBasePackage = getClass().getPackage();
-		return mappingBasePackage == null ? null : mappingBasePackage.getName();
-	}
-
-	/**
-	 * Creates a {@link MappingMongoConverter} using the configured {@link #mongoDbFactory()} and
-	 * {@link #mongoMappingContext()}. Will get {@link #customConversions()} applied.
-	 *
-	 * @see #customConversions()
-	 * @see #mongoMappingContext()
-	 * @see #mongoDbFactory()
-	 * @return
-	 * @throws Exception
-	 */
-	@Bean
-	public MappingMongoConverter mappingMongoConverter() throws Exception {
-
-		DbRefResolver dbRefResolver = new DefaultDbRefResolver(mongoDbFactory());
-		MappingMongoConverter converter = new MappingMongoConverter(dbRefResolver, mongoMappingContext());
-		converter.setCustomConversions(customConversions());
-		converter.setCodecRegistryProvider(mongoDbFactory());
-
-		return converter;
-	}
-
-}

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

@@ -18,13 +18,19 @@ package org.springframework.data.mongodb.config;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.data.mongodb.ReactiveMongoDatabaseFactory;
+import org.springframework.data.mongodb.SpringDataMongoDB;
 import org.springframework.data.mongodb.core.ReactiveMongoOperations;
 import org.springframework.data.mongodb.core.ReactiveMongoTemplate;
 import org.springframework.data.mongodb.core.SimpleReactiveMongoDatabaseFactory;
 import org.springframework.data.mongodb.core.convert.MappingMongoConverter;
+import org.springframework.data.mongodb.core.convert.MongoCustomConversions;
 import org.springframework.data.mongodb.core.convert.NoOpDbRefResolver;
+import org.springframework.data.mongodb.core.mapping.MongoMappingContext;
 
+import com.mongodb.MongoClientSettings;
+import com.mongodb.MongoClientSettings.Builder;
 import com.mongodb.reactivestreams.client.MongoClient;
+import com.mongodb.reactivestreams.client.MongoClients;
 
 /**
  * Base class for reactive Spring Data MongoDB configuration using JavaConfig.
@@ -34,25 +40,33 @@ import com.mongodb.reactivestreams.client.MongoClient;
  * @since 2.0
  * @see MongoConfigurationSupport
  */
-@Configuration
+@Configuration(proxyBeanMethods = false)
 public abstract class AbstractReactiveMongoConfiguration extends MongoConfigurationSupport {
 
 	/**
 	 * Return the Reactive Streams {@link MongoClient} instance to connect to. Annotate with {@link Bean} in case you want
-	 * to expose a {@link MongoClient} instance to the {@link org.springframework.context.ApplicationContext}.
+	 * to expose a {@link MongoClient} instance to the {@link org.springframework.context.ApplicationContext}. <br />
+	 * Override {@link #mongoClientSettings()} to configure connection details.
 	 *
 	 * @return never {@literal null}.
+	 * @see #mongoClientSettings()
+	 * @see #configureClientSettings(Builder)
 	 */
-	public abstract MongoClient reactiveMongoClient();
+	public MongoClient reactiveMongoClient() {
+		return createReactiveMongoClient(mongoClientSettings());
+	}
 
 	/**
 	 * Creates {@link ReactiveMongoOperations}.
 	 *
+	 * @see #reactiveMongoDbFactory()
+	 * @see #mappingMongoConverter(ReactiveMongoDatabaseFactory, MongoCustomConversions, MongoMappingContext)
 	 * @return never {@literal null}.
 	 */
 	@Bean
-	public ReactiveMongoOperations reactiveMongoTemplate() throws Exception {
-		return new ReactiveMongoTemplate(reactiveMongoDbFactory(), mappingMongoConverter());
+	public ReactiveMongoTemplate reactiveMongoTemplate(ReactiveMongoDatabaseFactory databaseFactory,
+			MappingMongoConverter mongoConverter) {
+		return new ReactiveMongoTemplate(databaseFactory, mongoConverter);
 	}
 
 	/**
@@ -60,7 +74,7 @@ public abstract class AbstractReactiveMongoConfiguration extends MongoConfigurat
 	 * {@link MongoClient} instance configured in {@link #reactiveMongoClient()}.
 	 *
 	 * @see #reactiveMongoClient()
-	 * @see #reactiveMongoTemplate()
+	 * @see #reactiveMongoTemplate(ReactiveMongoDatabaseFactory, MappingMongoConverter)
 	 * @return never {@literal null}.
 	 */
 	@Bean
@@ -70,21 +84,31 @@ public abstract class AbstractReactiveMongoConfiguration extends MongoConfigurat
 
 	/**
 	 * Creates a {@link MappingMongoConverter} using the configured {@link #reactiveMongoDbFactory()} and
-	 * {@link #mongoMappingContext()}. Will get {@link #customConversions()} applied.
+	 * {@link #mongoMappingContext(MongoCustomConversions)}. Will get {@link #customConversions()} applied.
 	 *
 	 * @see #customConversions()
-	 * @see #mongoMappingContext()
+	 * @see #mongoMappingContext(MongoCustomConversions)
 	 * @see #reactiveMongoDbFactory()
 	 * @return never {@literal null}.
-	 * @throws Exception
 	 */
 	@Bean
-	public MappingMongoConverter mappingMongoConverter() throws Exception {
+	public MappingMongoConverter mappingMongoConverter(ReactiveMongoDatabaseFactory databaseFactory,
+			MongoCustomConversions customConversions, MongoMappingContext mappingContext) {
 
-		MappingMongoConverter converter = new MappingMongoConverter(NoOpDbRefResolver.INSTANCE, mongoMappingContext());
-		converter.setCustomConversions(customConversions());
-		converter.setCodecRegistryProvider(reactiveMongoDbFactory());
+		MappingMongoConverter converter = new MappingMongoConverter(NoOpDbRefResolver.INSTANCE, mappingContext);
+		converter.setCustomConversions(customConversions);
+		converter.setCodecRegistryProvider(databaseFactory);
 
 		return converter;
 	}
+
+	/**
+	 * Create the Reactive Streams {@link MongoClient} instance with given {@link MongoClientSettings}.
+	 *
+	 * @return never {@literal null}.
+	 * @since 3.0
+	 */
+	protected MongoClient createReactiveMongoClient(MongoClientSettings settings) {
+		return MongoClients.create(settings, SpringDataMongoDB.driverInformation());
+	}
 }

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

@@ -0,0 +1,46 @@
+/*
+ * Copyright 2019 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
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.mongodb.config;
+
+import java.beans.PropertyEditorSupport;
+
+import org.springframework.lang.Nullable;
+import org.springframework.util.StringUtils;
+
+import com.mongodb.ConnectionString;
+
+/**
+ * Parse a {@link String} to a {@link com.mongodb.ConnectionString}.
+ *
+ * @author Christoph Strobl
+ * @since 3.0
+ */
+public class ConnectionStringPropertyEditor extends PropertyEditorSupport {
+
+	/*
+	 * (non-Javadoc)
+	 * @see java.beans.PropertyEditorSupport#setAsText(java.lang.String)
+	 */
+	@Override
+	public void setAsText(@Nullable String connectionString) {
+
+		if (!StringUtils.hasText(connectionString)) {
+			return;
+		}
+
+		setValue(new ConnectionString(connectionString));
+	}
+}

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

@@ -42,21 +42,21 @@ public @interface EnableMongoAuditing {
 	/**
 	 * Configures the {@link AuditorAware} bean to be used to lookup the current principal.
 	 *
-	 * @return
+	 * @return empty {@link String} by default.
 	 */
 	String auditorAwareRef() default "";
 
 	/**
 	 * Configures whether the creation and modification dates are set. Defaults to {@literal true}.
 	 *
-	 * @return
+	 * @return {@literal true} by default.
 	 */
 	boolean setDates() default true;
 
 	/**
 	 * Configures whether the entity shall be marked as modified on creation. Defaults to {@literal true}.
 	 *
-	 * @return
+	 * @return {@literal true} by default.
 	 */
 	boolean modifyOnCreate() default true;
 
@@ -64,7 +64,7 @@ public @interface EnableMongoAuditing {
 	 * Configures a {@link DateTimeProvider} bean name that allows customizing the {@link org.joda.time.DateTime} to be
 	 * used for setting creation and modification dates.
 	 *
-	 * @return
+	 * @return empty {@link String} by default.
 	 */
 	String dateTimeProviderRef() default "";
 }

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

@@ -96,6 +96,9 @@ public class MappingMongoConverterParser implements BeanDefinitionParser {
 		String id = element.getAttribute(AbstractBeanDefinitionParser.ID_ATTRIBUTE);
 		id = StringUtils.hasText(id) ? id : DEFAULT_CONVERTER_BEAN_NAME;
 
+		String autoIndexCreation = element.getAttribute("auto-index-creation");
+		boolean autoIndexCreationEnabled = StringUtils.hasText(autoIndexCreation) && Boolean.valueOf(autoIndexCreation);
+
 		parserContext.pushContainingComponent(new CompositeComponentDefinition("Mapping Mongo Converter", element));
 
 		BeanDefinition conversionsDefinition = getCustomConversions(element, parserContext);
@@ -199,6 +202,11 @@ public class MappingMongoConverterParser implements BeanDefinitionParser {
 
 	public static String potentiallyCreateMappingContext(Element element, ParserContext parserContext,
 			@Nullable BeanDefinition conversionsDefinition, @Nullable String converterId) {
+		return potentiallyCreateMappingContext(element, parserContext, conversionsDefinition, converterId, false);
+	}
+
+	public static String potentiallyCreateMappingContext(Element element, ParserContext parserContext,
+			@Nullable BeanDefinition conversionsDefinition, @Nullable String converterId, boolean autoIndexCreation) {
 
 		String ctxRef = element.getAttribute("mapping-context-ref");
 
@@ -226,6 +234,8 @@ public class MappingMongoConverterParser implements BeanDefinitionParser {
 			mappingContextBuilder.addPropertyValue("simpleTypeHolder", simpleTypesDefinition);
 		}
 
+		mappingContextBuilder.addPropertyValue("autoIndexCreation", autoIndexCreation);
+
 		parseFieldNamingStrategy(element, parserContext.getReaderContext(), mappingContextBuilder);
 
 		ctxRef = converterId == null || DEFAULT_CONVERTER_BEAN_NAME.equals(converterId) ? MAPPING_CONTEXT_BEAN_NAME

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

@@ -50,10 +50,11 @@ public class MongoClientParser implements BeanDefinitionParser {
 
 		ParsingUtils.setPropertyValue(builder, element, "port", "port");
 		ParsingUtils.setPropertyValue(builder, element, "host", "host");
-		ParsingUtils.setPropertyValue(builder, element, "credentials", "credentials");
+		ParsingUtils.setPropertyValue(builder, element, "credential", "credential");
+		ParsingUtils.setPropertyValue(builder, element, "replica-set", "replicaSet");
+		ParsingUtils.setPropertyValue(builder, element, "connection-string", "connectionString");
 
-		MongoParsingUtils.parseMongoClientOptions(element, builder);
-		MongoParsingUtils.parseReplicaSet(element, builder);
+		MongoParsingUtils.parseMongoClientSettings(element, builder);
 
 		String defaultedId = StringUtils.hasText(id) ? id : BeanNames.MONGO_BEAN_NAME;
 
@@ -62,22 +63,34 @@ public class MongoClientParser implements BeanDefinitionParser {
 		BeanComponentDefinition mongoComponent = helper.getComponent(builder, defaultedId);
 		parserContext.registerBeanComponent(mongoComponent);
 
-		BeanComponentDefinition serverAddressPropertyEditor = helper.getComponent(MongoParsingUtils
-				.getServerAddressPropertyEditorBuilder());
+		BeanComponentDefinition connectionStringPropertyEditor = helper
+				.getComponent(MongoParsingUtils.getConnectionStringPropertyEditorBuilder());
+		parserContext.registerBeanComponent(connectionStringPropertyEditor);
+
+		BeanComponentDefinition serverAddressPropertyEditor = helper
+				.getComponent(MongoParsingUtils.getServerAddressPropertyEditorBuilder());
 		parserContext.registerBeanComponent(serverAddressPropertyEditor);
 
-		BeanComponentDefinition writeConcernEditor = helper.getComponent(MongoParsingUtils
-				.getWriteConcernPropertyEditorBuilder());
+		BeanComponentDefinition writeConcernEditor = helper
+				.getComponent(MongoParsingUtils.getWriteConcernPropertyEditorBuilder());
 		parserContext.registerBeanComponent(writeConcernEditor);
 
-		BeanComponentDefinition readPreferenceEditor = helper.getComponent(MongoParsingUtils
-				.getReadPreferencePropertyEditorBuilder());
+		BeanComponentDefinition readConcernEditor = helper
+				.getComponent(MongoParsingUtils.getReadConcernPropertyEditorBuilder());
+		parserContext.registerBeanComponent(readConcernEditor);
+
+		BeanComponentDefinition readPreferenceEditor = helper
+				.getComponent(MongoParsingUtils.getReadPreferencePropertyEditorBuilder());
 		parserContext.registerBeanComponent(readPreferenceEditor);
 
-		BeanComponentDefinition credentialsEditor = helper.getComponent(MongoParsingUtils
-				.getMongoCredentialPropertyEditor());
+		BeanComponentDefinition credentialsEditor = helper
+				.getComponent(MongoParsingUtils.getMongoCredentialPropertyEditor());
 		parserContext.registerBeanComponent(credentialsEditor);
 
+		BeanComponentDefinition uuidRepresentationEditor = helper
+				.getComponent(MongoParsingUtils.getUUidRepresentationEditorBuilder());
+		parserContext.registerBeanComponent(uuidRepresentationEditor);
+
 		parserContext.popAndRegisterContainingComponent();
 
 		return mongoComponent.getBeanDefinition();

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

@@ -20,6 +20,7 @@ import java.util.Collections;
 import java.util.HashSet;
 import java.util.Set;
 
+import org.bson.UuidRepresentation;
 import org.springframework.beans.factory.config.BeanDefinition;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.ClassPathScanningCandidateComponentProvider;
@@ -31,11 +32,15 @@ import org.springframework.data.mapping.model.CamelCaseAbbreviatingFieldNamingSt
 import org.springframework.data.mapping.model.FieldNamingStrategy;
 import org.springframework.data.mapping.model.PropertyNameFieldNamingStrategy;
 import org.springframework.data.mongodb.core.convert.MongoCustomConversions;
+import org.springframework.data.mongodb.core.convert.MongoCustomConversions.MongoConverterConfigurationAdapter;
 import org.springframework.data.mongodb.core.mapping.Document;
 import org.springframework.data.mongodb.core.mapping.MongoMappingContext;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.StringUtils;
 
+import com.mongodb.MongoClientSettings;
+import com.mongodb.MongoClientSettings.Builder;
+
 /**
  * Base class for Spring Data MongoDB to be extended for JavaConfiguration usage.
  *
@@ -75,11 +80,12 @@ public abstract class MongoConfigurationSupport {
 	 * @throws ClassNotFoundException
 	 */
 	@Bean
-	public MongoMappingContext mongoMappingContext() throws ClassNotFoundException {
+	public MongoMappingContext mongoMappingContext(MongoCustomConversions customConversions)
+			throws ClassNotFoundException {
 
 		MongoMappingContext mappingContext = new MongoMappingContext();
 		mappingContext.setInitialEntitySet(getInitialEntitySet());
-		mappingContext.setSimpleTypeHolder(customConversions().getSimpleTypeHolder());
+		mappingContext.setSimpleTypeHolder(customConversions.getSimpleTypeHolder());
 		mappingContext.setFieldNamingStrategy(fieldNamingStrategy());
 		mappingContext.setAutoIndexCreation(autoIndexCreation());
 
@@ -88,14 +94,30 @@ public abstract class MongoConfigurationSupport {
 
 	/**
 	 * Register custom {@link Converter}s in a {@link CustomConversions} object if required. These
-	 * {@link CustomConversions} will be registered with the {@link #mappingMongoConverter()} and
-	 * {@link #mongoMappingContext()}. Returns an empty {@link MongoCustomConversions} instance by default.
+	 * {@link CustomConversions} will be registered with the
+	 * {@link org.springframework.data.mongodb.core.convert.MappingMongoConverter} and {@link MongoMappingContext}.
+	 * Returns an empty {@link MongoCustomConversions} instance by default.
+	 * <p>
+	 * <strong>NOTE:</strong> Use {@link #configureConverters(MongoConverterConfigurationAdapter)} to configure MongoDB
+	 * native simple types and register custom {@link Converter converters}.
 	 *
 	 * @return must not be {@literal null}.
 	 */
 	@Bean
-	public CustomConversions customConversions() {
-		return new MongoCustomConversions(Collections.emptyList());
+	public MongoCustomConversions customConversions() {
+		return MongoCustomConversions.create(this::configureConverters);
+	}
+
+	/**
+	 * Configuration hook for {@link MongoCustomConversions} creation.
+	 *
+	 * @param converterConfigurationAdapter never {@literal null}.
+	 * @since 2.3
+	 * @see MongoConverterConfigurationAdapter#useNativeDriverJavaTimeCodecs()
+	 * @see MongoConverterConfigurationAdapter#useSpringDataJavaTimeCodecs()
+	 */
+	protected void configureConverters(MongoConverterConfigurationAdapter converterConfigurationAdapter) {
+
 	}
 
 	/**
@@ -177,11 +199,36 @@ public abstract class MongoConfigurationSupport {
 	 * Configure whether to automatically create indices for domain types by deriving the
 	 * {@link org.springframework.data.mongodb.core.index.IndexDefinition} from the entity or not.
 	 *
-	 * @return {@literal true} by default. <br />
-	 *         <strong>INFO</strong>: As of 3.x the default will be set to {@literal false}.
+	 * @return {@literal false} by default. <br />
+	 *         <strong>INFO</strong>: As of 3.x the default is set to {@literal false}; In 2.x it was {@literal true}.
 	 * @since 2.2
 	 */
 	protected boolean autoIndexCreation() {
-		return true;
+		return false;
+	}
+
+	/**
+	 * Return the {@link MongoClientSettings} used to create the actual {@literal MongoClient}. <br />
+	 * Override either this method, or use {@link #configureClientSettings(Builder)} to alter the setup.
+	 *
+	 * @return never {@literal null}.
+	 * @since 3.0
+	 */
+	protected MongoClientSettings mongoClientSettings() {
+
+		MongoClientSettings.Builder builder = MongoClientSettings.builder();
+		builder.uuidRepresentation(UuidRepresentation.JAVA_LEGACY);
+		configureClientSettings(builder);
+		return builder.build();
+	}
+
+	/**
+	 * Configure {@link MongoClientSettings} via its {@link Builder} API.
+	 *
+	 * @param builder never {@literal null}.
+	 * @since 3.0
+	 */
+	protected void configureClientSettings(MongoClientSettings.Builder builder) {
+		// customization hook
 	}
 }

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

@@ -32,14 +32,12 @@ 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.MongoClientFactoryBean;
-import org.springframework.data.mongodb.core.SimpleMongoDbFactory;
+import org.springframework.data.mongodb.core.SimpleMongoClientDatabaseFactory;
 import org.springframework.lang.Nullable;
 import org.springframework.util.StringUtils;
 import org.w3c.dom.Element;
 
-import com.mongodb.Mongo;
-import com.mongodb.MongoClientURI;
-import com.mongodb.MongoURI;
+import com.mongodb.ConnectionString;
 
 /**
  * {@link BeanDefinitionParser} to parse {@code db-factory} elements into {@link BeanDefinition}s.
@@ -84,10 +82,11 @@ public class MongoDbFactoryParser extends AbstractBeanDefinitionParser {
 	protected AbstractBeanDefinition parseInternal(Element element, ParserContext parserContext) {
 
 		// Common setup
-		BeanDefinitionBuilder dbFactoryBuilder = BeanDefinitionBuilder.genericBeanDefinition(SimpleMongoDbFactory.class);
+		BeanDefinitionBuilder dbFactoryBuilder = BeanDefinitionBuilder
+				.genericBeanDefinition(SimpleMongoClientDatabaseFactory.class);
 		setPropertyValue(dbFactoryBuilder, element, "write-concern", "writeConcern");
 
-		BeanDefinition mongoUri = getMongoUri(element, parserContext);
+		BeanDefinition mongoUri = getConnectionString(element, parserContext);
 
 		if (mongoUri != null) {
 
@@ -97,7 +96,8 @@ public class MongoDbFactoryParser extends AbstractBeanDefinitionParser {
 
 		BeanComponentDefinitionBuilder helper = new BeanComponentDefinitionBuilder(element, parserContext);
 
-		String mongoRef = element.getAttribute("mongo-ref");
+		String mongoRef = element.getAttribute("mongo-client-ref");
+
 		String dbname = element.getAttribute("dbname");
 
 		// Defaulting
@@ -119,8 +119,8 @@ public class MongoDbFactoryParser extends AbstractBeanDefinitionParser {
 	}
 
 	/**
-	 * Registers a default {@link BeanDefinition} of a {@link Mongo} instance and returns the name under which the
-	 * {@link Mongo} instance was registered under.
+	 * Registers a default {@link BeanDefinition} of a {@link com.mongodb.client.MongoClient} instance and returns the
+	 * name under which the {@link com.mongodb.client.MongoClient} instance was registered under.
 	 *
 	 * @param element must not be {@literal null}.
 	 * @param parserContext must not be {@literal null}.
@@ -136,8 +136,7 @@ public class MongoDbFactoryParser extends AbstractBeanDefinitionParser {
 	}
 
 	/**
-	 * Creates a {@link BeanDefinition} for a {@link MongoURI} or {@link MongoClientURI} depending on configured
-	 * attributes. <br />
+	 * Creates a {@link BeanDefinition} for a {@link ConnectionString} depending on configured attributes. <br />
 	 * Errors when configured element contains {@literal uri} or {@literal client-uri} along with other attributes except
 	 * {@literal write-concern} and/or {@literal id}.
 	 *
@@ -146,11 +145,19 @@ public class MongoDbFactoryParser extends AbstractBeanDefinitionParser {
 	 * @return {@literal null} in case no client-/uri defined.
 	 */
 	@Nullable
-	private BeanDefinition getMongoUri(Element element, ParserContext parserContext) {
+	private BeanDefinition getConnectionString(Element element, ParserContext parserContext) {
 
-		boolean hasClientUri = element.hasAttribute("client-uri");
+		String type = null;
 
-		if (!hasClientUri && !element.hasAttribute("uri")) {
+		if (element.hasAttribute("client-uri")) {
+			type = "client-uri";
+		} else if (element.hasAttribute("connection-string")) {
+			type = "connection-string";
+		} else if (element.hasAttribute("uri")) {
+			type = "uri";
+		}
+
+		if (!StringUtils.hasText(type)) {
 			return null;
 		}
 
@@ -164,16 +171,12 @@ public class MongoDbFactoryParser extends AbstractBeanDefinitionParser {
 
 		if (element.getAttributes().getLength() > allowedAttributesCount) {
 
-			parserContext.getReaderContext().error(
-					"Configure either " + (hasClientUri ? "Mongo Client URI" : "Mongo URI") + " or details individually!",
+			parserContext.getReaderContext().error("Configure either MongoDB " + type + " or details individually!",
 					parserContext.extractSource(element));
 		}
 
-		Class<?> type = MongoClientURI.class;
-		String uri = hasClientUri ? element.getAttribute("client-uri") : element.getAttribute("uri");
-
-		BeanDefinitionBuilder builder = BeanDefinitionBuilder.genericBeanDefinition(type);
-		builder.addConstructorArgValue(uri);
+		BeanDefinitionBuilder builder = BeanDefinitionBuilder.genericBeanDefinition(ConnectionString.class);
+		builder.addConstructorArgValue(element.getAttribute(type));
 
 		return builder.getBeanDefinition();
 	}

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

@@ -24,7 +24,7 @@ import org.springframework.beans.factory.config.CustomEditorConfigurer;
 import org.springframework.beans.factory.support.BeanDefinitionBuilder;
 import org.springframework.beans.factory.support.ManagedMap;
 import org.springframework.beans.factory.xml.BeanDefinitionParser;
-import org.springframework.data.mongodb.core.MongoClientOptionsFactoryBean;
+import org.springframework.data.mongodb.core.MongoClientSettingsFactoryBean;
 import org.springframework.util.xml.DomUtils;
 import org.w3c.dom.Element;
 
@@ -43,60 +43,78 @@ abstract class MongoParsingUtils {
 	private MongoParsingUtils() {}
 
 	/**
-	 * Parses the mongo replica-set element.
-	 *
-	 * @param parserContext the parser context
-	 * @param element the mongo element
-	 * @param mongoBuilder the bean definition builder to populate
-	 * @return
-	 */
-	static void parseReplicaSet(Element element, BeanDefinitionBuilder mongoBuilder) {
-		setPropertyValue(mongoBuilder, element, "replica-set", "replicaSetSeeds");
-	}
-
-	/**
-	 * Parses the {@code mongo:client-options} sub-element. Populates the given attribute factory with the proper
+	 * Parses the {@code mongo:client-settings} sub-element. Populates the given attribute factory with the proper
 	 * attributes.
-	 *
-	 * @param element must not be {@literal null}.
-	 * @param mongoClientBuilder must not be {@literal null}.
+	 * 
+	 * @param element
+	 * @param mongoClientBuilder
 	 * @return
-	 * @since 1.7
+	 * @since 3.0
 	 */
-	public static boolean parseMongoClientOptions(Element element, BeanDefinitionBuilder mongoClientBuilder) {
+	public static boolean parseMongoClientSettings(Element element, BeanDefinitionBuilder mongoClientBuilder) {
 
-		Element optionsElement = DomUtils.getChildElementByTagName(element, "client-options");
-
-		if (optionsElement == null) {
+		Element settingsElement = DomUtils.getChildElementByTagName(element, "client-settings");
+		if (settingsElement == null) {
 			return false;
 		}
 
 		BeanDefinitionBuilder clientOptionsDefBuilder = BeanDefinitionBuilder
-				.genericBeanDefinition(MongoClientOptionsFactoryBean.class);
+				.genericBeanDefinition(MongoClientSettingsFactoryBean.class);
 
-		setPropertyValue(clientOptionsDefBuilder, optionsElement, "description", "description");
-		setPropertyValue(clientOptionsDefBuilder, optionsElement, "min-connections-per-host", "minConnectionsPerHost");
-		setPropertyValue(clientOptionsDefBuilder, optionsElement, "connections-per-host", "connectionsPerHost");
-		setPropertyValue(clientOptionsDefBuilder, optionsElement, "threads-allowed-to-block-for-connection-multiplier",
-				"threadsAllowedToBlockForConnectionMultiplier");
-		setPropertyValue(clientOptionsDefBuilder, optionsElement, "max-wait-time", "maxWaitTime");
-		setPropertyValue(clientOptionsDefBuilder, optionsElement, "max-connection-idle-time", "maxConnectionIdleTime");
-		setPropertyValue(clientOptionsDefBuilder, optionsElement, "max-connection-life-time", "maxConnectionLifeTime");
-		setPropertyValue(clientOptionsDefBuilder, optionsElement, "connect-timeout", "connectTimeout");
-		setPropertyValue(clientOptionsDefBuilder, optionsElement, "socket-timeout", "socketTimeout");
-		setPropertyValue(clientOptionsDefBuilder, optionsElement, "socket-keep-alive", "socketKeepAlive");
-		setPropertyValue(clientOptionsDefBuilder, optionsElement, "read-preference", "readPreference");
-		setPropertyValue(clientOptionsDefBuilder, optionsElement, "write-concern", "writeConcern");
-		setPropertyValue(clientOptionsDefBuilder, optionsElement, "heartbeat-frequency", "heartbeatFrequency");
-		setPropertyValue(clientOptionsDefBuilder, optionsElement, "min-heartbeat-frequency", "minHeartbeatFrequency");
-		setPropertyValue(clientOptionsDefBuilder, optionsElement, "heartbeat-connect-timeout", "heartbeatConnectTimeout");
-		setPropertyValue(clientOptionsDefBuilder, optionsElement, "heartbeat-socket-timeout", "heartbeatSocketTimeout");
-		setPropertyValue(clientOptionsDefBuilder, optionsElement, "ssl", "ssl");
-		setPropertyReference(clientOptionsDefBuilder, optionsElement, "ssl-socket-factory-ref", "sslSocketFactory");
-		setPropertyReference(clientOptionsDefBuilder, optionsElement, "encryption-settings-ref", "autoEncryptionSettings");
-		setPropertyValue(clientOptionsDefBuilder, optionsElement, "server-selection-timeout", "serverSelectionTimeout");
+		setPropertyValue(clientOptionsDefBuilder, settingsElement, "application-name", "applicationName");
+		setPropertyValue(clientOptionsDefBuilder, settingsElement, "read-preference", "readPreference");
+		setPropertyValue(clientOptionsDefBuilder, settingsElement, "read-concern", "readConcern");
+		setPropertyValue(clientOptionsDefBuilder, settingsElement, "write-concern", "writeConcern");
+		setPropertyValue(clientOptionsDefBuilder, settingsElement, "retry-reads", "retryReads");
+		setPropertyValue(clientOptionsDefBuilder, settingsElement, "retry-writes", "retryWrites");
+		setPropertyValue(clientOptionsDefBuilder, settingsElement, "uuid-representation", "uUidRepresentation");
 
-		mongoClientBuilder.addPropertyValue("mongoClientOptions", clientOptionsDefBuilder.getBeanDefinition());
+		// SocketSettings
+		setPropertyValue(clientOptionsDefBuilder, settingsElement, "socket-connect-timeout", "socketConnectTimeoutMS");
+		setPropertyValue(clientOptionsDefBuilder, settingsElement, "socket-read-timeout", "socketReadTimeoutMS");
+		setPropertyValue(clientOptionsDefBuilder, settingsElement, "socket-receive-buffer-size", "socketReceiveBufferSize");
+		setPropertyValue(clientOptionsDefBuilder, settingsElement, "socket-send-buffer-size", "socketSendBufferSize");
+
+		// Server Settings
+		setPropertyValue(clientOptionsDefBuilder, settingsElement, "server-heartbeat-frequency",
+				"serverHeartbeatFrequencyMS");
+		setPropertyValue(clientOptionsDefBuilder, settingsElement, "server-min-heartbeat-frequency",
+				"serverMinHeartbeatFrequencyMS");
+
+		// Cluster Settings
+		setPropertyValue(clientOptionsDefBuilder, settingsElement, "cluster-srv-host", "clusterSrvHost");
+		setPropertyValue(clientOptionsDefBuilder, settingsElement, "cluster-hosts", "clusterHosts");
+		setPropertyValue(clientOptionsDefBuilder, settingsElement, "cluster-connection-mode", "clusterConnectionMode");
+		setPropertyValue(clientOptionsDefBuilder, settingsElement, "cluster-type", "custerRequiredClusterType");
+		setPropertyValue(clientOptionsDefBuilder, settingsElement, "cluster-local-threshold", "clusterLocalThresholdMS");
+		setPropertyValue(clientOptionsDefBuilder, settingsElement, "cluster-server-selection-timeout",
+				"clusterServerSelectionTimeoutMS");
+
+		// Connection Pool Settings
+		setPropertyValue(clientOptionsDefBuilder, settingsElement, "connection-pool-max-size", "poolMaxSize");
+		setPropertyValue(clientOptionsDefBuilder, settingsElement, "connection-pool-min-size", "poolMinSize");
+		setPropertyValue(clientOptionsDefBuilder, settingsElement, "connection-pool-max-wait-time", "poolMaxWaitTimeMS");
+		setPropertyValue(clientOptionsDefBuilder, settingsElement, "connection-pool-max-connection-life-time",
+				"poolMaxConnectionLifeTimeMS");
+		setPropertyValue(clientOptionsDefBuilder, settingsElement, "connection-pool-max-connection-idle-time",
+				"poolMaxConnectionIdleTimeMS");
+		setPropertyValue(clientOptionsDefBuilder, settingsElement, "connection-pool-maintenance-initial-delay",
+				"poolMaintenanceInitialDelayMS");
+		setPropertyValue(clientOptionsDefBuilder, settingsElement, "connection-pool-maintenance-frequency",
+				"poolMaintenanceFrequencyMS");
+
+		// SSL Settings
+		setPropertyValue(clientOptionsDefBuilder, settingsElement, "ssl-enabled", "sslEnabled");
+		setPropertyValue(clientOptionsDefBuilder, settingsElement, "ssl-invalid-host-name-allowed",
+				"sslInvalidHostNameAllowed");
+		setPropertyValue(clientOptionsDefBuilder, settingsElement, "ssl-provider", "sslProvider");
+
+		// Field level encryption
+		setPropertyReference(clientOptionsDefBuilder, settingsElement, "encryption-settings-ref", "autoEncryptionSettings");
+
+		// and the rest
+
+		mongoClientBuilder.addPropertyValue("mongoClientSettings", clientOptionsDefBuilder.getBeanDefinition());
 
 		return true;
 	}
@@ -118,6 +136,24 @@ abstract class MongoParsingUtils {
 		return builder;
 	}
 
+	/**
+	 * Returns the {@link BeanDefinitionBuilder} to build a {@link BeanDefinition} for a
+	 * {@link ReadConcernPropertyEditor}.
+	 *
+	 * @return
+	 * @since 3.0
+	 */
+	static BeanDefinitionBuilder getReadConcernPropertyEditorBuilder() {
+
+		Map<String, Class<?>> customEditors = new ManagedMap<>();
+		customEditors.put("com.mongodb.ReadConcern", ReadConcernPropertyEditor.class);
+
+		BeanDefinitionBuilder builder = BeanDefinitionBuilder.genericBeanDefinition(CustomEditorConfigurer.class);
+		builder.addPropertyValue("customEditors", customEditors);
+
+		return builder;
+	}
+
 	/**
 	 * One should only register one bean definition but want to have the convenience of using
 	 * AbstractSingleBeanDefinitionParser but have the side effect of registering a 'default' property editor with the
@@ -125,7 +161,7 @@ abstract class MongoParsingUtils {
 	 */
 	static BeanDefinitionBuilder getServerAddressPropertyEditorBuilder() {
 
-		Map<String, String> customEditors = new ManagedMap<String, String>();
+		Map<String, String> customEditors = new ManagedMap<>();
 		customEditors.put("com.mongodb.ServerAddress[]",
 				"org.springframework.data.mongodb.config.ServerAddressPropertyEditor");
 
@@ -143,7 +179,7 @@ abstract class MongoParsingUtils {
 	 */
 	static BeanDefinitionBuilder getReadPreferencePropertyEditorBuilder() {
 
-		Map<String, Class<?>> customEditors = new ManagedMap<String, Class<?>>();
+		Map<String, Class<?>> customEditors = new ManagedMap<>();
 		customEditors.put("com.mongodb.ReadPreference", ReadPreferencePropertyEditor.class);
 
 		BeanDefinitionBuilder builder = BeanDefinitionBuilder.genericBeanDefinition(CustomEditorConfigurer.class);
@@ -169,4 +205,41 @@ abstract class MongoParsingUtils {
 
 		return builder;
 	}
+
+	/**
+	 * Returns the {@link BeanDefinitionBuilder} to build a {@link BeanDefinition} for a
+	 * {@link ConnectionStringPropertyEditor}.
+	 *
+	 * @return
+	 * @since 3.0
+	 */
+	static BeanDefinitionBuilder getConnectionStringPropertyEditorBuilder() {
+
+		Map<String, Class<?>> customEditors = new ManagedMap<>();
+		customEditors.put("com.mongodb.ConnectionString", ConnectionStringPropertyEditor.class);
+
+		BeanDefinitionBuilder builder = BeanDefinitionBuilder.genericBeanDefinition(CustomEditorConfigurer.class);
+		builder.addPropertyValue("customEditors", customEditors);
+
+		return builder;
+	}
+
+	/**
+	 * Returns the {@link BeanDefinitionBuilder} to build a {@link BeanDefinition} for a
+	 * {@link ConnectionStringPropertyEditor}.
+	 *
+	 * @return
+	 * @since 3.0
+	 */
+	static BeanDefinitionBuilder getUUidRepresentationEditorBuilder() {
+
+		Map<String, Class<?>> customEditors = new ManagedMap<>();
+		customEditors.put("org.bson.UuidRepresentation", UUidRepresentationPropertyEditor.class);
+
+		BeanDefinitionBuilder builder = BeanDefinitionBuilder.genericBeanDefinition(CustomEditorConfigurer.class);
+		builder.addPropertyValue("customEditors", customEditors);
+
+		return builder;
+	}
+
 }

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

@@ -0,0 +1,48 @@
+/*
+ * Copyright 2019 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
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.mongodb.config;
+
+import java.beans.PropertyEditorSupport;
+
+import org.springframework.lang.Nullable;
+import org.springframework.util.StringUtils;
+
+import com.mongodb.ReadConcern;
+import com.mongodb.ReadConcernLevel;
+
+/**
+ * Parse a {@link String} to a {@link ReadConcern}. If it is a well know {@link String} as identified by the
+ * {@link ReadConcernLevel#fromString(String)}.
+ *
+ * @author Christoph Strobl
+ * @since 3.0
+ */
+public class ReadConcernPropertyEditor extends PropertyEditorSupport {
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.beans.factory.xml.BeanDefinitionParser#parse(org.w3c.dom.Element, org.springframework.beans.factory.xml.ParserContext)
+	 */
+	@Override
+	public void setAsText(@Nullable String readConcernString) {
+
+		if (!StringUtils.hasText(readConcernString)) {
+			return;
+		}
+
+		setValue(new ReadConcern(ReadConcernLevel.fromString(readConcernString)));
+	}
+}

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

@@ -0,0 +1,45 @@
+/*
+ * Copyright 2020 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
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.mongodb.config;
+
+import java.beans.PropertyEditorSupport;
+
+import org.bson.UuidRepresentation;
+import org.springframework.lang.Nullable;
+import org.springframework.util.StringUtils;
+
+/**
+ * Parse a {@link String} to a {@link UuidRepresentation}.
+ *
+ * @author Christoph Strobl
+ * @since 3.0
+ */
+public class UUidRepresentationPropertyEditor extends PropertyEditorSupport {
+
+	/*
+	 * (non-Javadoc)
+	 * @see java.beans.PropertyEditorSupport#setAsText(java.lang.String)
+	 */
+	@Override
+	public void setAsText(@Nullable String value) {
+
+		if (!StringUtils.hasText(value)) {
+			return;
+		}
+
+		setValue(UuidRepresentation.valueOf(value));
+	}
+}

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

@@ -34,7 +34,7 @@ import com.mongodb.WriteConcern;
 public class WriteConcernPropertyEditor extends PropertyEditorSupport {
 
 	/**
-	 * Parse a string to a List<ServerAddress>
+	 * Parse a string to a {@link WriteConcern}.
 	 */
 	@Override
 	public void setAsText(@Nullable String writeConcernString) {
@@ -51,6 +51,5 @@ public class WriteConcernPropertyEditor extends PropertyEditorSupport {
 			// pass on the string to the constructor
 			setValue(new WriteConcern(writeConcernString));
 		}
-
 	}
 }

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

@@ -94,7 +94,6 @@ public interface BulkOperations {
 	 * Add a list of updates to the bulk operation. For each update request, all matching documents are updated.
 	 *
 	 * @param updates Update operations to perform.
-	 * @return The bulk operation.
 	 * @return the current {@link BulkOperations} instance with the update added, will never be {@literal null}.
 	 */
 	BulkOperations updateMulti(List<Pair<Query, Update>> updates);
@@ -105,7 +104,6 @@ public interface BulkOperations {
 	 *
 	 * @param query Update criteria.
 	 * @param update Update operation to perform.
-	 * @return The bulk operation.
 	 * @return the current {@link BulkOperations} instance with the update added, will never be {@literal null}.
 	 */
 	BulkOperations upsert(Query query, Update update);
@@ -115,7 +113,6 @@ public interface BulkOperations {
 	 * else an insert.
 	 *
 	 * @param updates Updates/insert operations to perform.
-	 * @return The bulk operation.
 	 * @return the current {@link BulkOperations} instance with the update added, will never be {@literal null}.
 	 */
 	BulkOperations upsert(List<Pair<Query, Update>> updates);

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

@@ -29,7 +29,7 @@ import com.mongodb.client.MongoCollection;
  * @author Grame Rocher
  * @author Oliver Gierke
  * @author John Brisbin
- * @auhtor Christoph Strobl
+ * @author Christoph Strobl
  * @since 1.0
  */
 public interface CollectionCallback<T> {

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

@@ -95,7 +95,7 @@ public class CollectionOptions {
 
 	/**
 	 * Create new {@link CollectionOptions} with already given settings and capped set to {@literal true}. <br />
-	 * <strong>NOTE</strong> Using capped collections requires defining {@link #size(int)}.
+	 * <strong>NOTE</strong> Using capped collections requires defining {@link #size(long)}.
 	 *
 	 * @return new {@link CollectionOptions}.
 	 * @since 2.0

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

@@ -43,9 +43,10 @@ public interface CursorPreparer extends ReadPreferenceAware {
 	/**
 	 * Prepare the given cursor (apply limits, skips and so on). Returns the prepared cursor.
 	 *
-	 * @param cursor
+	 * @param iterable must not be {@literal null}.
+	 * @return never {@literal null}.
 	 */
-	FindIterable<Document> prepare(FindIterable<Document> cursor);
+	FindIterable<Document> prepare(FindIterable<Document> iterable);
 
 	/**
 	 * Apply query specific settings to {@link MongoCollection} and initate a find operation returning a
@@ -53,7 +54,7 @@ public interface CursorPreparer extends ReadPreferenceAware {
 	 *
 	 * @param collection must not be {@literal null}.
 	 * @param find must not be {@literal null}.
-	 * @return
+	 * @return never {@literal null}.
 	 * @throws IllegalArgumentException if one of the required arguments is {@literal null}.
 	 * @since 2.2
 	 */

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

@@ -32,6 +32,7 @@ import org.springframework.data.mapping.callback.EntityCallbacks;
 import org.springframework.data.mongodb.core.convert.QueryMapper;
 import org.springframework.data.mongodb.core.convert.UpdateMapper;
 import org.springframework.data.mongodb.core.mapping.MongoPersistentEntity;
+import org.springframework.data.mongodb.core.mapping.event.AfterSaveCallback;
 import org.springframework.data.mongodb.core.mapping.event.AfterSaveEvent;
 import org.springframework.data.mongodb.core.mapping.event.BeforeConvertCallback;
 import org.springframework.data.mongodb.core.mapping.event.BeforeConvertEvent;
@@ -62,6 +63,7 @@ import com.mongodb.client.model.*;
  * @author Minsu Kim
  * @author Jens Schauder
  * @author Michail Nikolaev
+ * @author Roman Puchkovskiy
  * @since 1.9
  */
 class DefaultBulkOperations implements BulkOperations {
@@ -300,6 +302,7 @@ class DefaultBulkOperations implements BulkOperations {
 			Assert.state(result != null, "Result must not be null.");
 
 			models.forEach(this::maybeEmitAfterSaveEvent);
+			models.forEach(this::maybeInvokeAfterSaveCallback);
 
 			return result;
 		} finally {
@@ -421,38 +424,52 @@ class DefaultBulkOperations implements BulkOperations {
 		models.add(new SourceAwareWriteModelHolder(source, model));
 	}
 
-	private void maybeEmitBeforeSaveEvent(SourceAwareWriteModelHolder it) {
+	private void maybeEmitBeforeSaveEvent(SourceAwareWriteModelHolder holder) {
 
-		if (it.getModel() instanceof InsertOneModel) {
+		if (holder.getModel() instanceof InsertOneModel) {
 
-			Document target = ((InsertOneModel<Document>) it.getModel()).getDocument();
-			maybeEmitEvent(new BeforeSaveEvent<>(it.getSource(), target, collectionName));
-		} else if (it.getModel() instanceof ReplaceOneModel) {
+			Document target = ((InsertOneModel<Document>) holder.getModel()).getDocument();
+			maybeEmitEvent(new BeforeSaveEvent<>(holder.getSource(), target, collectionName));
+		} else if (holder.getModel() instanceof ReplaceOneModel) {
 
-			Document target = ((ReplaceOneModel<Document>) it.getModel()).getReplacement();
-			maybeEmitEvent(new BeforeSaveEvent<>(it.getSource(), target, collectionName));
+			Document target = ((ReplaceOneModel<Document>) holder.getModel()).getReplacement();
+			maybeEmitEvent(new BeforeSaveEvent<>(holder.getSource(), target, collectionName));
 		}
 	}
 
-	private void maybeEmitAfterSaveEvent(SourceAwareWriteModelHolder it) {
+	private void maybeEmitAfterSaveEvent(SourceAwareWriteModelHolder holder) {
 
-		if (it.getModel() instanceof InsertOneModel) {
+		if (holder.getModel() instanceof InsertOneModel) {
 
-			Document target = ((InsertOneModel<Document>) it.getModel()).getDocument();
-			maybeEmitEvent(new AfterSaveEvent<>(it.getSource(), target, collectionName));
-		} else if (it.getModel() instanceof ReplaceOneModel) {
+			Document target = ((InsertOneModel<Document>) holder.getModel()).getDocument();
+			maybeEmitEvent(new AfterSaveEvent<>(holder.getSource(), target, collectionName));
+		} else if (holder.getModel() instanceof ReplaceOneModel) {
 
-			Document target = ((ReplaceOneModel<Document>) it.getModel()).getReplacement();
-			maybeEmitEvent(new AfterSaveEvent<>(it.getSource(), target, collectionName));
+			Document target = ((ReplaceOneModel<Document>) holder.getModel()).getReplacement();
+			maybeEmitEvent(new AfterSaveEvent<>(holder.getSource(), target, collectionName));
+		}
+	}
+
+	private void maybeInvokeAfterSaveCallback(SourceAwareWriteModelHolder holder) {
+
+		if (holder.getModel() instanceof InsertOneModel) {
+
+			Document target = ((InsertOneModel<Document>) holder.getModel()).getDocument();
+			maybeInvokeAfterSaveCallback(holder.getSource(), target);
+		} else if (holder.getModel() instanceof ReplaceOneModel) {
+
+			Document target = ((ReplaceOneModel<Document>) holder.getModel()).getReplacement();
+			maybeInvokeAfterSaveCallback(holder.getSource(), target);
 		}
 	}
 
 	private <E extends MongoMappingEvent<T>, T> E maybeEmitEvent(E event) {
 
-		if (null != bulkOperationContext.getEventPublisher()) {
-			bulkOperationContext.getEventPublisher().publishEvent(event);
+		if (bulkOperationContext.getEventPublisher() == null) {
+			return event;
 		}
 
+		bulkOperationContext.getEventPublisher().publishEvent(event);
 		return event;
 	}
 
@@ -475,6 +492,16 @@ class DefaultBulkOperations implements BulkOperations {
 				collectionName);
 	}
 
+	private Object maybeInvokeAfterSaveCallback(Object value, Document mappedDocument) {
+
+		if (bulkOperationContext.getEntityCallbacks() == null) {
+			return value;
+		}
+
+		return bulkOperationContext.getEntityCallbacks().callback(AfterSaveCallback.class, value, mappedDocument,
+				collectionName);
+	}
+
 	private static BulkWriteOptions getBulkWriteOptions(BulkMode bulkMode) {
 
 		BulkWriteOptions options = new BulkWriteOptions();

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

@@ -21,7 +21,7 @@ import java.util.List;
 
 import org.bson.Document;
 import org.springframework.dao.DataAccessException;
-import org.springframework.data.mongodb.MongoDbFactory;
+import org.springframework.data.mongodb.MongoDatabaseFactory;
 import org.springframework.data.mongodb.core.convert.QueryMapper;
 import org.springframework.data.mongodb.core.index.IndexDefinition;
 import org.springframework.data.mongodb.core.index.IndexInfo;
@@ -64,7 +64,7 @@ public class DefaultIndexOperations implements IndexOperations {
 	 *             {@link DefaultIndexOperations#DefaultIndexOperations(MongoOperations, String, Class)}.
 	 */
 	@Deprecated
-	public DefaultIndexOperations(MongoDbFactory mongoDbFactory, String collectionName, QueryMapper queryMapper) {
+	public DefaultIndexOperations(MongoDatabaseFactory mongoDbFactory, String collectionName, QueryMapper queryMapper) {
 		this(mongoDbFactory, collectionName, queryMapper, null);
 	}
 
@@ -80,7 +80,7 @@ public class DefaultIndexOperations implements IndexOperations {
 	 *             {@link DefaultIndexOperations#DefaultIndexOperations(MongoOperations, String, Class)}.
 	 */
 	@Deprecated
-	public DefaultIndexOperations(MongoDbFactory mongoDbFactory, String collectionName, QueryMapper queryMapper,
+	public DefaultIndexOperations(MongoDatabaseFactory mongoDbFactory, String collectionName, QueryMapper queryMapper,
 			@Nullable Class<?> type) {
 
 		Assert.notNull(mongoDbFactory, "MongoDbFactory must not be null!");

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

@@ -15,13 +15,13 @@
  */
 package org.springframework.data.mongodb.core;
 
-import org.springframework.data.mongodb.MongoDbFactory;
+import org.springframework.data.mongodb.MongoDatabaseFactory;
 import org.springframework.data.mongodb.core.convert.QueryMapper;
 import org.springframework.data.mongodb.core.index.IndexOperations;
 import org.springframework.data.mongodb.core.index.IndexOperationsProvider;
 
 /**
- * {@link IndexOperationsProvider} to obtain {@link IndexOperations} from a given {@link MongoDbFactory}.
+ * {@link IndexOperationsProvider} to obtain {@link IndexOperations} from a given {@link MongoDatabaseFactory}.
  *
  * @author Mark Paluch
  * @author Christoph Strobl
@@ -29,14 +29,14 @@ import org.springframework.data.mongodb.core.index.IndexOperationsProvider;
  */
 class DefaultIndexOperationsProvider implements IndexOperationsProvider {
 
-	private final MongoDbFactory mongoDbFactory;
+	private final MongoDatabaseFactory mongoDbFactory;
 	private final QueryMapper mapper;
 
 	/**
 	 * @param mongoDbFactory must not be {@literal null}.
 	 * @param mapper must not be {@literal null}.
 	 */
-	DefaultIndexOperationsProvider(MongoDbFactory mongoDbFactory, QueryMapper mapper) {
+	DefaultIndexOperationsProvider(MongoDatabaseFactory mongoDbFactory, QueryMapper mapper) {
 
 		this.mongoDbFactory = mongoDbFactory;
 		this.mapper = mapper;

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

@@ -23,7 +23,7 @@ import com.mongodb.MongoException;
 /**
  * An interface used by {@link MongoTemplate} for processing documents returned from a MongoDB query on a per-document
  * basis. Implementations of this interface perform the actual work of prcoessing each document but don't need to worry
- * about exception handling. {@MongoException}s will be caught and translated by the calling MongoTemplate An
+ * about exception handling. {@link MongoException}s will be caught and translated by the calling MongoTemplate An
  * DocumentCallbackHandler is typically stateful: It keeps the result state within the object, to be available later for
  * later inspection.
  *

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

@@ -66,7 +66,7 @@ class EntityOperations {
 	 * Creates a new {@link Entity} for the given bean.
 	 *
 	 * @param entity must not be {@literal null}.
-	 * @return
+	 * @return new instance of {@link Entity}.
 	 */
 	@SuppressWarnings({ "unchecked", "rawtypes" })
 	public <T> Entity<T> forEntity(T entity) {
@@ -89,7 +89,7 @@ class EntityOperations {
 	 *
 	 * @param entity must not be {@literal null}.
 	 * @param conversionService must not be {@literal null}.
-	 * @return
+	 * @return new instance of {@link AdaptibleEntity}.
 	 */
 	@SuppressWarnings({ "unchecked", "rawtypes" })
 	public <T> AdaptibleEntity<T> forEntity(T entity, ConversionService conversionService) {
@@ -108,6 +108,10 @@ class EntityOperations {
 		return AdaptibleMappedEntity.of(entity, context, conversionService);
 	}
 
+	/**
+	 * @param entityClass should not be null.
+	 * @return the {@link MongoPersistentEntity#getCollection() collection name}.
+	 */
 	public String determineCollectionName(@Nullable Class<?> entityClass) {
 
 		if (entityClass == null) {
@@ -138,7 +142,7 @@ class EntityOperations {
 	 * {@code _id} if no identifier property can be found.
 	 *
 	 * @param type must not be {@literal null}.
-	 * @return
+	 * @return never {@literal null}.
 	 */
 	public String getIdPropertyName(Class<?> type) {
 

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

@@ -88,9 +88,9 @@ public interface ExecutableAggregationOperation {
 
 		/**
 		 * Apply pipeline operations as specified and stream all matching elements. <br />
-		 * Returns a {@link CloseableIterator} that wraps the a Mongo DB {@link com.mongodb.Cursor}
+		 * Returns a {@link CloseableIterator} that wraps the a Mongo DB {@link com.mongodb.client.FindIterable}
 		 *
-		 * @return a {@link CloseableIterator} that wraps the a Mongo DB {@link com.mongodb.Cursor} that needs to be closed.
+		 * @return a {@link CloseableIterator} that wraps the a Mongo DB {@link com.mongodb.client.FindIterable} that needs to be closed.
 		 *         Never {@literal null}.
 		 */
 		CloseableIterator<T> stream();

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

@@ -21,6 +21,7 @@ import java.util.stream.Stream;
 
 import org.springframework.dao.DataAccessException;
 import org.springframework.data.geo.GeoResults;
+import org.springframework.data.mongodb.core.query.CriteriaDefinition;
 import org.springframework.data.mongodb.core.query.NearQuery;
 import org.springframework.data.mongodb.core.query.Query;
 import org.springframework.lang.Nullable;
@@ -43,7 +44,7 @@ import com.mongodb.client.MongoCollection;
  *         query(Human.class)
  *             .inCollection("star-wars")
  *             .as(Jedi.class)
- *             .matching(query(where("firstname").is("luke")))
+ *             .matching(where("firstname").is("luke"))
  *             .all();
  *     </code>
  * </pre>
@@ -117,7 +118,7 @@ public interface ExecutableFindOperation {
 		/**
 		 * Stream all matching elements.
 		 *
-		 * @return a {@link Stream} that wraps the a Mongo DB {@link com.mongodb.Cursor} that needs to be closed. Never
+		 * @return a {@link Stream} that wraps the a Mongo DB {@link com.mongodb.client.FindIterable} that needs to be closed. Never
 		 *         {@literal null}.
 		 */
 		Stream<T> stream();
@@ -170,6 +171,18 @@ public interface ExecutableFindOperation {
 		 */
 		TerminatingFind<T> matching(Query query);
 
+		/**
+		 * Set the filter {@link CriteriaDefinition criteria} to be used.
+		 *
+		 * @param criteria must not be {@literal null}.
+		 * @return new instance of {@link TerminatingFind}.
+		 * @throws IllegalArgumentException if criteria is {@literal null}.
+		 * @since 3.0
+		 */
+		default TerminatingFind<T> matching(CriteriaDefinition criteria) {
+			return matching(Query.query(criteria));
+		}
+
 		/**
 		 * Set the filter query for the geoNear execution.
 		 *
@@ -291,9 +304,21 @@ public interface ExecutableFindOperation {
 		 *
 		 * @param query must not be {@literal null}.
 		 * @return new instance of {@link TerminatingDistinct}.
-		 * @throws IllegalArgumentException if resultType is {@literal null}.
+		 * @throws IllegalArgumentException if query is {@literal null}.
 		 */
 		TerminatingDistinct<T> matching(Query query);
+
+		/**
+		 * Set the filter {@link CriteriaDefinition criteria} to be used.
+		 *
+		 * @param criteria must not be {@literal null}.
+		 * @return new instance of {@link TerminatingDistinct}.
+		 * @throws IllegalArgumentException if criteria is {@literal null}.
+		 * @since 3.0
+		 */
+		default TerminatingDistinct<T> matching(CriteriaDefinition criteria) {
+			return matching(Query.query(criteria));
+		}
 	}
 
 	/**

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

@@ -257,9 +257,9 @@ class ExecutableFindOperationSupport implements ExecutableFindOperation {
 		 * @see org.springframework.data.mongodb.core.CursorPreparer#prepare(com.mongodb.clientFindIterable)
 		 */
 		@Override
-		public FindIterable<Document> prepare(FindIterable<Document> cursor) {
+		public FindIterable<Document> prepare(FindIterable<Document> iterable) {
 
-			FindIterable<Document> target = delegate != null ? delegate.prepare(cursor) : cursor;
+			FindIterable<Document> target = delegate != null ? delegate.prepare(iterable) : iterable;
 			return limit.map(target::limit).orElse(target);
 		}
 

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

@@ -19,6 +19,7 @@ import java.util.List;
 
 import org.springframework.data.mongodb.core.ExecutableFindOperation.ExecutableFind;
 import org.springframework.data.mongodb.core.mapreduce.MapReduceOptions;
+import org.springframework.data.mongodb.core.query.CriteriaDefinition;
 import org.springframework.data.mongodb.core.query.Query;
 
 /**
@@ -30,7 +31,7 @@ import org.springframework.data.mongodb.core.query.Query;
  * The collection to operate on is by default derived from the initial {@literal domainType} and can be defined there
  * via {@link org.springframework.data.mongodb.core.mapping.Document}. Using {@code inCollection} allows to override the
  * collection name for the execution.
- * 
+ *
  * <pre>
  *     <code>
  *         mapReduce(Human.class)
@@ -44,6 +45,7 @@ import org.springframework.data.mongodb.core.query.Query;
  * </pre>
  *
  * @author Christoph Strobl
+ * @author Mark Paluch
  * @since 2.1
  */
 public interface ExecutableMapReduceOperation {
@@ -146,6 +148,18 @@ public interface ExecutableMapReduceOperation {
 		 * @throws IllegalArgumentException if query is {@literal null}.
 		 */
 		TerminatingMapReduce<T> matching(Query query);
+
+		/**
+		 * Set the filter {@link CriteriaDefinition criteria} to be used.
+		 *
+		 * @param criteria must not be {@literal null}.
+		 * @return new instance of {@link TerminatingMapReduce}.
+		 * @throws IllegalArgumentException if query is {@literal null}.
+		 * @since 3.0
+		 */
+		default TerminatingMapReduce<T> matching(CriteriaDefinition criteria) {
+			return matching(Query.query(criteria));
+		}
 	}
 
 	/**

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

@@ -17,6 +17,7 @@ package org.springframework.data.mongodb.core;
 
 import java.util.List;
 
+import org.springframework.data.mongodb.core.query.CriteriaDefinition;
 import org.springframework.data.mongodb.core.query.Query;
 
 import com.mongodb.client.result.DeleteResult;
@@ -119,6 +120,18 @@ public interface ExecutableRemoveOperation {
 		 * @throws IllegalArgumentException if query is {@literal null}.
 		 */
 		TerminatingRemove<T> matching(Query query);
+
+		/**
+		 * Set the filter {@link CriteriaDefinition criteria} to be used.
+		 *
+		 * @param criteria must not be {@literal null}.
+		 * @return new instance of {@link TerminatingRemove}.
+		 * @throws IllegalArgumentException if query is {@literal null}.
+		 * @since 3.0
+		 */
+		default TerminatingRemove<T> matching(CriteriaDefinition criteria) {
+			return matching(Query.query(criteria));
+		}
 	}
 
 	/**

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

@@ -18,6 +18,7 @@ package org.springframework.data.mongodb.core;
 import java.util.Optional;
 
 import org.springframework.data.mongodb.core.aggregation.AggregationUpdate;
+import org.springframework.data.mongodb.core.query.CriteriaDefinition;
 import org.springframework.data.mongodb.core.query.Query;
 import org.springframework.data.mongodb.core.query.Update;
 import org.springframework.data.mongodb.core.query.UpdateDefinition;
@@ -210,6 +211,18 @@ public interface ExecutableUpdateOperation {
 		 * @throws IllegalArgumentException if query is {@literal null}.
 		 */
 		UpdateWithUpdate<T> matching(Query query);
+
+		/**
+		 * Set the filter {@link CriteriaDefinition criteria} to be used.
+		 *
+		 * @param criteria must not be {@literal null}.
+		 * @return new instance of {@link UpdateWithUpdate}.
+		 * @throws IllegalArgumentException if query is {@literal null}.
+		 * @since 3.0
+		 */
+		default UpdateWithUpdate<T> matching(CriteriaDefinition criteria) {
+			return matching(Query.query(criteria));
+		}
 	}
 
 	/**

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

@@ -78,7 +78,7 @@ public class FindAndModifyOptions {
 	}
 
 	/**
-	 * Create new {@link FindAndModifyOptions} based on option of given {@litearl source}.
+	 * Create new {@link FindAndModifyOptions} based on option of given {@literal source}.
 	 *
 	 * @param source can be {@literal null}.
 	 * @return new instance of {@link FindAndModifyOptions}.
@@ -117,8 +117,8 @@ public class FindAndModifyOptions {
 	/**
 	 * Define the {@link Collation} specifying language-specific rules for string comparison.
 	 *
-	 * @param collation
-	 * @return
+	 * @param collation can be {@literal null}.
+	 * @return this.
 	 * @since 2.0
 	 */
 	public FindAndModifyOptions collation(@Nullable Collation collation) {
@@ -142,7 +142,7 @@ public class FindAndModifyOptions {
 	/**
 	 * Get the {@link Collation} specifying language-specific rules for string comparison.
 	 *
-	 * @return
+	 * @return never {@literal null}.
 	 * @since 2.0
 	 */
 	public Optional<Collation> getCollation() {

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

@@ -116,7 +116,7 @@ public class FindAndReplaceOptions {
 	/**
 	 * Get the bit indicating to return the replacement document.
 	 *
-	 * @return
+	 * @return {@literal true} if set.
 	 */
 	public boolean isReturnNew() {
 		return returnNew;
@@ -125,7 +125,7 @@ public class FindAndReplaceOptions {
 	/**
 	 * Get the bit indicating if to create a new document if not exists.
 	 *
-	 * @return
+	 * @return {@literal true} if set.
 	 */
 	public boolean isUpsert() {
 		return upsert;

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

@@ -54,7 +54,7 @@ public interface FindPublisherPreparer extends ReadPreferenceAware {
 	 *
 	 * @param collection must not be {@literal null}.
 	 * @param find must not be {@literal null}.
-	 * @return
+	 * @return never {@literal null}.
 	 * @throws IllegalArgumentException if one of the required arguments is {@literal null}.
 	 * @since 2.2
 	 */

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

@@ -47,7 +47,7 @@ class GeoCommandStatistics {
 	 * Creates a new {@link GeoCommandStatistics} from the given command result extracting the statistics.
 	 *
 	 * @param commandResult must not be {@literal null}.
-	 * @return
+	 * @return never {@literal null}.
 	 */
 	public static GeoCommandStatistics from(Document commandResult) {
 
@@ -61,7 +61,7 @@ class GeoCommandStatistics {
 	 * Returns the average distance reported by the command result. Mitigating a removal of the field in case the command
 	 * didn't return any result introduced in MongoDB 3.2 RC1.
 	 *
-	 * @return
+	 * @return never {@literal null}, uses {@link Double#NaN} if {@literal avgDistance} does not exist.
 	 * @see <a href="https://jira.mongodb.org/browse/SERVER-21024">MongoDB Jira SERVER-21024</a>
 	 */
 	public double getAverageDistance() {

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

@@ -80,7 +80,11 @@ public class MappedDocument {
 	}
 
 	public Bson getIdFilter() {
-		return Filters.eq(ID_FIELD, document.get(ID_FIELD));
+		return new Document(ID_FIELD, document.get(ID_FIELD));
+	}
+
+	public Object get(String key) {
+		return document.get(key);
 	}
 
 	public UpdateDefinition updateWithoutId() {

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

@@ -20,7 +20,7 @@ import org.springframework.jmx.export.annotation.ManagedOperation;
 import org.springframework.jmx.export.annotation.ManagedResource;
 import org.springframework.util.Assert;
 
-import com.mongodb.MongoClient;
+import com.mongodb.client.MongoClient;
 import com.mongodb.client.MongoDatabase;
 
 /**
@@ -34,24 +34,13 @@ import com.mongodb.client.MongoDatabase;
 @ManagedResource(description = "Mongo Admin Operations")
 public class MongoAdmin implements MongoAdminOperations {
 
-	private final Object mongoClient;
-
-	/**
-	 * @param mongoClient
-	 * @deprecated since 2.2 in favor of {@link MongoAdmin#MongoAdmin(com.mongodb.client.MongoClient)}.
-	 */
-	@Deprecated
-	public MongoAdmin(MongoClient mongoClient) {
-
-		Assert.notNull(mongoClient, "MongoClient must not be null!");
-		this.mongoClient = mongoClient;
-	}
+	private final MongoClient mongoClient;
 
 	/**
 	 * @param client the underlying {@link com.mongodb.client.MongoClient} used for data access.
 	 * @since 2.2
 	 */
-	public MongoAdmin(com.mongodb.client.MongoClient client) {
+	public MongoAdmin(MongoClient client) {
 
 		Assert.notNull(client, "Client must not be null!");
 		this.mongoClient = client;
@@ -88,11 +77,6 @@ public class MongoAdmin implements MongoAdminOperations {
 	}
 
 	MongoDatabase getDB(String databaseName) {
-
-		if (mongoClient instanceof MongoClient) {
-			return ((MongoClient) mongoClient).getDatabase(databaseName);
-		}
-
-		return ((com.mongodb.client.MongoClient) mongoClient).getDatabase(databaseName);
+		return mongoClient.getDatabase(databaseName);
 	}
 }

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

@@ -16,70 +16,72 @@
 package org.springframework.data.mongodb.core;
 
 import java.net.UnknownHostException;
-import java.util.ArrayList;
-import java.util.Collections;
+import java.util.Arrays;
 import java.util.List;
+import java.util.concurrent.TimeUnit;
+import java.util.function.Consumer;
+import java.util.function.Function;
+import java.util.stream.Collectors;
 
+import org.bson.UuidRepresentation;
 import org.springframework.beans.factory.config.AbstractFactoryBean;
 import org.springframework.dao.DataAccessException;
 import org.springframework.dao.support.PersistenceExceptionTranslator;
+import org.springframework.data.mongodb.SpringDataMongoDB;
 import org.springframework.lang.Nullable;
 import org.springframework.util.CollectionUtils;
+import org.springframework.util.ObjectUtils;
 import org.springframework.util.StringUtils;
 
-import com.mongodb.MongoClient;
-import com.mongodb.MongoClientOptions;
+import com.mongodb.ConnectionString;
+import com.mongodb.MongoClientSettings;
+import com.mongodb.MongoClientSettings.Builder;
 import com.mongodb.MongoCredential;
 import com.mongodb.ServerAddress;
+import com.mongodb.client.MongoClient;
+import com.mongodb.client.MongoClients;
+import com.mongodb.connection.ClusterSettings;
+import com.mongodb.connection.ConnectionPoolSettings;
+import com.mongodb.connection.ServerSettings;
+import com.mongodb.connection.SocketSettings;
+import com.mongodb.connection.SslSettings;
+import com.mongodb.event.ClusterListener;
 
 /**
  * Convenient factory for configuring MongoDB.
  *
  * @author Christoph Strobl
  * @author Mark Paluch
- * @since 1.7
- * @deprecated since 2.2 - There is no replacement for this {@link org.springframework.beans.factory.FactoryBean} at
- *             this time. However moving forward the {@link org.springframework.beans.factory.FactoryBean} will be
- *             suitable to provide instances of {@link com.mongodb.client.MongoClient}.
  */
-@Deprecated
 public class MongoClientFactoryBean extends AbstractFactoryBean<MongoClient> implements PersistenceExceptionTranslator {
 
 	private static final PersistenceExceptionTranslator DEFAULT_EXCEPTION_TRANSLATOR = new MongoExceptionTranslator();
 
-	private @Nullable MongoClientOptions mongoClientOptions;
+	private @Nullable MongoClientSettings mongoClientSettings;
 	private @Nullable String host;
 	private @Nullable Integer port;
-	private List<ServerAddress> replicaSetSeeds = Collections.emptyList();
-	private List<MongoCredential> credentials = Collections.emptyList();
+	private @Nullable List<MongoCredential> credential = null;
+	private @Nullable ConnectionString connectionString;
+	private @Nullable String replicaSet = null;
 
 	private PersistenceExceptionTranslator exceptionTranslator = DEFAULT_EXCEPTION_TRANSLATOR;
 
 	/**
-	 * Set the {@link MongoClientOptions} to be used when creating {@link MongoClient}.
+	 * Set the {@link MongoClientSettings} to be used when creating {@link MongoClient}.
 	 *
 	 * @param mongoClientOptions
 	 */
-	public void setMongoClientOptions(@Nullable MongoClientOptions mongoClientOptions) {
-		this.mongoClientOptions = mongoClientOptions;
+	public void setMongoClientSettings(@Nullable MongoClientSettings mongoClientOptions) {
+		this.mongoClientSettings = mongoClientOptions;
 	}
 
 	/**
 	 * Set the list of credentials to be used when creating {@link MongoClient}.
 	 *
-	 * @param credentials can be {@literal null}.
+	 * @param credential can be {@literal null}.
 	 */
-	public void setCredentials(@Nullable MongoCredential[] credentials) {
-		this.credentials = filterNonNullElementsAsList(credentials);
-	}
-
-	/**
-	 * Set the list of {@link ServerAddress} to build up a replica set for.
-	 *
-	 * @param replicaSetSeeds can be {@literal null}.
-	 */
-	public void setReplicaSetSeeds(@Nullable ServerAddress[] replicaSetSeeds) {
-		this.replicaSetSeeds = filterNonNullElementsAsList(replicaSetSeeds);
+	public void setCredential(@Nullable MongoCredential[] credential) {
+		this.credential = Arrays.asList(credential);
 	}
 
 	/**
@@ -100,6 +102,14 @@ public class MongoClientFactoryBean extends AbstractFactoryBean<MongoClient> imp
 		this.port = port;
 	}
 
+	public void setConnectionString(@Nullable ConnectionString connectionString) {
+		this.connectionString = connectionString;
+	}
+
+	public void setReplicaSet(@Nullable String replicaSet) {
+		this.replicaSet = replicaSet;
+	}
+
 	/**
 	 * Configures the {@link PersistenceExceptionTranslator} to use.
 	 *
@@ -132,12 +142,198 @@ public class MongoClientFactoryBean extends AbstractFactoryBean<MongoClient> imp
 	 */
 	@Override
 	protected MongoClient createInstance() throws Exception {
+		return createMongoClient(computeClientSetting());
+	}
 
-		if (mongoClientOptions == null) {
-			mongoClientOptions = MongoClientOptions.builder().build();
+	/**
+	 * Create {@link MongoClientSettings} based on configuration and priority (lower is better).
+	 * <ol>
+	 * <li>{@link MongoClientFactoryBean#mongoClientSettings}</li>
+	 * <li>{@link MongoClientFactoryBean#connectionString}</li>
+	 * <li>default {@link MongoClientSettings}</li>
+	 * </ol>
+	 *
+	 * @since 3.0
+	 */
+	protected MongoClientSettings computeClientSetting() {
+
+		if (connectionString != null && (StringUtils.hasText(host) || port != null)) {
+			throw new IllegalStateException("ConnectionString and host/port configuration exclude one another!");
 		}
 
-		return createMongoClient();
+		ConnectionString connectionString = this.connectionString != null ? this.connectionString
+				: new ConnectionString(String.format("mongodb://%s:%s", getOrDefault(host, ServerAddress.defaultHost()),
+						getOrDefault(port, "" + ServerAddress.defaultPort())));
+
+		Builder builder = MongoClientSettings.builder().applyConnectionString(connectionString);
+		builder.uuidRepresentation(UuidRepresentation.JAVA_LEGACY);
+
+		if (mongoClientSettings != null) {
+
+			MongoClientSettings defaultSettings = MongoClientSettings.builder().build();
+
+			SslSettings sslSettings = mongoClientSettings.getSslSettings();
+			ClusterSettings clusterSettings = mongoClientSettings.getClusterSettings();
+			ConnectionPoolSettings connectionPoolSettings = mongoClientSettings.getConnectionPoolSettings();
+			SocketSettings socketSettings = mongoClientSettings.getSocketSettings();
+			ServerSettings serverSettings = mongoClientSettings.getServerSettings();
+
+			builder = builder //
+					.applicationName(computeSettingsValue(defaultSettings.getApplicationName(),
+							mongoClientSettings.getApplicationName(), connectionString.getApplicationName())) //
+					.applyToSslSettings(settings -> {
+
+						applySettings(settings::enabled, computeSettingsValue(SslSettings::isEnabled,
+								defaultSettings.getSslSettings(), sslSettings, connectionString.getSslEnabled()));
+						applySettings(settings::invalidHostNameAllowed, (computeSettingsValue(SslSettings::isInvalidHostNameAllowed,
+								defaultSettings.getSslSettings(), sslSettings, connectionString.getSslInvalidHostnameAllowed())));
+						settings.context(sslSettings.getContext());
+					}).applyToClusterSettings(settings -> {
+
+						applySettings(settings::hosts,
+								computeSettingsValue(ClusterSettings::getHosts, defaultSettings.getClusterSettings(), clusterSettings,
+										connectionString.getHosts().stream().map(ServerAddress::new).collect(Collectors.toList())));
+
+						applySettings(settings::requiredReplicaSetName,
+								computeSettingsValue(ClusterSettings::getRequiredReplicaSetName, defaultSettings.getClusterSettings(),
+										clusterSettings, connectionString.getRequiredReplicaSetName()));
+
+						applySettings(settings::srvHost, computeSettingsValue(ClusterSettings::getSrvHost,
+								defaultSettings.getClusterSettings(), clusterSettings, null));
+
+						applySettings(settings::mode, computeSettingsValue(ClusterSettings::getMode,
+								defaultSettings.getClusterSettings(), clusterSettings, null));
+
+						applySettings(it -> settings.localThreshold(it.longValue(), TimeUnit.MILLISECONDS),
+								computeSettingsValue((ClusterSettings it) -> it.getLocalThreshold(TimeUnit.MILLISECONDS),
+										defaultSettings.getClusterSettings(), clusterSettings, connectionString.getLocalThreshold()));
+
+						applySettings(settings::requiredClusterType, computeSettingsValue(ClusterSettings::getRequiredClusterType,
+								defaultSettings.getClusterSettings(), clusterSettings, null));
+						applySettings(it -> settings.serverSelectionTimeout(it.longValue(), TimeUnit.MILLISECONDS),
+								computeSettingsValue((ClusterSettings it) -> it.getServerSelectionTimeout(TimeUnit.MILLISECONDS),
+										defaultSettings.getClusterSettings(), clusterSettings,
+										connectionString.getServerSelectionTimeout()));
+
+						applySettings(settings::serverSelector, computeSettingsValue(ClusterSettings::getServerSelector,
+								defaultSettings.getClusterSettings(), clusterSettings, null));
+						List<ClusterListener> clusterListeners = computeSettingsValue(ClusterSettings::getClusterListeners,
+								defaultSettings.getClusterSettings(), clusterSettings, null);
+						if (clusterListeners != null) {
+							clusterListeners.forEach(settings::addClusterListener);
+						}
+					}) //
+					.applyToConnectionPoolSettings(settings -> {
+
+						applySettings(it -> settings.maintenanceFrequency(it, TimeUnit.MILLISECONDS),
+								computeSettingsValue((ConnectionPoolSettings it) -> it.getMaintenanceFrequency(TimeUnit.MILLISECONDS),
+										defaultSettings.getConnectionPoolSettings(), connectionPoolSettings, null));
+
+						applySettings(it -> settings.maxConnectionIdleTime(it.longValue(), TimeUnit.MILLISECONDS),
+								computeSettingsValue((ConnectionPoolSettings it) -> it.getMaxConnectionIdleTime(TimeUnit.MILLISECONDS),
+										defaultSettings.getConnectionPoolSettings(), connectionPoolSettings,
+										connectionString.getMaxConnectionIdleTime()));
+
+						applySettings(it -> settings.maxConnectionLifeTime(it.longValue(), TimeUnit.MILLISECONDS),
+								computeSettingsValue((ConnectionPoolSettings it) -> it.getMaxConnectionLifeTime(TimeUnit.MILLISECONDS),
+										defaultSettings.getConnectionPoolSettings(), connectionPoolSettings,
+										connectionString.getMaxConnectionLifeTime()));
+
+						applySettings(it -> settings.maxWaitTime(it.longValue(), TimeUnit.MILLISECONDS),
+								computeSettingsValue((ConnectionPoolSettings it) -> it.getMaxWaitTime(TimeUnit.MILLISECONDS),
+										defaultSettings.getConnectionPoolSettings(), connectionPoolSettings,
+										connectionString.getMaxWaitTime()));
+
+						applySettings(it -> settings.maintenanceInitialDelay(it, TimeUnit.MILLISECONDS),
+								computeSettingsValue(
+										(ConnectionPoolSettings it) -> it.getMaintenanceInitialDelay(TimeUnit.MILLISECONDS),
+										defaultSettings.getConnectionPoolSettings(), connectionPoolSettings, null));
+
+						applySettings(settings::minSize,
+								computeSettingsValue(ConnectionPoolSettings::getMinSize, defaultSettings.getConnectionPoolSettings(),
+										connectionPoolSettings, connectionString.getMinConnectionPoolSize()));
+						applySettings(settings::maxSize,
+								computeSettingsValue(ConnectionPoolSettings::getMaxSize, defaultSettings.getConnectionPoolSettings(),
+										connectionPoolSettings, connectionString.getMaxConnectionPoolSize()));
+					}) //
+					.applyToSocketSettings(settings -> {
+
+						applySettings(it -> settings.connectTimeout(it, TimeUnit.MILLISECONDS),
+								computeSettingsValue((SocketSettings it) -> it.getConnectTimeout(TimeUnit.MILLISECONDS),
+										defaultSettings.getSocketSettings(), socketSettings, connectionString.getConnectTimeout()));
+
+						applySettings(it -> settings.readTimeout(it, TimeUnit.MILLISECONDS),
+								computeSettingsValue((SocketSettings it) -> it.getReadTimeout(TimeUnit.MILLISECONDS),
+										defaultSettings.getSocketSettings(), socketSettings, connectionString.getSocketTimeout()));
+						applySettings(settings::receiveBufferSize, computeSettingsValue(SocketSettings::getReceiveBufferSize,
+								defaultSettings.getSocketSettings(), socketSettings, null));
+						applySettings(settings::sendBufferSize, computeSettingsValue(SocketSettings::getSendBufferSize,
+								defaultSettings.getSocketSettings(), socketSettings, null));
+					}) //
+					.applyToServerSettings(settings -> {
+
+						applySettings(it -> settings.minHeartbeatFrequency(it.intValue(), TimeUnit.MILLISECONDS),
+								computeSettingsValue((ServerSettings it) -> it.getMinHeartbeatFrequency(TimeUnit.MILLISECONDS),
+										defaultSettings.getServerSettings(), serverSettings, null));
+
+						applySettings(it -> settings.heartbeatFrequency(it.intValue(), TimeUnit.MILLISECONDS),
+								computeSettingsValue((ServerSettings it) -> it.getHeartbeatFrequency(TimeUnit.MILLISECONDS),
+										defaultSettings.getServerSettings(), serverSettings, connectionString.getHeartbeatFrequency()));
+						settings.applySettings(serverSettings);
+					}) //
+					.autoEncryptionSettings(mongoClientSettings.getAutoEncryptionSettings()) //
+					.codecRegistry(mongoClientSettings.getCodecRegistry()); //
+
+			applySettings(builder::readConcern, computeSettingsValue(defaultSettings.getReadConcern(),
+					mongoClientSettings.getReadConcern(), connectionString.getReadConcern()));
+			applySettings(builder::writeConcern, computeSettingsValue(defaultSettings.getWriteConcern(),
+					mongoClientSettings.getWriteConcern(), connectionString.getWriteConcern()));
+			applySettings(builder::readPreference, computeSettingsValue(defaultSettings.getReadPreference(),
+					mongoClientSettings.getReadPreference(), connectionString.getReadPreference()));
+			applySettings(builder::retryReads, computeSettingsValue(defaultSettings.getRetryReads(),
+					mongoClientSettings.getRetryReads(), connectionString.getRetryReads()));
+			applySettings(builder::retryWrites, computeSettingsValue(defaultSettings.getRetryWrites(),
+					mongoClientSettings.getRetryWrites(), connectionString.getRetryWritesValue()));
+			applySettings(builder::uuidRepresentation,
+					computeSettingsValue(null, mongoClientSettings.getUuidRepresentation(), UuidRepresentation.JAVA_LEGACY));
+		}
+
+		if (!CollectionUtils.isEmpty(credential)) {
+			builder = builder.credential(credential.iterator().next());
+		}
+
+		if (StringUtils.hasText(replicaSet)) {
+			builder.applyToClusterSettings((settings) -> {
+				settings.requiredReplicaSetName(replicaSet);
+			});
+		}
+
+		return builder.build();
+	}
+
+	private <T> void applySettings(Consumer<T> settingsBuilder, @Nullable T value) {
+
+		if (ObjectUtils.isEmpty(value)) {
+			return;
+		}
+		settingsBuilder.accept(value);
+	}
+
+	private <S, T> T computeSettingsValue(Function<S, T> function, S defaultValueHolder, S settingsValueHolder,
+			@Nullable T connectionStringValue) {
+		return computeSettingsValue(function.apply(defaultValueHolder), function.apply(settingsValueHolder),
+				connectionStringValue);
+	}
+
+	private <T> T computeSettingsValue(T defaultValue, T fromSettings, T fromConnectionString) {
+
+		boolean fromSettingsIsDefault = ObjectUtils.nullSafeEquals(defaultValue, fromSettings);
+		boolean fromConnectionStringIsDefault = ObjectUtils.nullSafeEquals(defaultValue, fromConnectionString);
+
+		if (!fromSettingsIsDefault) {
+			return fromSettings;
+		}
+		return !fromConnectionStringIsDefault ? fromConnectionString : defaultValue;
 	}
 
 	/*
@@ -152,43 +348,11 @@ public class MongoClientFactoryBean extends AbstractFactoryBean<MongoClient> imp
 		}
 	}
 
-	private MongoClient createMongoClient() throws UnknownHostException {
-
-		if (!CollectionUtils.isEmpty(replicaSetSeeds)) {
-			return new MongoClient(replicaSetSeeds, credentials, mongoClientOptions);
-		}
-
-		return new MongoClient(createConfiguredOrDefaultServerAddress(), credentials, mongoClientOptions);
+	private MongoClient createMongoClient(MongoClientSettings settings) throws UnknownHostException {
+		return MongoClients.create(settings, SpringDataMongoDB.driverInformation());
 	}
 
-	private ServerAddress createConfiguredOrDefaultServerAddress() throws UnknownHostException {
-
-		ServerAddress defaultAddress = new ServerAddress();
-
-		return new ServerAddress(StringUtils.hasText(host) ? host : defaultAddress.getHost(),
-				port != null ? port.intValue() : defaultAddress.getPort());
-	}
-
-	/**
-	 * Returns the given array as {@link List} with all {@literal null} elements removed.
-	 *
-	 * @param elements the elements to filter <T>, can be {@literal null}.
-	 * @return a new unmodifiable {@link List#} from the given elements without {@literal null}s.
-	 */
-	private static <T> List<T> filterNonNullElementsAsList(@Nullable 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);
+	private String getOrDefault(Object value, String defaultValue) {
+		return !StringUtils.isEmpty(value) ? value.toString() : defaultValue;
 	}
 }

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

@@ -1,338 +0,0 @@
-/*
- * Copyright 2015-2020 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
- *
- *      https://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 javax.net.SocketFactory;
-import javax.net.ssl.SSLSocketFactory;
-
-import org.springframework.beans.factory.config.AbstractFactoryBean;
-import org.springframework.data.mongodb.MongoDbFactory;
-import org.springframework.lang.Nullable;
-
-import com.mongodb.AutoEncryptionSettings;
-import com.mongodb.DBDecoderFactory;
-import com.mongodb.DBEncoderFactory;
-import com.mongodb.MongoClient;
-import com.mongodb.MongoClientOptions;
-import com.mongodb.ReadPreference;
-import com.mongodb.WriteConcern;
-
-/**
- * A factory bean for construction of a {@link MongoClientOptions} instance.
- *
- * @author Christoph Strobl
- * @author Oliver Gierke
- * @author Mark Paluch
- * @since 1.7
- * @deprecated since 2.2 - There is no replacement for this {@link org.springframework.beans.factory.FactoryBean}.
- *             However moving forward there will be a dedicated factory bean for {@link com.mongodb.MongoClientSettings}
- *             replacing {@link MongoClientOptions}.
- */
-@Deprecated
-public class MongoClientOptionsFactoryBean extends AbstractFactoryBean<MongoClientOptions> {
-
-	private static final MongoClientOptions DEFAULT_MONGO_OPTIONS = MongoClientOptions.builder().build();
-
-	// TODO: Mongo Driver 4 - use application name insetad of description if not available
-	private @Nullable String description = DEFAULT_MONGO_OPTIONS.getApplicationName();
-	private int minConnectionsPerHost = DEFAULT_MONGO_OPTIONS.getMinConnectionsPerHost();
-	private int connectionsPerHost = DEFAULT_MONGO_OPTIONS.getConnectionsPerHost();
-	private int threadsAllowedToBlockForConnectionMultiplier = DEFAULT_MONGO_OPTIONS
-			.getThreadsAllowedToBlockForConnectionMultiplier();
-	private int maxWaitTime = DEFAULT_MONGO_OPTIONS.getMaxWaitTime();
-	private int maxConnectionIdleTime = DEFAULT_MONGO_OPTIONS.getMaxConnectionIdleTime();
-	private int maxConnectionLifeTime = DEFAULT_MONGO_OPTIONS.getMaxConnectionLifeTime();
-	private int connectTimeout = DEFAULT_MONGO_OPTIONS.getConnectTimeout();
-	private int socketTimeout = DEFAULT_MONGO_OPTIONS.getSocketTimeout();
-
-	// TODO: Mongo Driver 4 - check if available
-	private boolean socketKeepAlive = DEFAULT_MONGO_OPTIONS.isSocketKeepAlive();
-	private @Nullable ReadPreference readPreference = DEFAULT_MONGO_OPTIONS.getReadPreference();
-	private DBDecoderFactory dbDecoderFactory = DEFAULT_MONGO_OPTIONS.getDbDecoderFactory();
-	private DBEncoderFactory dbEncoderFactory = DEFAULT_MONGO_OPTIONS.getDbEncoderFactory();
-	private @Nullable WriteConcern writeConcern = DEFAULT_MONGO_OPTIONS.getWriteConcern();
-	private @Nullable SocketFactory socketFactory = DEFAULT_MONGO_OPTIONS.getSocketFactory();
-	private boolean cursorFinalizerEnabled = DEFAULT_MONGO_OPTIONS.isCursorFinalizerEnabled();
-
-	// TODO: Mongo Driver 4 - remove this option
-	private boolean alwaysUseMBeans = DEFAULT_MONGO_OPTIONS.isAlwaysUseMBeans();
-	private int heartbeatFrequency = DEFAULT_MONGO_OPTIONS.getHeartbeatFrequency();
-	private int minHeartbeatFrequency = DEFAULT_MONGO_OPTIONS.getMinHeartbeatFrequency();
-	private int heartbeatConnectTimeout = DEFAULT_MONGO_OPTIONS.getHeartbeatConnectTimeout();
-	private int heartbeatSocketTimeout = DEFAULT_MONGO_OPTIONS.getHeartbeatSocketTimeout();
-	private String requiredReplicaSetName = DEFAULT_MONGO_OPTIONS.getRequiredReplicaSetName();
-	private int serverSelectionTimeout = DEFAULT_MONGO_OPTIONS.getServerSelectionTimeout();
-
-	private boolean ssl;
-	private @Nullable SSLSocketFactory sslSocketFactory;
-	private @Nullable AutoEncryptionSettings autoEncryptionSettings;
-
-	/**
-	 * Set the {@link MongoClient} description.
-	 *
-	 * @param description
-	 */
-	// TODO: Mongo Driver 4 - deprecate that one and add application name
-	public void setDescription(@Nullable String description) {
-		this.description = description;
-	}
-
-	/**
-	 * Set the minimum number of connections per host.
-	 *
-	 * @param minConnectionsPerHost
-	 */
-	public void setMinConnectionsPerHost(int minConnectionsPerHost) {
-		this.minConnectionsPerHost = minConnectionsPerHost;
-	}
-
-	/**
-	 * Set the number of connections allowed per host. Will block if run out. Default is 10. System property
-	 * {@code MONGO.POOLSIZE} can override
-	 *
-	 * @param connectionsPerHost
-	 */
-	public void setConnectionsPerHost(int connectionsPerHost) {
-		this.connectionsPerHost = connectionsPerHost;
-	}
-
-	/**
-	 * Set the multiplier for connectionsPerHost for # of threads that can block. Default is 5. If connectionsPerHost is
-	 * 10, and threadsAllowedToBlockForConnectionMultiplier is 5, then 50 threads can block more than that and an
-	 * exception will be thrown.
-	 *
-	 * @param threadsAllowedToBlockForConnectionMultiplier
-	 */
-	public void setThreadsAllowedToBlockForConnectionMultiplier(int threadsAllowedToBlockForConnectionMultiplier) {
-		this.threadsAllowedToBlockForConnectionMultiplier = threadsAllowedToBlockForConnectionMultiplier;
-	}
-
-	/**
-	 * Set the max wait time of a blocking thread for a connection. Default is 12000 ms (2 minutes)
-	 *
-	 * @param maxWaitTime
-	 */
-	public void setMaxWaitTime(int maxWaitTime) {
-		this.maxWaitTime = maxWaitTime;
-	}
-
-	/**
-	 * The maximum idle time for a pooled connection.
-	 *
-	 * @param maxConnectionIdleTime
-	 */
-	public void setMaxConnectionIdleTime(int maxConnectionIdleTime) {
-		this.maxConnectionIdleTime = maxConnectionIdleTime;
-	}
-
-	/**
-	 * Set the maximum life time for a pooled connection.
-	 *
-	 * @param maxConnectionLifeTime
-	 */
-	public void setMaxConnectionLifeTime(int maxConnectionLifeTime) {
-		this.maxConnectionLifeTime = maxConnectionLifeTime;
-	}
-
-	/**
-	 * Set the connect timeout in milliseconds. 0 is default and infinite.
-	 *
-	 * @param connectTimeout
-	 */
-	public void setConnectTimeout(int connectTimeout) {
-		this.connectTimeout = connectTimeout;
-	}
-
-	/**
-	 * Set the socket timeout. 0 is default and infinite.
-	 *
-	 * @param socketTimeout
-	 */
-	public void setSocketTimeout(int socketTimeout) {
-		this.socketTimeout = socketTimeout;
-	}
-
-	/**
-	 * Set the keep alive flag, controls whether or not to have socket keep alive timeout. Defaults to false.
-	 *
-	 * @param socketKeepAlive
-	 */
-	public void setSocketKeepAlive(boolean socketKeepAlive) {
-		this.socketKeepAlive = socketKeepAlive;
-	}
-
-	/**
-	 * Set the {@link ReadPreference}.
-	 *
-	 * @param readPreference
-	 */
-	public void setReadPreference(@Nullable ReadPreference readPreference) {
-		this.readPreference = readPreference;
-	}
-
-	/**
-	 * Set the {@link WriteConcern} that will be the default value used when asking the {@link MongoDbFactory} for a DB
-	 * object.
-	 *
-	 * @param writeConcern
-	 */
-	public void setWriteConcern(@Nullable WriteConcern writeConcern) {
-		this.writeConcern = writeConcern;
-	}
-
-	/**
-	 * @param socketFactory
-	 */
-	public void setSocketFactory(@Nullable SocketFactory socketFactory) {
-		this.socketFactory = socketFactory;
-	}
-
-	/**
-	 * Set the frequency that the driver will attempt to determine the current state of each server in the cluster.
-	 *
-	 * @param heartbeatFrequency
-	 */
-	public void setHeartbeatFrequency(int heartbeatFrequency) {
-		this.heartbeatFrequency = heartbeatFrequency;
-	}
-
-	/**
-	 * In the event that the driver has to frequently re-check a server's availability, it will wait at least this long
-	 * since the previous check to avoid wasted effort.
-	 *
-	 * @param minHeartbeatFrequency
-	 */
-	public void setMinHeartbeatFrequency(int minHeartbeatFrequency) {
-		this.minHeartbeatFrequency = minHeartbeatFrequency;
-	}
-
-	/**
-	 * Set the connect timeout for connections used for the cluster heartbeat.
-	 *
-	 * @param heartbeatConnectTimeout
-	 */
-	public void setHeartbeatConnectTimeout(int heartbeatConnectTimeout) {
-		this.heartbeatConnectTimeout = heartbeatConnectTimeout;
-	}
-
-	/**
-	 * Set the socket timeout for connections used for the cluster heartbeat.
-	 *
-	 * @param heartbeatSocketTimeout
-	 */
-	public void setHeartbeatSocketTimeout(int heartbeatSocketTimeout) {
-		this.heartbeatSocketTimeout = heartbeatSocketTimeout;
-	}
-
-	/**
-	 * Configures the name of the replica set.
-	 *
-	 * @param requiredReplicaSetName
-	 */
-	public void setRequiredReplicaSetName(String requiredReplicaSetName) {
-		this.requiredReplicaSetName = requiredReplicaSetName;
-	}
-
-	/**
-	 * This controls if the driver should us an SSL connection. Defaults to {@literal false}.
-	 *
-	 * @param ssl
-	 */
-	public void setSsl(boolean ssl) {
-		this.ssl = ssl;
-	}
-
-	/**
-	 * Set the {@link SSLSocketFactory} to use for the {@literal SSL} connection. If none is configured here,
-	 * {@link SSLSocketFactory#getDefault()} will be used.
-	 *
-	 * @param sslSocketFactory
-	 */
-	public void setSslSocketFactory(@Nullable SSLSocketFactory sslSocketFactory) {
-
-		this.sslSocketFactory = sslSocketFactory;
-		this.ssl = sslSocketFactory != null;
-	}
-
-	/**
-	 * Set the {@literal server selection timeout} in msec for a 3.x MongoDB Java driver. If not set the default value of
-	 * 30 sec will be used. A value of 0 means that it will timeout immediately if no server is available. A negative
-	 * value means to wait indefinitely.
-	 *
-	 * @param serverSelectionTimeout in msec.
-	 */
-	public void setServerSelectionTimeout(int serverSelectionTimeout) {
-		this.serverSelectionTimeout = serverSelectionTimeout;
-	}
-
-	/**
-	 * Set the {@link AutoEncryptionSettings} to be used.
-	 *
-	 * @param autoEncryptionSettings can be {@literal null}.
-	 * @since 2.2
-	 */
-	public void setAutoEncryptionSettings(@Nullable AutoEncryptionSettings autoEncryptionSettings) {
-		this.autoEncryptionSettings = autoEncryptionSettings;
-	}
-
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.beans.factory.config.AbstractFactoryBean#createInstance()
-	 */
-	@SuppressWarnings("ConstantConditions")
-	@Override
-	protected MongoClientOptions createInstance() throws Exception {
-
-		SocketFactory socketFactoryToUse = ssl
-				? (sslSocketFactory != null ? sslSocketFactory : SSLSocketFactory.getDefault())
-				: this.socketFactory;
-
-		return MongoClientOptions.builder() //
-				.alwaysUseMBeans(this.alwaysUseMBeans) //
-				.connectionsPerHost(this.connectionsPerHost) //
-				.connectTimeout(connectTimeout) //
-				.cursorFinalizerEnabled(cursorFinalizerEnabled) //
-				.dbDecoderFactory(dbDecoderFactory) //
-				.dbEncoderFactory(dbEncoderFactory) //
-				.applicationName(description) // TODO: Mongo Driver 4 - use application name if description not available
-				.heartbeatConnectTimeout(heartbeatConnectTimeout) //
-				.heartbeatFrequency(heartbeatFrequency) //
-				.heartbeatSocketTimeout(heartbeatSocketTimeout) //
-				.maxConnectionIdleTime(maxConnectionIdleTime) //
-				.maxConnectionLifeTime(maxConnectionLifeTime) //
-				.maxWaitTime(maxWaitTime) //
-				.minConnectionsPerHost(minConnectionsPerHost) //
-				.minHeartbeatFrequency(minHeartbeatFrequency) //
-				.readPreference(readPreference) //
-				.requiredReplicaSetName(requiredReplicaSetName) //
-				.serverSelectionTimeout(serverSelectionTimeout) //
-				.sslEnabled(ssl) //
-				.autoEncryptionSettings(autoEncryptionSettings) //
-				.socketFactory(socketFactoryToUse) // TODO: Mongo Driver 4 -
-				.socketKeepAlive(socketKeepAlive) // TODO: Mongo Driver 4 - remove if not available
-				.socketTimeout(socketTimeout) //
-				.threadsAllowedToBlockForConnectionMultiplier(threadsAllowedToBlockForConnectionMultiplier) //
-				.writeConcern(writeConcern).build();
-	}
-
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.beans.factory.FactoryBean#getObjectType()
-	 */
-	public Class<?> getObjectType() {
-		return MongoClientOptions.class;
-	}
-}

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

@@ -0,0 +1,486 @@
+/*
+ * Copyright 2019 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
+ *
+ *      https://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 java.security.NoSuchAlgorithmException;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+import java.util.concurrent.TimeUnit;
+
+import javax.net.ssl.SSLContext;
+
+import org.bson.UuidRepresentation;
+import org.bson.codecs.configuration.CodecRegistry;
+import org.springframework.beans.factory.config.AbstractFactoryBean;
+import org.springframework.lang.Nullable;
+import org.springframework.util.CollectionUtils;
+import org.springframework.util.StringUtils;
+
+import com.mongodb.AutoEncryptionSettings;
+import com.mongodb.MongoClientSettings;
+import com.mongodb.MongoClientSettings.Builder;
+import com.mongodb.ReadConcern;
+import com.mongodb.ReadPreference;
+import com.mongodb.ServerAddress;
+import com.mongodb.WriteConcern;
+import com.mongodb.connection.ClusterConnectionMode;
+import com.mongodb.connection.ClusterType;
+import com.mongodb.connection.StreamFactoryFactory;
+
+/**
+ * A factory bean for construction of a {@link MongoClientSettings} instance to be used with a MongoDB driver.
+ *
+ * @author Christoph Strobl
+ * @author Mark Paluch
+ * @since 3.0
+ */
+public class MongoClientSettingsFactoryBean extends AbstractFactoryBean<MongoClientSettings> {
+
+	private static final MongoClientSettings DEFAULT_MONGO_SETTINGS = MongoClientSettings.builder().build();
+
+	private CodecRegistry codecRegistry = DEFAULT_MONGO_SETTINGS.getCodecRegistry();
+	private StreamFactoryFactory streamFactoryFactory = DEFAULT_MONGO_SETTINGS.getStreamFactoryFactory();
+
+	private ReadPreference readPreference = DEFAULT_MONGO_SETTINGS.getReadPreference();
+	private ReadConcern readConcern = DEFAULT_MONGO_SETTINGS.getReadConcern();
+	private @Nullable Boolean retryReads = null;
+
+	private WriteConcern writeConcern = DEFAULT_MONGO_SETTINGS.getWriteConcern();
+	private @Nullable Boolean retryWrites = null;
+
+	private @Nullable String applicationName = null;
+
+	private @Nullable UuidRepresentation uUidRepresentation = null;
+
+	// --> Socket Settings
+
+	private int socketConnectTimeoutMS = DEFAULT_MONGO_SETTINGS.getSocketSettings()
+			.getConnectTimeout(TimeUnit.MILLISECONDS);
+	private int socketReadTimeoutMS = DEFAULT_MONGO_SETTINGS.getSocketSettings().getReadTimeout(TimeUnit.MILLISECONDS);
+	private int socketReceiveBufferSize = DEFAULT_MONGO_SETTINGS.getSocketSettings().getReceiveBufferSize();
+	private int socketSendBufferSize = DEFAULT_MONGO_SETTINGS.getSocketSettings().getSendBufferSize();
+
+	// --> Cluster Settings
+
+	private @Nullable String clusterSrvHost = DEFAULT_MONGO_SETTINGS.getClusterSettings().getSrvHost();
+	private List<ServerAddress> clusterHosts = Collections.emptyList();
+	private @Nullable ClusterConnectionMode clusterConnectionMode = null;
+	private ClusterType custerRequiredClusterType = DEFAULT_MONGO_SETTINGS.getClusterSettings().getRequiredClusterType();
+	private String clusterRequiredReplicaSetName = DEFAULT_MONGO_SETTINGS.getClusterSettings()
+			.getRequiredReplicaSetName();
+	private long clusterLocalThresholdMS = DEFAULT_MONGO_SETTINGS.getClusterSettings()
+			.getLocalThreshold(TimeUnit.MILLISECONDS);
+	private long clusterServerSelectionTimeoutMS = DEFAULT_MONGO_SETTINGS.getClusterSettings()
+			.getServerSelectionTimeout(TimeUnit.MILLISECONDS);
+
+	// --> ConnectionPoolSettings
+
+	private int poolMaxSize = DEFAULT_MONGO_SETTINGS.getConnectionPoolSettings().getMaxSize();
+	private int poolMinSize = DEFAULT_MONGO_SETTINGS.getConnectionPoolSettings().getMinSize();
+	private long poolMaxWaitTimeMS = DEFAULT_MONGO_SETTINGS.getConnectionPoolSettings()
+			.getMaxWaitTime(TimeUnit.MILLISECONDS);
+	private long poolMaxConnectionLifeTimeMS = DEFAULT_MONGO_SETTINGS.getConnectionPoolSettings()
+			.getMaxConnectionLifeTime(TimeUnit.MILLISECONDS);
+	private long poolMaxConnectionIdleTimeMS = DEFAULT_MONGO_SETTINGS.getConnectionPoolSettings()
+			.getMaxConnectionIdleTime(TimeUnit.MILLISECONDS);
+	private long poolMaintenanceInitialDelayMS = DEFAULT_MONGO_SETTINGS.getConnectionPoolSettings()
+			.getMaintenanceInitialDelay(TimeUnit.MILLISECONDS);
+	private long poolMaintenanceFrequencyMS = DEFAULT_MONGO_SETTINGS.getConnectionPoolSettings()
+			.getMaintenanceFrequency(TimeUnit.MILLISECONDS);
+
+	// --> SSL Settings
+
+	private boolean sslEnabled = DEFAULT_MONGO_SETTINGS.getSslSettings().isEnabled();
+	private boolean sslInvalidHostNameAllowed = DEFAULT_MONGO_SETTINGS.getSslSettings().isInvalidHostNameAllowed();
+	private String sslProvider = DEFAULT_MONGO_SETTINGS.getSslSettings().isEnabled()
+			? DEFAULT_MONGO_SETTINGS.getSslSettings().getContext().getProvider().getName()
+			: "";
+
+	// encryption and retry
+
+	private @Nullable AutoEncryptionSettings autoEncryptionSettings;
+
+	/**
+	 * @param socketConnectTimeoutMS in msec
+	 * @see com.mongodb.connection.SocketSettings.Builder#connectTimeout(int, TimeUnit)
+	 */
+	public void setSocketConnectTimeoutMS(int socketConnectTimeoutMS) {
+		this.socketConnectTimeoutMS = socketConnectTimeoutMS;
+	}
+
+	/**
+	 * @param socketReadTimeoutMS in msec
+	 * @see com.mongodb.connection.SocketSettings.Builder#readTimeout(int, TimeUnit)
+	 */
+	public void setSocketReadTimeoutMS(int socketReadTimeoutMS) {
+		this.socketReadTimeoutMS = socketReadTimeoutMS;
+	}
+
+	/**
+	 * @param socketReceiveBufferSize
+	 * @see com.mongodb.connection.SocketSettings.Builder#receiveBufferSize(int)
+	 */
+	public void setSocketReceiveBufferSize(int socketReceiveBufferSize) {
+		this.socketReceiveBufferSize = socketReceiveBufferSize;
+	}
+
+	/**
+	 * @param socketSendBufferSize
+	 * @see com.mongodb.connection.SocketSettings.Builder#sendBufferSize(int)
+	 */
+	public void setSocketSendBufferSize(int socketSendBufferSize) {
+		this.socketSendBufferSize = socketSendBufferSize;
+	}
+
+	// --> Server Settings
+
+	private long serverHeartbeatFrequencyMS = DEFAULT_MONGO_SETTINGS.getServerSettings()
+			.getHeartbeatFrequency(TimeUnit.MILLISECONDS);
+	private long serverMinHeartbeatFrequencyMS = DEFAULT_MONGO_SETTINGS.getServerSettings()
+			.getMinHeartbeatFrequency(TimeUnit.MILLISECONDS);
+
+	/**
+	 * @param serverHeartbeatFrequencyMS in msec
+	 * @see com.mongodb.connection.ServerSettings.Builder#heartbeatFrequency(long, TimeUnit)
+	 */
+	public void setServerHeartbeatFrequencyMS(long serverHeartbeatFrequencyMS) {
+		this.serverHeartbeatFrequencyMS = serverHeartbeatFrequencyMS;
+	}
+
+	/**
+	 * @param serverMinHeartbeatFrequencyMS in msec
+	 * @see com.mongodb.connection.ServerSettings.Builder#minHeartbeatFrequency(long, TimeUnit)
+	 */
+	public void setServerMinHeartbeatFrequencyMS(long serverMinHeartbeatFrequencyMS) {
+		this.serverMinHeartbeatFrequencyMS = serverMinHeartbeatFrequencyMS;
+	}
+
+	// --> Cluster Settings
+
+	/**
+	 * @param clusterSrvHost
+	 * @see com.mongodb.connection.ClusterSettings.Builder#srvHost(String)
+	 */
+	public void setClusterSrvHost(String clusterSrvHost) {
+		this.clusterSrvHost = clusterSrvHost;
+	}
+
+	/**
+	 * @param clusterHosts
+	 * @see com.mongodb.connection.ClusterSettings.Builder#hosts(List)
+	 */
+	public void setClusterHosts(ServerAddress[] clusterHosts) {
+		this.clusterHosts = Arrays.asList(clusterHosts);
+	}
+
+	/**
+	 * ????
+	 *
+	 * @param clusterConnectionMode
+	 * @see com.mongodb.connection.ClusterSettings.Builder#mode(ClusterConnectionMode)
+	 */
+	public void setClusterConnectionMode(ClusterConnectionMode clusterConnectionMode) {
+		this.clusterConnectionMode = clusterConnectionMode;
+	}
+
+	/**
+	 * @param custerRequiredClusterType
+	 * @see com.mongodb.connection.ClusterSettings.Builder#requiredClusterType(ClusterType)
+	 */
+	public void setCusterRequiredClusterType(ClusterType custerRequiredClusterType) {
+		this.custerRequiredClusterType = custerRequiredClusterType;
+	}
+
+	/**
+	 * @param clusterRequiredReplicaSetName
+	 * @see com.mongodb.connection.ClusterSettings.Builder#requiredReplicaSetName(String)
+	 */
+	public void setClusterRequiredReplicaSetName(String clusterRequiredReplicaSetName) {
+		this.clusterRequiredReplicaSetName = clusterRequiredReplicaSetName;
+	}
+
+	/**
+	 * @param clusterLocalThresholdMS in msec
+	 * @see com.mongodb.connection.ClusterSettings.Builder#localThreshold(long, TimeUnit)
+	 */
+	public void setClusterLocalThresholdMS(long clusterLocalThresholdMS) {
+		this.clusterLocalThresholdMS = clusterLocalThresholdMS;
+	}
+
+	/**
+	 * @param clusterServerSelectionTimeoutMS in msec
+	 * @see com.mongodb.connection.ClusterSettings.Builder#serverSelectionTimeout(long, TimeUnit)
+	 */
+	public void setClusterServerSelectionTimeoutMS(long clusterServerSelectionTimeoutMS) {
+		this.clusterServerSelectionTimeoutMS = clusterServerSelectionTimeoutMS;
+	}
+
+	// --> ConnectionPoolSettings
+
+	/**
+	 * @param poolMaxSize
+	 * @see com.mongodb.connection.ConnectionPoolSettings.Builder#maxSize(int)
+	 */
+	public void setPoolMaxSize(int poolMaxSize) {
+		this.poolMaxSize = poolMaxSize;
+	}
+
+	/**
+	 * @param poolMinSize
+	 * @see com.mongodb.connection.ConnectionPoolSettings.Builder#minSize(int)
+	 */
+	public void setPoolMinSize(int poolMinSize) {
+		this.poolMinSize = poolMinSize;
+	}
+
+	/**
+	 * @param poolMaxWaitTimeMS in mesec
+	 * @see com.mongodb.connection.ConnectionPoolSettings.Builder#maxWaitTime(long, TimeUnit)
+	 */
+	public void setPoolMaxWaitTimeMS(long poolMaxWaitTimeMS) {
+		this.poolMaxWaitTimeMS = poolMaxWaitTimeMS;
+	}
+
+	/**
+	 * @param poolMaxConnectionLifeTimeMS in msec
+	 * @see com.mongodb.connection.ConnectionPoolSettings.Builder#maxConnectionLifeTime(long, TimeUnit)
+	 */
+	public void setPoolMaxConnectionLifeTimeMS(long poolMaxConnectionLifeTimeMS) {
+		this.poolMaxConnectionLifeTimeMS = poolMaxConnectionLifeTimeMS;
+	}
+
+	/**
+	 * @param poolMaxConnectionIdleTimeMS in msec
+	 * @see com.mongodb.connection.ConnectionPoolSettings.Builder#maxConnectionIdleTime(long, TimeUnit)
+	 */
+	public void setPoolMaxConnectionIdleTimeMS(long poolMaxConnectionIdleTimeMS) {
+		this.poolMaxConnectionIdleTimeMS = poolMaxConnectionIdleTimeMS;
+	}
+
+	/**
+	 * @param poolMaintenanceInitialDelayMS in msec
+	 * @see com.mongodb.connection.ConnectionPoolSettings.Builder#maintenanceInitialDelay(long, TimeUnit)
+	 */
+	public void setPoolMaintenanceInitialDelayMS(long poolMaintenanceInitialDelayMS) {
+		this.poolMaintenanceInitialDelayMS = poolMaintenanceInitialDelayMS;
+	}
+
+	/**
+	 * @param poolMaintenanceFrequencyMS in msec
+	 * @see com.mongodb.connection.ConnectionPoolSettings.Builder#maintenanceFrequency(long, TimeUnit)
+	 */
+	public void setPoolMaintenanceFrequencyMS(long poolMaintenanceFrequencyMS) {
+		this.poolMaintenanceFrequencyMS = poolMaintenanceFrequencyMS;
+	}
+
+	// --> SSL Settings
+
+	/**
+	 * @param sslEnabled
+	 * @see com.mongodb.connection.SslSettings.Builder#enabled(boolean)
+	 */
+	public void setSslEnabled(Boolean sslEnabled) {
+		this.sslEnabled = sslEnabled;
+	}
+
+	/**
+	 * @param sslInvalidHostNameAllowed
+	 * @see com.mongodb.connection.SslSettings.Builder#invalidHostNameAllowed(boolean)
+	 */
+	public void setSslInvalidHostNameAllowed(Boolean sslInvalidHostNameAllowed) {
+		this.sslInvalidHostNameAllowed = sslInvalidHostNameAllowed;
+	}
+
+	/**
+	 * @param sslProvider
+	 * @see com.mongodb.connection.SslSettings.Builder#context(SSLContext)
+	 * @see SSLContext#getInstance(String)
+	 */
+	public void setSslProvider(String sslProvider) {
+		this.sslProvider = sslProvider;
+	}
+
+	// encryption and retry
+
+	/**
+	 * @param applicationName
+	 * @see MongoClientSettings.Builder#applicationName(String)
+	 */
+	public void setApplicationName(@Nullable String applicationName) {
+		this.applicationName = applicationName;
+	}
+
+	/**
+	 * @param retryReads
+	 * @see MongoClientSettings.Builder#retryReads(boolean)
+	 */
+	public void setRetryReads(@Nullable Boolean retryReads) {
+		this.retryReads = retryReads;
+	}
+
+	/**
+	 * @param readConcern
+	 * @see MongoClientSettings.Builder#readConcern(ReadConcern)
+	 */
+	public void setReadConcern(ReadConcern readConcern) {
+		this.readConcern = readConcern;
+	}
+
+	/**
+	 * @param writeConcern
+	 * @see MongoClientSettings.Builder#writeConcern(WriteConcern)
+	 */
+	public void setWriteConcern(WriteConcern writeConcern) {
+		this.writeConcern = writeConcern;
+	}
+
+	/**
+	 * @param retryWrites
+	 * @see MongoClientSettings.Builder#retryWrites(boolean)
+	 */
+	public void setRetryWrites(@Nullable Boolean retryWrites) {
+		this.retryWrites = retryWrites;
+	}
+
+	/**
+	 * @param readPreference
+	 * @see MongoClientSettings.Builder#readPreference(ReadPreference)
+	 */
+	public void setReadPreference(ReadPreference readPreference) {
+		this.readPreference = readPreference;
+	}
+
+	/**
+	 * @param streamFactoryFactory
+	 * @see MongoClientSettings.Builder#streamFactoryFactory(StreamFactoryFactory)
+	 */
+	public void setStreamFactoryFactory(StreamFactoryFactory streamFactoryFactory) {
+		this.streamFactoryFactory = streamFactoryFactory;
+	}
+
+	/**
+	 * @param codecRegistry
+	 * @see MongoClientSettings.Builder#codecRegistry(CodecRegistry)
+	 */
+	public void setCodecRegistry(CodecRegistry codecRegistry) {
+		this.codecRegistry = codecRegistry;
+	}
+
+	/**
+	 * @param uUidRepresentation
+	 */
+	public void setuUidRepresentation(@Nullable UuidRepresentation uUidRepresentation) {
+		this.uUidRepresentation = uUidRepresentation;
+	}
+
+	/**
+	 * @param autoEncryptionSettings can be {@literal null}.
+	 * @see MongoClientSettings.Builder#autoEncryptionSettings(AutoEncryptionSettings)
+	 */
+	public void setAutoEncryptionSettings(@Nullable AutoEncryptionSettings autoEncryptionSettings) {
+		this.autoEncryptionSettings = autoEncryptionSettings;
+	}
+
+	@Override
+	public Class<?> getObjectType() {
+		return MongoClientSettings.class;
+	}
+
+	@Override
+	protected MongoClientSettings createInstance() {
+
+		Builder builder = MongoClientSettings.builder() //
+				.readPreference(readPreference) //
+				.writeConcern(writeConcern) //
+				.readConcern(readConcern) //
+				.codecRegistry(codecRegistry) //
+				.applicationName(applicationName) //
+				.autoEncryptionSettings(autoEncryptionSettings) //
+				.applyToClusterSettings((settings) -> {
+
+					settings.serverSelectionTimeout(clusterServerSelectionTimeoutMS, TimeUnit.MILLISECONDS);
+					if (clusterConnectionMode != null) {
+						settings.mode(clusterConnectionMode);
+					}
+					settings.requiredReplicaSetName(clusterRequiredReplicaSetName);
+
+					if (!CollectionUtils.isEmpty(clusterHosts)) {
+						settings.hosts(clusterHosts);
+					}
+					settings.localThreshold(clusterLocalThresholdMS, TimeUnit.MILLISECONDS);
+					// settings.maxWaitQueueSize(clusterMaxWaitQueueSize);
+					settings.requiredClusterType(custerRequiredClusterType);
+
+					if (StringUtils.hasText(clusterSrvHost)) {
+						settings.srvHost(clusterSrvHost);
+					}
+				}) //
+				.applyToConnectionPoolSettings((settings) -> {
+
+					settings.minSize(poolMinSize);
+					settings.maxSize(poolMaxSize);
+					settings.maxConnectionIdleTime(poolMaxConnectionIdleTimeMS, TimeUnit.MILLISECONDS);
+					settings.maxWaitTime(poolMaxWaitTimeMS, TimeUnit.MILLISECONDS);
+					settings.maxConnectionLifeTime(poolMaxConnectionLifeTimeMS, TimeUnit.MILLISECONDS);
+					// settings.maxWaitQueueSize(poolMaxWaitQueueSize);
+					settings.maintenanceFrequency(poolMaintenanceFrequencyMS, TimeUnit.MILLISECONDS);
+					settings.maintenanceInitialDelay(poolMaintenanceInitialDelayMS, TimeUnit.MILLISECONDS);
+				}) //
+				.applyToServerSettings((settings) -> {
+
+					settings.minHeartbeatFrequency(serverMinHeartbeatFrequencyMS, TimeUnit.MILLISECONDS);
+					settings.heartbeatFrequency(serverHeartbeatFrequencyMS, TimeUnit.MILLISECONDS);
+				}) //
+				.applyToSocketSettings((settings) -> {
+
+					settings.connectTimeout(socketConnectTimeoutMS, TimeUnit.MILLISECONDS);
+					settings.readTimeout(socketReadTimeoutMS, TimeUnit.MILLISECONDS);
+					settings.receiveBufferSize(socketReceiveBufferSize);
+					settings.sendBufferSize(socketSendBufferSize);
+				}) //
+				.applyToSslSettings((settings) -> {
+
+					settings.enabled(sslEnabled);
+					if (sslEnabled) {
+
+						settings.invalidHostNameAllowed(sslInvalidHostNameAllowed);
+						try {
+							settings.context(
+									StringUtils.hasText(sslProvider) ? SSLContext.getInstance(sslProvider) : SSLContext.getDefault());
+						} catch (NoSuchAlgorithmException e) {
+							throw new IllegalArgumentException(e.getMessage(), e);
+						}
+					}
+				});
+
+		if (streamFactoryFactory != null) {
+			builder = builder.streamFactoryFactory(streamFactoryFactory);
+		}
+		if (retryReads != null) {
+			builder = builder.retryReads(retryReads);
+		}
+		if (retryWrites != null) {
+			builder = builder.retryWrites(retryWrites);
+		}
+
+		if (uUidRepresentation != null) {
+			builder.uuidRepresentation(uUidRepresentation);
+		}
+
+		return builder.build();
+	}
+}

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

@@ -16,10 +16,9 @@
 package org.springframework.data.mongodb.core;
 
 import org.springframework.dao.DataIntegrityViolationException;
-import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 
-import com.mongodb.WriteResult;
+import com.mongodb.WriteConcernResult;
 
 /**
  * Mongo-specific {@link DataIntegrityViolationException}.
@@ -30,18 +29,18 @@ public class MongoDataIntegrityViolationException extends DataIntegrityViolation
 
 	private static final long serialVersionUID = -186980521176764046L;
 
-	private final WriteResult writeResult;
+	private final WriteConcernResult writeResult;
 	private final MongoActionOperation actionOperation;
 
 	/**
-	 * Creates a new {@link MongoDataIntegrityViolationException} using the given message and {@link WriteResult}.
+	 * Creates a new {@link MongoDataIntegrityViolationException} using the given message and {@link WriteConcernResult}.
 	 *
 	 * @param message the exception message
-	 * @param writeResult the {@link WriteResult} that causes the exception, must not be {@literal null}.
+	 * @param writeResult the {@link WriteConcernResult} 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) {
+	public MongoDataIntegrityViolationException(String message, WriteConcernResult writeResult,
+			MongoActionOperation actionOperation) {
 
 		super(message);
 
@@ -53,11 +52,11 @@ public class MongoDataIntegrityViolationException extends DataIntegrityViolation
 	}
 
 	/**
-	 * Returns the {@link WriteResult} that caused the exception.
+	 * Returns the {@link WriteConcernResult} that caused the exception.
 	 *
 	 * @return the writeResult
 	 */
-	public WriteResult getWriteResult() {
+	public WriteConcernResult getWriteResult() {
 		return writeResult;
 	}
 

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

@@ -0,0 +1,260 @@
+/*
+ * Copyright 2018-2019 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
+ *
+ *      https://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 lombok.Value;
+
+import org.springframework.aop.framework.ProxyFactory;
+import org.springframework.dao.DataAccessException;
+import org.springframework.dao.support.PersistenceExceptionTranslator;
+import org.springframework.data.mongodb.MongoDatabaseFactory;
+import org.springframework.data.mongodb.SessionAwareMethodInterceptor;
+import org.springframework.lang.Nullable;
+import org.springframework.util.Assert;
+
+import com.mongodb.ClientSessionOptions;
+import com.mongodb.WriteConcern;
+import com.mongodb.client.ClientSession;
+import com.mongodb.client.MongoCollection;
+import com.mongodb.client.MongoDatabase;
+
+/**
+ * Common base class for usage with both {@link com.mongodb.client.MongoClients} defining common properties such as
+ * database name and exception translator.
+ * <p/>
+ * Not intended to be used directly.
+ *
+ * @author Christoph Strobl
+ * @author Mark Paluch
+ * @param <C> Client type.
+ * @since 3.0
+ * @see SimpleMongoClientDatabaseFactory
+ */
+public abstract class MongoDatabaseFactorySupport<C> implements MongoDatabaseFactory {
+
+	private final C mongoClient;
+	private final String databaseName;
+	private final boolean mongoInstanceCreated;
+	private final PersistenceExceptionTranslator exceptionTranslator;
+
+	private @Nullable WriteConcern writeConcern;
+
+	/**
+	 * Create a new {@link MongoDatabaseFactorySupport} object given {@code mongoClient}, {@code databaseName},
+	 * {@code mongoInstanceCreated} and {@link PersistenceExceptionTranslator}.
+	 *
+	 * @param mongoClient must not be {@literal null}.
+	 * @param databaseName must not be {@literal null} or empty.
+	 * @param mongoInstanceCreated {@literal true} if the client instance was created by a subclass of
+	 *          {@link MongoDatabaseFactorySupport} to close the client on {@link #destroy()}.
+	 * @param exceptionTranslator must not be {@literal null}.
+	 */
+	protected MongoDatabaseFactorySupport(C mongoClient, String databaseName, boolean mongoInstanceCreated,
+			PersistenceExceptionTranslator exceptionTranslator) {
+
+		Assert.notNull(mongoClient, "MongoClient must not be null!");
+		Assert.hasText(databaseName, "Database name must not be empty!");
+		Assert.isTrue(databaseName.matches("[^/\\\\.$\"\\s]+"),
+				"Database name must not contain slashes, dots, spaces, quotes, or dollar signs!");
+
+		this.mongoClient = mongoClient;
+		this.databaseName = databaseName;
+		this.mongoInstanceCreated = mongoInstanceCreated;
+		this.exceptionTranslator = exceptionTranslator;
+	}
+
+	/**
+	 * Configures the {@link WriteConcern} to be used on the {@link MongoDatabase} instance being created.
+	 *
+	 * @param writeConcern the writeConcern to set
+	 */
+	public void setWriteConcern(WriteConcern writeConcern) {
+		this.writeConcern = writeConcern;
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.MongoDbFactory#getMongoDatabase()
+	 */
+	public MongoDatabase getMongoDatabase() throws DataAccessException {
+		return getMongoDatabase(getDefaultDatabaseName());
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.MongoDbFactory#getMongoDatabase(java.lang.String)
+	 */
+	@Override
+	public MongoDatabase getMongoDatabase(String dbName) throws DataAccessException {
+
+		Assert.hasText(dbName, "Database name must not be empty!");
+
+		MongoDatabase db = doGetMongoDatabase(dbName);
+
+		if (writeConcern == null) {
+			return db;
+		}
+
+		return db.withWriteConcern(writeConcern);
+	}
+
+	/**
+	 * Get the actual {@link MongoDatabase} from the client.
+	 *
+	 * @param dbName must not be {@literal null} or empty.
+	 * @return
+	 */
+	protected abstract MongoDatabase doGetMongoDatabase(String dbName);
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.beans.factory.DisposableBean#destroy()
+	 */
+	public void destroy() throws Exception {
+		if (mongoInstanceCreated) {
+			closeClient();
+		}
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.MongoDbFactory#getExceptionTranslator()
+	 */
+	public PersistenceExceptionTranslator getExceptionTranslator() {
+		return this.exceptionTranslator;
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.MongoDbFactory#withSession(com.mongodb.session.Session)
+	 */
+	public MongoDatabaseFactory withSession(ClientSession session) {
+		return new MongoDatabaseFactorySupport.ClientSessionBoundMongoDbFactory(session, this);
+	}
+
+	/**
+	 * Close the client instance.
+	 */
+	protected abstract void closeClient();
+
+	/**
+	 * @return the Mongo client object.
+	 */
+	protected C getMongoClient() {
+		return mongoClient;
+	}
+
+	/**
+	 * @return the database name.
+	 */
+	protected String getDefaultDatabaseName() {
+		return databaseName;
+	}
+
+	/**
+	 * {@link ClientSession} bound {@link MongoDatabaseFactory} decorating the database with a
+	 * {@link SessionAwareMethodInterceptor}.
+	 *
+	 * @author Christoph Strobl
+	 * @since 2.1
+	 */
+	@Value
+	static class ClientSessionBoundMongoDbFactory implements MongoDatabaseFactory {
+
+		ClientSession session;
+		MongoDatabaseFactory delegate;
+
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.MongoDbFactory#getMongoDatabase()
+		 */
+		@Override
+		public MongoDatabase getMongoDatabase() throws DataAccessException {
+			return proxyMongoDatabase(delegate.getMongoDatabase());
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.MongoDbFactory#getMongoDatabase(java.lang.String)
+		 */
+		@Override
+		public MongoDatabase getMongoDatabase(String dbName) throws DataAccessException {
+			return proxyMongoDatabase(delegate.getMongoDatabase(dbName));
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.MongoDbFactory#getExceptionTranslator()
+		 */
+		@Override
+		public PersistenceExceptionTranslator getExceptionTranslator() {
+			return delegate.getExceptionTranslator();
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.MongoDbFactory#getSession(com.mongodb.ClientSessionOptions)
+		 */
+		@Override
+		public ClientSession getSession(ClientSessionOptions options) {
+			return delegate.getSession(options);
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.MongoDbFactory#withSession(com.mongodb.session.ClientSession)
+		 */
+		@Override
+		public MongoDatabaseFactory withSession(ClientSession session) {
+			return delegate.withSession(session);
+		}
+
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.MongoDbFactory#isTransactionActive()
+		 */
+		@Override
+		public boolean isTransactionActive() {
+			return session != null && session.hasActiveTransaction();
+		}
+
+		private MongoDatabase proxyMongoDatabase(MongoDatabase database) {
+			return createProxyInstance(session, database, MongoDatabase.class);
+		}
+
+		private MongoDatabase proxyDatabase(com.mongodb.session.ClientSession session, MongoDatabase database) {
+			return createProxyInstance(session, database, MongoDatabase.class);
+		}
+
+		private MongoCollection<?> proxyCollection(com.mongodb.session.ClientSession session,
+				MongoCollection<?> collection) {
+			return createProxyInstance(session, collection, MongoCollection.class);
+		}
+
+		private <T> T createProxyInstance(com.mongodb.session.ClientSession session, T target, Class<T> targetType) {
+
+			ProxyFactory factory = new ProxyFactory();
+			factory.setTarget(target);
+			factory.setInterfaces(targetType);
+			factory.setOpaque(true);
+
+			factory.addAdvice(new SessionAwareMethodInterceptor<>(session, target, ClientSession.class, MongoDatabase.class,
+					this::proxyDatabase, MongoCollection.class, this::proxyCollection));
+
+			return targetType.cast(factory.getProxy(target.getClass().getClassLoader()));
+		}
+	}
+}

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

@@ -15,26 +15,11 @@
  */
 package org.springframework.data.mongodb.core;
 
-import lombok.Value;
-
-import org.springframework.aop.framework.ProxyFactory;
-import org.springframework.dao.DataAccessException;
 import org.springframework.dao.support.PersistenceExceptionTranslator;
-import org.springframework.data.mongodb.MongoDbFactory;
-import org.springframework.data.mongodb.SessionAwareMethodInterceptor;
-import org.springframework.lang.Nullable;
-import org.springframework.util.Assert;
-
-import com.mongodb.ClientSessionOptions;
-import com.mongodb.DB;
-import com.mongodb.WriteConcern;
-import com.mongodb.client.ClientSession;
-import com.mongodb.client.MongoCollection;
-import com.mongodb.client.MongoDatabase;
 
 /**
- * Common base class for usage with both {@link com.mongodb.client.MongoClients} and {@link com.mongodb.MongoClient}
- * defining common properties such as database name and exception translator.
+ * Common base class for usage with both {@link com.mongodb.client.MongoClients} defining common properties such as
+ * database name and exception translator.
  * <p/>
  * Not intended to be used directly.
  *
@@ -42,22 +27,16 @@ import com.mongodb.client.MongoDatabase;
  * @author Mark Paluch
  * @param <C> Client type.
  * @since 2.1
- * @see SimpleMongoDbFactory
- * @see SimpleMongoClientDbFactory
+ * @see SimpleMongoClientDatabaseFactory
+ * @deprecated since 3.0, use {@link MongoDatabaseFactorySupport} instead.
  */
-public abstract class MongoDbFactorySupport<C> implements MongoDbFactory {
-
-	private final C mongoClient;
-	private final String databaseName;
-	private final boolean mongoInstanceCreated;
-	private final PersistenceExceptionTranslator exceptionTranslator;
-
-	private @Nullable WriteConcern writeConcern;
+@Deprecated
+public abstract class MongoDbFactorySupport<C> extends MongoDatabaseFactorySupport<C> {
 
 	/**
 	 * Create a new {@link MongoDbFactorySupport} object given {@code mongoClient}, {@code databaseName},
 	 * {@code mongoInstanceCreated} and {@link PersistenceExceptionTranslator}.
-	 * 
+	 *
 	 * @param mongoClient must not be {@literal null}.
 	 * @param databaseName must not be {@literal null} or empty.
 	 * @param mongoInstanceCreated {@literal true} if the client instance was created by a subclass of
@@ -66,207 +45,6 @@ public abstract class MongoDbFactorySupport<C> implements MongoDbFactory {
 	 */
 	protected MongoDbFactorySupport(C mongoClient, String databaseName, boolean mongoInstanceCreated,
 			PersistenceExceptionTranslator exceptionTranslator) {
-
-		Assert.notNull(mongoClient, "MongoClient must not be null!");
-		Assert.hasText(databaseName, "Database name must not be empty!");
-		Assert.isTrue(databaseName.matches("[^/\\\\.$\"\\s]+"),
-				"Database name must not contain slashes, dots, spaces, quotes, or dollar signs!");
-
-		this.mongoClient = mongoClient;
-		this.databaseName = databaseName;
-		this.mongoInstanceCreated = mongoInstanceCreated;
-		this.exceptionTranslator = exceptionTranslator;
+		super(mongoClient, databaseName, mongoInstanceCreated, exceptionTranslator);
 	}
-
-	/**
-	 * Configures the {@link WriteConcern} to be used on the {@link MongoDatabase} instance being created.
-	 *
-	 * @param writeConcern the writeConcern to set
-	 */
-	public void setWriteConcern(WriteConcern writeConcern) {
-		this.writeConcern = writeConcern;
-	}
-
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.MongoDbFactory#getDb()
-	 */
-	public MongoDatabase getDb() throws DataAccessException {
-		return getDb(databaseName);
-	}
-
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.MongoDbFactory#getDb(java.lang.String)
-	 */
-	@Override
-	public MongoDatabase getDb(String dbName) throws DataAccessException {
-
-		Assert.hasText(dbName, "Database name must not be empty!");
-
-		MongoDatabase db = doGetMongoDatabase(dbName);
-
-		if (writeConcern == null) {
-			return db;
-		}
-
-		return db.withWriteConcern(writeConcern);
-	}
-
-	/**
-	 * Get the actual {@link MongoDatabase} from the client.
-	 * 
-	 * @param dbName must not be {@literal null} or empty.
-	 * @return
-	 */
-	protected abstract MongoDatabase doGetMongoDatabase(String dbName);
-
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.beans.factory.DisposableBean#destroy()
-	 */
-	public void destroy() throws Exception {
-		if (mongoInstanceCreated) {
-			closeClient();
-		}
-	}
-
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.MongoDbFactory#getExceptionTranslator()
-	 */
-	public PersistenceExceptionTranslator getExceptionTranslator() {
-		return this.exceptionTranslator;
-	}
-
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.MongoDbFactory#withSession(com.mongodb.session.Session)
-	 */
-	public MongoDbFactory withSession(ClientSession session) {
-		return new MongoDbFactorySupport.ClientSessionBoundMongoDbFactory(session, this);
-	}
-
-	/**
-	 * Close the client instance.
-	 */
-	protected abstract void closeClient();
-
-	/**
-	 * @return the Mongo client object.
-	 */
-	protected C getMongoClient() {
-		return mongoClient;
-	}
-
-	/**
-	 * @return the database name.
-	 */
-	protected String getDefaultDatabaseName() {
-		return databaseName;
-	}
-
-	/**
-	 * {@link ClientSession} bound {@link MongoDbFactory} decorating the database with a
-	 * {@link SessionAwareMethodInterceptor}.
-	 *
-	 * @author Christoph Strobl
-	 * @since 2.1
-	 */
-	@Value
-	static class ClientSessionBoundMongoDbFactory implements MongoDbFactory {
-
-		ClientSession session;
-		MongoDbFactory delegate;
-
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.MongoDbFactory#getDb()
-		 */
-		@Override
-		public MongoDatabase getDb() throws DataAccessException {
-			return proxyMongoDatabase(delegate.getDb());
-		}
-
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.MongoDbFactory#getDb(java.lang.String)
-		 */
-		@Override
-		public MongoDatabase getDb(String dbName) throws DataAccessException {
-			return proxyMongoDatabase(delegate.getDb(dbName));
-		}
-
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.MongoDbFactory#getExceptionTranslator()
-		 */
-		@Override
-		public PersistenceExceptionTranslator getExceptionTranslator() {
-			return delegate.getExceptionTranslator();
-		}
-
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.MongoDbFactory#getLegacyDb()
-		 */
-		@Override
-		public DB getLegacyDb() {
-			return delegate.getLegacyDb();
-		}
-
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.MongoDbFactory#getSession(com.mongodb.ClientSessionOptions)
-		 */
-		@Override
-		public ClientSession getSession(ClientSessionOptions options) {
-			return delegate.getSession(options);
-		}
-
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.MongoDbFactory#withSession(com.mongodb.session.ClientSession)
-		 */
-		@Override
-		public MongoDbFactory withSession(ClientSession session) {
-			return delegate.withSession(session);
-		}
-
-		/*
-		 * (non-Javadoc)
-		 * @see org.springframework.data.mongodb.MongoDbFactory#isTransactionActive()
-		 */
-		@Override
-		public boolean isTransactionActive() {
-			return session != null && session.hasActiveTransaction();
-		}
-
-		private MongoDatabase proxyMongoDatabase(MongoDatabase database) {
-			return createProxyInstance(session, database, MongoDatabase.class);
-		}
-
-		private MongoDatabase proxyDatabase(com.mongodb.session.ClientSession session, MongoDatabase database) {
-			return createProxyInstance(session, database, MongoDatabase.class);
-		}
-
-		private MongoCollection<?> proxyCollection(com.mongodb.session.ClientSession session,
-				MongoCollection<?> collection) {
-			return createProxyInstance(session, collection, MongoCollection.class);
-		}
-
-		private <T> T createProxyInstance(com.mongodb.session.ClientSession session, T target, Class<T> targetType) {
-
-			ProxyFactory factory = new ProxyFactory();
-			factory.setTarget(target);
-			factory.setInterfaces(targetType);
-			factory.setOpaque(true);
-
-			factory.addAdvice(new SessionAwareMethodInterceptor<>(session, target, ClientSession.class, MongoDatabase.class,
-					this::proxyDatabase, MongoCollection.class, this::proxyCollection));
-
-			return targetType.cast(factory.getProxy());
-		}
-	}
-
 }

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

@@ -29,7 +29,6 @@ import org.springframework.dao.InvalidDataAccessApiUsageException;
 import org.springframework.dao.InvalidDataAccessResourceUsageException;
 import org.springframework.dao.PermissionDeniedDataAccessException;
 import org.springframework.dao.support.PersistenceExceptionTranslator;
-import org.springframework.data.mongodb.BulkOperationException;
 import org.springframework.data.mongodb.ClientSessionException;
 import org.springframework.data.mongodb.MongoTransactionException;
 import org.springframework.data.mongodb.UncategorizedMongoDbException;
@@ -37,7 +36,6 @@ import org.springframework.data.mongodb.util.MongoDbErrorCodes;
 import org.springframework.lang.Nullable;
 import org.springframework.util.ClassUtils;
 
-import com.mongodb.BulkWriteException;
 import com.mongodb.MongoBulkWriteException;
 import com.mongodb.MongoException;
 import com.mongodb.MongoServerException;
@@ -112,10 +110,6 @@ public class MongoExceptionTranslator implements PersistenceExceptionTranslator
 			return new DataIntegrityViolationException(ex.getMessage(), ex);
 		}
 
-		if (ex instanceof BulkWriteException) {
-			return new BulkOperationException(ex.getMessage(), (BulkWriteException) ex);
-		}
-
 		// All other MongoExceptions
 		if (ex instanceof MongoException) {
 
@@ -135,6 +129,7 @@ public class MongoExceptionTranslator implements PersistenceExceptionTranslator
 			} else if (MongoDbErrorCodes.isTransactionFailureCode(code)) {
 				return new MongoTransactionException(ex.getMessage(), ex);
 			}
+
 			return new UncategorizedMongoDbException(ex.getMessage(), ex);
 		}
 

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

@@ -48,7 +48,6 @@ import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
 
 import com.mongodb.ClientSessionOptions;
-import com.mongodb.Cursor;
 import com.mongodb.ReadPreference;
 import com.mongodb.client.ClientSession;
 import com.mongodb.client.MongoCollection;
@@ -80,7 +79,7 @@ public interface MongoOperations extends FluentMongoOperations {
 	 * The collection name used for the specified class by this template.
 	 *
 	 * @param entityClass must not be {@literal null}.
-	 * @return
+	 * @return never {@literal null}.
 	 */
 	String getCollectionName(Class<?> entityClass);
 
@@ -224,9 +223,10 @@ public interface MongoOperations extends FluentMongoOperations {
 
 	/**
 	 * Executes the given {@link Query} on the entity collection of the specified {@code entityType} backed by a Mongo DB
-	 * {@link Cursor}.
+	 * {@link com.mongodb.client.FindIterable}.
 	 * <p>
-	 * Returns a {@link CloseableIterator} that wraps the a Mongo DB {@link Cursor} that needs to be closed.
+	 * Returns a {@link CloseableIterator} that wraps the a Mongo DB {@link com.mongodb.client.FindIterable} that needs to
+	 * be closed.
 	 *
 	 * @param query the query class that specifies the criteria used to find a record and also an optional fields
 	 *          specification. Must not be {@literal null}.
@@ -239,9 +239,10 @@ public interface MongoOperations extends FluentMongoOperations {
 
 	/**
 	 * Executes the given {@link Query} on the entity collection of the specified {@code entityType} and collection backed
-	 * by a Mongo DB {@link Cursor}.
+	 * by a Mongo DB {@link com.mongodb.client.FindIterable}.
 	 * <p>
-	 * Returns a {@link CloseableIterator} that wraps the a Mongo DB {@link Cursor} that needs to be closed.
+	 * Returns a {@link CloseableIterator} that wraps the a Mongo DB {@link com.mongodb.client.FindIterable} that needs to
+	 * be closed.
 	 *
 	 * @param query the query class that specifies the criteria used to find a record and also an optional fields
 	 *          specification. Must not be {@literal null}.
@@ -360,9 +361,9 @@ public interface MongoOperations extends FluentMongoOperations {
 	IndexOperations indexOps(Class<?> entityClass);
 
 	/**
-	 * Returns the {@link ScriptOperations} that can be performed on {@link com.mongodb.DB} level.
+	 * Returns the {@link ScriptOperations} that can be performed on {@link com.mongodb.client.MongoDatabase} level.
 	 *
-	 * @return
+	 * @return never {@literal null}.
 	 * @since 1.7
 	 * @deprecated since 2.2. The {@code eval} command has been removed without replacement in MongoDB Server 4.2.0.
 	 */
@@ -518,11 +519,11 @@ public interface MongoOperations extends FluentMongoOperations {
 	<O> AggregationResults<O> aggregate(Aggregation aggregation, String collectionName, Class<O> outputType);
 
 	/**
-	 * Execute an aggregation operation backed by a Mongo DB {@link Cursor}.
+	 * Execute an aggregation operation backed by a Mongo DB {@link com.mongodb.client.AggregateIterable}.
 	 * <p>
-	 * Returns a {@link CloseableIterator} that wraps the a Mongo DB {@link Cursor} that needs to be closed. The raw
-	 * results will be mapped to the given entity class. The name of the inputCollection is derived from the inputType of
-	 * the aggregation.
+	 * Returns a {@link CloseableIterator} that wraps the a Mongo DB {@link com.mongodb.client.AggregateIterable} that
+	 * needs to be closed. The raw results will be mapped to the given entity class. The name of the inputCollection is
+	 * derived from the inputType of the aggregation.
 	 * <p>
 	 * Aggregation streaming can't be used with {@link AggregationOptions#isExplain() aggregation explain}. Enabling
 	 * explanation mode will throw an {@link IllegalArgumentException}.
@@ -537,11 +538,11 @@ public interface MongoOperations extends FluentMongoOperations {
 	<O> CloseableIterator<O> aggregateStream(TypedAggregation<?> aggregation, String collectionName, Class<O> outputType);
 
 	/**
-	 * Execute an aggregation operation backed by a Mongo DB {@link Cursor}.
+	 * Execute an aggregation operation backed by a Mongo DB {@link com.mongodb.client.AggregateIterable}.
 	 * <p/>
-	 * Returns a {@link CloseableIterator} that wraps the a Mongo DB {@link Cursor} that needs to be closed. The raw
-	 * results will be mapped to the given entity class and are returned as stream. The name of the inputCollection is
-	 * derived from the inputType of the aggregation.
+	 * Returns a {@link CloseableIterator} that wraps the a Mongo DB {@link com.mongodb.client.AggregateIterable} that
+	 * needs to be closed. The raw results will be mapped to the given entity class and are returned as stream. The name
+	 * of the inputCollection is derived from the inputType of the aggregation.
 	 * <p/>
 	 * Aggregation streaming can't be used with {@link AggregationOptions#isExplain() aggregation explain}. Enabling
 	 * explanation mode will throw an {@link IllegalArgumentException}.
@@ -555,10 +556,10 @@ public interface MongoOperations extends FluentMongoOperations {
 	<O> CloseableIterator<O> aggregateStream(TypedAggregation<?> aggregation, Class<O> outputType);
 
 	/**
-	 * Execute an aggregation operation backed by a Mongo DB {@link Cursor}.
+	 * Execute an aggregation operation backed by a Mongo DB {@link com.mongodb.client.AggregateIterable}.
 	 * <p/>
-	 * Returns a {@link CloseableIterator} that wraps the a Mongo DB {@link Cursor} that needs to be closed. The raw
-	 * results will be mapped to the given entity class.
+	 * Returns a {@link CloseableIterator} that wraps the a Mongo DB {@link com.mongodb.client.AggregateIterable} that
+	 * needs to be closed. The raw results will be mapped to the given entity class.
 	 * <p/>
 	 * Aggregation streaming can't be used with {@link AggregationOptions#isExplain() aggregation explain}. Enabling
 	 * explanation mode will throw an {@link IllegalArgumentException}.
@@ -574,10 +575,10 @@ public interface MongoOperations extends FluentMongoOperations {
 	<O> CloseableIterator<O> aggregateStream(Aggregation aggregation, Class<?> inputType, Class<O> outputType);
 
 	/**
-	 * Execute an aggregation operation backed by a Mongo DB {@link Cursor}.
+	 * Execute an aggregation operation backed by a Mongo DB {@link com.mongodb.client.AggregateIterable}.
 	 * <p/>
-	 * Returns a {@link CloseableIterator} that wraps the a Mongo DB {@link Cursor} that needs to be closed. The raw
-	 * results will be mapped to the given entity class.
+	 * Returns a {@link CloseableIterator} that wraps the a Mongo DB {@link com.mongodb.client.AggregateIterable} that
+	 * needs to be closed. The raw results will be mapped to the given entity class.
 	 * <p/>
 	 * Aggregation streaming can't be used with {@link AggregationOptions#isExplain() aggregation explain}. Enabling
 	 * explanation mode will throw an {@link IllegalArgumentException}.
@@ -1373,10 +1374,9 @@ public interface MongoOperations extends FluentMongoOperations {
 	 * the provided updated document. <br />
 	 * <strong>NOTE:</strong> Any additional support for field mapping, versions, etc. is not available due to the lack of
 	 * domain type information. Use {@link #updateFirst(Query, UpdateDefinition, Class, String)} to get full type specific
-	 * support.
-	 * <br />
+	 * support. <br />
 	 * <strong>NOTE:</strong> {@link Query#getSortObject() sorting} is not supported by {@code db.collection.updateOne}.
-	 * Use {@link #findAndModify(Query, Update, Class, String)} instead.
+	 * Use {@link #findAndModify(Query, UpdateDefinition, Class, String)} instead.
 	 *
 	 * @param query the query document that specifies the criteria used to select a record to be updated. Must not be
 	 *          {@literal null}.
@@ -1557,7 +1557,7 @@ public interface MongoOperations extends FluentMongoOperations {
 	/**
 	 * Returns the underlying {@link MongoConverter}.
 	 *
-	 * @return
+	 * @return never {@literal null}.
 	 */
 	MongoConverter getConverter();
 }

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

@@ -29,9 +29,7 @@ import java.util.*;
 import java.util.concurrent.TimeUnit;
 import java.util.stream.Collectors;
 
-import org.bson.BsonValue;
 import org.bson.Document;
-import org.bson.codecs.Codec;
 import org.bson.conversions.Bson;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -54,24 +52,23 @@ import org.springframework.data.geo.Distance;
 import org.springframework.data.geo.GeoResult;
 import org.springframework.data.geo.GeoResults;
 import org.springframework.data.geo.Metric;
-import org.springframework.data.mapping.PropertyPath;
-import org.springframework.data.mapping.PropertyReferenceException;
 import org.springframework.data.mapping.callback.EntityCallbacks;
 import org.springframework.data.mapping.context.MappingContext;
+import org.springframework.data.mongodb.MongoDatabaseFactory;
 import org.springframework.data.mongodb.MongoDatabaseUtils;
-import org.springframework.data.mongodb.MongoDbFactory;
 import org.springframework.data.mongodb.SessionSynchronization;
 import org.springframework.data.mongodb.core.BulkOperations.BulkMode;
 import org.springframework.data.mongodb.core.DefaultBulkOperations.BulkOperationContext;
 import org.springframework.data.mongodb.core.EntityOperations.AdaptibleEntity;
-import org.springframework.data.mongodb.core.MappedDocument.MappedUpdate;
+import org.springframework.data.mongodb.core.QueryOperations.CountContext;
+import org.springframework.data.mongodb.core.QueryOperations.DeleteContext;
+import org.springframework.data.mongodb.core.QueryOperations.DistinctQueryContext;
+import org.springframework.data.mongodb.core.QueryOperations.QueryContext;
+import org.springframework.data.mongodb.core.QueryOperations.UpdateContext;
 import org.springframework.data.mongodb.core.aggregation.Aggregation;
 import org.springframework.data.mongodb.core.aggregation.AggregationOperationContext;
 import org.springframework.data.mongodb.core.aggregation.AggregationOptions;
 import org.springframework.data.mongodb.core.aggregation.AggregationResults;
-import org.springframework.data.mongodb.core.aggregation.AggregationUpdate;
-import org.springframework.data.mongodb.core.aggregation.Fields;
-import org.springframework.data.mongodb.core.aggregation.RelaxedTypeBasedAggregationOperationContext;
 import org.springframework.data.mongodb.core.aggregation.TypeBasedAggregationOperationContext;
 import org.springframework.data.mongodb.core.aggregation.TypedAggregation;
 import org.springframework.data.mongodb.core.convert.DbRefResolver;
@@ -91,20 +88,12 @@ import org.springframework.data.mongodb.core.index.MongoPersistentEntityIndexCre
 import org.springframework.data.mongodb.core.mapping.MongoMappingContext;
 import org.springframework.data.mongodb.core.mapping.MongoPersistentEntity;
 import org.springframework.data.mongodb.core.mapping.MongoPersistentProperty;
-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.BeforeConvertCallback;
-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.BeforeSaveCallback;
-import org.springframework.data.mongodb.core.mapping.event.BeforeSaveEvent;
-import org.springframework.data.mongodb.core.mapping.event.MongoMappingEvent;
+import org.springframework.data.mongodb.core.mapping.event.*;
 import org.springframework.data.mongodb.core.mapreduce.GroupBy;
 import org.springframework.data.mongodb.core.mapreduce.GroupByResults;
 import org.springframework.data.mongodb.core.mapreduce.MapReduceOptions;
 import org.springframework.data.mongodb.core.mapreduce.MapReduceResults;
+import org.springframework.data.mongodb.core.query.BasicQuery;
 import org.springframework.data.mongodb.core.query.Collation;
 import org.springframework.data.mongodb.core.query.Criteria;
 import org.springframework.data.mongodb.core.query.Meta;
@@ -114,6 +103,7 @@ import org.springframework.data.mongodb.core.query.Query;
 import org.springframework.data.mongodb.core.query.UpdateDefinition;
 import org.springframework.data.mongodb.core.query.UpdateDefinition.ArrayFilter;
 import org.springframework.data.mongodb.core.validation.Validator;
+import org.springframework.data.mongodb.util.BsonUtils;
 import org.springframework.data.projection.SpelAwareProxyProjectionFactory;
 import org.springframework.data.util.CloseableIterator;
 import org.springframework.data.util.Optionals;
@@ -128,11 +118,6 @@ import org.springframework.util.ResourceUtils;
 import org.springframework.util.StringUtils;
 
 import com.mongodb.ClientSessionOptions;
-import com.mongodb.Cursor;
-import com.mongodb.DBCollection;
-import com.mongodb.DBCursor;
-import com.mongodb.Mongo;
-import com.mongodb.MongoClient;
 import com.mongodb.MongoException;
 import com.mongodb.ReadPreference;
 import com.mongodb.WriteConcern;
@@ -141,6 +126,7 @@ import com.mongodb.client.ClientSession;
 import com.mongodb.client.DistinctIterable;
 import com.mongodb.client.FindIterable;
 import com.mongodb.client.MapReduceIterable;
+import com.mongodb.client.MongoClient;
 import com.mongodb.client.MongoCollection;
 import com.mongodb.client.MongoCursor;
 import com.mongodb.client.MongoDatabase;
@@ -173,8 +159,8 @@ import com.mongodb.client.result.UpdateResult;
  * @author Andreas Zink
  * @author Cimon Lucas
  * @author Michael J. Simons
+ * @author Roman Puchkovskiy
  */
-@SuppressWarnings("deprecation")
 public class MongoTemplate implements MongoOperations, ApplicationContextAware, IndexOperationsProvider {
 
 	private static final Logger LOGGER = LoggerFactory.getLogger(MongoTemplate.class);
@@ -193,7 +179,7 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 
 	private final MongoConverter mongoConverter;
 	private final MappingContext<? extends MongoPersistentEntity<?>, MongoPersistentProperty> mappingContext;
-	private final MongoDbFactory mongoDbFactory;
+	private final MongoDatabaseFactory mongoDbFactory;
 	private final PersistenceExceptionTranslator exceptionTranslator;
 	private final QueryMapper queryMapper;
 	private final UpdateMapper updateMapper;
@@ -201,6 +187,7 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 	private final SpelAwareProxyProjectionFactory projectionFactory;
 	private final EntityOperations operations;
 	private final PropertyOperations propertyOperations;
+	private final QueryOperations queryOperations;
 
 	private @Nullable WriteConcern writeConcern;
 	private WriteConcernResolver writeConcernResolver = DefaultWriteConcernResolver.INSTANCE;
@@ -213,18 +200,6 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 
 	private SessionSynchronization sessionSynchronization = SessionSynchronization.ON_ACTUAL_TRANSACTION;
 
-	/**
-	 * Constructor used for a basic template configuration.
-	 *
-	 * @param mongoClient must not be {@literal null}.
-	 * @param databaseName must not be {@literal null} or empty.
-	 * @deprecated since 2.2 in favor of {@link #MongoTemplate(com.mongodb.client.MongoClient, String)}.
-	 */
-	@Deprecated
-	public MongoTemplate(MongoClient mongoClient, String databaseName) {
-		this(new SimpleMongoDbFactory(mongoClient, databaseName), (MongoConverter) null);
-	}
-
 	/**
 	 * Constructor used for a basic template configuration.
 	 *
@@ -232,8 +207,8 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 	 * @param databaseName must not be {@literal null} or empty.
 	 * @since 2.1
 	 */
-	public MongoTemplate(com.mongodb.client.MongoClient mongoClient, String databaseName) {
-		this(new SimpleMongoClientDbFactory(mongoClient, databaseName), (MongoConverter) null);
+	public MongoTemplate(MongoClient mongoClient, String databaseName) {
+		this(new SimpleMongoClientDatabaseFactory(mongoClient, databaseName), (MongoConverter) null);
 	}
 
 	/**
@@ -241,7 +216,7 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 	 *
 	 * @param mongoDbFactory must not be {@literal null}.
 	 */
-	public MongoTemplate(MongoDbFactory mongoDbFactory) {
+	public MongoTemplate(MongoDatabaseFactory mongoDbFactory) {
 		this(mongoDbFactory, (MongoConverter) null);
 	}
 
@@ -251,7 +226,7 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 	 * @param mongoDbFactory must not be {@literal null}.
 	 * @param mongoConverter
 	 */
-	public MongoTemplate(MongoDbFactory mongoDbFactory, @Nullable MongoConverter mongoConverter) {
+	public MongoTemplate(MongoDatabaseFactory mongoDbFactory, @Nullable MongoConverter mongoConverter) {
 
 		Assert.notNull(mongoDbFactory, "MongoDbFactory must not be null!");
 
@@ -264,6 +239,8 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 		this.projectionFactory = new SpelAwareProxyProjectionFactory();
 		this.operations = new EntityOperations(this.mongoConverter.getMappingContext());
 		this.propertyOperations = new PropertyOperations(this.mongoConverter.getMappingContext());
+		this.queryOperations = new QueryOperations(queryMapper, updateMapper, operations, propertyOperations,
+				mongoDbFactory);
 
 		// We always have a mapping context in the converter, whether it's a simple one or not
 		mappingContext = this.mongoConverter.getMappingContext();
@@ -281,7 +258,7 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 		}
 	}
 
-	private MongoTemplate(MongoDbFactory dbFactory, MongoTemplate that) {
+	private MongoTemplate(MongoDatabaseFactory dbFactory, MongoTemplate that) {
 
 		this.mongoDbFactory = dbFactory;
 		this.exceptionTranslator = that.exceptionTranslator;
@@ -302,6 +279,7 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 		this.mappingContext = that.mappingContext;
 		this.operations = that.operations;
 		this.propertyOperations = that.propertyOperations;
+		this.queryOperations = that.queryOperations;
 	}
 
 	/**
@@ -316,8 +294,7 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 
 	/**
 	 * Configures the {@link WriteConcern} to be used with the template. If none is configured the {@link WriteConcern}
-	 * configured on the {@link MongoDbFactory} will apply. If you configured a {@link Mongo} instance no
-	 * {@link WriteConcern} will be used.
+	 * configured on the {@link MongoDatabaseFactory} will apply.
 	 *
 	 * @param writeConcern
 	 */
@@ -449,8 +426,10 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 
 			MongoPersistentEntity<?> persistentEntity = mappingContext.getPersistentEntity(entityType);
 
-			Document mappedFields = getMappedFieldsObject(query.getFieldsObject(), persistentEntity, returnType);
-			Document mappedQuery = queryMapper.getMappedObject(query.getQueryObject(), persistentEntity);
+			QueryContext queryContext = queryOperations.createQueryContext(query);
+
+			Document mappedQuery = queryContext.getMappedQuery(persistentEntity);
+			Document mappedFields = queryContext.getMappedFields(persistentEntity, returnType, projectionFactory);
 
 			FindIterable<Document> cursor = new QueryCursorPreparer(query, entityType).initiateFind(collection,
 					col -> col.find(mappedQuery, Document.class).projection(mappedFields));
@@ -524,8 +503,8 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 	 *          specification, must not be {@literal null}.
 	 * @param collectionName name of the collection to retrieve the objects from
 	 * @param documentCallbackHandler the handler that will extract results, one document at a time
-	 * @param preparer allows for customization of the {@link DBCursor} used when iterating over the result set, (apply
-	 *          limits, skips and so on).
+	 * @param preparer allows for customization of the {@link FindIterable} used when iterating over the result set,
+	 *          (apply limits, skips and so on).
 	 */
 	protected void executeQuery(Query query, String collectionName, DocumentCallbackHandler documentCallbackHandler,
 			@Nullable CursorPreparer preparer) {
@@ -845,10 +824,11 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 		}
 		Assert.notNull(collectionName, "CollectionName must not be null!");
 
-		Document mappedQuery = queryMapper.getMappedObject(query.getQueryObject(), getPersistentEntity(entityClass));
+		QueryContext queryContext = queryOperations.createQueryContext(query);
+		Document mappedQuery = queryContext.getMappedQuery(entityClass, this::getPersistentEntity);
 
-		return execute(collectionName, new ExistsCallback(mappedQuery,
-				operations.forType(entityClass).getCollation(query).map(Collation::toMongoCollation).orElse(null)));
+		return execute(collectionName,
+				new ExistsCallback(mappedQuery, queryContext.getCollation(entityClass).orElse(null)));
 	}
 
 	// Find methods that take a Query to express the query and that return a List of objects.
@@ -921,13 +901,11 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 		Assert.notNull(resultClass, "ResultClass must not be null!");
 
 		MongoPersistentEntity<?> entity = entityClass != Object.class ? getPersistentEntity(entityClass) : null;
+		DistinctQueryContext distinctQueryContext = queryOperations.distinctQueryContext(query, field);
 
-		Document mappedQuery = queryMapper.getMappedObject(query.getQueryObject(), entity);
-		String mappedFieldName = queryMapper.getMappedFields(new Document(field, 1), entity).keySet().iterator().next();
-
-		Class<T> mongoDriverCompatibleType = getMongoDbFactory().getCodecFor(resultClass) //
-				.map(Codec::getEncoderClass) //
-				.orElse((Class<T>) BsonValue.class);
+		Document mappedQuery = distinctQueryContext.getMappedQuery(entity);
+		String mappedFieldName = distinctQueryContext.getMappedFieldName(entity);
+		Class<T> mongoDriverCompatibleType = distinctQueryContext.getDriverCompatibleClass(resultClass);
 
 		MongoIterable<?> result = execute(collectionName, (collection) -> {
 
@@ -942,12 +920,9 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 			}
 
 			DistinctIterable<T> iterable = collection.distinct(mappedFieldName, mappedQuery, mongoDriverCompatibleType);
+			distinctQueryContext.applyCollation(entityClass, iterable::collation);
 
-			return operations.forType(entityClass) //
-					.getCollation(query) //
-					.map(Collation::toMongoCollation) //
-					.map(iterable::collation) //
-					.orElse(iterable);
+			return iterable;
 		});
 
 		if (resultClass == Object.class || mongoDriverCompatibleType != resultClass) {
@@ -956,7 +931,7 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 			DefaultDbRefResolver dbRefResolver = new DefaultDbRefResolver(mongoDbFactory);
 
 			result = result.map((source) -> converter.mapValueToTargetType(source,
-					getMostSpecificConversionTargetType(resultClass, entityClass, field), dbRefResolver));
+					distinctQueryContext.getMostSpecificConversionTargetType(resultClass, entityClass), dbRefResolver));
 		}
 
 		try {
@@ -966,32 +941,6 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 		}
 	}
 
-	/**
-	 * @param userType must not be {@literal null}.
-	 * @param domainType must not be {@literal null}.
-	 * @param field must not be {@literal null}.
-	 * @return the most specific conversion target type depending on user preference and domain type property.
-	 * @since 2.1
-	 */
-	private static Class<?> getMostSpecificConversionTargetType(Class<?> userType, Class<?> domainType, String field) {
-
-		Class<?> conversionTargetType = userType;
-		try {
-
-			Class<?> propertyType = PropertyPath.from(field, domainType).getLeafProperty().getLeafType();
-
-			// use the more specific type but favor UserType over property one
-			if (ClassUtils.isAssignable(userType, propertyType)) {
-				conversionTargetType = propertyType;
-			}
-
-		} catch (PropertyReferenceException e) {
-			// just don't care about it as we default to Object.class anyway.
-		}
-
-		return conversionTargetType;
-	}
-
 	@Override
 	public <T> GeoResults<T> geoNear(NearQuery near, Class<T> entityClass) {
 		return geoNear(near, entityClass, getCollectionName(entityClass));
@@ -1106,10 +1055,11 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 		Assert.isTrue(query.getSkip() <= 0, "Query must not define skip.");
 
 		MongoPersistentEntity<?> entity = mappingContext.getPersistentEntity(entityType);
+		QueryContext queryContext = queryOperations.createQueryContext(query);
 
-		Document mappedQuery = queryMapper.getMappedObject(query.getQueryObject(), entity);
-		Document mappedFields = queryMapper.getMappedFields(query.getFieldsObject(), entity);
-		Document mappedSort = queryMapper.getMappedSort(query.getSortObject(), entity);
+		Document mappedQuery = queryContext.getMappedQuery(entity);
+		Document mappedFields = queryContext.getMappedFields(entity, resultType, projectionFactory);
+		Document mappedSort = queryContext.getMappedSort(entity);
 
 		replacement = maybeCallBeforeConvert(replacement, collectionName);
 		Document mappedReplacement = operations.forEntity(replacement).toMappedDocument(this.mongoConverter).getDocument();
@@ -1117,9 +1067,15 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 		maybeEmitEvent(new BeforeSaveEvent<>(replacement, mappedReplacement, collectionName));
 		maybeCallBeforeSave(replacement, mappedReplacement, collectionName);
 
-		return doFindAndReplace(collectionName, mappedQuery, mappedFields, mappedSort,
-				operations.forType(entityType).getCollation(query).map(Collation::toMongoCollation).orElse(null), entityType,
-				mappedReplacement, options, resultType);
+		T saved = doFindAndReplace(collectionName, mappedQuery, mappedFields, mappedSort,
+				queryContext.getCollation(entityType).orElse(null), entityType, mappedReplacement, options, resultType);
+
+		if (saved != null) {
+			maybeEmitEvent(new AfterSaveEvent<>(saved, mappedReplacement, collectionName));
+			return maybeCallAfterSave(saved, mappedReplacement, collectionName);
+		}
+
+		return saved;
 	}
 
 	// Find methods that take a Query to express the query and that return a single object that is also removed from the
@@ -1165,23 +1121,12 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 		Assert.notNull(query, "Query must not be null!");
 		Assert.hasText(collectionName, "Collection name must not be null or empty!");
 
-		CountOptions options = new CountOptions();
-		query.getCollation().map(Collation::toMongoCollation).ifPresent(options::collation);
+		CountContext countContext = queryOperations.countQueryContext(query);
 
-		if (query.getLimit() > 0) {
-			options.limit(query.getLimit());
-		}
-		if (query.getSkip() > 0) {
-			options.skip((int) query.getSkip());
-		}
-		if (StringUtils.hasText(query.getHint())) {
-			options.hint(Document.parse(query.getHint()));
-		}
+		CountOptions options = countContext.getCountOptions(entityClass);
+		Document mappedQuery = countContext.getMappedQuery(entityClass, mappingContext::getPersistentEntity);
 
-		Document document = queryMapper.getMappedObject(query.getQueryObject(),
-				Optional.ofNullable(entityClass).map(it -> mappingContext.getPersistentEntity(entityClass)));
-
-		return doCount(collectionName, document, options);
+		return doCount(collectionName, mappedQuery, options);
 	}
 
 	@SuppressWarnings("ConstantConditions")
@@ -1224,7 +1169,7 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 	}
 
 	protected void ensureNotIterable(@Nullable Object o) {
-		if (null != o) {
+		if (o != null) {
 			if (o.getClass().isArray() || ITERABLE_CLASSES.contains(o.getClass().getName())) {
 				throw new IllegalArgumentException("Cannot use a collection here.");
 			}
@@ -1233,7 +1178,7 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 
 	/**
 	 * Prepare the collection before any processing is done using it. This allows a convenient way to apply settings like
-	 * slaveOk() etc. Can be overridden in sub-classes.
+	 * withCodecRegistry() etc. Can be overridden in sub-classes.
 	 *
 	 * @param collection
 	 */
@@ -1292,8 +1237,7 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 
 		T saved = populateIdIfNecessary(initialized, id);
 		maybeEmitEvent(new AfterSaveEvent<>(saved, dbDoc, collectionName));
-
-		return saved;
+		return maybeCallAfterSave(saved, dbDoc, collectionName);
 	}
 
 	@Override
@@ -1386,8 +1330,9 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 
 			if (i < ids.size()) {
 				T saved = populateIdIfNecessary(obj, ids.get(i));
-				maybeEmitEvent(new AfterSaveEvent<>(saved, documentList.get(i), collectionName));
-				savedObjects.add(saved);
+				Document doc = documentList.get(i);
+				maybeEmitEvent(new AfterSaveEvent<>(saved, doc, collectionName));
+				savedObjects.add(maybeCallAfterSave(saved, doc, collectionName));
 			} else {
 				savedObjects.add(obj);
 			}
@@ -1457,7 +1402,7 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 		}
 		maybeEmitEvent(new AfterSaveEvent<>(toSave, mapped.getDocument(), collectionName));
 
-		return toSave;
+		return maybeCallAfterSave(toSave, mapped.getDocument(), collectionName);
 	}
 
 	protected <T> T doSave(String collectionName, T objectToSave, MongoWriter<T> writer) {
@@ -1478,7 +1423,7 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 		T saved = populateIdIfNecessary(objectToSave, id);
 		maybeEmitEvent(new AfterSaveEvent<>(saved, dbDoc, collectionName));
 
-		return saved;
+		return maybeCallAfterSave(saved, dbDoc, collectionName);
 	}
 
 	@SuppressWarnings("ConstantConditions")
@@ -1538,23 +1483,38 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 		}
 
 		return execute(collectionName, collection -> {
+
 			MongoAction mongoAction = new MongoAction(writeConcern, MongoActionOperation.SAVE, collectionName, entityClass,
 					dbDoc, null);
 			WriteConcern writeConcernToUse = prepareWriteConcern(mongoAction);
 
 			MappedDocument mapped = MappedDocument.of(dbDoc);
 
+			MongoCollection<Document> collectionToUse = writeConcernToUse == null //
+					? collection //
+					: collection.withWriteConcern(writeConcernToUse);
+
 			if (!mapped.hasId()) {
-				if (writeConcernToUse == null) {
-					collection.insertOne(dbDoc);
-				} else {
-					collection.withWriteConcern(writeConcernToUse).insertOne(dbDoc);
-				}
-			} else if (writeConcernToUse == null) {
-				collection.replaceOne(mapped.getIdFilter(), dbDoc, new ReplaceOptions().upsert(true));
+				collectionToUse.insertOne(dbDoc);
 			} else {
-				collection.withWriteConcern(writeConcernToUse).replaceOne(mapped.getIdFilter(), dbDoc,
-						new ReplaceOptions().upsert(true));
+
+				MongoPersistentEntity<?> entity = mappingContext.getPersistentEntity(entityClass);
+				UpdateContext updateContext = queryOperations.replaceSingleContext(mapped, true);
+				Document replacement = updateContext.getMappedUpdate(entity);
+
+				Document filter = updateContext.getMappedQuery(entity);
+
+				if (updateContext.requiresShardKey(filter, entity)) {
+
+					if (entity.getShardKey().isImmutable()) {
+						filter = updateContext.applyShardKey(entity, filter, null);
+					} else {
+						filter = updateContext.applyShardKey(entity, filter,
+								collection.find(filter, Document.class).projection(updateContext.getMappedShardKey(entity)).first());
+					}
+				}
+
+				collectionToUse.replaceOne(filter, replacement, new ReplaceOptions().upsert(true));
 			}
 			return mapped.getId();
 		});
@@ -1629,33 +1589,20 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 		}
 
 		MongoPersistentEntity<?> entity = entityClass == null ? null : getPersistentEntity(entityClass);
-		increaseVersionForUpdateIfNecessary(entity, update);
 
-		UpdateOptions opts = new UpdateOptions();
-		opts.upsert(upsert);
+		UpdateContext updateContext = multi ? queryOperations.updateContext(update, query, upsert)
+				: queryOperations.updateSingleContext(update, query, upsert);
+		updateContext.increaseVersionForUpdateIfNecessary(entity);
 
-		if (update.hasArrayFilters()) {
-			opts.arrayFilters(update.getArrayFilters().stream().map(ArrayFilter::asDocument).collect(Collectors.toList()));
-		}
+		Document queryObj = updateContext.getMappedQuery(entity);
+		UpdateOptions opts = updateContext.getUpdateOptions(entityClass);
 
-		Document queryObj = new Document();
+		if (updateContext.isAggregationUpdate()) {
 
-		if (query != null) {
-			queryObj.putAll(queryMapper.getMappedObject(query.getQueryObject(), entity));
-		}
-
-		if (multi && update.isIsolated() && !queryObj.containsKey("$isolated")) {
-			queryObj.put("$isolated", 1);
-		}
-
-		if (update instanceof AggregationUpdate) {
-
-			AggregationOperationContext context = entityClass != null
-					? new RelaxedTypeBasedAggregationOperationContext(entityClass, mappingContext, queryMapper)
-					: Aggregation.DEFAULT_CONTEXT;
-
-			List<Document> pipeline = new AggregationUtil(queryMapper, mappingContext)
-					.createPipeline((AggregationUpdate) update, context);
+			List<Document> pipeline = updateContext.getUpdatePipeline(entityClass);
+			MongoAction mongoAction = new MongoAction(writeConcern, MongoActionOperation.UPDATE, collectionName, entityClass,
+					update.getUpdateObject(), queryObj);
+			WriteConcern writeConcernToUse = prepareWriteConcern(mongoAction);
 
 			return execute(collectionName, collection -> {
 
@@ -1664,44 +1611,42 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 							serializeToJsonSafely(queryObj), serializeToJsonSafely(pipeline), collectionName);
 				}
 
-				MongoAction mongoAction = new MongoAction(writeConcern, MongoActionOperation.UPDATE, collectionName,
-						entityClass, update.getUpdateObject(), queryObj);
-				WriteConcern writeConcernToUse = prepareWriteConcern(mongoAction);
-
 				collection = writeConcernToUse != null ? collection.withWriteConcern(writeConcernToUse) : collection;
 
 				return multi ? collection.updateMany(queryObj, pipeline, opts) : collection.updateOne(queryObj, pipeline, opts);
 			});
 		}
 
+		Document updateObj = updateContext.getMappedUpdate(entity);
+		MongoAction mongoAction = new MongoAction(writeConcern, MongoActionOperation.UPDATE, collectionName, entityClass,
+				updateObj, queryObj);
+		WriteConcern writeConcernToUse = prepareWriteConcern(mongoAction);
+
 		return execute(collectionName, collection -> {
 
-			operations.forType(entityClass) //
-					.getCollation(query) //
-					.map(Collation::toMongoCollation) //
-					.ifPresent(opts::collation);
-
-			Document updateObj = update instanceof MappedUpdate ? update.getUpdateObject()
-					: updateMapper.getMappedObject(update.getUpdateObject(), entity);
-
 			if (LOGGER.isDebugEnabled()) {
 				LOGGER.debug("Calling update using query: {} and update: {} in collection: {}", serializeToJsonSafely(queryObj),
 						serializeToJsonSafely(updateObj), collectionName);
 			}
 
-			MongoAction mongoAction = new MongoAction(writeConcern, MongoActionOperation.UPDATE, collectionName, entityClass,
-					updateObj, queryObj);
-			WriteConcern writeConcernToUse = prepareWriteConcern(mongoAction);
-
 			collection = writeConcernToUse != null ? collection.withWriteConcern(writeConcernToUse) : collection;
 
 			if (!UpdateMapper.isUpdateObject(updateObj)) {
 
-				ReplaceOptions replaceOptions = new ReplaceOptions();
-				replaceOptions.collation(opts.getCollation());
-				replaceOptions.upsert(opts.isUpsert());
+				Document filter = new Document(queryObj);
 
-				return collection.replaceOne(queryObj, updateObj, replaceOptions);
+				if (updateContext.requiresShardKey(filter, entity)) {
+
+					if (entity.getShardKey().isImmutable()) {
+						filter = updateContext.applyShardKey(entity, filter, null);
+					} else {
+						filter = updateContext.applyShardKey(entity, filter,
+								collection.find(filter, Document.class).projection(updateContext.getMappedShardKey(entity)).first());
+					}
+				}
+
+				ReplaceOptions replaceOptions = updateContext.getReplaceOptions(entityClass);
+				return collection.replaceOne(filter, updateObj, replaceOptions);
 			} else {
 				return multi ? collection.updateMany(queryObj, updateObj, opts)
 						: collection.updateOne(queryObj, updateObj, opts);
@@ -1709,17 +1654,6 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 		});
 	}
 
-	private void increaseVersionForUpdateIfNecessary(@Nullable MongoPersistentEntity<?> persistentEntity,
-			UpdateDefinition update) {
-
-		if (persistentEntity != null && persistentEntity.hasVersionProperty()) {
-			String versionFieldName = persistentEntity.getRequiredVersionProperty().getFieldName();
-			if (!update.modifies(versionFieldName)) {
-				update.inc(versionFieldName);
-			}
-		}
-	}
-
 	@Override
 	public DeleteResult remove(Object object) {
 
@@ -1764,7 +1698,16 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 		Assert.hasText(collectionName, "Collection name must not be null or empty!");
 
 		MongoPersistentEntity<?> entity = getPersistentEntity(entityClass);
-		Document queryObject = queryMapper.getMappedObject(query.getQueryObject(), entity);
+
+		DeleteContext deleteContext = multi ? queryOperations.deleteQueryContext(query)
+				: queryOperations.deleteSingleContext(query);
+		Document queryObject = deleteContext.getMappedQuery(entity);
+		DeleteOptions options = deleteContext.getDeleteOptions(entityClass);
+
+		MongoAction mongoAction = new MongoAction(writeConcern, MongoActionOperation.REMOVE, collectionName, entityClass,
+				null, queryObject);
+
+		WriteConcern writeConcernToUse = prepareWriteConcern(mongoAction);
 
 		return execute(collectionName, collection -> {
 
@@ -1772,18 +1715,6 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 
 			Document removeQuery = queryObject;
 
-			DeleteOptions options = new DeleteOptions();
-
-			operations.forType(entityClass) //
-					.getCollation(query) //
-					.map(Collation::toMongoCollation) //
-					.ifPresent(options::collation);
-
-			MongoAction mongoAction = new MongoAction(writeConcern, MongoActionOperation.REMOVE, collectionName, entityClass,
-					null, queryObject);
-
-			WriteConcern writeConcernToUse = prepareWriteConcern(mongoAction);
-
 			if (LOGGER.isDebugEnabled()) {
 				LOGGER.debug("Remove using query: {} in collection: {}.",
 						new Object[] { serializeToJsonSafely(removeQuery), collectionName });
@@ -1892,7 +1823,11 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 		if (query.getMeta().getMaxTimeMsec() != null) {
 			mapReduce = mapReduce.maxTime(query.getMeta().getMaxTimeMsec(), TimeUnit.MILLISECONDS);
 		}
-		mapReduce = mapReduce.sort(getMappedSortObject(query, domainType));
+
+		Document mappedSort = getMappedSortObject(query, domainType);
+		if (mappedSort != null && !mappedSort.isEmpty()) {
+			mapReduce = mapReduce.sort(getMappedSortObject(query, domainType));
+		}
 
 		mapReduce = mapReduce
 				.filter(queryMapper.getMappedObject(query.getQueryObject(), mappingContext.getPersistentEntity(domainType)));
@@ -2190,7 +2125,7 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 
 			List<Document> rawResult = new ArrayList<>();
 
-			Class<?> domainType = aggregation instanceof TypedAggregation ? ((TypedAggregation) aggregation).getInputType()
+			Class<?> domainType = aggregation instanceof TypedAggregation ? ((TypedAggregation<?>) aggregation).getInputType()
 					: null;
 
 			Optional<Collation> collation = Optionals.firstNonEmpty(options::getCollation,
@@ -2211,6 +2146,17 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 				aggregateIterable = aggregateIterable.maxTime(options.getMaxTime().toMillis(), TimeUnit.MILLISECONDS);
 			}
 
+			if (options.isSkipResults()) {
+
+				// toCollection only allowed for $out and $merge if those are the last stages
+				if (aggregation.getPipeline().isOutOrMerge()) {
+					aggregateIterable.toCollection();
+				} else {
+					aggregateIterable.first();
+				}
+				return new AggregationResults<>(Collections.emptyList(), new Document());
+			}
+
 			MongoIterable<O> iterable = aggregateIterable.map(val -> {
 
 				rawResult.add(val);
@@ -2378,33 +2324,49 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 
 	protected <E extends MongoMappingEvent<T>, T> E maybeEmitEvent(E event) {
 
-		if (null != eventPublisher) {
+		if (eventPublisher != null) {
 			eventPublisher.publishEvent(event);
 		}
 
 		return event;
 	}
 
-	@SuppressWarnings("unchecked")
 	protected <T> T maybeCallBeforeConvert(T object, String collection) {
 
-		if (null != entityCallbacks) {
+		if (entityCallbacks != null) {
 			return entityCallbacks.callback(BeforeConvertCallback.class, object, collection);
 		}
 
 		return object;
 	}
 
-	@SuppressWarnings("unchecked")
 	protected <T> T maybeCallBeforeSave(T object, Document document, String collection) {
 
-		if (null != entityCallbacks) {
+		if (entityCallbacks != null) {
 			return entityCallbacks.callback(BeforeSaveCallback.class, object, document, collection);
 		}
 
 		return object;
 	}
 
+	protected <T> T maybeCallAfterSave(T object, Document document, String collection) {
+
+		if (entityCallbacks != null) {
+			return entityCallbacks.callback(AfterSaveCallback.class, object, document, collection);
+		}
+
+		return object;
+	}
+
+	protected <T> T maybeCallAfterConvert(T object, Document document, String collection) {
+
+		if (entityCallbacks != null) {
+			return entityCallbacks.callback(AfterConvertCallback.class, object, document, collection);
+		}
+
+		return object;
+	}
+
 	/**
 	 * Create the specified collection using the provided options
 	 *
@@ -2491,8 +2453,10 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 			Class<T> entityClass) {
 
 		MongoPersistentEntity<?> entity = mappingContext.getPersistentEntity(entityClass);
-		Document mappedQuery = queryMapper.getMappedObject(query, entity);
-		Document mappedFields = queryMapper.getMappedObject(fields, entity);
+
+		QueryContext queryContext = queryOperations.createQueryContext(new BasicQuery(query, fields));
+		Document mappedFields = queryContext.getMappedFields(entity, entityClass, projectionFactory);
+		Document mappedQuery = queryContext.getMappedQuery(entity);
 
 		if (LOGGER.isDebugEnabled()) {
 			LOGGER.debug("findOne using query: {} fields: {} for class: {} in collection: {}", serializeToJsonSafely(query),
@@ -2527,8 +2491,8 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 	 * @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).
+	 * @param preparer allows for customization of the {@link FindIterable} 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, Document query, Document fields, Class<T> entityClass,
@@ -2542,8 +2506,9 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 
 		MongoPersistentEntity<?> entity = mappingContext.getPersistentEntity(entityClass);
 
-		Document mappedFields = queryMapper.getMappedFields(fields, entity);
-		Document mappedQuery = queryMapper.getMappedObject(query, entity);
+		QueryContext queryContext = queryOperations.createQueryContext(new BasicQuery(query, fields));
+		Document mappedFields = queryContext.getMappedFields(entity, entityClass, projectionFactory);
+		Document mappedQuery = queryContext.getMappedQuery(entity);
 
 		if (LOGGER.isDebugEnabled()) {
 			LOGGER.debug("find using query: {} fields: {} for class: {} in collection: {}",
@@ -2565,8 +2530,9 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 
 		MongoPersistentEntity<?> entity = mappingContext.getPersistentEntity(sourceClass);
 
-		Document mappedFields = getMappedFieldsObject(fields, entity, targetClass);
-		Document mappedQuery = queryMapper.getMappedObject(query, entity);
+		QueryContext queryContext = queryOperations.createQueryContext(new BasicQuery(query, fields));
+		Document mappedFields = queryContext.getMappedFields(entity, targetClass, projectionFactory);
+		Document mappedQuery = queryContext.getMappedQuery(entity);
 
 		if (LOGGER.isDebugEnabled()) {
 			LOGGER.debug("find using query: {} fields: {} for class: {} in collection: {}",
@@ -2682,21 +2648,12 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 
 		MongoPersistentEntity<?> entity = mappingContext.getPersistentEntity(entityClass);
 
-		increaseVersionForUpdateIfNecessary(entity, update);
+		UpdateContext updateContext = queryOperations.updateSingleContext(update, query, false);
+		updateContext.increaseVersionForUpdateIfNecessary(entity);
 
-		Document mappedQuery = queryMapper.getMappedObject(query, entity);
-
-		Object mappedUpdate;
-		if (update instanceof AggregationUpdate) {
-
-			AggregationOperationContext context = entityClass != null
-					? new RelaxedTypeBasedAggregationOperationContext(entityClass, mappingContext, queryMapper)
-					: Aggregation.DEFAULT_CONTEXT;
-
-			mappedUpdate = new AggregationUtil(queryMapper, mappingContext).createPipeline((Aggregation) update, context);
-		} else {
-			mappedUpdate = updateMapper.getMappedObject(update.getUpdateObject(), entity);
-		}
+		Document mappedQuery = updateContext.getMappedQuery(entity);
+		Object mappedUpdate = updateContext.isAggregationUpdate() ? updateContext.getUpdatePipeline(entityClass)
+				: updateContext.getMappedUpdate(entity);
 
 		if (LOGGER.isDebugEnabled()) {
 			LOGGER.debug(
@@ -2797,16 +2754,16 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 	 * Internal method using callback to do queries against the datastore that requires reading a collection of objects.
 	 * It will take the following steps
 	 * <ol>
-	 * <li>Execute the given {@link ConnectionCallback} for a {@link DBCursor}.</li>
-	 * <li>Prepare that {@link DBCursor} with the given {@link CursorPreparer} (will be skipped if {@link CursorPreparer}
-	 * is {@literal null}</li>
-	 * <li>Iterate over the {@link DBCursor} and applies the given {@link DocumentCallback} to each of the
+	 * <li>Execute the given {@link ConnectionCallback} for a {@link FindIterable}.</li>
+	 * <li>Prepare that {@link FindIterable} with the given {@link CursorPreparer} (will be skipped if
+	 * {@link CursorPreparer} is {@literal null}</li>
+	 * <li>Iterate over the {@link FindIterable} and applies the given {@link DocumentCallback} to each of the
 	 * {@link Document}s collecting the actual result {@link List}.</li>
 	 * <ol>
 	 *
 	 * @param <T>
-	 * @param collectionCallback the callback to retrieve the {@link DBCursor} with
-	 * @param preparer the {@link CursorPreparer} to potentially modify the {@link DBCursor} before iterating over it
+	 * @param collectionCallback the callback to retrieve the {@link FindIterable} with
+	 * @param preparer the {@link CursorPreparer} to potentially modify the {@link FindIterable} before iterating over it
 	 * @param objectCallback the {@link DocumentCallback} to transform {@link Document}s into the actual domain type
 	 * @param collectionName the collection to be queried
 	 * @return
@@ -2878,7 +2835,7 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 		return type != null ? mappingContext.getPersistentEntity(type) : null;
 	}
 
-	private static MongoConverter getDefaultMongoConverter(MongoDbFactory factory) {
+	private static MongoConverter getDefaultMongoConverter(MongoDatabaseFactory factory) {
 
 		DbRefResolver dbRefResolver = new DefaultDbRefResolver(factory);
 		MongoCustomConversions conversions = new MongoCustomConversions(Collections.emptyList());
@@ -2904,23 +2861,6 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 		return queryMapper.getMappedSort(query.getSortObject(), mappingContext.getPersistentEntity(type));
 	}
 
-	private Document getMappedFieldsObject(Document fields, @Nullable MongoPersistentEntity<?> entity,
-			Class<?> targetType) {
-
-		if (entity == null) {
-			return fields;
-		}
-
-		Document projectedFields = propertyOperations.computeFieldsForProjection(projectionFactory, fields,
-				entity.getType(), targetType);
-
-		if (ObjectUtils.nullSafeEquals(fields, projectedFields)) {
-			return queryMapper.getMappedFields(projectedFields, entity);
-		}
-
-		return queryMapper.getMappedFields(projectedFields, mappingContext.getRequiredPersistentEntity(targetType));
-	}
-
 	/**
 	 * Tries to convert the given {@link RuntimeException} into a {@link DataAccessException} but returns the original
 	 * exception if the conversation failed. Thus allows safe re-throwing of the return value.
@@ -2939,7 +2879,7 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 
 	/**
 	 * Simple {@link CollectionCallback} that takes a query {@link Document} plus an optional fields specification
-	 * {@link Document} and executes that against the {@link DBCollection}.
+	 * {@link Document} and executes that against the {@link MongoCollection}.
 	 *
 	 * @author Oliver Gierke
 	 * @author Thomas Risberg
@@ -2980,7 +2920,7 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 
 	/**
 	 * Simple {@link CollectionCallback} that takes a query {@link Document} plus an optional fields specification
-	 * {@link Document} and executes that against the {@link DBCollection}.
+	 * {@link Document} and executes that against the {@link MongoCollection}.
 	 *
 	 * @author Oliver Gierke
 	 * @author Thomas Risberg
@@ -3037,7 +2977,7 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 
 	/**
 	 * Simple {@link CollectionCallback} that takes a query {@link Document} plus an optional fields specification
-	 * {@link Document} and executes that against the {@link DBCollection}.
+	 * {@link Document} and executes that against the {@link MongoCollection}.
 	 *
 	 * @author Thomas Risberg
 	 */
@@ -3182,6 +3122,7 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 	 *
 	 * @author Oliver Gierke
 	 * @author Christoph Strobl
+	 * @author Roman Puchkovskiy
 	 */
 	@RequiredArgsConstructor
 	private class ReadDocumentCallback<T> implements DocumentCallback<T> {
@@ -3191,16 +3132,18 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 		private final String collectionName;
 
 		@Nullable
-		public T doWith(@Nullable Document object) {
+		public T doWith(@Nullable Document document) {
 
-			if (null != object) {
-				maybeEmitEvent(new AfterLoadEvent<>(object, type, collectionName));
+			T source = null;
+
+			if (document != null) {
+				maybeEmitEvent(new AfterLoadEvent<>(document, type, collectionName));
+				source = reader.read(type, document);
 			}
 
-			T source = reader.read(type, object);
-
-			if (null != source) {
-				maybeEmitEvent(new AfterConvertEvent<>(object, source, collectionName));
+			if (source != null) {
+				maybeEmitEvent(new AfterConvertEvent<>(document, source, collectionName));
+				source = maybeCallAfterConvert(source, document, collectionName);
 			}
 
 			return source;
@@ -3229,24 +3172,23 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 		 */
 		@SuppressWarnings("unchecked")
 		@Nullable
-		public T doWith(@Nullable Document object) {
+		public T doWith(@Nullable Document document) {
 
-			if (object == null) {
+			if (document == null) {
 				return null;
 			}
 
 			Class<?> typeToRead = targetType.isInterface() || targetType.isAssignableFrom(entityType) ? entityType
 					: targetType;
 
-			if (null != object) {
-				maybeEmitEvent(new AfterLoadEvent<>(object, targetType, collectionName));
-			}
+			maybeEmitEvent(new AfterLoadEvent<>(document, targetType, collectionName));
 
-			Object source = reader.read(typeToRead, object);
+			Object source = reader.read(typeToRead, document);
 			Object result = targetType.isInterface() ? projectionFactory.createProjection(targetType, source) : source;
 
-			if (null != result) {
-				maybeEmitEvent(new AfterConvertEvent<>(object, result, collectionName));
+			if (result != null) {
+				maybeEmitEvent(new AfterConvertEvent<>(document, result, collectionName));
+				result = maybeCallAfterConvert(result, document, collectionName);
 			}
 
 			return (T) result;
@@ -3268,9 +3210,9 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 		 * (non-Javadoc)
 		 * @see org.springframework.data.mongodb.core.CursorPreparer#prepare(com.mongodb.DBCursor)
 		 */
-		public FindIterable<Document> prepare(FindIterable<Document> cursor) {
+		public FindIterable<Document> prepare(FindIterable<Document> iterable) {
 
-			FindIterable<Document> cursorToUse = cursor;
+			FindIterable<Document> cursorToUse = iterable;
 
 			operations.forType(type).getCollation(query) //
 					.map(Collation::toMongoCollation) //
@@ -3295,7 +3237,14 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 				}
 
 				if (StringUtils.hasText(query.getHint())) {
-					cursorToUse = cursorToUse.hint(Document.parse(query.getHint()));
+
+					String hint = query.getHint();
+
+					if (BsonUtils.isJsonDocument(hint)) {
+						cursorToUse = cursorToUse.hint(BsonUtils.parse(hint, mongoDbFactory));
+					} else {
+						cursorToUse = cursorToUse.hintString(hint);
+					}
 				}
 
 				if (meta.hasValues()) {
@@ -3304,14 +3253,6 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 						cursorToUse = cursorToUse.comment(meta.getComment());
 					}
 
-					if (meta.getSnapshot()) {
-						cursorToUse = cursorToUse.snapshot(meta.getSnapshot());
-					}
-
-					if (meta.getMaxScan() != null) {
-						cursorToUse = cursorToUse.maxScan(meta.getMaxScan());
-					}
-
 					if (meta.getMaxTimeMsec() != null) {
 						cursorToUse = cursorToUse.maxTime(meta.getMaxTimeMsec(), TimeUnit.MILLISECONDS);
 					}
@@ -3330,6 +3271,7 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 							case PARTIAL:
 								cursorToUse = cursorToUse.partial(true);
 								break;
+							case SECONDARY_READS:
 							case SLAVE_OK:
 								break;
 							default:
@@ -3347,7 +3289,8 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 
 		@Override
 		public ReadPreference getReadPreference() {
-			return query.getMeta().getFlags().contains(CursorOption.SLAVE_OK) ? ReadPreference.primaryPreferred() : null;
+			return (query.getMeta().getFlags().contains(CursorOption.SECONDARY_READS)
+					|| query.getMeta().getFlags().contains(CursorOption.SLAVE_OK)) ? ReadPreference.primaryPreferred() : null;
 		}
 	}
 
@@ -3396,7 +3339,7 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 	}
 
 	/**
-	 * A {@link CloseableIterator} that is backed by a MongoDB {@link Cursor}.
+	 * A {@link CloseableIterator} that is backed by a MongoDB {@link MongoCollection}.
 	 *
 	 * @author Thomas Darimont
 	 * @since 1.7
@@ -3409,7 +3352,7 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 		private DocumentCallback<T> objectReadCallback;
 
 		/**
-		 * Creates a new {@link CloseableIterableCursorAdapter} backed by the given {@link Cursor}.
+		 * Creates a new {@link CloseableIterableCursorAdapter} backed by the given {@link MongoCollection}.
 		 *
 		 * @param cursor
 		 * @param exceptionTranslator
@@ -3476,7 +3419,7 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 		}
 	}
 
-	public MongoDbFactory getMongoDbFactory() {
+	public MongoDatabaseFactory getMongoDbFactory() {
 		return mongoDbFactory;
 	}
 

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

@@ -0,0 +1,763 @@
+/*
+ * Copyright 2020 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
+ *
+ *      https://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 java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.function.Consumer;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+
+import org.bson.BsonValue;
+import org.bson.Document;
+import org.bson.codecs.Codec;
+import org.springframework.data.mapping.PropertyPath;
+import org.springframework.data.mapping.PropertyReferenceException;
+import org.springframework.data.mapping.context.MappingContext;
+import org.springframework.data.mongodb.CodecRegistryProvider;
+import org.springframework.data.mongodb.core.MappedDocument.MappedUpdate;
+import org.springframework.data.mongodb.core.aggregation.Aggregation;
+import org.springframework.data.mongodb.core.aggregation.AggregationOperationContext;
+import org.springframework.data.mongodb.core.aggregation.AggregationUpdate;
+import org.springframework.data.mongodb.core.aggregation.RelaxedTypeBasedAggregationOperationContext;
+import org.springframework.data.mongodb.core.convert.QueryMapper;
+import org.springframework.data.mongodb.core.convert.UpdateMapper;
+import org.springframework.data.mongodb.core.mapping.MongoPersistentEntity;
+import org.springframework.data.mongodb.core.mapping.MongoPersistentProperty;
+import org.springframework.data.mongodb.core.mapping.ShardKey;
+import org.springframework.data.mongodb.core.query.BasicQuery;
+import org.springframework.data.mongodb.core.query.Collation;
+import org.springframework.data.mongodb.core.query.Query;
+import org.springframework.data.mongodb.core.query.UpdateDefinition;
+import org.springframework.data.mongodb.core.query.UpdateDefinition.ArrayFilter;
+import org.springframework.data.mongodb.util.BsonUtils;
+import org.springframework.data.projection.ProjectionFactory;
+import org.springframework.lang.Nullable;
+import org.springframework.util.ClassUtils;
+import org.springframework.util.ObjectUtils;
+import org.springframework.util.StringUtils;
+
+import com.mongodb.client.model.CountOptions;
+import com.mongodb.client.model.DeleteOptions;
+import com.mongodb.client.model.ReplaceOptions;
+import com.mongodb.client.model.UpdateOptions;
+
+/**
+ * {@link QueryOperations} centralizes common operations required before an operation is actually ready to be executed.
+ * This involves mapping {@link Query queries} into their respective MongoDB representation, computing execution options
+ * for {@literal count}, {@literal remove}, and other methods.
+ *
+ * @author Christoph Strobl
+ * @author Mark Paluch
+ * @since 3.0
+ */
+class QueryOperations {
+
+	private final QueryMapper queryMapper;
+	private final UpdateMapper updateMapper;
+	private final EntityOperations entityOperations;
+	private final PropertyOperations propertyOperations;
+	private final CodecRegistryProvider codecRegistryProvider;
+	private final MappingContext<? extends MongoPersistentEntity<?>, MongoPersistentProperty> mappingContext;
+	private final AggregationUtil aggregationUtil;
+	private final Map<Class<?>, Document> mappedShardKey = new ConcurrentHashMap<>(1);
+
+	/**
+	 * Create a new instance of {@link QueryOperations}.
+	 *
+	 * @param queryMapper must not be {@literal null}.
+	 * @param updateMapper must not be {@literal null}.
+	 * @param entityOperations must not be {@literal null}.
+	 * @param propertyOperations must not be {@literal null}.
+	 * @param codecRegistryProvider must not be {@literal null}.
+	 */
+	QueryOperations(QueryMapper queryMapper, UpdateMapper updateMapper, EntityOperations entityOperations,
+			PropertyOperations propertyOperations, CodecRegistryProvider codecRegistryProvider) {
+
+		this.queryMapper = queryMapper;
+		this.updateMapper = updateMapper;
+		this.entityOperations = entityOperations;
+		this.propertyOperations = propertyOperations;
+		this.codecRegistryProvider = codecRegistryProvider;
+		this.mappingContext = queryMapper.getMappingContext();
+		this.aggregationUtil = new AggregationUtil(queryMapper, mappingContext);
+	}
+
+	/**
+	 * Create a new {@link QueryContext} instance.
+	 *
+	 * @param query must not be {@literal null}.
+	 * @return new instance of {@link QueryContext}.
+	 */
+	QueryContext createQueryContext(Query query) {
+		return new QueryContext(query);
+	}
+
+	/**
+	 * Create a new {@link DistinctQueryContext} instance.
+	 *
+	 * @param query must not be {@literal null}.
+	 * @return new instance of {@link DistinctQueryContext}.
+	 */
+	DistinctQueryContext distinctQueryContext(Query query, String fieldName) {
+		return new DistinctQueryContext(query, fieldName);
+	}
+
+	/**
+	 * Create a new {@link CountContext} instance.
+	 *
+	 * @param query must not be {@literal null}.
+	 * @return new instance of {@link CountContext}.
+	 */
+	CountContext countQueryContext(Query query) {
+		return new CountContext(query);
+	}
+
+	/**
+	 * Create a new {@link UpdateContext} instance affecting multiple documents.
+	 *
+	 * @param updateDefinition must not be {@literal null}.
+	 * @param query must not be {@literal null}.
+	 * @param upsert use {@literal true} to insert diff when no existing document found.
+	 * @return new instance of {@link UpdateContext}.
+	 */
+	UpdateContext updateContext(UpdateDefinition updateDefinition, Query query, boolean upsert) {
+		return new UpdateContext(updateDefinition, query, true, upsert);
+	}
+
+	/**
+	 * Create a new {@link UpdateContext} instance affecting a single document.
+	 *
+	 * @param updateDefinition must not be {@literal null}.
+	 * @param query must not be {@literal null}.
+	 * @param upsert use {@literal true} to insert diff when no existing document found.
+	 * @return new instance of {@link UpdateContext}.
+	 */
+	UpdateContext updateSingleContext(UpdateDefinition updateDefinition, Query query, boolean upsert) {
+		return new UpdateContext(updateDefinition, query, false, upsert);
+	}
+
+	/**
+	 * Create a new {@link UpdateContext} instance affecting a single document.
+	 *
+	 * @param updateDefinition must not be {@literal null}.
+	 * @param query must not be {@literal null}.
+	 * @param upsert use {@literal true} to insert diff when no existing document found.
+	 * @return new instance of {@link UpdateContext}.
+	 */
+	UpdateContext updateSingleContext(UpdateDefinition updateDefinition, Document query, boolean upsert) {
+		return new UpdateContext(updateDefinition, query, false, upsert);
+	}
+
+	/**
+	 * @param replacement the {@link MappedDocument mapped replacement} document.
+	 * @param upsert use {@literal true} to insert diff when no existing document found.
+	 * @return new instance of {@link UpdateContext}.
+	 */
+	UpdateContext replaceSingleContext(MappedDocument replacement, boolean upsert) {
+		return new UpdateContext(replacement, upsert);
+	}
+
+	/**
+	 * Create a new {@link DeleteContext} instance removing all matching documents.
+	 *
+	 * @param query must not be {@literal null}.
+	 * @return new instance of {@link QueryContext}.
+	 */
+	DeleteContext deleteQueryContext(Query query) {
+		return new DeleteContext(query, true);
+	}
+
+	/**
+	 * Create a new {@link DeleteContext} instance only the first matching document.
+	 *
+	 * @param query must not be {@literal null}.
+	 * @return new instance of {@link QueryContext}.
+	 */
+	DeleteContext deleteSingleContext(Query query) {
+		return new DeleteContext(query, false);
+	}
+
+	/**
+	 * {@link QueryContext} encapsulates common tasks required to convert a {@link Query} into its MongoDB document
+	 * representation, mapping fieldnames, as well as determinging and applying {@link Collation collations}.
+	 *
+	 * @author Christoph Strobl
+	 */
+	class QueryContext {
+
+		private final Query query;
+
+		/**
+		 * Create new a {@link QueryContext} instance from the given {@literal query} (can be eihter a {@link Query} or a
+		 * plain {@link Document}.
+		 *
+		 * @param query can be {@literal null}.
+		 */
+		private QueryContext(@Nullable Query query) {
+			this.query = query != null ? query : new Query();
+		}
+
+		/**
+		 * @return never {@literal null}.
+		 */
+		Query getQuery() {
+			return query;
+		}
+
+		/**
+		 * Extract the raw {@link Query#getQueryObject() unmapped document} from the {@link Query}.
+		 *
+		 * @return
+		 */
+		Document getQueryObject() {
+			return query.getQueryObject();
+		}
+
+		/**
+		 * Get the already mapped MongoDB query representation.
+		 *
+		 * @param domainType can be {@literal null}.
+		 * @param entityLookup the {@link Function lookup} used to provide the {@link MongoPersistentEntity} for the
+		 *          given{@literal domainType}
+		 * @param <T>
+		 * @return never {@literal null}.
+		 */
+		<T> Document getMappedQuery(@Nullable Class<T> domainType,
+				Function<Class<T>, MongoPersistentEntity<?>> entityLookup) {
+			return getMappedQuery(domainType == null ? null : entityLookup.apply(domainType));
+		}
+
+		/**
+		 * Get the already mapped MongoDB query representation.
+		 *
+		 * @param entity the Entity to map field names to. Can be {@literal null}.
+		 * @param <T>
+		 * @return never {@literal null}.
+		 */
+		<T> Document getMappedQuery(@Nullable MongoPersistentEntity<T> entity) {
+			return queryMapper.getMappedObject(getQueryObject(), entity);
+		}
+
+		Document getMappedFields(@Nullable MongoPersistentEntity<?> entity, Class<?> targetType,
+				ProjectionFactory projectionFactory) {
+
+			Document fields = query.getFieldsObject();
+			Document mappedFields = fields;
+
+			if (entity == null) {
+				return mappedFields;
+			}
+
+			Document projectedFields = propertyOperations.computeFieldsForProjection(projectionFactory, fields,
+					entity.getType(), targetType);
+
+			if (ObjectUtils.nullSafeEquals(fields, projectedFields)) {
+				mappedFields = queryMapper.getMappedFields(projectedFields, entity);
+			} else {
+				mappedFields = queryMapper.getMappedFields(projectedFields,
+						mappingContext.getRequiredPersistentEntity(targetType));
+			}
+
+			if (entity != null && entity.hasTextScoreProperty() && !query.getQueryObject().containsKey("$text")) {
+				mappedFields.remove(entity.getTextScoreProperty().getFieldName());
+			}
+
+			return mappedFields;
+		}
+
+		/**
+		 * Get the already mapped {@link Query#getSortObject() sort} option.
+		 *
+		 * @param entity the Entity to map field names to. Can be {@literal null}.
+		 * @return never {@literal null}.
+		 */
+		Document getMappedSort(@Nullable MongoPersistentEntity<?> entity) {
+			return queryMapper.getMappedSort(query.getSortObject(), entity);
+		}
+
+		/**
+		 * Apply the {@link com.mongodb.client.model.Collation} if present extracted from the {@link Query} or fall back to
+		 * the {@literal domain types} default {@link org.springframework.data.mongodb.core.mapping.Document#collation()
+		 * collation}.
+		 *
+		 * @param domainType can be {@literal null}.
+		 * @param consumer must not be {@literal null}.
+		 */
+		void applyCollation(@Nullable Class<?> domainType, Consumer<com.mongodb.client.model.Collation> consumer) {
+			getCollation(domainType).ifPresent(consumer::accept);
+		}
+
+		/**
+		 * Get the {@link com.mongodb.client.model.Collation} extracted from the {@link Query} if present or fall back to
+		 * the {@literal domain types} default {@link org.springframework.data.mongodb.core.mapping.Document#collation()
+		 * collation}.
+		 *
+		 * @param domainType can be {@literal null}.
+		 * @return never {@literal null}.
+		 */
+		Optional<com.mongodb.client.model.Collation> getCollation(@Nullable Class<?> domainType) {
+
+			return entityOperations.forType(domainType).getCollation(query) //
+					.map(Collation::toMongoCollation);
+		}
+	}
+
+	/**
+	 * A {@link QueryContext} that encapsulates common tasks required when running {@literal distinct} queries.
+	 *
+	 * @author Christoph Strobl
+	 */
+	class DistinctQueryContext extends QueryContext {
+
+		private final String fieldName;
+
+		/**
+		 * Create a new {@link DistinctQueryContext} instance.
+		 *
+		 * @param query can be {@literal null}.
+		 * @param fieldName must not be {@literal null}.
+		 */
+		private DistinctQueryContext(@Nullable Object query, String fieldName) {
+
+			super(query instanceof Document ? new BasicQuery((Document) query) : (Query) query);
+			this.fieldName = fieldName;
+		}
+
+		@Override
+		Document getMappedFields(@Nullable MongoPersistentEntity<?> entity, Class<?> targetType, ProjectionFactory projectionFactory) {
+			return getMappedFields(entity);
+		}
+
+		Document getMappedFields(@Nullable MongoPersistentEntity<?> entity) {
+			return queryMapper.getMappedFields(new Document(fieldName, 1), entity);
+		}
+
+		/**
+		 * Get the mapped field name to project to.
+		 *
+		 * @param entity can be {@literal null}.
+		 * @return never {@literal null}.
+		 */
+		String getMappedFieldName(@Nullable MongoPersistentEntity<?> entity) {
+			return getMappedFields(entity).keySet().iterator().next();
+		}
+
+		/**
+		 * Get the MongoDB native representation of the given {@literal type}.
+		 *
+		 * @param type must not be {@literal null}.
+		 * @param <T>
+		 * @return never {@literal null}.
+		 */
+		@SuppressWarnings("unchecked")
+		<T> Class<T> getDriverCompatibleClass(Class<T> type) {
+
+			return codecRegistryProvider.getCodecFor(type) //
+					.map(Codec::getEncoderClass) //
+					.orElse((Class<T>) BsonValue.class);
+		}
+
+		/**
+		 * Get the most speficic read target type based on the user {@literal requestedTargetType} an the property type
+		 * based on meta information extracted from the {@literal domainType}.
+		 *
+		 * @param requestedTargetType must not be {@literal null}.
+		 * @param domainType must not be {@literal null}.
+		 * @return never {@literal null}.
+		 */
+		Class<?> getMostSpecificConversionTargetType(Class<?> requestedTargetType, Class<?> domainType) {
+
+			Class<?> conversionTargetType = requestedTargetType;
+			try {
+
+				Class<?> propertyType = PropertyPath.from(fieldName, domainType).getLeafProperty().getLeafType();
+
+				// use the more specific type but favor UserType over property one
+				if (ClassUtils.isAssignable(requestedTargetType, propertyType)) {
+					conversionTargetType = propertyType;
+				}
+			} catch (PropertyReferenceException e) {
+				// just don't care about it as we default to Object.class anyway.
+			}
+
+			return conversionTargetType;
+		}
+	}
+
+	/**
+	 * A {@link QueryContext} that encapsulates common tasks required when running {@literal count} queries.
+	 *
+	 * @author Christoph Strobl
+	 */
+	class CountContext extends QueryContext {
+
+		/**
+		 * Creates a new {@link CountContext} instance.
+		 *
+		 * @param query can be {@literal null}.
+		 */
+		CountContext(@Nullable Query query) {
+			super(query);
+		}
+
+		/**
+		 * Get the {@link CountOptions} applicable for the {@link Query}.
+		 *
+		 * @param domainType must not be {@literal null}.
+		 * @return never {@literal null}.
+		 */
+		CountOptions getCountOptions(@Nullable Class<?> domainType) {
+			return getCountOptions(domainType, null);
+		}
+
+		/**
+		 * Get the {@link CountOptions} applicable for the {@link Query}.
+		 *
+		 * @param domainType can be {@literal null}.
+		 * @param callback a callback to modify the generated options. Can be {@literal null}.
+		 * @return
+		 */
+		CountOptions getCountOptions(@Nullable Class<?> domainType, @Nullable Consumer<CountOptions> callback) {
+
+			CountOptions options = new CountOptions();
+			Query query = getQuery();
+
+			applyCollation(domainType, options::collation);
+
+			if (query.getLimit() > 0) {
+				options.limit(query.getLimit());
+			}
+			if (query.getSkip() > 0) {
+				options.skip((int) query.getSkip());
+			}
+			if (StringUtils.hasText(query.getHint())) {
+
+				String hint = query.getHint();
+				if (BsonUtils.isJsonDocument(hint)) {
+					options.hint(BsonUtils.parse(hint, codecRegistryProvider));
+				} else {
+					options.hintString(hint);
+				}
+			}
+
+			if (callback != null) {
+				callback.accept(options);
+			}
+
+			return options;
+		}
+	}
+
+	/**
+	 * A {@link QueryContext} that encapsulates common tasks required when running {@literal delete} queries.
+	 *
+	 * @author Christoph Strobl
+	 */
+	class DeleteContext extends QueryContext {
+
+		private final boolean multi;
+
+		/**
+		 * Crate a new {@link DeleteContext} instance.
+		 *
+		 * @param query can be {@literal null}.
+		 * @param multi use {@literal true} to remove all matching documents, {@literal false} for just the first one.
+		 */
+		DeleteContext(@Nullable Query query, boolean multi) {
+
+			super(query);
+			this.multi = multi;
+		}
+
+		/**
+		 * Get the {@link DeleteOptions} applicable for the {@link Query}.
+		 *
+		 * @param domainType must not be {@literal null}.
+		 * @return never {@literal null}.
+		 */
+		DeleteOptions getDeleteOptions(@Nullable Class<?> domainType) {
+			return getDeleteOptions(domainType, null);
+		}
+
+		/**
+		 * Get the {@link DeleteOptions} applicable for the {@link Query}.
+		 *
+		 * @param domainType can be {@literal null}.
+		 * @param callback a callback to modify the generated options. Can be {@literal null}.
+		 * @return
+		 */
+		DeleteOptions getDeleteOptions(@Nullable Class<?> domainType, @Nullable Consumer<DeleteOptions> callback) {
+
+			DeleteOptions options = new DeleteOptions();
+			applyCollation(domainType, options::collation);
+
+			if (callback != null) {
+				callback.accept(options);
+			}
+
+			return options;
+		}
+
+		/**
+		 * @return {@literal true} if all matching documents shall be deleted.
+		 */
+		boolean isMulti() {
+			return multi;
+		}
+	}
+
+	/**
+	 * A {@link QueryContext} that encapsulates common tasks required when running {@literal updates}.
+	 */
+	class UpdateContext extends QueryContext {
+
+		private final boolean multi;
+		private final boolean upsert;
+		private final @Nullable UpdateDefinition update;
+		private final @Nullable MappedDocument mappedDocument;
+
+		/**
+		 * Create a new {@link UpdateContext} instance.
+		 *
+		 * @param update must not be {@literal null}.
+		 * @param query must not be {@literal null}.
+		 * @param multi use {@literal true} to update all matching documents.
+		 * @param upsert use {@literal true} to insert a new document if none match.
+		 */
+		UpdateContext(UpdateDefinition update, Document query, boolean multi, boolean upsert) {
+			this(update, new BasicQuery(query), multi, upsert);
+		}
+
+		/**
+		 * Create a new {@link UpdateContext} instance.
+		 *
+		 * @param update must not be {@literal null}.
+		 * @param query can be {@literal null}.
+		 * @param multi use {@literal true} to update all matching documents.
+		 * @param upsert use {@literal true} to insert a new document if none match.
+		 */
+		UpdateContext(UpdateDefinition update, @Nullable Query query, boolean multi, boolean upsert) {
+
+			super(query);
+
+			this.multi = multi;
+			this.upsert = upsert;
+			this.update = update;
+			this.mappedDocument = null;
+		}
+
+		UpdateContext(MappedDocument update, boolean upsert) {
+
+			super(new BasicQuery(new Document(BsonUtils.asMap(update.getIdFilter()))));
+			this.multi = false;
+			this.upsert = upsert;
+			this.mappedDocument = update;
+			this.update = null;
+		}
+
+		/**
+		 * Get the {@link UpdateOptions} applicable for the {@link Query}.
+		 *
+		 * @param domainType must not be {@literal null}.
+		 * @return never {@literal null}.
+		 */
+		UpdateOptions getUpdateOptions(@Nullable Class<?> domainType) {
+			return getUpdateOptions(domainType, null);
+		}
+
+		/**
+		 * Get the {@link UpdateOptions} applicable for the {@link Query}.
+		 *
+		 * @param domainType can be {@literal null}.
+		 * @param callback a callback to modify the generated options. Can be {@literal null}.
+		 * @return
+		 */
+		UpdateOptions getUpdateOptions(@Nullable Class<?> domainType, @Nullable Consumer<UpdateOptions> callback) {
+
+			UpdateOptions options = new UpdateOptions();
+			options.upsert(upsert);
+
+			if (update != null && update.hasArrayFilters()) {
+				options
+						.arrayFilters(update.getArrayFilters().stream().map(ArrayFilter::asDocument).collect(Collectors.toList()));
+			}
+
+			applyCollation(domainType, options::collation);
+
+			if (callback != null) {
+				callback.accept(options);
+			}
+
+			return options;
+		}
+
+		/**
+		 * Get the {@link ReplaceOptions} applicable for the {@link Query}.
+		 *
+		 * @param domainType must not be {@literal null}.
+		 * @return never {@literal null}.
+		 */
+		ReplaceOptions getReplaceOptions(@Nullable Class<?> domainType) {
+			return getReplaceOptions(domainType, null);
+		}
+
+		/**
+		 * Get the {@link ReplaceOptions} applicable for the {@link Query}.
+		 *
+		 * @param domainType can be {@literal null}.
+		 * @param callback a callback to modify the generated options. Can be {@literal null}.
+		 * @return
+		 */
+		ReplaceOptions getReplaceOptions(@Nullable Class<?> domainType, @Nullable Consumer<ReplaceOptions> callback) {
+
+			UpdateOptions updateOptions = getUpdateOptions(domainType);
+
+			ReplaceOptions options = new ReplaceOptions();
+			options.collation(updateOptions.getCollation());
+			options.upsert(updateOptions.isUpsert());
+
+			if (callback != null) {
+				callback.accept(options);
+			}
+
+			return options;
+		}
+
+		@Override
+		<T> Document getMappedQuery(@Nullable MongoPersistentEntity<T> domainType) {
+
+			Document mappedQuery = super.getMappedQuery(domainType);
+
+			if (multi && update.isIsolated() && !mappedQuery.containsKey("$isolated")) {
+				mappedQuery.put("$isolated", 1);
+			}
+
+			return mappedQuery;
+		}
+
+		<T> Document applyShardKey(MongoPersistentEntity<T> domainType, Document filter, @Nullable Document existing) {
+
+			Document shardKeySource = existing != null ? existing
+					: mappedDocument != null ? mappedDocument.getDocument() : getMappedUpdate(domainType);
+
+			Document filterWithShardKey = new Document(filter);
+			getMappedShardKeyFields(domainType).forEach(key -> filterWithShardKey.putIfAbsent(key, shardKeySource.get(key)));
+
+			return filterWithShardKey;
+		}
+
+		boolean requiresShardKey(Document filter, @Nullable MongoPersistentEntity<?> domainType) {
+
+			return !multi && domainType != null && domainType.isSharded() && !shardedById(domainType)
+					&& !filter.keySet().containsAll(getMappedShardKeyFields(domainType));
+		}
+
+		/**
+		 * @return {@literal true} if the {@link MongoPersistentEntity#getShardKey() shard key} is the entities
+		 *         {@literal id} property.
+		 * @since 3.0
+		 */
+		private boolean shardedById(MongoPersistentEntity<?> domainType) {
+
+			ShardKey shardKey = domainType.getShardKey();
+			if (shardKey.size() != 1) {
+				return false;
+			}
+
+			String key = shardKey.getPropertyNames().iterator().next();
+			if ("_id".equals(key)) {
+				return true;
+			}
+
+			MongoPersistentProperty idProperty = domainType.getIdProperty();
+			return idProperty != null && idProperty.getName().equals(key);
+		}
+
+		Set<String> getMappedShardKeyFields(MongoPersistentEntity<?> entity) {
+			return getMappedShardKey(entity).keySet();
+		}
+
+		Document getMappedShardKey(MongoPersistentEntity<?> entity) {
+			return mappedShardKey.computeIfAbsent(entity.getType(),
+					key -> queryMapper.getMappedFields(entity.getShardKey().getDocument(), entity));
+		}
+
+		/**
+		 * Get the already mapped aggregation pipeline to use with an {@link #isAggregationUpdate()}.
+		 *
+		 * @param domainType must not be {@literal null}.
+		 * @return never {@literal null}.
+		 */
+		List<Document> getUpdatePipeline(@Nullable Class<?> domainType) {
+
+			AggregationOperationContext context = domainType != null
+					? new RelaxedTypeBasedAggregationOperationContext(domainType, mappingContext, queryMapper)
+					: Aggregation.DEFAULT_CONTEXT;
+
+			return aggregationUtil.createPipeline((AggregationUpdate) update, context);
+		}
+
+		/**
+		 * Get the already mapped update {@link Document}.
+		 *
+		 * @param entity
+		 * @return
+		 */
+		Document getMappedUpdate(@Nullable MongoPersistentEntity<?> entity) {
+
+			if (update != null) {
+				return update instanceof MappedUpdate ? update.getUpdateObject()
+						: updateMapper.getMappedObject(update.getUpdateObject(), entity);
+			}
+			return mappedDocument.getDocument();
+		}
+
+		/**
+		 * Increase a potential {@link MongoPersistentEntity#getVersionProperty() version property} prior to update if not
+		 * already done in the actual {@link UpdateDefinition}
+		 *
+		 * @param persistentEntity can be {@literal null}.
+		 */
+		void increaseVersionForUpdateIfNecessary(@Nullable MongoPersistentEntity<?> persistentEntity) {
+
+			if (persistentEntity != null && persistentEntity.hasVersionProperty()) {
+
+				String versionFieldName = persistentEntity.getRequiredVersionProperty().getFieldName();
+				if (!update.modifies(versionFieldName)) {
+					update.inc(versionFieldName);
+				}
+			}
+		}
+
+		/**
+		 * @return {@literal true} if the update holds an aggregation pipeline.
+		 */
+		boolean isAggregationUpdate() {
+			return update instanceof AggregationUpdate;
+		}
+
+		/**
+		 * @return {@literal true} if all matching documents should be updated.
+		 */
+		boolean isMulti() {
+			return multi;
+		}
+	}
+}

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

@@ -19,6 +19,7 @@ import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 
 import org.springframework.data.geo.GeoResult;
+import org.springframework.data.mongodb.core.query.CriteriaDefinition;
 import org.springframework.data.mongodb.core.query.NearQuery;
 import org.springframework.data.mongodb.core.query.Query;
 
@@ -38,13 +39,14 @@ import org.springframework.data.mongodb.core.query.Query;
  *         query(Human.class)
  *             .inCollection("star-wars")
  *             .as(Jedi.class)
- *             .matching(query(where("firstname").is("luke")))
+ *             .matching(where("firstname").is("luke"))
  *             .all();
  *     </code>
  * </pre>
  *
  * @author Mark Paluch
  * @author Christoph Strobl
+ * @author Juergen Zimmermann
  * @since 2.0
  */
 public interface ReactiveFindOperation {
@@ -144,6 +146,18 @@ public interface ReactiveFindOperation {
 		 */
 		TerminatingFind<T> matching(Query query);
 
+		/**
+		 * Set the filter {@link CriteriaDefinition criteria} to be used.
+		 *
+		 * @param criteria must not be {@literal null}.
+		 * @return new instance of {@link TerminatingFind}.
+		 * @throws IllegalArgumentException if criteria is {@literal null}.
+		 * @since 3.0
+		 */
+		default TerminatingFind<T> matching(CriteriaDefinition criteria) {
+			return matching(Query.query(criteria));
+		}
+
 		/**
 		 * Set the filter query for the geoNear execution.
 		 *
@@ -259,9 +273,21 @@ public interface ReactiveFindOperation {
 		 *
 		 * @param query must not be {@literal null}.
 		 * @return new instance of {@link TerminatingDistinct}.
-		 * @throws IllegalArgumentException if resultType is {@literal null}.
+		 * @throws IllegalArgumentException if query is {@literal null}.
 		 */
 		TerminatingDistinct<T> matching(Query query);
+
+		/**
+		 * Set the filter {@link CriteriaDefinition criteria} to be used.
+		 *
+		 * @param criteria must not be {@literal null}.
+		 * @return new instance of {@link TerminatingDistinct}.
+		 * @throws IllegalArgumentException if criteria is {@literal null}.
+		 * @since 3.0
+		 */
+		default TerminatingDistinct<T> matching(CriteriaDefinition criteria) {
+			return matching(Query.query(criteria));
+		}
 	}
 
 	/**

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

@@ -19,6 +19,7 @@ import reactor.core.publisher.Flux;
 
 import org.springframework.data.mongodb.core.ExecutableFindOperation.ExecutableFind;
 import org.springframework.data.mongodb.core.mapreduce.MapReduceOptions;
+import org.springframework.data.mongodb.core.query.CriteriaDefinition;
 import org.springframework.data.mongodb.core.query.Query;
 
 /**
@@ -30,7 +31,7 @@ import org.springframework.data.mongodb.core.query.Query;
  * The collection to operate on is by default derived from the initial {@literal domainType} and can be defined there
  * via {@link org.springframework.data.mongodb.core.mapping.Document}. Using {@code inCollection} allows to override the
  * collection name for the execution.
- * 
+ *
  * <pre>
  *     <code>
  *         mapReduce(Human.class)
@@ -146,6 +147,18 @@ public interface ReactiveMapReduceOperation {
 		 * @throws IllegalArgumentException if query is {@literal null}.
 		 */
 		TerminatingMapReduce<T> matching(Query query);
+
+		/**
+		 * Set the filter {@link CriteriaDefinition criteria} to be used.
+		 *
+		 * @param criteria must not be {@literal null}.
+		 * @return new instance of {@link TerminatingMapReduce}.
+		 * @throws IllegalArgumentException if query is {@literal null}.
+		 * @since 3.0
+		 */
+		default TerminatingMapReduce<T> matching(CriteriaDefinition criteria) {
+			return matching(Query.query(criteria));
+		}
 	}
 
 	/**

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

@@ -22,7 +22,7 @@ import org.springframework.dao.support.PersistenceExceptionTranslator;
 import org.springframework.lang.Nullable;
 import org.springframework.util.StringUtils;
 
-import com.mongodb.async.client.MongoClientSettings;
+import com.mongodb.MongoClientSettings;
 import com.mongodb.reactivestreams.client.MongoClient;
 import com.mongodb.reactivestreams.client.MongoClients;
 

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

@@ -15,192 +15,17 @@
  */
 package org.springframework.data.mongodb.core;
 
-import java.util.ArrayList;
-import java.util.List;
-
-import org.bson.codecs.configuration.CodecRegistry;
-import org.springframework.beans.factory.config.AbstractFactoryBean;
-import org.springframework.util.Assert;
-
-import com.mongodb.MongoCredential;
-import com.mongodb.ReadConcern;
-import com.mongodb.ReadPreference;
-import com.mongodb.WriteConcern;
-import com.mongodb.async.client.MongoClientSettings;
-import com.mongodb.connection.ClusterSettings;
-import com.mongodb.connection.ConnectionPoolSettings;
-import com.mongodb.connection.ServerSettings;
-import com.mongodb.connection.SocketSettings;
-import com.mongodb.connection.SslSettings;
-import com.mongodb.connection.StreamFactoryFactory;
+import com.mongodb.MongoClientSettings;
 
 /**
  * A factory bean for construction of a {@link MongoClientSettings} instance to be used with the async MongoDB driver.
  *
  * @author Mark Paluch
+ * @author Christoph Strobl
  * @since 2.0
+ * @deprecated since 3.0 - Use {@link MongoClientSettingsFactoryBean} instead.
  */
-public class ReactiveMongoClientSettingsFactoryBean extends AbstractFactoryBean<MongoClientSettings> {
+@Deprecated
+public class ReactiveMongoClientSettingsFactoryBean extends MongoClientSettingsFactoryBean {
 
-	private static final MongoClientSettings DEFAULT_MONGO_SETTINGS = MongoClientSettings.builder().build();
-
-	private ReadPreference readPreference = DEFAULT_MONGO_SETTINGS.getReadPreference();
-	private WriteConcern writeConcern = DEFAULT_MONGO_SETTINGS.getWriteConcern();
-	private ReadConcern readConcern = DEFAULT_MONGO_SETTINGS.getReadConcern();
-	private List<MongoCredential> credentialList = new ArrayList<>();
-	private StreamFactoryFactory streamFactoryFactory = DEFAULT_MONGO_SETTINGS.getStreamFactoryFactory();
-	private CodecRegistry codecRegistry = DEFAULT_MONGO_SETTINGS.getCodecRegistry();
-	private ClusterSettings clusterSettings = DEFAULT_MONGO_SETTINGS.getClusterSettings();
-	private SocketSettings socketSettings = DEFAULT_MONGO_SETTINGS.getSocketSettings();
-	private SocketSettings heartbeatSocketSettings = DEFAULT_MONGO_SETTINGS.getHeartbeatSocketSettings();
-	private ConnectionPoolSettings connectionPoolSettings = DEFAULT_MONGO_SETTINGS.getConnectionPoolSettings();
-	private ServerSettings serverSettings = DEFAULT_MONGO_SETTINGS.getServerSettings();
-	private SslSettings sslSettings = DEFAULT_MONGO_SETTINGS.getSslSettings();
-
-	/**
-	 * Set the {@link ReadPreference}.
-	 *
-	 * @param readPreference
-	 */
-	public void setReadPreference(ReadPreference readPreference) {
-		this.readPreference = readPreference;
-	}
-
-	/**
-	 * Set the {@link WriteConcern}.
-	 *
-	 * @param writeConcern
-	 */
-	public void setWriteConcern(WriteConcern writeConcern) {
-		this.writeConcern = writeConcern;
-	}
-
-	/**
-	 * Set the {@link ReadConcern}.
-	 *
-	 * @param readConcern
-	 */
-	public void setReadConcern(ReadConcern readConcern) {
-		this.readConcern = readConcern;
-	}
-
-	/**
-	 * Set the List of {@link MongoCredential}s.
-	 *
-	 * @param credentialList must not be {@literal null}.
-	 */
-	public void setCredentialList(List<MongoCredential> credentialList) {
-
-		Assert.notNull(credentialList, "CredendialList must not be null!");
-
-		this.credentialList.addAll(credentialList);
-	}
-
-	/**
-	 * Adds the {@link MongoCredential} to the list of credentials.
-	 *
-	 * @param mongoCredential must not be {@literal null}.
-	 */
-	public void addMongoCredential(MongoCredential mongoCredential) {
-
-		Assert.notNull(mongoCredential, "MongoCredential must not be null!");
-
-		this.credentialList.add(mongoCredential);
-	}
-
-	/**
-	 * Set the {@link StreamFactoryFactory}.
-	 *
-	 * @param streamFactoryFactory
-	 */
-	public void setStreamFactoryFactory(StreamFactoryFactory streamFactoryFactory) {
-		this.streamFactoryFactory = streamFactoryFactory;
-	}
-
-	/**
-	 * Set the {@link CodecRegistry}.
-	 *
-	 * @param codecRegistry
-	 */
-	public void setCodecRegistry(CodecRegistry codecRegistry) {
-		this.codecRegistry = codecRegistry;
-	}
-
-	/**
-	 * Set the {@link ClusterSettings}.
-	 *
-	 * @param clusterSettings
-	 */
-	public void setClusterSettings(ClusterSettings clusterSettings) {
-		this.clusterSettings = clusterSettings;
-	}
-
-	/**
-	 * Set the {@link SocketSettings}.
-	 *
-	 * @param socketSettings
-	 */
-	public void setSocketSettings(SocketSettings socketSettings) {
-		this.socketSettings = socketSettings;
-	}
-
-	/**
-	 * Set the heartbeat {@link SocketSettings}.
-	 *
-	 * @param heartbeatSocketSettings
-	 */
-	public void setHeartbeatSocketSettings(SocketSettings heartbeatSocketSettings) {
-		this.heartbeatSocketSettings = heartbeatSocketSettings;
-	}
-
-	/**
-	 * Set the {@link ConnectionPoolSettings}.
-	 *
-	 * @param connectionPoolSettings
-	 */
-	public void setConnectionPoolSettings(ConnectionPoolSettings connectionPoolSettings) {
-		this.connectionPoolSettings = connectionPoolSettings;
-	}
-
-	/**
-	 * Set the {@link ServerSettings}.
-	 *
-	 * @param serverSettings
-	 */
-	public void setServerSettings(ServerSettings serverSettings) {
-		this.serverSettings = serverSettings;
-	}
-
-	/**
-	 * Set the {@link SslSettings}.
-	 *
-	 * @param sslSettings
-	 */
-	public void setSslSettings(SslSettings sslSettings) {
-		this.sslSettings = sslSettings;
-	}
-
-	@Override
-	public Class<?> getObjectType() {
-		return MongoClientSettings.class;
-	}
-
-	@Override
-	protected MongoClientSettings createInstance() throws Exception {
-
-		return MongoClientSettings.builder() //
-				.readPreference(readPreference) //
-				.writeConcern(writeConcern) //
-				.readConcern(readConcern) //
-				.credentialList(credentialList) //
-				.streamFactoryFactory(streamFactoryFactory) //
-				.codecRegistry(codecRegistry) //
-				.clusterSettings(clusterSettings) //
-				.socketSettings(socketSettings) //
-				.heartbeatSocketSettings(heartbeatSocketSettings) //
-				.connectionPoolSettings(connectionPoolSettings) //
-				.serverSettings(serverSettings) //
-				.sslSettings(sslSettings) //
-				.build();
-	}
 }

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

@@ -66,6 +66,7 @@ import com.mongodb.reactivestreams.client.MongoCollection;
  *
  * @author Mark Paluch
  * @author Christoph Strobl
+ * @author Mathieu Ouellet
  * @since 2.0
  * @see Flux
  * @see Mono
@@ -298,7 +299,7 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	 * @param collectionName name of the collection.
 	 * @return an existing collection or one created on first server interaction.
 	 */
-	MongoCollection<Document> getCollection(String collectionName);
+	Mono<MongoCollection<Document>> getCollection(String collectionName);
 
 	/**
 	 * Check to see if a collection with a name indicated by the entity class exists.
@@ -1238,7 +1239,7 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	 * domain type information. Use {@link #updateFirst(Query, UpdateDefinition, Class, String)} to get full type specific
 	 * support. <br />
 	 * <strong>NOTE:</strong> {@link Query#getSortObject() sorting} is not supported by {@code db.collection.updateOne}.
-	 * Use {@link #findAndModify(Query, Update, Class, String)} instead.
+	 * Use {@link #findAndModify(Query, UpdateDefinition, Class, String)} instead.
 	 *
 	 * @param query the query document that specifies the criteria used to select a record to be updated. Must not be
 	 *          {@literal null}.
@@ -1571,7 +1572,7 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	/**
 	 * Returns the underlying {@link MongoConverter}.
 	 *
-	 * @return
+	 * @return never {@literal null}.
 	 */
 	MongoConverter getConverter();
 
@@ -1579,7 +1580,7 @@ public interface ReactiveMongoOperations extends ReactiveFluentMongoOperations {
 	 * The collection name used for the specified class by this template.
 	 *
 	 * @param entityClass must not be {@literal null}.
-	 * @return
+	 * @return never {@literal null}.
 	 * @since 2.1
 	 */
 	String getCollectionName(Class<?> entityClass);

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

@@ -18,6 +18,7 @@ package org.springframework.data.mongodb.core;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 
+import org.springframework.data.mongodb.core.query.CriteriaDefinition;
 import org.springframework.data.mongodb.core.query.Query;
 
 import com.mongodb.client.result.DeleteResult;
@@ -106,6 +107,18 @@ public interface ReactiveRemoveOperation {
 		 * @throws IllegalArgumentException if query is {@literal null}.
 		 */
 		TerminatingRemove<T> matching(Query query);
+
+		/**
+		 * Set the filter {@link CriteriaDefinition criteria} to be used.
+		 *
+		 * @param criteria must not be {@literal null}.
+		 * @return new instance of {@link TerminatingRemove}.
+		 * @throws IllegalArgumentException if query is {@literal null}.
+		 * @since 3.0
+		 */
+		default TerminatingRemove<T> matching(CriteriaDefinition criteria) {
+			return matching(Query.query(criteria));
+		}
 	}
 
 	interface ReactiveRemove<T> extends RemoveWithCollection<T> {}

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

@@ -15,12 +15,13 @@
  */
 package org.springframework.data.mongodb.core;
 
-import org.springframework.data.mongodb.core.aggregation.AggregationUpdate;
-import org.springframework.data.mongodb.core.query.UpdateDefinition;
 import reactor.core.publisher.Mono;
 
+import org.springframework.data.mongodb.core.aggregation.AggregationUpdate;
+import org.springframework.data.mongodb.core.query.CriteriaDefinition;
 import org.springframework.data.mongodb.core.query.Query;
 import org.springframework.data.mongodb.core.query.Update;
+import org.springframework.data.mongodb.core.query.UpdateDefinition;
 
 import com.mongodb.client.result.UpdateResult;
 
@@ -171,6 +172,18 @@ public interface ReactiveUpdateOperation {
 		 * @throws IllegalArgumentException if query is {@literal null}.
 		 */
 		UpdateWithUpdate<T> matching(Query query);
+
+		/**
+		 * Set the filter {@link CriteriaDefinition criteria} to be used.
+		 *
+		 * @param criteria must not be {@literal null}.
+		 * @return new instance of {@link UpdateWithUpdate}.
+		 * @throws IllegalArgumentException if query is {@literal null}.
+		 * @since 3.0
+		 */
+		default UpdateWithUpdate<T> matching(CriteriaDefinition criteria) {
+			return matching(Query.query(criteria));
+		}
 	}
 
 	/**

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

@@ -21,7 +21,6 @@ import org.springframework.data.mongodb.core.script.ExecutableMongoScript;
 import org.springframework.data.mongodb.core.script.NamedMongoScript;
 import org.springframework.lang.Nullable;
 
-import com.mongodb.DB;
 
 /**
  * Script operations on {@link com.mongodb.DB} level. Allows interaction with server side JavaScript functions.

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2011-2020 the original author or authors.
+ * Copyright 2018-2019 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.
@@ -18,66 +18,63 @@ package org.springframework.data.mongodb.core;
 import org.springframework.beans.factory.DisposableBean;
 
 import com.mongodb.ClientSessionOptions;
-import com.mongodb.DB;
-import com.mongodb.MongoClient;
-import com.mongodb.MongoClientURI;
+import com.mongodb.ConnectionString;
 import com.mongodb.client.ClientSession;
+import com.mongodb.client.MongoClient;
+import com.mongodb.client.MongoClients;
 import com.mongodb.client.MongoDatabase;
 
 /**
  * Factory to create {@link MongoDatabase} instances from a {@link MongoClient} instance.
  *
- * @author Mark Pollack
- * @author Oliver Gierke
- * @author Thomas Darimont
  * @author Christoph Strobl
- * @author George Moraitis
- * @author Mark Paluch
- * @deprecated since 2.2 in favor of {@link SimpleMongoClientDbFactory}.
+ * @since 3.0
  */
-@Deprecated
-public class SimpleMongoDbFactory extends MongoDbFactorySupport<MongoClient> implements DisposableBean {
+public class SimpleMongoClientDatabaseFactory extends MongoDatabaseFactorySupport<MongoClient>
+		implements DisposableBean {
 
 	/**
-	 * Creates a new {@link SimpleMongoDbFactory} instance from the given {@link MongoClientURI}.
+	 * Creates a new {@link SimpleMongoClientDatabaseFactory} instance for the given {@code connectionString}.
 	 *
-	 * @param uri coordinates for a database connection. Must contain a database name and must not be {@literal null}.
-	 * @since 1.7
+	 * @param connectionString connection coordinates for a database connection. Must contain a database name and must not
+	 *          be {@literal null} or empty.
+	 * @see <a href="https://docs.mongodb.com/manual/reference/connection-string/">MongoDB Connection String reference</a>
 	 */
-	public SimpleMongoDbFactory(MongoClientURI uri) {
-		this(new MongoClient(uri), uri.getDatabase(), true);
+	public SimpleMongoClientDatabaseFactory(String connectionString) {
+		this(new ConnectionString(connectionString));
 	}
 
 	/**
-	 * Creates a new {@link SimpleMongoDbFactory} instance from the given {@link MongoClient}.
+	 * Creates a new {@link SimpleMongoClientDatabaseFactory} instance from the given {@link MongoClient}.
+	 *
+	 * @param connectionString connection coordinates for a database connection. Must contain also a database name and not
+	 *          be {@literal null}.
+	 */
+	public SimpleMongoClientDatabaseFactory(ConnectionString connectionString) {
+		this(MongoClients.create(connectionString), connectionString.getDatabase(), true);
+	}
+
+	/**
+	 * Creates a new {@link SimpleMongoClientDatabaseFactory} instance from the given {@link MongoClient}.
 	 *
 	 * @param mongoClient must not be {@literal null}.
 	 * @param databaseName must not be {@literal null} or empty.
-	 * @since 1.7
 	 */
-	public SimpleMongoDbFactory(MongoClient mongoClient, String databaseName) {
+	public SimpleMongoClientDatabaseFactory(MongoClient mongoClient, String databaseName) {
 		this(mongoClient, databaseName, false);
 	}
 
 	/**
-	 * @param mongoClient
-	 * @param databaseName
+	 * Creates a new {@link SimpleMongoClientDatabaseFactory} instance from the given {@link MongoClient}.
+	 *
+	 * @param mongoClient must not be {@literal null}.
+	 * @param databaseName must not be {@literal null} or empty.
 	 * @param mongoInstanceCreated
-	 * @since 1.7
 	 */
-	private SimpleMongoDbFactory(MongoClient mongoClient, String databaseName, boolean mongoInstanceCreated) {
+	SimpleMongoClientDatabaseFactory(MongoClient mongoClient, String databaseName, boolean mongoInstanceCreated) {
 		super(mongoClient, databaseName, mongoInstanceCreated, new MongoExceptionTranslator());
 	}
 
-	/* 
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.MongoDbFactory#getLegacyDb()
-	 */
-	@Override
-	public DB getLegacyDb() {
-		return getMongoClient().getDB(getDefaultDatabaseName());
-	}
-
 	/*
 	 * (non-Javadoc)
 	 * @see org.springframework.data.mongodb.MongoDbFactory#getSession(com.mongodb.ClientSessionOptions)
@@ -87,7 +84,7 @@ public class SimpleMongoDbFactory extends MongoDbFactorySupport<MongoClient> imp
 		return getMongoClient().startSession(options);
 	}
 
-	/* 
+	/*
 	 * (non-Javadoc)
 	 * @see org.springframework.data.mongodb.core.MongoDbFactoryBase#closeClient()
 	 */
@@ -96,7 +93,7 @@ public class SimpleMongoDbFactory extends MongoDbFactorySupport<MongoClient> imp
 		getMongoClient().close();
 	}
 
-	/* 
+	/*
 	 * (non-Javadoc)
 	 * @see org.springframework.data.mongodb.core.MongoDbFactoryBase#doGetMongoDatabase(java.lang.String)
 	 */

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

@@ -15,12 +15,7 @@
  */
 package org.springframework.data.mongodb.core;
 
-import org.springframework.beans.factory.DisposableBean;
-
-import com.mongodb.ClientSessionOptions;
 import com.mongodb.ConnectionString;
-import com.mongodb.DB;
-import com.mongodb.client.ClientSession;
 import com.mongodb.client.MongoClient;
 import com.mongodb.client.MongoClients;
 import com.mongodb.client.MongoDatabase;
@@ -30,8 +25,10 @@ import com.mongodb.client.MongoDatabase;
  *
  * @author Christoph Strobl
  * @since 2.1
+ * @deprecated since 3.0, use {@link SimpleMongoClientDatabaseFactory} instead.
  */
-public class SimpleMongoClientDbFactory extends MongoDbFactorySupport<MongoClient> implements DisposableBean {
+@Deprecated
+public class SimpleMongoClientDbFactory extends SimpleMongoClientDatabaseFactory {
 
 	/**
 	 * Creates a new {@link SimpleMongoClientDbFactory} instance for the given {@code connectionString}.
@@ -72,45 +69,6 @@ public class SimpleMongoClientDbFactory extends MongoDbFactorySupport<MongoClien
 	 * @param mongoInstanceCreated
 	 */
 	private SimpleMongoClientDbFactory(MongoClient mongoClient, String databaseName, boolean mongoInstanceCreated) {
-		super(mongoClient, databaseName, mongoInstanceCreated, new MongoExceptionTranslator());
-	}
-
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.MongoDbFactory#getLegacyDb()
-	 */
-	@Override
-	public DB getLegacyDb() {
-
-		throw new UnsupportedOperationException(String.format(
-				"%s does not support legacy DBObject API! Please consider using SimpleMongoDbFactory for that purpose.",
-				MongoClient.class));
-	}
-
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.MongoDbFactory#getSession(com.mongodb.ClientSessionOptions)
-	 */
-	@Override
-	public ClientSession getSession(ClientSessionOptions options) {
-		return getMongoClient().startSession(options);
-	}
-
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.MongoDbFactoryBase#closeClient()
-	 */
-	@Override
-	protected void closeClient() {
-		getMongoClient().close();
-	}
-
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.data.mongodb.core.MongoDbFactoryBase#doGetMongoDatabase(java.lang.String)
-	 */
-	@Override
-	protected MongoDatabase doGetMongoDatabase(String dbName) {
-		return getMongoClient().getDatabase(dbName);
+		super(mongoClient, databaseName, mongoInstanceCreated);
 	}
 }

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

@@ -18,6 +18,7 @@ package org.springframework.data.mongodb.core;
 import lombok.Value;
 import reactor.core.publisher.Mono;
 
+import org.bson.codecs.configuration.CodecRegistry;
 import org.springframework.aop.framework.ProxyFactory;
 import org.springframework.beans.factory.DisposableBean;
 import org.springframework.dao.DataAccessException;
@@ -41,6 +42,7 @@ import com.mongodb.reactivestreams.client.MongoDatabase;
  *
  * @author Mark Paluch
  * @author Christoph Strobl
+ * @author Mathieu Ouellet
  * @since 2.0
  */
 public class SimpleReactiveMongoDatabaseFactory implements DisposableBean, ReactiveMongoDatabaseFactory {
@@ -99,7 +101,7 @@ public class SimpleReactiveMongoDatabaseFactory implements DisposableBean, React
 	 * (non-Javadoc)
 	 * @see org.springframework.data.mongodb.ReactiveMongoDbFactory#getMongoDatabase()
 	 */
-	public MongoDatabase getMongoDatabase() throws DataAccessException {
+	public Mono<MongoDatabase> getMongoDatabase() throws DataAccessException {
 		return getMongoDatabase(databaseName);
 	}
 
@@ -107,12 +109,16 @@ public class SimpleReactiveMongoDatabaseFactory implements DisposableBean, React
 	 * (non-Javadoc)
 	 * @see org.springframework.data.mongodb.ReactiveMongoDbFactory#getMongoDatabase(java.lang.String)
 	 */
-	public MongoDatabase getMongoDatabase(String dbName) throws DataAccessException {
+	public Mono<MongoDatabase> getMongoDatabase(String dbName) throws DataAccessException {
 
 		Assert.hasText(dbName, "Database name must not be empty.");
 
-		MongoDatabase db = mongo.getDatabase(dbName);
-		return writeConcern != null ? db.withWriteConcern(writeConcern) : db;
+		return Mono.fromSupplier(() -> {
+
+			MongoDatabase db = mongo.getDatabase(dbName);
+
+			return writeConcern != null ? db.withWriteConcern(writeConcern) : db;
+		});
 	}
 
 	/**
@@ -135,6 +141,15 @@ public class SimpleReactiveMongoDatabaseFactory implements DisposableBean, React
 		return this.exceptionTranslator;
 	}
 
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.ReactiveMongoDatabaseFactory#getCodecRegistry()
+	 */
+	@Override
+	public CodecRegistry getCodecRegistry() {
+		return this.mongo.getDatabase(databaseName).getCodecRegistry();
+	}
+
 	/*
 	 * (non-Javadoc)
 	 * @see org.springframework.data.mongodb.ReactiveMongoDbFactory#getSession(com.mongodb.ClientSessionOptions)
@@ -171,8 +186,8 @@ public class SimpleReactiveMongoDatabaseFactory implements DisposableBean, React
 		 * @see org.springframework.data.mongodb.ReactiveMongoDatabaseFactory#getMongoDatabase()
 		 */
 		@Override
-		public MongoDatabase getMongoDatabase() throws DataAccessException {
-			return decorateDatabase(delegate.getMongoDatabase());
+		public Mono<MongoDatabase> getMongoDatabase() throws DataAccessException {
+			return delegate.getMongoDatabase().map(this::decorateDatabase);
 		}
 
 		/*
@@ -180,8 +195,8 @@ public class SimpleReactiveMongoDatabaseFactory implements DisposableBean, React
 		 * @see org.springframework.data.mongodb.ReactiveMongoDatabaseFactory#getMongoDatabase(java.lang.String)
 		 */
 		@Override
-		public MongoDatabase getMongoDatabase(String dbName) throws DataAccessException {
-			return decorateDatabase(delegate.getMongoDatabase(dbName));
+		public Mono<MongoDatabase> getMongoDatabase(String dbName) throws DataAccessException {
+			return delegate.getMongoDatabase(dbName).map(this::decorateDatabase);
 		}
 
 		/*
@@ -193,6 +208,15 @@ public class SimpleReactiveMongoDatabaseFactory implements DisposableBean, React
 			return delegate.getExceptionTranslator();
 		}
 
+		/*
+		 * (non-Javadoc)
+		 * @see org.springframework.data.mongodb.ReactiveMongoDatabaseFactory#getCodecRegistry()
+		 */
+		@Override
+		public CodecRegistry getCodecRegistry() {
+			return delegate.getCodecRegistry();
+		}
+
 		/*
 		 * (non-Javadoc)
 		 * @see org.springframework.data.mongodb.ReactiveMongoDatabaseFactory#getSession(com.mongodb.ClientSessionOptions)
@@ -242,7 +266,7 @@ public class SimpleReactiveMongoDatabaseFactory implements DisposableBean, React
 			factory.addAdvice(new SessionAwareMethodInterceptor<>(session, target, ClientSession.class, MongoDatabase.class,
 					this::proxyDatabase, MongoCollection.class, this::proxyCollection));
 
-			return targetType.cast(factory.getProxy());
+			return targetType.cast(factory.getProxy(target.getClass().getClassLoader()));
 		}
 	}
 }

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

@@ -16,8 +16,8 @@
 package org.springframework.data.mongodb.core;
 
 /**
- * Enum to represent how strict the check of {@link com.mongodb.WriteResult} shall be. It can either be skipped entirely
- * (use {@link #NONE}) or cause an exception to be thrown {@link #EXCEPTION}.
+ * Enum to represent how strict the check of {@link com.mongodb.WriteConcernResult} shall be. It can either be skipped
+ * entirely (use {@link #NONE}) or cause an exception to be thrown {@link #EXCEPTION}.
  *
  * @author Thomas Risberg
  * @author Oliver Gierke

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

@@ -17,6 +17,7 @@ package org.springframework.data.mongodb.core.aggregation;
 
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.LinkedHashMap;
 import java.util.List;
@@ -100,14 +101,14 @@ abstract class AbstractAggregationExpression implements AggregationExpression {
 		return value;
 	}
 
-	protected List<Object> append(Object value) {
+	protected List<Object> append(Object value, Expand expandList) {
 
 		if (this.value instanceof List) {
 
 			List<Object> clone = new ArrayList<Object>((List) this.value);
 
-			if (value instanceof List) {
-				clone.addAll((List) value);
+			if (value instanceof Collection && Expand.EXPAND_VALUES.equals(expandList)) {
+				clone.addAll((Collection<?>) value);
 			} else {
 				clone.add(value);
 			}
@@ -117,6 +118,17 @@ abstract class AbstractAggregationExpression implements AggregationExpression {
 		return Arrays.asList(this.value, value);
 	}
 
+	/**
+	 * Expand a nested list of values to single entries or keep the list.
+	 */
+	protected enum Expand {
+		EXPAND_VALUES, KEEP_SOURCE
+	}
+
+	protected List<Object> append(Object value) {
+		return append(value, Expand.EXPAND_VALUES);
+	}
+
 	@SuppressWarnings("unchecked")
 	protected java.util.Map<String, Object> append(String key, Object value) {
 

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

@@ -34,7 +34,7 @@ public class AccumulatorOperators {
 	 * Take the numeric value referenced by given {@literal fieldReference}.
 	 *
 	 * @param fieldReference must not be {@literal null}.
-	 * @return
+	 * @return new instance of {@link AccumulatorOperatorFactory}.
 	 */
 	public static AccumulatorOperatorFactory valueOf(String fieldReference) {
 		return new AccumulatorOperatorFactory(fieldReference);
@@ -44,7 +44,7 @@ public class AccumulatorOperators {
 	 * Take the numeric value referenced resulting from given {@link AggregationExpression}.
 	 *
 	 * @param expression must not be {@literal null}.
-	 * @return
+	 * @return new instance of {@link AccumulatorOperatorFactory}.
 	 */
 	public static AccumulatorOperatorFactory valueOf(AggregationExpression expression) {
 		return new AccumulatorOperatorFactory(expression);
@@ -86,7 +86,7 @@ public class AccumulatorOperators {
 		 * Creates new {@link AggregationExpression} that takes the associated numeric value expression and calculates and
 		 * returns the sum.
 		 *
-		 * @return
+		 * @return new instance of {@link Sum}.
 		 */
 		public Sum sum() {
 			return usesFieldRef() ? Sum.sumOf(fieldReference) : Sum.sumOf(expression);
@@ -96,7 +96,7 @@ public class AccumulatorOperators {
 		 * Creates new {@link AggregationExpression} that takes the associated numeric value expression and returns the
 		 * average value.
 		 *
-		 * @return
+		 * @return new instance of {@link Avg}.
 		 */
 		public Avg avg() {
 			return usesFieldRef() ? Avg.avgOf(fieldReference) : Avg.avgOf(expression);
@@ -106,7 +106,7 @@ public class AccumulatorOperators {
 		 * Creates new {@link AggregationExpression} that takes the associated numeric value expression and returns the
 		 * maximum value.
 		 *
-		 * @return
+		 * @return new instance of {@link Max}.
 		 */
 		public Max max() {
 			return usesFieldRef() ? Max.maxOf(fieldReference) : Max.maxOf(expression);
@@ -116,7 +116,7 @@ public class AccumulatorOperators {
 		 * Creates new {@link AggregationExpression} that takes the associated numeric value expression and returns the
 		 * minimum value.
 		 *
-		 * @return
+		 * @return new instance of {@link Min}.
 		 */
 		public Min min() {
 			return usesFieldRef() ? Min.minOf(fieldReference) : Min.minOf(expression);
@@ -126,7 +126,7 @@ public class AccumulatorOperators {
 		 * Creates new {@link AggregationExpression} that takes the associated numeric value expression and calculates the
 		 * population standard deviation of the input values.
 		 *
-		 * @return
+		 * @return new instance of {@link StdDevPop}.
 		 */
 		public StdDevPop stdDevPop() {
 			return usesFieldRef() ? StdDevPop.stdDevPopOf(fieldReference) : StdDevPop.stdDevPopOf(expression);
@@ -136,7 +136,7 @@ public class AccumulatorOperators {
 		 * Creates new {@link AggregationExpression} that takes the associated numeric value expression and calculates the
 		 * sample standard deviation of the input values.
 		 *
-		 * @return
+		 * @return new instance of {@link StdDevSamp}.
 		 */
 		public StdDevSamp stdDevSamp() {
 			return usesFieldRef() ? StdDevSamp.stdDevSampOf(fieldReference) : StdDevSamp.stdDevSampOf(expression);
@@ -167,7 +167,7 @@ public class AccumulatorOperators {
 		 * Creates new {@link Sum}.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Sum}.
 		 */
 		public static Sum sumOf(String fieldReference) {
 
@@ -179,7 +179,7 @@ public class AccumulatorOperators {
 		 * Creates new {@link Sum}.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Sum}.
 		 */
 		public static Sum sumOf(AggregationExpression expression) {
 
@@ -192,7 +192,7 @@ public class AccumulatorOperators {
 		 * <strong>NOTE:</strong> Only possible in {@code $project} stage.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Sum}.
 		 */
 		public Sum and(String fieldReference) {
 
@@ -205,7 +205,7 @@ public class AccumulatorOperators {
 		 * <strong>NOTE:</strong> Only possible in {@code $project} stage.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Sum}.
 		 */
 		public Sum and(AggregationExpression expression) {
 
@@ -264,7 +264,7 @@ public class AccumulatorOperators {
 		 * Creates new {@link Avg}.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Avg}.
 		 */
 		public static Avg avgOf(String fieldReference) {
 
@@ -276,7 +276,7 @@ public class AccumulatorOperators {
 		 * Creates new {@link Avg}.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Avg}.
 		 */
 		public static Avg avgOf(AggregationExpression expression) {
 
@@ -289,7 +289,7 @@ public class AccumulatorOperators {
 		 * <strong>NOTE:</strong> Only possible in {@code $project} stage.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Avg}.
 		 */
 		public Avg and(String fieldReference) {
 
@@ -302,7 +302,7 @@ public class AccumulatorOperators {
 		 * <strong>NOTE:</strong> Only possible in {@code $project} stage.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Avg}.
 		 */
 		public Avg and(AggregationExpression expression) {
 
@@ -347,7 +347,7 @@ public class AccumulatorOperators {
 		 * Creates new {@link Max}.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Max}.
 		 */
 		public static Max maxOf(String fieldReference) {
 
@@ -359,7 +359,7 @@ public class AccumulatorOperators {
 		 * Creates new {@link Max}.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Max}.
 		 */
 		public static Max maxOf(AggregationExpression expression) {
 
@@ -372,7 +372,7 @@ public class AccumulatorOperators {
 		 * <strong>NOTE:</strong> Only possible in {@code $project} stage.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Max}.
 		 */
 		public Max and(String fieldReference) {
 
@@ -385,7 +385,7 @@ public class AccumulatorOperators {
 		 * <strong>NOTE:</strong> Only possible in {@code $project} stage.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Max}.
 		 */
 		public Max and(AggregationExpression expression) {
 
@@ -430,7 +430,7 @@ public class AccumulatorOperators {
 		 * Creates new {@link Min}.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Min}.
 		 */
 		public static Min minOf(String fieldReference) {
 
@@ -442,7 +442,7 @@ public class AccumulatorOperators {
 		 * Creates new {@link Min}.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Min}.
 		 */
 		public static Min minOf(AggregationExpression expression) {
 
@@ -455,7 +455,7 @@ public class AccumulatorOperators {
 		 * <strong>NOTE:</strong> Only possible in {@code $project} stage.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Min}.
 		 */
 		public Min and(String fieldReference) {
 
@@ -468,7 +468,7 @@ public class AccumulatorOperators {
 		 * <strong>NOTE:</strong> Only possible in {@code $project} stage.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Min}.
 		 */
 		public Min and(AggregationExpression expression) {
 
@@ -513,7 +513,7 @@ public class AccumulatorOperators {
 		 * Creates new {@link StdDevPop}.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link StdDevPop}.
 		 */
 		public static StdDevPop stdDevPopOf(String fieldReference) {
 
@@ -525,7 +525,7 @@ public class AccumulatorOperators {
 		 * Creates new {@link StdDevPop} with all previously added arguments appending the given one.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link StdDevPop}.
 		 */
 		public static StdDevPop stdDevPopOf(AggregationExpression expression) {
 
@@ -538,7 +538,7 @@ public class AccumulatorOperators {
 		 * <strong>NOTE:</strong> Only possible in {@code $project} stage.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link StdDevPop}.
 		 */
 		public StdDevPop and(String fieldReference) {
 
@@ -551,7 +551,7 @@ public class AccumulatorOperators {
 		 * <strong>NOTE:</strong> Only possible in {@code $project} stage.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link StdDevPop}.
 		 */
 		public StdDevPop and(AggregationExpression expression) {
 
@@ -596,7 +596,7 @@ public class AccumulatorOperators {
 		 * Creates new {@link StdDevSamp}.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link StdDevSamp}.
 		 */
 		public static StdDevSamp stdDevSampOf(String fieldReference) {
 
@@ -608,7 +608,7 @@ public class AccumulatorOperators {
 		 * Creates new {@link StdDevSamp}.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link StdDevSamp}.
 		 */
 		public static StdDevSamp stdDevSampOf(AggregationExpression expression) {
 
@@ -621,7 +621,7 @@ public class AccumulatorOperators {
 		 * <strong>NOTE:</strong> Only possible in {@code $project} stage.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link StdDevSamp}.
 		 */
 		public StdDevSamp and(String fieldReference) {
 
@@ -634,7 +634,7 @@ public class AccumulatorOperators {
 		 * <strong>NOTE:</strong> Only possible in {@code $project} stage.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link StdDevSamp}.
 		 */
 		public StdDevSamp and(AggregationExpression expression) {
 

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

@@ -0,0 +1,204 @@
+/*
+ * Copyright 2020 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
+ *
+ *      https://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.LinkedHashMap;
+import java.util.Map;
+
+import org.springframework.data.mongodb.core.aggregation.AddFieldsOperation.AddFieldsOperationBuilder.ValueAppender;
+import org.springframework.lang.Nullable;
+
+/**
+ * Adds new fields to documents. {@code $addFields} outputs documents that contain all existing fields from the input
+ * documents and newly added fields.
+ *
+ * <pre class="code">
+ * AddFieldsOperation.addField("totalHomework").withValue("A+").and().addField("totalQuiz").withValue("B-")
+ * </pre>
+ *
+ * @author Christoph Strobl
+ * @since 3.0
+ * @see <a href="https://docs.mongodb.com/manual/reference/operator/aggregation/addFields/">MongoDB Aggregation
+ *      Framework: $addFields</a>
+ */
+public class AddFieldsOperation extends DocumentEnhancingOperation {
+
+	/**
+	 * Create new instance of {@link AddFieldsOperation} adding map keys as exposed fields.
+	 *
+	 * @param source must not be {@literal null}.
+	 */
+	private AddFieldsOperation(Map<Object, Object> source) {
+		super(source);
+	}
+
+	/**
+	 * Create new instance of {@link AddFieldsOperation}
+	 *
+	 * @param field must not be {@literal null}.
+	 * @param value can be {@literal null}.
+	 */
+	public AddFieldsOperation(Object field, @Nullable Object value) {
+		this(Collections.singletonMap(field, value));
+	}
+
+	/**
+	 * Define the {@link AddFieldsOperation} via {@link AddFieldsOperationBuilder}.
+	 *
+	 * @return new instance of {@link AddFieldsOperationBuilder}.
+	 */
+	public static AddFieldsOperationBuilder builder() {
+		return new AddFieldsOperationBuilder();
+	}
+
+	/**
+	 * Concatenate another field to add.
+	 *
+	 * @param field must not be {@literal null}.
+	 * @return new instance of {@link AddFieldsOperationBuilder}.
+	 */
+	public static ValueAppender addField(String field) {
+		return new AddFieldsOperationBuilder().addField(field);
+	}
+
+	/**
+	 * Append the value for a specific field to the operation.
+	 *
+	 * @param field the target field to add.
+	 * @param value the value to assign.
+	 * @return new instance of {@link AddFieldsOperation}.
+	 */
+	public AddFieldsOperation addField(Object field, Object value) {
+
+		LinkedHashMap<Object, Object> target = new LinkedHashMap<>(getValueMap());
+		target.put(field, value);
+
+		return new AddFieldsOperation(target);
+	}
+
+	/**
+	 * Concatenate additional fields to add.
+	 *
+	 * @return new instance of {@link AddFieldsOperationBuilder}.
+	 */
+	public AddFieldsOperationBuilder and() {
+		return new AddFieldsOperationBuilder(getValueMap());
+	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.DocumentEnhancingOperation#mongoOperator()
+	 */
+	@Override
+	protected String mongoOperator() {
+		return "$addFields";
+	}
+
+	/**
+	 * @author Christoph Strobl
+	 * @since 3.0
+	 */
+	public static class AddFieldsOperationBuilder {
+
+		private final Map<Object, Object> valueMap;
+
+		private AddFieldsOperationBuilder() {
+			this.valueMap = new LinkedHashMap<>();
+		}
+
+		private AddFieldsOperationBuilder(Map<Object, Object> source) {
+			this.valueMap = new LinkedHashMap<>(source);
+		}
+
+		public AddFieldsOperationBuilder addFieldWithValue(String field, @Nullable Object value) {
+			return addField(field).withValue(value);
+		}
+
+		public AddFieldsOperationBuilder addFieldWithValueOf(String field, Object value) {
+			return addField(field).withValueOf(value);
+		}
+
+		/**
+		 * Define the field to add.
+		 *
+		 * @param field must not be {@literal null}.
+		 * @return new instance of {@link ValueAppender}.
+		 */
+		public ValueAppender addField(String field) {
+
+			return new ValueAppender() {
+
+				@Override
+				public AddFieldsOperationBuilder withValue(Object value) {
+
+					valueMap.put(field, value);
+					return AddFieldsOperationBuilder.this;
+				}
+
+				@Override
+				public AddFieldsOperationBuilder withValueOf(Object value) {
+
+					valueMap.put(field, value instanceof String ? Fields.fields((String) value) : value);
+					return AddFieldsOperationBuilder.this;
+				}
+
+				@Override
+				public AddFieldsOperationBuilder withValueOfExpression(String operation, Object... values) {
+
+					valueMap.put(field, new ExpressionProjection(operation, values));
+					return AddFieldsOperationBuilder.this;
+				}
+			};
+		}
+
+		public AddFieldsOperation build() {
+			return new AddFieldsOperation(valueMap);
+		}
+
+		/**
+		 * @author Christoph Strobl
+		 * @since 3.0
+		 */
+		public interface ValueAppender {
+
+			/**
+			 * Define the value to assign as is.
+			 *
+			 * @param value can be {@literal null}.
+			 * @return new instance of {@link AddFieldsOperation}.
+			 */
+			AddFieldsOperationBuilder withValue(@Nullable Object value);
+
+			/**
+			 * Define the value to assign. Plain {@link String} values are treated as {@link Field field references}.
+			 *
+			 * @param value must not be {@literal null}.
+			 * @return new instance of {@link AddFieldsOperation}.
+			 */
+			AddFieldsOperationBuilder withValueOf(Object value);
+
+			/**
+			 * 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 new instance of {@link AddFieldsOperation}.
+			 */
+			AddFieldsOperationBuilder withValueOfExpression(String operation, Object... values);
+		}
+	}
+}

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

@@ -23,9 +23,11 @@ import java.util.List;
 import org.bson.Document;
 import org.springframework.data.domain.Sort;
 import org.springframework.data.domain.Sort.Direction;
+import org.springframework.data.mongodb.core.aggregation.AddFieldsOperation.AddFieldsOperationBuilder;
 import org.springframework.data.mongodb.core.aggregation.CountOperation.CountOperationBuilder;
 import org.springframework.data.mongodb.core.aggregation.FacetOperation.FacetOperationBuilder;
 import org.springframework.data.mongodb.core.aggregation.GraphLookupOperation.StartWithBuilder;
+import org.springframework.data.mongodb.core.aggregation.MergeOperation.MergeOperationBuilder;
 import org.springframework.data.mongodb.core.aggregation.ReplaceRootOperation.ReplaceRootDocumentOperationBuilder;
 import org.springframework.data.mongodb.core.aggregation.ReplaceRootOperation.ReplaceRootOperationBuilder;
 import org.springframework.data.mongodb.core.query.Criteria;
@@ -94,7 +96,7 @@ public class Aggregation {
 	public static final AggregationOperationContext DEFAULT_CONTEXT = AggregationOperationRenderer.DEFAULT_CONTEXT;
 	public static final AggregationOptions DEFAULT_OPTIONS = newAggregationOptions().build();
 
-	protected final List<AggregationOperation> operations;
+	protected final AggregationPipeline pipeline;
 	private final AggregationOptions options;
 
 	/**
@@ -117,7 +119,7 @@ public class Aggregation {
 
 	/**
 	 * Creates a new {@link AggregationUpdate} from the given {@link AggregationOperation}s.
-	 * 
+	 *
 	 * @param operations can be {@literal empty} but must not be {@literal null}.
 	 * @return new instance of {@link AggregationUpdate}.
 	 * @since 3.0
@@ -131,13 +133,13 @@ public class Aggregation {
 	 * supported in MongoDB version 2.6+.
 	 *
 	 * @param options must not be {@literal null}.
-	 * @return
+	 * @return new instance of {@link Aggregation}.
 	 * @since 1.6
 	 */
 	public Aggregation withOptions(AggregationOptions options) {
 
 		Assert.notNull(options, "AggregationOptions must not be null.");
-		return new Aggregation(this.operations, options);
+		return new Aggregation(this.pipeline.getOperations(), options);
 	}
 
 	/**
@@ -200,21 +202,10 @@ public class Aggregation {
 		Assert.notNull(aggregationOperations, "AggregationOperations must not be null!");
 		Assert.notNull(options, "AggregationOptions must not be null!");
 
-		// check $out is the last operation if it exists
-		for (AggregationOperation aggregationOperation : aggregationOperations) {
-			if (aggregationOperation instanceof OutOperation && !isLast(aggregationOperation, aggregationOperations)) {
-				throw new IllegalArgumentException("The $out operator must be the last stage in the pipeline.");
-			}
-		}
-
-		this.operations = aggregationOperations;
+		this.pipeline = new AggregationPipeline(aggregationOperations);
 		this.options = options;
 	}
 
-	private boolean isLast(AggregationOperation aggregationOperation, List<AggregationOperation> aggregationOperations) {
-		return aggregationOperations.indexOf(aggregationOperation) == aggregationOperations.size() - 1;
-	}
-
 	/**
 	 * Get the {@link AggregationOptions}.
 	 *
@@ -234,11 +225,25 @@ public class Aggregation {
 		return "_id";
 	}
 
+	/**
+	 * Obtain an {@link AddFieldsOperationBuilder builder} instance to create a new {@link AddFieldsOperation}.
+	 * <p/>
+	 * Starting in version 4.2, MongoDB adds a new aggregation pipeline stage {@link AggregationUpdate#set $set} that is
+	 * an alias for {@code $addFields}.
+	 *
+	 * @return new instance of {@link AddFieldsOperationBuilder}.
+	 * @see AddFieldsOperation
+	 * @since 3.0
+	 */
+	public static AddFieldsOperationBuilder addFields() {
+		return AddFieldsOperation.builder();
+	}
+
 	/**
 	 * Creates a new {@link ProjectionOperation} including the given fields.
 	 *
 	 * @param fields must not be {@literal null}.
-	 * @return
+	 * @return new instance of {@link ProjectionOperation}.
 	 */
 	public static ProjectionOperation project(String... fields) {
 		return project(fields(fields));
@@ -248,7 +253,7 @@ public class Aggregation {
 	 * Creates a new {@link ProjectionOperation} including the given {@link Fields}.
 	 *
 	 * @param fields must not be {@literal null}.
-	 * @return
+	 * @return new instance of {@link ProjectionOperation}.
 	 */
 	public static ProjectionOperation project(Fields fields) {
 		return new ProjectionOperation(fields);
@@ -271,7 +276,7 @@ public class Aggregation {
 	 * Factory method to create a new {@link UnwindOperation} for the field with the given name.
 	 *
 	 * @param field must not be {@literal null} or empty.
-	 * @return
+	 * @return new instance of {@link UnwindOperation}.
 	 */
 	public static UnwindOperation unwind(String field) {
 		return new UnwindOperation(field(field));
@@ -281,7 +286,7 @@ public class Aggregation {
 	 * Factory method to create a new {@link ReplaceRootOperation} for the field with the given name.
 	 *
 	 * @param fieldName must not be {@literal null} or empty.
-	 * @return
+	 * @return new instance of {@link ReplaceRootOperation}.
 	 * @since 1.10
 	 */
 	public static ReplaceRootOperation replaceRoot(String fieldName) {
@@ -293,7 +298,7 @@ public class Aggregation {
 	 * {@link AggregationExpression}.
 	 *
 	 * @param aggregationExpression must not be {@literal null}.
-	 * @return
+	 * @return new instance of {@link ReplaceRootOperation}.
 	 * @since 1.10
 	 */
 	public static ReplaceRootOperation replaceRoot(AggregationExpression aggregationExpression) {
@@ -359,7 +364,7 @@ public class Aggregation {
 	 * Creates a new {@link GroupOperation} for the given fields.
 	 *
 	 * @param fields must not be {@literal null}.
-	 * @return
+	 * @return new instance of {@link GroupOperation}.
 	 */
 	public static GroupOperation group(String... fields) {
 		return group(fields(fields));
@@ -380,7 +385,7 @@ public class Aggregation {
 	 * {@link GraphLookupOperation} given {@literal fromCollection}.
 	 *
 	 * @param fromCollection must not be {@literal null} or empty.
-	 * @return
+	 * @return new instance of {@link StartWithBuilder} for creating a {@link GraphLookupOperation}.
 	 * @since 1.10
 	 */
 	public static StartWithBuilder graphLookup(String fromCollection) {
@@ -391,7 +396,7 @@ public class Aggregation {
 	 * Factory method to create a new {@link SortOperation} for the given {@link Sort}.
 	 *
 	 * @param sort must not be {@literal null}.
-	 * @return
+	 * @return new instance of {@link SortOperation}.
 	 */
 	public static SortOperation sort(Sort sort) {
 		return new SortOperation(sort);
@@ -402,7 +407,7 @@ public class Aggregation {
 	 *
 	 * @param direction must not be {@literal null}.
 	 * @param fields must not be {@literal null}.
-	 * @return
+	 * @return new instance of {@link SortOperation}.
 	 */
 	public static SortOperation sort(Direction direction, String... fields) {
 		return new SortOperation(Sort.by(direction, fields));
@@ -412,7 +417,7 @@ public class Aggregation {
 	 * Creates a new {@link SortByCountOperation} given {@literal groupByField}.
 	 *
 	 * @param field must not be {@literal null} or empty.
-	 * @return
+	 * @return new instance of {@link SortByCountOperation}.
 	 * @since 2.1
 	 */
 	public static SortByCountOperation sortByCount(String field) {
@@ -423,7 +428,7 @@ public class Aggregation {
 	 * Creates a new {@link SortByCountOperation} given {@link AggregationExpression group and sort expression}.
 	 *
 	 * @param groupAndSortExpression must not be {@literal null}.
-	 * @return
+	 * @return new instance of {@link SortByCountOperation}.
 	 * @since 2.1
 	 */
 	public static SortByCountOperation sortByCount(AggregationExpression groupAndSortExpression) {
@@ -434,9 +439,10 @@ public class Aggregation {
 	 * Creates a new {@link SkipOperation} skipping the given number of elements.
 	 *
 	 * @param elementsToSkip must not be less than zero.
-	 * @return
+	 * @return new instance of {@link SkipOperation}.
 	 * @deprecated prepare to get this one removed in favor of {@link #skip(long)}.
 	 */
+	@Deprecated
 	public static SkipOperation skip(int elementsToSkip) {
 		return new SkipOperation(elementsToSkip);
 	}
@@ -445,7 +451,7 @@ public class Aggregation {
 	 * Creates a new {@link SkipOperation} skipping the given number of elements.
 	 *
 	 * @param elementsToSkip must not be less than zero.
-	 * @return
+	 * @return new instance of {@link SkipOperation}.
 	 */
 	public static SkipOperation skip(long elementsToSkip) {
 		return new SkipOperation(elementsToSkip);
@@ -455,7 +461,7 @@ public class Aggregation {
 	 * Creates a new {@link LimitOperation} limiting the result to the given number of elements.
 	 *
 	 * @param maxElements must not be less than zero.
-	 * @return
+	 * @return new instance of {@link LimitOperation}.
 	 */
 	public static LimitOperation limit(long maxElements) {
 		return new LimitOperation(maxElements);
@@ -465,7 +471,7 @@ public class Aggregation {
 	 * Creates a new {@link SampleOperation} to select the specified number of documents from its input randomly.
 	 *
 	 * @param sampleSize must not be less than zero.
-	 * @return
+	 * @return new instance of {@link SampleOperation}.
 	 * @since 2.0
 	 */
 	public static SampleOperation sample(long sampleSize) {
@@ -476,7 +482,7 @@ public class Aggregation {
 	 * Creates a new {@link MatchOperation} using the given {@link Criteria}.
 	 *
 	 * @param criteria must not be {@literal null}.
-	 * @return
+	 * @return new instance of {@link MatchOperation}.
 	 */
 	public static MatchOperation match(Criteria criteria) {
 		return new MatchOperation(criteria);
@@ -486,13 +492,37 @@ public class Aggregation {
 	 * Creates a new {@link MatchOperation} using the given {@link CriteriaDefinition}.
 	 *
 	 * @param criteria must not be {@literal null}.
-	 * @return
+	 * @return new instance of {@link MatchOperation}.
 	 * @since 1.10
 	 */
 	public static MatchOperation match(CriteriaDefinition criteria) {
 		return new MatchOperation(criteria);
 	}
 
+	/**
+	 * Creates a new {@link GeoNearOperation} instance from the given {@link NearQuery} and the {@code distanceField}. The
+	 * {@code distanceField} defines output field that contains the calculated distance.
+	 *
+	 * @param query must not be {@literal null}.
+	 * @param distanceField must not be {@literal null} or empty.
+	 * @return new instance of {@link GeoNearOperation}.
+	 * @since 1.7
+	 */
+	public static GeoNearOperation geoNear(NearQuery query, String distanceField) {
+		return new GeoNearOperation(query, distanceField);
+	}
+
+	/**
+	 * Obtain a {@link MergeOperationBuilder builder} instance to create a new {@link MergeOperation}.
+	 *
+	 * @return new instance of {@link MergeOperationBuilder}.
+	 * @see MergeOperation
+	 * @since 3.0
+	 */
+	public static MergeOperationBuilder merge() {
+		return MergeOperation.builder();
+	}
+
 	/**
 	 * Creates a new {@link OutOperation} using the given collection name. This operation must be the last operation in
 	 * the pipeline.
@@ -501,7 +531,7 @@ public class Aggregation {
 	 *          collection in the current database if one does not already exist. The collection is not visible until the
 	 *          aggregation completes. If the aggregation fails, MongoDB does not create the collection. Must not be
 	 *          {@literal null}.
-	 * @return
+	 * @return new instance of {@link OutOperation}.
 	 */
 	public static OutOperation out(String outCollectionName) {
 		return new OutOperation(outCollectionName);
@@ -511,7 +541,7 @@ public class Aggregation {
 	 * Creates a new {@link BucketOperation} given {@literal groupByField}.
 	 *
 	 * @param groupByField must not be {@literal null} or empty.
-	 * @return
+	 * @return new instance of {@link BucketOperation}.
 	 * @since 1.10
 	 */
 	public static BucketOperation bucket(String groupByField) {
@@ -522,7 +552,7 @@ public class Aggregation {
 	 * Creates a new {@link BucketOperation} given {@link AggregationExpression group-by expression}.
 	 *
 	 * @param groupByExpression must not be {@literal null}.
-	 * @return
+	 * @return new instance of {@link BucketOperation}.
 	 * @since 1.10
 	 */
 	public static BucketOperation bucket(AggregationExpression groupByExpression) {
@@ -534,7 +564,7 @@ public class Aggregation {
 	 *
 	 * @param groupByField must not be {@literal null} or empty.
 	 * @param buckets number of buckets, must be a positive integer.
-	 * @return
+	 * @return new instance of {@link BucketAutoOperation}.
 	 * @since 1.10
 	 */
 	public static BucketAutoOperation bucketAuto(String groupByField, int buckets) {
@@ -546,7 +576,7 @@ public class Aggregation {
 	 *
 	 * @param groupByExpression must not be {@literal null}.
 	 * @param buckets number of buckets, must be a positive integer.
-	 * @return
+	 * @return new instance of {@link BucketAutoOperation}.
 	 * @since 1.10
 	 */
 	public static BucketAutoOperation bucketAuto(AggregationExpression groupByExpression, int buckets) {
@@ -556,7 +586,7 @@ public class Aggregation {
 	/**
 	 * Creates a new {@link FacetOperation}.
 	 *
-	 * @return
+	 * @return new instance of {@link FacetOperation}.
 	 * @since 1.10
 	 */
 	public static FacetOperation facet() {
@@ -567,7 +597,7 @@ public class Aggregation {
 	 * Creates a new {@link FacetOperationBuilder} given {@link Aggregation}.
 	 *
 	 * @param aggregationOperations the sub-pipeline, must not be {@literal null}.
-	 * @return
+	 * @return new instance of {@link FacetOperation}.
 	 * @since 1.10
 	 */
 	public static FacetOperationBuilder facet(AggregationOperation... aggregationOperations) {
@@ -612,11 +642,31 @@ public class Aggregation {
 		return new CountOperationBuilder();
 	}
 
+	/**
+	 * Creates a new {@link RedactOperation} that can restrict the content of a document based on information stored
+	 * within the document itself.
+	 *
+	 * <pre class="code">
+	 *
+	 * Aggregation.redact(ConditionalOperators.when(Criteria.where("level").is(5)) //
+	 * 		.then(RedactOperation.PRUNE) //
+	 * 		.otherwise(RedactOperation.DESCEND));
+	 * </pre>
+	 *
+	 * @param condition Any {@link AggregationExpression} that resolves to {@literal $$DESCEND}, {@literal $$PRUNE}, or
+	 *          {@literal $$KEEP}. Must not be {@literal null}.
+	 * @return new instance of {@link RedactOperation}. Never {@literal null}.
+	 * @since 3.0
+	 */
+	public static RedactOperation redact(AggregationExpression condition) {
+		return new RedactOperation(condition);
+	}
+
 	/**
 	 * Creates a new {@link Fields} instance for the given field names.
 	 *
 	 * @param fields must not be {@literal null}.
-	 * @return
+	 * @return new instance of {@link Fields}.
 	 * @see Fields#fields(String...)
 	 */
 	public static Fields fields(String... fields) {
@@ -628,29 +678,16 @@ public class Aggregation {
 	 *
 	 * @param name must not be {@literal null} or empty.
 	 * @param target must not be {@literal null} or empty.
-	 * @return
+	 * @return new instance of {@link Fields}.
 	 */
 	public static Fields bind(String name, String target) {
 		return Fields.from(field(name, target));
 	}
 
-	/**
-	 * Creates a new {@link GeoNearOperation} instance from the given {@link NearQuery} and the {@code distanceField}. The
-	 * {@code distanceField} defines output field that contains the calculated distance.
-	 *
-	 * @param query must not be {@literal null}.
-	 * @param distanceField must not be {@literal null} or empty.
-	 * @return
-	 * @since 1.7
-	 */
-	public static GeoNearOperation geoNear(NearQuery query, String distanceField) {
-		return new GeoNearOperation(query, distanceField);
-	}
-
 	/**
 	 * Returns a new {@link AggregationOptions.Builder}.
 	 *
-	 * @return
+	 * @return new instance of {@link AggregationOptions.Builder}.
 	 * @since 1.6
 	 */
 	public static AggregationOptions.Builder newAggregationOptions() {
@@ -665,7 +702,15 @@ public class Aggregation {
 	 * @since 2.1
 	 */
 	public List<Document> toPipeline(AggregationOperationContext rootContext) {
-		return AggregationOperationRenderer.toDocument(operations, rootContext);
+		return pipeline.toDocuments(rootContext);
+	}
+
+	/**
+	 * @return the {@link AggregationPipeline}.
+	 * @since 3.0.2
+	 */
+	public AggregationPipeline getPipeline() {
+		return pipeline;
 	}
 
 	/**
@@ -712,7 +757,7 @@ public class Aggregation {
 		 * otherwise.
 		 *
 		 * @param fieldRef may be {@literal null}.
-		 * @return
+		 * @return {@literal true} if the given field refers to a {@link SystemVariable}.
 		 */
 		public static boolean isReferingToSystemVariable(@Nullable String fieldRef) {
 

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

@@ -31,8 +31,8 @@ public interface AggregationExpression {
 	 * Turns the {@link AggregationExpression} into a {@link Document} within the given
 	 * {@link AggregationOperationContext}.
 	 *
-	 * @param context
-	 * @return
+	 * @param context must not be {@literal null}.
+	 * @return the MongoDB native ({@link Document}) form of the expression.
 	 */
 	Document toDocument(AggregationOperationContext context);
 }

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

@@ -53,7 +53,7 @@ interface AggregationExpressionTransformer
 		 * @param currentNode must not be {@literal null}.
 		 * @param parentNode may be {@literal null}.
 		 * @param previousOperationObject may be {@literal null}.
-		 * @param aggregationContext must not be {@literal null}.
+		 * @param context must not be {@literal null}.
 		 */
 		public AggregationExpressionTransformationContext(T currentNode, @Nullable ExpressionNode parentNode,
 				@Nullable Document previousOperationObject, AggregationOperationContext context) {
@@ -67,7 +67,7 @@ interface AggregationExpressionTransformer
 		/**
 		 * Returns the underlying {@link AggregationOperationContext}.
 		 *
-		 * @return
+		 * @return never {@literal null}.
 		 */
 		public AggregationOperationContext getAggregationContext() {
 			return aggregationContext;
@@ -76,7 +76,7 @@ interface AggregationExpressionTransformer
 		/**
 		 * Returns the {@link FieldReference} for the current {@link ExpressionNode}.
 		 *
-		 * @return
+		 * @return never {@literal null}.
 		 */
 		public FieldReference getFieldReference() {
 			return aggregationContext.getReference(getCurrentNode().getName());

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

@@ -41,7 +41,7 @@ public enum AggregationFunctionExpressions {
 	 * Returns an {@link AggregationExpression} build from the current {@link Enum} name and the given parameters.
 	 *
 	 * @param parameters must not be {@literal null}
-	 * @return
+	 * @return new instance of {@link AggregationExpression}.
 	 */
 	public AggregationExpression of(Object... parameters) {
 

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

@@ -54,4 +54,15 @@ public interface AggregationOperation {
 	default List<Document> toPipelineStages(AggregationOperationContext context) {
 		return Collections.singletonList(toDocument(context));
 	}
+
+	/**
+	 * Return the MongoDB operator that is used for this {@link AggregationOperation}. Aggregation operations should
+	 * implement this method to avoid document rendering.
+	 *
+	 * @return the operator used for this {@link AggregationOperation}.
+	 * @since 3.0.2
+	 */
+	default String getOperator() {
+		return toDocument(Aggregation.DEFAULT_CONTEXT).keySet().iterator().next();
+	}
 }

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

@@ -20,7 +20,6 @@ import java.lang.reflect.Method;
 import java.util.Arrays;
 
 import org.bson.Document;
-
 import org.springframework.beans.BeanUtils;
 import org.springframework.data.mongodb.core.aggregation.ExposedFields.FieldReference;
 import org.springframework.lang.Nullable;
@@ -58,20 +57,20 @@ public interface AggregationOperationContext {
 	Document getMappedObject(Document document, @Nullable Class<?> type);
 
 	/**
-	 * Returns a {@link FieldReference} for the given field or {@literal null} if the context does not expose the given
-	 * field.
+	 * Returns a {@link FieldReference} for the given field.
 	 *
 	 * @param field must not be {@literal null}.
-	 * @return
+	 * @return the {@link FieldReference} for the given {@link Field}.
+	 * @throws IllegalArgumentException if the context does not expose a field with the given name
 	 */
 	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.
+	 * Returns the {@link FieldReference} for the field with the given name.
 	 *
 	 * @param name must not be {@literal null} or empty.
-	 * @return
+	 * @return the {@link FieldReference} for the field with given {@literal name}.
+	 * @throws IllegalArgumentException if the context does not expose a field with the given name
 	 */
 	FieldReference getReference(String name);
 
@@ -103,4 +102,16 @@ public interface AggregationOperationContext {
 				.map(PropertyDescriptor::getName) //
 				.toArray(String[]::new));
 	}
+
+	/**
+	 * This toggle allows the {@link AggregationOperationContext context} to use any given field name without checking for
+	 * its existence. Typically the {@link AggregationOperationContext} fails when referencing unknown fields, those that
+	 * are not present in one of the previous stages or the input source, throughout the pipeline.
+	 * 
+	 * @return a more relaxed {@link AggregationOperationContext}.
+	 * @since 3.0
+	 */
+	default AggregationOperationContext continueOnMissingFieldReference() {
+		return this;
+	}
 }

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

@@ -23,8 +23,6 @@ import org.springframework.data.mongodb.core.query.Collation;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 
-import com.mongodb.DBObject;
-
 /**
  * Holds a set of configurable aggregation options that can be used within an aggregation pipeline. A list of support
  * aggregation options can be found in the MongoDB reference documentation
@@ -54,6 +52,7 @@ public class AggregationOptions {
 	private final Optional<Collation> collation;
 	private final Optional<String> comment;
 	private Duration maxTime = Duration.ZERO;
+	private ResultOptions resultOptions = ResultOptions.READ;
 
 	/**
 	 * Creates a new {@link AggregationOptions}.
@@ -72,7 +71,7 @@ public class AggregationOptions {
 	 * @param allowDiskUse whether to off-load intensive sort-operations to disk.
 	 * @param explain whether to get the execution plan for the aggregation instead of the actual results.
 	 * @param cursor can be {@literal null}, used to pass additional options (such as {@code batchSize}) to the
-	 *          aggregation.
+	 * aggregation.
 	 * @param collation collation for string comparison. Can be {@literal null}.
 	 * @since 2.0
 	 */
@@ -87,7 +86,7 @@ public class AggregationOptions {
 	 * @param allowDiskUse whether to off-load intensive sort-operations to disk.
 	 * @param explain whether to get the execution plan for the aggregation instead of the actual results.
 	 * @param cursor can be {@literal null}, used to pass additional options (such as {@code batchSize}) to the
-	 *          aggregation.
+	 * aggregation.
 	 * @param collation collation for string comparison. Can be {@literal null}.
 	 * @param comment execution comment. Can be {@literal null}.
 	 * @since 2.2
@@ -115,7 +114,7 @@ public class AggregationOptions {
 	}
 
 	/**
-	 * Creates new {@link AggregationOptions} given {@link DBObject} containing aggregation options.
+	 * Creates new {@link AggregationOptions} given {@link Document} containing aggregation options.
 	 *
 	 * @param document must not be {@literal null}.
 	 * @return the {@link AggregationOptions}.
@@ -153,7 +152,7 @@ public class AggregationOptions {
 	 * Enables writing to temporary files. When set to true, aggregation stages can write data to the _tmp subdirectory in
 	 * the dbPath directory.
 	 *
-	 * @return
+	 * @return {@literal true} if enabled.
 	 */
 	public boolean isAllowDiskUse() {
 		return allowDiskUse;
@@ -162,7 +161,7 @@ public class AggregationOptions {
 	/**
 	 * Specifies to return the information on the processing of the pipeline.
 	 *
-	 * @return
+	 * @return {@literal true} if enabled.
 	 */
 	public boolean isExplain() {
 		return explain;
@@ -187,7 +186,7 @@ public class AggregationOptions {
 	/**
 	 * Specify a document that contains options that control the creation of the cursor object.
 	 *
-	 * @return
+	 * @return never {@literal null}.
 	 */
 	public Optional<Document> getCursor() {
 		return cursor;
@@ -196,7 +195,7 @@ public class AggregationOptions {
 	/**
 	 * Get collation settings for string comparison.
 	 *
-	 * @return
+	 * @return never {@literal null}.
 	 * @since 2.0
 	 */
 	public Optional<Collation> getCollation() {
@@ -206,7 +205,7 @@ public class AggregationOptions {
 	/**
 	 * Get the comment for the aggregation.
 	 *
-	 * @return
+	 * @return never {@literal null}.
 	 * @since 2.2
 	 */
 	public Optional<String> getComment() {
@@ -221,6 +220,15 @@ public class AggregationOptions {
 		return maxTime;
 	}
 
+	/**
+	 * @return {@literal true} to skip results when running an aggregation. Useful in combination with {@code $merge} or
+	 *         {@code $out}.
+	 * @since 3.0.2
+	 */
+	public boolean isSkipResults() {
+		return ResultOptions.SKIP.equals(resultOptions);
+	}
+
 	/**
 	 * Returns a new potentially adjusted copy for the given {@code aggregationCommandObject} with the configuration
 	 * applied.
@@ -258,7 +266,7 @@ public class AggregationOptions {
 	/**
 	 * Returns a {@link Document} representation of this {@link AggregationOptions}.
 	 *
-	 * @return
+	 * @return never {@literal null}.
 	 */
 	public Document toDocument() {
 
@@ -278,7 +286,7 @@ public class AggregationOptions {
 	}
 
 	/**
-	 * @return
+	 * @return {@literal true} if {@link #maxTime} is set to a positive value.
 	 * @since 3.0
 	 */
 	public boolean hasExecutionTimeLimit() {
@@ -311,12 +319,13 @@ public class AggregationOptions {
 		private @Nullable Collation collation;
 		private @Nullable String comment;
 		private @Nullable Duration maxTime;
+		private @Nullable ResultOptions resultOptions;
 
 		/**
 		 * Defines whether to off-load intensive sort-operations to disk.
 		 *
-		 * @param allowDiskUse
-		 * @return
+		 * @param allowDiskUse use {@literal true} to allow disk use during the aggregation.
+		 * @return this.
 		 */
 		public Builder allowDiskUse(boolean allowDiskUse) {
 
@@ -327,8 +336,8 @@ public class AggregationOptions {
 		/**
 		 * Defines whether to get the execution plan for the aggregation instead of the actual results.
 		 *
-		 * @param explain
-		 * @return
+		 * @param explain use {@literal true} to enable explain feature.
+		 * @return this.
 		 */
 		public Builder explain(boolean explain) {
 
@@ -339,8 +348,8 @@ public class AggregationOptions {
 		/**
 		 * Additional options to the aggregation.
 		 *
-		 * @param cursor
-		 * @return
+		 * @param cursor must not be {@literal null}.
+		 * @return this.
 		 */
 		public Builder cursor(Document cursor) {
 
@@ -351,8 +360,8 @@ public class AggregationOptions {
 		/**
 		 * Define the initial cursor batch size.
 		 *
-		 * @param batchSize
-		 * @return
+		 * @param batchSize use a positive int.
+		 * @return this.
 		 * @since 2.0
 		 */
 		public Builder cursorBatchSize(int batchSize) {
@@ -365,7 +374,7 @@ public class AggregationOptions {
 		 * Define collation settings for string comparison.
 		 *
 		 * @param collation can be {@literal null}.
-		 * @return
+		 * @return this.
 		 * @since 2.0
 		 */
 		public Builder collation(@Nullable Collation collation) {
@@ -378,7 +387,7 @@ public class AggregationOptions {
 		 * Define a comment to describe the execution.
 		 *
 		 * @param comment can be {@literal null}.
-		 * @return
+		 * @return this.
 		 * @since 2.2
 		 */
 		public Builder comment(@Nullable String comment) {
@@ -391,7 +400,7 @@ public class AggregationOptions {
 		 * Set the time limit for processing.
 		 *
 		 * @param maxTime {@link Duration#ZERO} is used for the default unbounded behavior. {@link Duration#isNegative()
-		 *          Negative} values will be ignored.
+		 * Negative} values will be ignored.
 		 * @return this.
 		 * @since 3.0
 		 */
@@ -401,10 +410,24 @@ public class AggregationOptions {
 			return this;
 		}
 
+		/**
+		 * Run the aggregation, but do NOT read the aggregation result from the store. <br />
+		 * If the expected result of the aggregation is rather large, eg. when using an {@literal $out} operation, this
+		 * option allows to execute the aggregation without having the cursor return the operation result.
+		 *
+		 * @return this.
+		 * @since 3.0.2
+		 */
+		public Builder skipOutput() {
+
+			this.resultOptions = ResultOptions.SKIP;
+			return this;
+		}
+
 		/**
 		 * Returns a new {@link AggregationOptions} instance with the given configuration.
 		 *
-		 * @return
+		 * @return new instance of {@link AggregationOptions}.
 		 */
 		public AggregationOptions build() {
 
@@ -412,8 +435,26 @@ public class AggregationOptions {
 			if (maxTime != null) {
 				options.maxTime = maxTime;
 			}
+			if (resultOptions != null) {
+				options.resultOptions = resultOptions;
+			}
 
 			return options;
 		}
 	}
+
+	/**
+	 * @since 3.0
+	 */
+	private enum ResultOptions {
+
+		/**
+		 * Just do it!, and do not read the operation result.
+		 */
+		SKIP,
+		/**
+		 * Read the aggregation result from the cursor.
+		 */
+		READ;
+	}
 }

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

@@ -0,0 +1,111 @@
+/*
+ * Copyright 2020 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
+ *
+ *      https://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.Collections;
+import java.util.List;
+
+import org.bson.Document;
+import org.springframework.util.Assert;
+
+/**
+ * The {@link AggregationPipeline} holds the collection of {@link AggregationOperation aggregation stages}.
+ *
+ * @author Christoph Strobl
+ * @since 3.0.2
+ */
+public class AggregationPipeline {
+
+	private final List<AggregationOperation> pipeline;
+
+	/**
+	 * Create an empty pipeline
+	 */
+	public AggregationPipeline() {
+		this(new ArrayList<>());
+	}
+
+	/**
+	 * Create a new pipeline with given {@link AggregationOperation stages}.
+	 *
+	 * @param aggregationOperations must not be {@literal null}.
+	 */
+	public AggregationPipeline(List<AggregationOperation> aggregationOperations) {
+		pipeline = new ArrayList<>(aggregationOperations);
+	}
+
+	/**
+	 * Append the given {@link AggregationOperation stage} to the pipeline.
+	 *
+	 * @param aggregationOperation must not be {@literal null}.
+	 * @return this.
+	 */
+	public AggregationPipeline add(AggregationOperation aggregationOperation) {
+
+		Assert.notNull(aggregationOperation, "AggregationOperation must not be null!");
+
+		pipeline.add(aggregationOperation);
+		return this;
+	}
+
+	/**
+	 * Get the list of {@link AggregationOperation aggregation stages}.
+	 *
+	 * @return never {@literal null}.
+	 */
+	public List<AggregationOperation> getOperations() {
+		return Collections.unmodifiableList(pipeline);
+	}
+
+	List<Document> toDocuments(AggregationOperationContext context) {
+
+		verify();
+		return AggregationOperationRenderer.toDocument(pipeline, context);
+	}
+
+	/**
+	 * @return {@literal true} if the last aggregation stage is either {@literal $out} or {@literal $merge}.
+	 */
+	public boolean isOutOrMerge() {
+
+		if (pipeline.isEmpty()) {
+			return false;
+		}
+
+		String operator = pipeline.get(pipeline.size() - 1).getOperator();
+		return operator.equals("$out") || operator.equals("$merge");
+	}
+
+	void verify() {
+
+		// check $out/$merge is the last operation if it exists
+		for (AggregationOperation aggregationOperation : pipeline) {
+
+			if (aggregationOperation instanceof OutOperation && !isLast(aggregationOperation)) {
+				throw new IllegalArgumentException("The $out operator must be the last stage in the pipeline.");
+			}
+
+			if (aggregationOperation instanceof MergeOperation && !isLast(aggregationOperation)) {
+				throw new IllegalArgumentException("The $merge operator must be the last stage in the pipeline.");
+			}
+		}
+	}
+
+	private boolean isLast(AggregationOperation aggregationOperation) {
+		return pipeline.indexOf(aggregationOperation) == pipeline.size() - 1;
+	}
+}

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

@@ -59,7 +59,7 @@ public class AggregationResults<T> implements Iterable<T> {
 	/**
 	 * Returns the aggregation results.
 	 *
-	 * @return
+	 * @return the list of already mapped results or an empty one if none found.
 	 */
 	public List<T> getMappedResults() {
 		return mappedResults;
@@ -68,7 +68,7 @@ public class AggregationResults<T> implements Iterable<T> {
 	/**
 	 * Returns the unique mapped result. Assumes no result or exactly one.
 	 *
-	 * @return
+	 * @return the single already mapped result object or raise an error if more than one found.
 	 * @throws IllegalArgumentException in case more than one result is available.
 	 */
 	@Nullable
@@ -88,7 +88,7 @@ public class AggregationResults<T> implements Iterable<T> {
 	/**
 	 * Returns the server that has been used to perform the aggregation.
 	 *
-	 * @return
+	 * @return can be {@literal null}.
 	 */
 	@Nullable
 	public String getServerUsed() {
@@ -98,7 +98,7 @@ public class AggregationResults<T> implements Iterable<T> {
 	/**
 	 * Returns the raw result that was returned by the server.
 	 *
-	 * @return
+	 * @return the raw response.
 	 * @since 1.6
 	 */
 	public Document getRawResults() {

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

@@ -56,7 +56,7 @@ public class AggregationSpELExpression implements AggregationExpression {
 	 *
 	 * @param expressionString must not be {@literal null}.
 	 * @param parameters can be empty.
-	 * @return
+	 * @return new instance of {@link AggregationSpELExpression}.
 	 */
 	public static AggregationSpELExpression expressionOf(String expressionString, Object... parameters) {
 

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

@@ -79,7 +79,7 @@ import org.springframework.util.Assert;
 public class AggregationUpdate extends Aggregation implements UpdateDefinition {
 
 	private boolean isolated = false;
-	private Set<String> keysTouched = new HashSet<>();
+	private final Set<String> keysTouched = new HashSet<>();
 
 	/**
 	 * Create new {@link AggregationUpdate}.
@@ -139,7 +139,7 @@ public class AggregationUpdate extends Aggregation implements UpdateDefinition {
 		setOperation.getFields().forEach(it -> {
 			keysTouched.add(it.getName());
 		});
-		operations.add(setOperation);
+		pipeline.add(setOperation);
 		return this;
 	}
 
@@ -155,7 +155,7 @@ public class AggregationUpdate extends Aggregation implements UpdateDefinition {
 
 		Assert.notNull(unsetOperation, "UnsetOperation must not be null!");
 
-		operations.add(unsetOperation);
+		pipeline.add(unsetOperation);
 		keysTouched.addAll(unsetOperation.removedFieldNames());
 		return this;
 	}
@@ -164,7 +164,7 @@ public class AggregationUpdate extends Aggregation implements UpdateDefinition {
 	 * {@code $replaceWith} replaces the input document with the specified document. The operation replaces all existing
 	 * fields in the input document, including the <strong>_id</strong> field.
 	 *
-	 * @param replaceWithOperation
+	 * @param replaceWithOperation must not be {@literal null}.
 	 * @return this.
 	 * @see <a href="https://docs.mongodb.com/manual/reference/operator/aggregation/replaceWith/">$replaceWith Aggregation
 	 *      Reference</a>
@@ -172,7 +172,7 @@ public class AggregationUpdate extends Aggregation implements UpdateDefinition {
 	public AggregationUpdate replaceWith(ReplaceWithOperation replaceWithOperation) {
 
 		Assert.notNull(replaceWithOperation, "ReplaceWithOperation must not be null!");
-		operations.add(replaceWithOperation);
+		pipeline.add(replaceWithOperation);
 		return this;
 	}
 
@@ -219,8 +219,8 @@ public class AggregationUpdate extends Aggregation implements UpdateDefinition {
 	/**
 	 * Short for {@link #unset(UnsetOperation)}.
 	 *
-	 * @param keys
-	 * @return
+	 * @param keys the fields to remove.
+	 * @return this.
 	 */
 	public AggregationUpdate unset(String... keys) {
 

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

@@ -32,9 +32,9 @@ interface AggregationUtils {
 	 * Converts the given {@link Range} into an array of values.
 	 *
 	 * @param range must not be {@literal null}.
-	 * @return
+	 * @return never {@literal null}.
 	 */
-	public static List<Long> toRangeValues(Range<Long> range) {
+	static List<Long> toRangeValues(Range<Long> range) {
 
 		Assert.notNull(range, "Range must not be null!");
 

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

@@ -38,7 +38,7 @@ public class ArithmeticOperators {
 	 * Take the field referenced by given {@literal fieldReference}.
 	 *
 	 * @param fieldReference must not be {@literal null}.
-	 * @return
+	 * @return new instance of {@link ArithmeticOperatorFactory}.
 	 */
 	public static ArithmeticOperatorFactory valueOf(String fieldReference) {
 		return new ArithmeticOperatorFactory(fieldReference);
@@ -48,7 +48,7 @@ public class ArithmeticOperators {
 	 * Take the value resulting from the given {@link AggregationExpression}.
 	 *
 	 * @param expression must not be {@literal null}.
-	 * @return
+	 * @return new instance of {@link ArithmeticOperatorFactory}.
 	 */
 	public static ArithmeticOperatorFactory valueOf(AggregationExpression expression) {
 		return new ArithmeticOperatorFactory(expression);
@@ -89,7 +89,7 @@ public class ArithmeticOperators {
 		/**
 		 * Creates new {@link AggregationExpression} that returns the absolute value of the associated number.
 		 *
-		 * @return
+		 * @return new instance of {@link Abs}.
 		 */
 		public Abs abs() {
 			return usesFieldRef() ? Abs.absoluteValueOf(fieldReference) : Abs.absoluteValueOf(expression);
@@ -100,7 +100,7 @@ public class ArithmeticOperators {
 		 * number.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Add}.
 		 */
 		public Add add(String fieldReference) {
 
@@ -113,7 +113,7 @@ public class ArithmeticOperators {
 		 * {@link AggregationExpression} to the associated number.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Add}.
 		 */
 		public Add add(AggregationExpression expression) {
 
@@ -125,7 +125,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link AggregationExpression} that adds the given {@literal value} to the associated number.
 		 *
 		 * @param value must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Add}.
 		 */
 		public Add add(Number value) {
 
@@ -141,7 +141,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link AggregationExpression} that returns the smallest integer greater than or equal to the
 		 * assoicated number.
 		 *
-		 * @return
+		 * @return new instance of {@link Ceil}.
 		 */
 		public Ceil ceil() {
 			return usesFieldRef() ? Ceil.ceilValueOf(fieldReference) : Ceil.ceilValueOf(expression);
@@ -152,7 +152,7 @@ public class ArithmeticOperators {
 		 * {@literal fieldReference}.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Divide}.
 		 */
 		public Divide divideBy(String fieldReference) {
 
@@ -165,7 +165,7 @@ public class ArithmeticOperators {
 		 * {@literal expression}.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Divide}.
 		 */
 		public Divide divideBy(AggregationExpression expression) {
 
@@ -176,8 +176,8 @@ public class ArithmeticOperators {
 		/**
 		 * Creates new {@link AggregationExpression} that divides the associated number by given {@literal value}.
 		 *
-		 * @param value
-		 * @return
+		 * @param value must not be {@literal null}.
+		 * @return new instance of {@link Divide}.
 		 */
 		public Divide divideBy(Number value) {
 
@@ -192,7 +192,7 @@ public class ArithmeticOperators {
 		/**
 		 * Creates new {@link AggregationExpression} that raises Euler’s number (i.e. e ) on the associated number.
 		 *
-		 * @return
+		 * @return new instance of {@link Exp}.
 		 */
 		public Exp exp() {
 			return usesFieldRef() ? Exp.expValueOf(fieldReference) : Exp.expValueOf(expression);
@@ -202,7 +202,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link AggregationExpression} that returns the largest integer less than or equal to the associated
 		 * number.
 		 *
-		 * @return
+		 * @return new instance of {@link Floor}.
 		 */
 		public Floor floor() {
 			return usesFieldRef() ? Floor.floorValueOf(fieldReference) : Floor.floorValueOf(expression);
@@ -212,7 +212,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link AggregationExpression} that calculates the natural logarithm ln (i.e loge) of the assoicated
 		 * number.
 		 *
-		 * @return
+		 * @return new instance of {@link Ln}.
 		 */
 		public Ln ln() {
 			return usesFieldRef() ? Ln.lnValueOf(fieldReference) : Ln.lnValueOf(expression);
@@ -223,7 +223,7 @@ public class ArithmeticOperators {
 		 * referenced via {@literal fieldReference}.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Log}.
 		 */
 		public Log log(String fieldReference) {
 
@@ -236,7 +236,7 @@ public class ArithmeticOperators {
 		 * extracted by given {@link AggregationExpression}.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Log}.
 		 */
 		public Log log(AggregationExpression expression) {
 
@@ -249,7 +249,7 @@ public class ArithmeticOperators {
 		 * {@literal base}.
 		 *
 		 * @param base must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Log}.
 		 */
 		public Log log(Number base) {
 
@@ -264,7 +264,7 @@ public class ArithmeticOperators {
 		/**
 		 * Creates new {@link AggregationExpression} that calculates the log base 10 for the associated number.
 		 *
-		 * @return
+		 * @return new instance of {@link Log10}.
 		 */
 		public Log10 log10() {
 			return usesFieldRef() ? Log10.log10ValueOf(fieldReference) : Log10.log10ValueOf(expression);
@@ -275,7 +275,7 @@ public class ArithmeticOperators {
 		 * remainder.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Mod}.
 		 */
 		public Mod mod(String fieldReference) {
 
@@ -288,7 +288,7 @@ public class ArithmeticOperators {
 		 * remainder.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Mod}.
 		 */
 		public Mod mod(AggregationExpression expression) {
 
@@ -301,7 +301,7 @@ public class ArithmeticOperators {
 		 * remainder.
 		 *
 		 * @param value must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Mod}.
 		 */
 		public Mod mod(Number value) {
 
@@ -317,7 +317,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link AggregationExpression} that multiplies the associated number with another.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Multiply}.
 		 */
 		public Multiply multiplyBy(String fieldReference) {
 
@@ -329,7 +329,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link AggregationExpression} that multiplies the associated number with another.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Multiply}.
 		 */
 		public Multiply multiplyBy(AggregationExpression expression) {
 
@@ -341,7 +341,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link AggregationExpression} that multiplies the associated number with another.
 		 *
 		 * @param value must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Multiply}.
 		 */
 		public Multiply multiplyBy(Number value) {
 
@@ -357,7 +357,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link AggregationExpression} that raises the associated number to the specified exponent.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Pow}.
 		 */
 		public Pow pow(String fieldReference) {
 
@@ -369,7 +369,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link AggregationExpression} that raises the associated number to the specified exponent.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Pow}.
 		 */
 		public Pow pow(AggregationExpression expression) {
 
@@ -381,7 +381,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link AggregationExpression} that raises the associated number to the specified exponent.
 		 *
 		 * @param value must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Pow}.
 		 */
 		public Pow pow(Number value) {
 
@@ -396,7 +396,7 @@ public class ArithmeticOperators {
 		/**
 		 * Creates new {@link AggregationExpression} that calculates the square root of the associated number.
 		 *
-		 * @return
+		 * @return new instance of {@link Sqrt}.
 		 */
 		public Sqrt sqrt() {
 			return usesFieldRef() ? Sqrt.sqrtOf(fieldReference) : Sqrt.sqrtOf(expression);
@@ -406,7 +406,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link AggregationExpression} that subtracts value of given from the associated number.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Subtract}.
 		 */
 		public Subtract subtract(String fieldReference) {
 
@@ -418,7 +418,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link AggregationExpression} that subtracts value of given from the associated number.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Subtract}.
 		 */
 		public Subtract subtract(AggregationExpression expression) {
 
@@ -429,8 +429,8 @@ public class ArithmeticOperators {
 		/**
 		 * Creates new {@link AggregationExpression} that subtracts value from the associated number.
 		 *
-		 * @param value
-		 * @return
+		 * @param value must not be {@literal null}.
+		 * @return new instance of {@link Subtract}.
 		 */
 		public Subtract subtract(Number value) {
 
@@ -445,7 +445,7 @@ public class ArithmeticOperators {
 		/**
 		 * Creates new {@link AggregationExpression} that truncates a number to its integer.
 		 *
-		 * @return
+		 * @return new instance of {@link Trunc}.
 		 */
 		public Trunc trunc() {
 			return usesFieldRef() ? Trunc.truncValueOf(fieldReference) : Trunc.truncValueOf(expression);
@@ -454,7 +454,7 @@ public class ArithmeticOperators {
 		/**
 		 * Creates new {@link AggregationExpression} that calculates and returns the sum of numeric values.
 		 *
-		 * @return
+		 * @return new instance of {@link Sum}.
 		 */
 		public Sum sum() {
 			return usesFieldRef() ? AccumulatorOperators.Sum.sumOf(fieldReference)
@@ -464,7 +464,7 @@ public class ArithmeticOperators {
 		/**
 		 * Creates new {@link AggregationExpression} that returns the average value of the numeric values.
 		 *
-		 * @return
+		 * @return new instance of {@link Avg}.
 		 */
 		public Avg avg() {
 			return usesFieldRef() ? AccumulatorOperators.Avg.avgOf(fieldReference)
@@ -474,7 +474,7 @@ public class ArithmeticOperators {
 		/**
 		 * Creates new {@link AggregationExpression} that returns the maximum value.
 		 *
-		 * @return
+		 * @return new instance of {@link Max}.
 		 */
 		public Max max() {
 			return usesFieldRef() ? AccumulatorOperators.Max.maxOf(fieldReference)
@@ -484,7 +484,7 @@ public class ArithmeticOperators {
 		/**
 		 * Creates new {@link AggregationExpression} that returns the minimum value.
 		 *
-		 * @return
+		 * @return new instance of {@link Min}.
 		 */
 		public Min min() {
 			return usesFieldRef() ? AccumulatorOperators.Min.minOf(fieldReference)
@@ -494,7 +494,7 @@ public class ArithmeticOperators {
 		/**
 		 * Creates new {@link AggregationExpression} that calculates the population standard deviation of the input values.
 		 *
-		 * @return
+		 * @return new instance of {@link StdDevPop}.
 		 */
 		public StdDevPop stdDevPop() {
 			return usesFieldRef() ? AccumulatorOperators.StdDevPop.stdDevPopOf(fieldReference)
@@ -504,7 +504,7 @@ public class ArithmeticOperators {
 		/**
 		 * Creates new {@link AggregationExpression} that calculates the sample standard deviation of the input values.
 		 *
-		 * @return
+		 * @return new instance of {@link StdDevSamp}.
 		 */
 		public StdDevSamp stdDevSamp() {
 			return usesFieldRef() ? AccumulatorOperators.StdDevSamp.stdDevSampOf(fieldReference)
@@ -557,7 +557,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link Abs}.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Abs}.
 		 */
 		public static Abs absoluteValueOf(String fieldReference) {
 
@@ -569,7 +569,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link Abs}.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Abs}.
 		 */
 		public static Abs absoluteValueOf(AggregationExpression expression) {
 
@@ -581,7 +581,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link Abs}.
 		 *
 		 * @param value must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Abs}.
 		 */
 		public static Abs absoluteValueOf(Number value) {
 
@@ -610,7 +610,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link Add}.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Add}.
 		 */
 		public static Add valueOf(String fieldReference) {
 
@@ -622,7 +622,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link Add}.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Add}.
 		 */
 		public static Add valueOf(AggregationExpression expression) {
 
@@ -634,7 +634,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link Add}.
 		 *
 		 * @param value must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Add}.
 		 */
 		public static Add valueOf(Number value) {
 
@@ -642,18 +642,36 @@ public class ArithmeticOperators {
 			return new Add(Collections.singletonList(value));
 		}
 
+		/**
+		 * Add the value stored at the given field.
+		 * 
+		 * @param fieldReference must not be {@literal null}.
+		 * @return new instance of {@link Add}.
+		 */
 		public Add add(String fieldReference) {
 
 			Assert.notNull(fieldReference, "FieldReference must not be null!");
 			return new Add(append(Fields.field(fieldReference)));
 		}
 
+		/**
+		 * Add the evaluation result of the given {@link AggregationExpression}.
+		 * 
+		 * @param expression must not be {@literal null}.
+		 * @return new instance of {@link Add}.
+		 */
 		public Add add(AggregationExpression expression) {
 
 			Assert.notNull(expression, "Expression must not be null!");
 			return new Add(append(expression));
 		}
 
+		/**
+		 * Add the given value.
+		 * 
+		 * @param value must not be {@literal null}.
+		 * @return new instance of {@link Add}.
+		 */
 		public Add add(Number value) {
 			return new Add(append(value));
 		}
@@ -679,7 +697,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link Ceil}.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Ceil}.
 		 */
 		public static Ceil ceilValueOf(String fieldReference) {
 
@@ -691,7 +709,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link Ceil}.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Ceil}.
 		 */
 		public static Ceil ceilValueOf(AggregationExpression expression) {
 
@@ -703,7 +721,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link Ceil}.
 		 *
 		 * @param value must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Ceil}.
 		 */
 		public static Ceil ceilValueOf(Number value) {
 
@@ -732,7 +750,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link Divide}.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Divide}.
 		 */
 		public static Divide valueOf(String fieldReference) {
 
@@ -744,7 +762,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link Divide}.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Divide}.
 		 */
 		public static Divide valueOf(AggregationExpression expression) {
 
@@ -756,7 +774,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link Divide}.
 		 *
 		 * @param value must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Divide}.
 		 */
 		public static Divide valueOf(Number value) {
 
@@ -764,18 +782,36 @@ public class ArithmeticOperators {
 			return new Divide(Collections.singletonList(value));
 		}
 
+		/**
+		 * Divide by the value stored at the given field.
+		 * 
+		 * @param fieldReference must not be {@literal null}.
+		 * @return new instance of {@link Divide}.
+		 */
 		public Divide divideBy(String fieldReference) {
 
 			Assert.notNull(fieldReference, "FieldReference must not be null!");
 			return new Divide(append(Fields.field(fieldReference)));
 		}
 
+		/**
+		 * Divide by the evaluation results of the given {@link AggregationExpression}.
+		 * 
+		 * @param expression must not be {@literal null}.
+		 * @return new instance of {@link Divide}.
+		 */
 		public Divide divideBy(AggregationExpression expression) {
 
 			Assert.notNull(expression, "Expression must not be null!");
 			return new Divide(append(expression));
 		}
 
+		/**
+		 * Divide by the given value.
+		 * 
+		 * @param value must not be {@literal null}.
+		 * @return new instance of {@link Divide}.
+		 */
 		public Divide divideBy(Number value) {
 			return new Divide(append(value));
 		}
@@ -801,7 +837,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link Exp}.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Exp}.
 		 */
 		public static Exp expValueOf(String fieldReference) {
 
@@ -813,7 +849,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link Exp}.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Exp}.
 		 */
 		public static Exp expValueOf(AggregationExpression expression) {
 
@@ -825,7 +861,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link Exp}.
 		 *
 		 * @param value must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Exp}.
 		 */
 		public static Exp expValueOf(Number value) {
 
@@ -854,7 +890,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link Floor}.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Floor}.
 		 */
 		public static Floor floorValueOf(String fieldReference) {
 
@@ -866,7 +902,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link Floor}.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Floor}.
 		 */
 		public static Floor floorValueOf(AggregationExpression expression) {
 
@@ -878,7 +914,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link Floor}.
 		 *
 		 * @param value must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Floor}.
 		 */
 		public static Floor floorValueOf(Number value) {
 
@@ -907,7 +943,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link Ln}.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Ln}.
 		 */
 		public static Ln lnValueOf(String fieldReference) {
 
@@ -919,7 +955,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link Ln}.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Ln}.
 		 */
 		public static Ln lnValueOf(AggregationExpression expression) {
 
@@ -931,7 +967,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link Ln}.
 		 *
 		 * @param value must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Ln}.
 		 */
 		public static Ln lnValueOf(Number value) {
 
@@ -960,7 +996,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link Min}.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Log}.
 		 */
 		public static Log valueOf(String fieldReference) {
 
@@ -972,7 +1008,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link Log}.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Log}.
 		 */
 		public static Log valueOf(AggregationExpression expression) {
 
@@ -992,18 +1028,36 @@ public class ArithmeticOperators {
 			return new Log(Collections.singletonList(value));
 		}
 
+		/**
+		 * Use the value stored at the given field as log base.
+		 * 
+		 * @param fieldReference must not be {@literal null}.
+		 * @return new instance of {@link Log}.
+		 */
 		public Log log(String fieldReference) {
 
 			Assert.notNull(fieldReference, "FieldReference must not be null!");
 			return new Log(append(Fields.field(fieldReference)));
 		}
 
+		/**
+		 * Use the evaluated value of the given {@link AggregationExpression} as log base.
+		 * 
+		 * @param expression must not be {@literal null}.
+		 * @return new instance of {@link Log}.
+		 */
 		public Log log(AggregationExpression expression) {
 
 			Assert.notNull(expression, "Expression must not be null!");
 			return new Log(append(expression));
 		}
 
+		/**
+		 * Use the given value as log base.
+		 * 
+		 * @param base must not be {@literal null}.
+		 * @return new instance of {@link Log}.
+		 */
 		public Log log(Number base) {
 			return new Log(append(base));
 		}
@@ -1029,7 +1083,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link Log10}.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Log10}.
 		 */
 		public static Log10 log10ValueOf(String fieldReference) {
 
@@ -1041,7 +1095,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link Log10}.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Log10}.
 		 */
 		public static Log10 log10ValueOf(AggregationExpression expression) {
 
@@ -1053,7 +1107,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link Log10}.
 		 *
 		 * @param value must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Log10}.
 		 */
 		public static Log10 log10ValueOf(Number value) {
 
@@ -1082,7 +1136,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link Mod}.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Mod}.
 		 */
 		public static Mod valueOf(String fieldReference) {
 
@@ -1094,7 +1148,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link Mod}.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Mod}.
 		 */
 		public static Mod valueOf(AggregationExpression expression) {
 
@@ -1106,7 +1160,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link Mod}.
 		 *
 		 * @param value must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Mod}.
 		 */
 		public static Mod valueOf(Number value) {
 
@@ -1114,18 +1168,36 @@ public class ArithmeticOperators {
 			return new Mod(Collections.singletonList(value));
 		}
 
+		/**
+		 * Use the value stored at the given field as mod base.
+		 * 
+		 * @param fieldReference must not be {@literal null}.
+		 * @return new instance of {@link Mod}.
+		 */
 		public Mod mod(String fieldReference) {
 
 			Assert.notNull(fieldReference, "FieldReference must not be null!");
 			return new Mod(append(Fields.field(fieldReference)));
 		}
 
+		/**
+		 * Use evaluated value of the given {@link AggregationExpression} as mod base.
+		 * 
+		 * @param expression must not be {@literal null}.
+		 * @return new instance of {@link Mod}.
+		 */
 		public Mod mod(AggregationExpression expression) {
 
 			Assert.notNull(expression, "Expression must not be null!");
 			return new Mod(append(expression));
 		}
 
+		/**
+		 * Use the given value as mod base.
+		 * 
+		 * @param base must not be {@literal null}.
+		 * @return new instance of {@link Mod}.
+		 */
 		public Mod mod(Number base) {
 			return new Mod(append(base));
 		}
@@ -1151,7 +1223,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link Multiply}.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Multiply}.
 		 */
 		public static Multiply valueOf(String fieldReference) {
 
@@ -1163,7 +1235,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link Multiply}.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Multiply}.
 		 */
 		public static Multiply valueOf(AggregationExpression expression) {
 
@@ -1175,7 +1247,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link Multiply}.
 		 *
 		 * @param value must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Multiply}.
 		 */
 		public static Multiply valueOf(Number value) {
 
@@ -1183,18 +1255,36 @@ public class ArithmeticOperators {
 			return new Multiply(Collections.singletonList(value));
 		}
 
+		/**
+		 * Multiply by the value stored at the given field.
+		 * 
+		 * @param fieldReference must not be {@literal null}.
+		 * @return new instance of {@link Multiply}.
+		 */
 		public Multiply multiplyBy(String fieldReference) {
 
 			Assert.notNull(fieldReference, "FieldReference must not be null!");
 			return new Multiply(append(Fields.field(fieldReference)));
 		}
 
+		/**
+		 * Multiply by the evaluated value of the given {@link AggregationExpression}.
+		 * 
+		 * @param expression must not be {@literal null}.
+		 * @return new instance of {@link Multiply}.
+		 */
 		public Multiply multiplyBy(AggregationExpression expression) {
 
 			Assert.notNull(expression, "Expression must not be null!");
 			return new Multiply(append(expression));
 		}
 
+		/**
+		 * Multiply by the given value.
+		 * 
+		 * @param value must not be {@literal null}.
+		 * @return new instance of {@link Multiply}.
+		 */
 		public Multiply multiplyBy(Number value) {
 			return new Multiply(append(value));
 		}
@@ -1252,18 +1342,36 @@ public class ArithmeticOperators {
 			return new Pow(Collections.singletonList(value));
 		}
 
+		/**
+		 * Pow by the value stored at the given field.
+		 * 
+		 * @param fieldReference must not be {@literal null}.
+		 * @return new instance of {@link Pow}.
+		 */
 		public Pow pow(String fieldReference) {
 
 			Assert.notNull(fieldReference, "FieldReference must not be null!");
 			return new Pow(append(Fields.field(fieldReference)));
 		}
 
+		/**
+		 * Pow by the evaluated value of the given {@link AggregationExpression}.
+		 * 
+		 * @param expression must not be {@literal null}.
+		 * @return new instance of {@link Pow}.
+		 */
 		public Pow pow(AggregationExpression expression) {
 
 			Assert.notNull(expression, "Expression must not be null!");
 			return new Pow(append(expression));
 		}
 
+		/**
+		 * Pow by the given value.
+		 * 
+		 * @param value must not be {@literal null}.
+		 * @return new instance of {@link Pow}.
+		 */
 		public Pow pow(Number value) {
 			return new Pow(append(value));
 		}
@@ -1289,7 +1397,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link Sqrt}.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Sqrt}.
 		 */
 		public static Sqrt sqrtOf(String fieldReference) {
 
@@ -1301,7 +1409,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link Sqrt}.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Sqrt}.
 		 */
 		public static Sqrt sqrtOf(AggregationExpression expression) {
 
@@ -1313,7 +1421,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link Sqrt}.
 		 *
 		 * @param value must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Sqrt}.
 		 */
 		public static Sqrt sqrtOf(Number value) {
 
@@ -1342,7 +1450,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link Subtract}.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Subtract}.
 		 */
 		public static Subtract valueOf(String fieldReference) {
 
@@ -1354,7 +1462,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link Subtract}.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Subtract}.
 		 */
 		public static Subtract valueOf(AggregationExpression expression) {
 
@@ -1366,7 +1474,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link Subtract}.
 		 *
 		 * @param value must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Subtract}.
 		 */
 		public static Subtract valueOf(Number value) {
 
@@ -1374,18 +1482,36 @@ public class ArithmeticOperators {
 			return new Subtract(Collections.singletonList(value));
 		}
 
+		/**
+		 * Subtract the value stored at the given field.
+		 * 
+		 * @param fieldReference must not be {@literal null}.
+		 * @return new instance of {@link Pow}.
+		 */
 		public Subtract subtract(String fieldReference) {
 
 			Assert.notNull(fieldReference, "FieldReference must not be null!");
 			return new Subtract(append(Fields.field(fieldReference)));
 		}
 
+		/**
+		 * Subtract the evaluated value of the given {@link AggregationExpression}.
+		 * 
+		 * @param expression must not be {@literal null}.
+		 * @return new instance of {@link Pow}.
+		 */
 		public Subtract subtract(AggregationExpression expression) {
 
 			Assert.notNull(expression, "Expression must not be null!");
 			return new Subtract(append(expression));
 		}
 
+		/**
+		 * Subtract the given value.
+		 * 
+		 * @param value must not be {@literal null}.
+		 * @return new instance of {@link Pow}.
+		 */
 		public Subtract subtract(Number value) {
 			return new Subtract(append(value));
 		}
@@ -1411,7 +1537,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link Trunc}.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Trunc}.
 		 */
 		public static Trunc truncValueOf(String fieldReference) {
 
@@ -1423,7 +1549,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link Trunc}.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Trunc}.
 		 */
 		public static Trunc truncValueOf(AggregationExpression expression) {
 
@@ -1435,7 +1561,7 @@ public class ArithmeticOperators {
 		 * Creates new {@link Trunc}.
 		 *
 		 * @param value must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Trunc}.
 		 */
 		public static Trunc truncValueOf(Number value) {
 
@@ -1502,7 +1628,7 @@ public class ArithmeticOperators {
 		/**
 		 * The place to round to. Can be between -20 and 100, exclusive.
 		 *
-		 * @param place
+		 * @param place value between -20 and 100, exclusive.
 		 * @return new instance of {@link Round}.
 		 */
 		public Round place(int place) {

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

@@ -43,7 +43,7 @@ public class ArrayOperators {
 	 * Take the array referenced by given {@literal fieldReference}.
 	 *
 	 * @param fieldReference must not be {@literal null}.
-	 * @return
+	 * @return new instance of {@link ArrayOperatorFactory}.
 	 */
 	public static ArrayOperatorFactory arrayOf(String fieldReference) {
 		return new ArrayOperatorFactory(fieldReference);
@@ -53,7 +53,7 @@ public class ArrayOperators {
 	 * Take the array referenced resulting from the given {@link AggregationExpression}.
 	 *
 	 * @param expression must not be {@literal null}.
-	 * @return
+	 * @return new instance of {@link ArrayOperatorFactory}.
 	 */
 	public static ArrayOperatorFactory arrayOf(AggregationExpression expression) {
 		return new ArrayOperatorFactory(expression);
@@ -123,8 +123,8 @@ public class ArrayOperators {
 		 * Creates new {@link AggregationExpression} that takes the associated array and returns the element at the
 		 * specified array {@literal position}.
 		 *
-		 * @param position
-		 * @return
+		 * @param position the element index.
+		 * @return new instance of {@link ArrayElemAt}.
 		 */
 		public ArrayElemAt elementAt(int position) {
 			return createArrayElemAt().elementAt(position);
@@ -135,7 +135,7 @@ public class ArrayOperators {
 		 * resulting form the given {@literal expression}.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link ArrayElemAt}.
 		 */
 		public ArrayElemAt elementAt(AggregationExpression expression) {
 
@@ -148,7 +148,7 @@ public class ArrayOperators {
 		 * defined by the referenced {@literal field}.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link ArrayElemAt}.
 		 */
 		public ArrayElemAt elementAt(String fieldReference) {
 
@@ -170,7 +170,7 @@ public class ArrayOperators {
 		 * {@literal arrayFieldReference} to it.
 		 *
 		 * @param arrayFieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link ConcatArrays}.
 		 */
 		public ConcatArrays concat(String arrayFieldReference) {
 
@@ -183,7 +183,7 @@ public class ArrayOperators {
 		 * the given {@literal expression} to it.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link ConcatArrays}.
 		 */
 		public ConcatArrays concat(AggregationExpression expression) {
 
@@ -204,7 +204,7 @@ public class ArrayOperators {
 		 * Creates new {@link AggregationExpression} that takes the associated array and selects a subset of the array to
 		 * return based on the specified condition.
 		 *
-		 * @return
+		 * @return new instance of {@link AsBuilder} to create a {@link Filter}.
 		 */
 		public AsBuilder filter() {
 
@@ -219,7 +219,7 @@ public class ArrayOperators {
 		/**
 		 * Creates new {@link AggregationExpression} that takes the associated array and an check if its an array.
 		 *
-		 * @return
+		 * @return new instance of {@link IsArray}.
 		 */
 		public IsArray isArray() {
 
@@ -231,7 +231,7 @@ public class ArrayOperators {
 		/**
 		 * Creates new {@link AggregationExpression} that takes the associated array and retrieves its length.
 		 *
-		 * @return
+		 * @return new instance of {@link Size}.
 		 */
 		public Size length() {
 
@@ -245,7 +245,7 @@ public class ArrayOperators {
 		/**
 		 * Creates new {@link AggregationExpression} that takes the associated array and selects a subset from it.
 		 *
-		 * @return
+		 * @return new instance of {@link Slice}.
 		 */
 		public Slice slice() {
 
@@ -261,7 +261,7 @@ public class ArrayOperators {
 		 * value and returns the array index (zero-based) of the first occurrence.
 		 *
 		 * @param value must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link IndexOfArray}.
 		 */
 		public IndexOfArray indexOf(Object value) {
 
@@ -276,7 +276,7 @@ public class ArrayOperators {
 		/**
 		 * Creates new {@link AggregationExpression} that returns an array with the elements in reverse order.
 		 *
-		 * @return
+		 * @return new instance of {@link ReverseArray}.
 		 */
 		public ReverseArray reverse() {
 
@@ -293,7 +293,7 @@ public class ArrayOperators {
 		 * an array and combines them into a single value.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link ReduceInitialValueBuilder} to create {@link Reduce}.
 		 */
 		public ArrayOperatorFactory.ReduceInitialValueBuilder reduce(AggregationExpression expression) {
 
@@ -305,8 +305,8 @@ public class ArrayOperators {
 		 * Start creating new {@link AggregationExpression} that applies an {@link AggregationExpression} to each element in
 		 * an array and combines them into a single value.
 		 *
-		 * @param expressions
-		 * @return
+		 * @param expressions must not be {@literal null}.
+		 * @return new instance of {@link ReduceInitialValueBuilder} to create {@link Reduce}.
 		 */
 		public ArrayOperatorFactory.ReduceInitialValueBuilder reduce(PropertyExpression... expressions) {
 
@@ -320,7 +320,7 @@ public class ArrayOperators {
 		 * the second input array, etc.
 		 *
 		 * @param arrays must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Zip}.
 		 */
 		public Zip zipWith(Object... arrays) {
 
@@ -336,7 +336,7 @@ public class ArrayOperators {
 		 * associated array.
 		 *
 		 * @param value must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link In}.
 		 */
 		public In containsValue(Object value) {
 
@@ -413,7 +413,7 @@ public class ArrayOperators {
 		 * Creates new {@link ArrayElemAt}.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link ArrayElemAt}.
 		 */
 		public static ArrayElemAt arrayOf(String fieldReference) {
 
@@ -425,7 +425,7 @@ public class ArrayOperators {
 		 * Creates new {@link ArrayElemAt}.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link ArrayElemAt}.
 		 */
 		public static ArrayElemAt arrayOf(AggregationExpression expression) {
 
@@ -446,16 +446,34 @@ public class ArrayOperators {
 			return new ArrayElemAt(Collections.singletonList(values));
 		}
 
+		/**
+		 * Use the element with given index number.
+		 *
+		 * @param index the index number
+		 * @return new instance of {@link ArrayElemAt}.
+		 */
 		public ArrayElemAt elementAt(int index) {
 			return new ArrayElemAt(append(index));
 		}
 
+		/**
+		 * Use the element at the index number evaluated from the given {@link AggregationExpression}.
+		 *
+		 * @param expression must not be {@literal null}.
+		 * @return new instance of {@link ArrayElemAt}.
+		 */
 		public ArrayElemAt elementAt(AggregationExpression expression) {
 
 			Assert.notNull(expression, "Expression must not be null!");
 			return new ArrayElemAt(append(expression));
 		}
 
+		/**
+		 * Use the element at the index number traken from the given field.
+		 *
+		 * @param arrayFieldReference the field name.
+		 * @return new instance of {@link ArrayElemAt}.
+		 */
 		public ArrayElemAt elementAt(String arrayFieldReference) {
 
 			Assert.notNull(arrayFieldReference, "ArrayReference must not be null!");
@@ -483,7 +501,7 @@ public class ArrayOperators {
 		 * Creates new {@link ConcatArrays}.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link ConcatArrays}.
 		 */
 		public static ConcatArrays arrayOf(String fieldReference) {
 
@@ -495,7 +513,7 @@ public class ArrayOperators {
 		 * Creates new {@link ConcatArrays}.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link ConcatArrays}.
 		 */
 		public static ConcatArrays arrayOf(AggregationExpression expression) {
 
@@ -516,12 +534,24 @@ public class ArrayOperators {
 			return new ConcatArrays(Collections.singletonList(values));
 		}
 
+		/**
+		 * Concat with the array stored at the given field.
+		 *
+		 * @param arrayFieldReference must not be {@literal null}.
+		 * @return new instance of {@link ConcatArrays}.
+		 */
 		public ConcatArrays concat(String arrayFieldReference) {
 
 			Assert.notNull(arrayFieldReference, "ArrayFieldReference must not be null!");
 			return new ConcatArrays(append(Fields.field(arrayFieldReference)));
 		}
 
+		/**
+		 * Concat with the array resulting from the given {@link AggregationExpression}.
+		 *
+		 * @param expression must not be {@literal null}.
+		 * @return new instance of {@link ConcatArrays}.
+		 */
 		public ConcatArrays concat(AggregationExpression expression) {
 
 			Assert.notNull(expression, "Expression must not be null!");
@@ -574,7 +604,7 @@ public class ArrayOperators {
 		 * Set the {@literal values} to apply the {@code $filter} to.
 		 *
 		 * @param values must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link AsBuilder} to create the {@link Filter}.
 		 */
 		public static AsBuilder filter(List<?> values) {
 
@@ -651,7 +681,7 @@ public class ArrayOperators {
 			 * Set the {@literal variableName} for the elements in the input array.
 			 *
 			 * @param variableName must not be {@literal null}.
-			 * @return
+			 * @return never {@literal null}.
 			 */
 			ConditionBuilder as(String variableName);
 		}
@@ -665,7 +695,7 @@ public class ArrayOperators {
 			 * Set the {@link AggregationExpression} that determines whether to include the element in the resulting array.
 			 *
 			 * @param expression must not be {@literal null}.
-			 * @return
+			 * @return never {@literal null}.
 			 */
 			Filter by(AggregationExpression expression);
 
@@ -673,7 +703,7 @@ public class ArrayOperators {
 			 * Set the {@literal expression} that determines whether to include the element in the resulting array.
 			 *
 			 * @param expression must not be {@literal null}.
-			 * @return
+			 * @return never {@literal null}.
 			 */
 			Filter by(String expression);
 
@@ -681,7 +711,7 @@ public class ArrayOperators {
 			 * Set the {@literal expression} that determines whether to include the element in the resulting array.
 			 *
 			 * @param expression must not be {@literal null}.
-			 * @return
+			 * @return never {@literal null}.
 			 */
 			Filter by(Document expression);
 		}
@@ -700,7 +730,7 @@ public class ArrayOperators {
 			/**
 			 * Creates new {@link InputBuilder}.
 			 *
-			 * @return
+			 * @return new instance of {@link FilterExpressionBuilder}.
 			 */
 			public static InputBuilder newBuilder() {
 				return new FilterExpressionBuilder();
@@ -800,7 +830,7 @@ public class ArrayOperators {
 		 * Creates new {@link IsArray}.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link IsArray}.
 		 */
 		public static IsArray isArray(String fieldReference) {
 
@@ -812,7 +842,7 @@ public class ArrayOperators {
 		 * Creates new {@link IsArray}.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link IsArray}.
 		 */
 		public static IsArray isArray(AggregationExpression expression) {
 
@@ -841,7 +871,7 @@ public class ArrayOperators {
 		 * Creates new {@link Size}.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Size}.
 		 */
 		public static Size lengthOfArray(String fieldReference) {
 
@@ -853,7 +883,7 @@ public class ArrayOperators {
 		 * Creates new {@link Size}.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Size}.
 		 */
 		public static Size lengthOfArray(AggregationExpression expression) {
 
@@ -895,7 +925,7 @@ public class ArrayOperators {
 		 * Creates new {@link Slice}.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Slice}.
 		 */
 		public static Slice sliceArrayOf(String fieldReference) {
 
@@ -907,7 +937,7 @@ public class ArrayOperators {
 		 * Creates new {@link Slice}.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Slice}.
 		 */
 		public static Slice sliceArrayOf(AggregationExpression expression) {
 
@@ -928,10 +958,22 @@ public class ArrayOperators {
 			return new Slice(Collections.singletonList(values));
 		}
 
+		/**
+		 * Slice the number of elements.
+		 *
+		 * @param nrElements elements to slice.
+		 * @return new instance of {@link Slice}.
+		 */
 		public Slice itemCount(int nrElements) {
 			return new Slice(append(nrElements));
 		}
 
+		/**
+		 * Slice using offset and count.
+		 *
+		 * @param position the start position
+		 * @return new instance of {@link SliceElementsBuilder} to create {@link Slice}.
+		 */
 		public SliceElementsBuilder offset(final int position) {
 
 			return new SliceElementsBuilder() {
@@ -978,7 +1020,7 @@ public class ArrayOperators {
 		 * Start creating new {@link IndexOfArray}.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link IndexOfArray}.
 		 */
 		public static IndexOfArrayBuilder arrayOf(String fieldReference) {
 
@@ -990,7 +1032,7 @@ public class ArrayOperators {
 		 * Start creating new {@link IndexOfArray}.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link IndexOfArray}.
 		 */
 		public static IndexOfArrayBuilder arrayOf(AggregationExpression expression) {
 
@@ -1002,7 +1044,7 @@ public class ArrayOperators {
 		 * Start creating new {@link IndexOfArray}.
 		 *
 		 * @param values must not be {@literal null}.
-		 * @return new instance of {@link IndexOfArray}.
+		 * @return new instance of {@link IndexOfArrayBuilder} to create {@link IndexOfArray}.
 		 * @since 2.2
 		 */
 		public static IndexOfArrayBuilder arrayOf(Collection<?> values) {
@@ -1011,6 +1053,12 @@ public class ArrayOperators {
 			return new IndexOfArrayBuilder(values);
 		}
 
+		/**
+		 * Lookup within a given range.
+		 *
+		 * @param range the lookup range.
+		 * @return new instance of {@link IndexOfArray}.
+		 */
 		public IndexOfArray within(Range<Long> range) {
 			return new IndexOfArray(append(AggregationUtils.toRangeValues(range)));
 		}
@@ -1030,7 +1078,7 @@ public class ArrayOperators {
 			 * Set the {@literal value} to check for its index in the array.
 			 *
 			 * @param value must not be {@literal null}.
-			 * @return
+			 * @return new instance of {@link IndexOfArray}.
 			 */
 			public IndexOfArray indexOf(Object value) {
 
@@ -1060,7 +1108,7 @@ public class ArrayOperators {
 		 * Start creating new {@link RangeOperator}.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link RangeOperatorBuilder} to create {@link RangeOperator}.
 		 */
 		public static RangeOperatorBuilder rangeStartingAt(String fieldReference) {
 			return new RangeOperatorBuilder(Fields.field(fieldReference));
@@ -1070,7 +1118,7 @@ public class ArrayOperators {
 		 * Start creating new {@link RangeOperator}.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link RangeOperatorBuilder} to create {@link RangeOperator}.
 		 */
 		public static RangeOperatorBuilder rangeStartingAt(AggregationExpression expression) {
 			return new RangeOperatorBuilder(expression);
@@ -1080,7 +1128,7 @@ public class ArrayOperators {
 		 * Start creating new {@link RangeOperator}.
 		 *
 		 * @param value
-		 * @return
+		 * @return new instance of {@link RangeOperator}.
 		 */
 		public static RangeOperatorBuilder rangeStartingAt(long value) {
 			return new RangeOperatorBuilder(value);
@@ -1102,7 +1150,7 @@ public class ArrayOperators {
 			 * Creates new {@link RangeOperator}.
 			 *
 			 * @param index
-			 * @return
+			 * @return new instance of {@link RangeOperator}.
 			 */
 			public RangeOperator to(long index) {
 				return new RangeOperator(Arrays.asList(startPoint, index));
@@ -1112,7 +1160,7 @@ public class ArrayOperators {
 			 * Creates new {@link RangeOperator}.
 			 *
 			 * @param expression must not be {@literal null}.
-			 * @return
+			 * @return new instance of {@link RangeOperator}.
 			 */
 			public RangeOperator to(AggregationExpression expression) {
 				return new RangeOperator(Arrays.asList(startPoint, expression));
@@ -1122,7 +1170,7 @@ public class ArrayOperators {
 			 * Creates new {@link RangeOperator}.
 			 *
 			 * @param fieldReference must not be {@literal null}.
-			 * @return
+			 * @return new instance of {@link RangeOperator}.
 			 */
 			public RangeOperator to(String fieldReference) {
 				return new RangeOperator(Arrays.asList(startPoint, Fields.field(fieldReference)));
@@ -1150,7 +1198,7 @@ public class ArrayOperators {
 		 * Creates new {@link ReverseArray} given {@literal fieldReference}.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link ReverseArray}.
 		 */
 		public static ReverseArray reverseArrayOf(String fieldReference) {
 			return new ReverseArray(Fields.field(fieldReference));
@@ -1160,7 +1208,7 @@ public class ArrayOperators {
 		 * Creates new {@link ReverseArray} given {@link AggregationExpression}.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link ReverseArray}.
 		 */
 		public static ReverseArray reverseArrayOf(AggregationExpression expression) {
 			return new ReverseArray(expression);
@@ -1239,7 +1287,7 @@ public class ArrayOperators {
 		 * Start creating new {@link Reduce}.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link InitialValueBuilder} to create {@link Reduce}.
 		 */
 		public static InitialValueBuilder arrayOf(final String fieldReference) {
 
@@ -1267,7 +1315,7 @@ public class ArrayOperators {
 							Assert.notNull(expressions, "PropertyExpressions must not be null");
 
 							return new Reduce(Fields.field(fieldReference), initialValue,
-									Arrays.<AggregationExpression> asList(expressions));
+									Arrays.<AggregationExpression>asList(expressions));
 						}
 					};
 				}
@@ -1278,7 +1326,7 @@ public class ArrayOperators {
 		 * Start creating new {@link Reduce}.
 		 *
 		 * @param arrayValueExpression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link InitialValueBuilder} to create {@link Reduce}.
 		 */
 		public static InitialValueBuilder arrayOf(final AggregationExpression arrayValueExpression) {
 
@@ -1318,7 +1366,7 @@ public class ArrayOperators {
 			 * Define the initial cumulative value set before in is applied to the first element of the input array.
 			 *
 			 * @param initialValue must not be {@literal null}.
-			 * @return
+			 * @return never {@literal null}.
 			 */
 			ReduceBuilder withInitialValue(Object initialValue);
 		}
@@ -1335,7 +1383,7 @@ public class ArrayOperators {
 			 * {@link Variable#VALUE} are available.
 			 *
 			 * @param expression must not be {@literal null}.
-			 * @return
+			 * @return new instance of {@link Reduce}.
 			 */
 			Reduce reduce(AggregationExpression expression);
 
@@ -1346,7 +1394,7 @@ public class ArrayOperators {
 			 * {@link Variable#VALUE} are available.
 			 *
 			 * @param expressions must not be {@literal null}.
-			 * @return
+			 * @return new instance of {@link Reduce}.
 			 */
 			Reduce reduce(PropertyExpression... expressions);
 		}
@@ -1372,7 +1420,7 @@ public class ArrayOperators {
 			 * Define a result property for an {@link AggregationExpression} used in {@link Reduce}.
 			 *
 			 * @param name must not be {@literal null}.
-			 * @return
+			 * @return new instance of {@link AsBuilder} to create {@link Reduce}.
 			 */
 			public static AsBuilder property(final String name) {
 
@@ -1402,7 +1450,7 @@ public class ArrayOperators {
 				 * Set the {@link AggregationExpression} resulting in the properties value.
 				 *
 				 * @param expression must not be {@literal null}.
-				 * @return
+				 * @return never {@literal null}.
 				 */
 				PropertyExpression definedAs(AggregationExpression expression);
 			}
@@ -1459,7 +1507,7 @@ public class ArrayOperators {
 			 * eg. {@code $$value.product}
 			 *
 			 * @param property must not be {@literal null}.
-			 * @return
+			 * @return never {@literal null}.
 			 */
 			public Field referringTo(final String property) {
 
@@ -1508,7 +1556,7 @@ public class ArrayOperators {
 		 * Start creating new {@link Zip}.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link ZipBuilder} to create {@link Zip}.
 		 */
 		public static ZipBuilder arrayOf(String fieldReference) {
 
@@ -1520,7 +1568,7 @@ public class ArrayOperators {
 		 * Start creating new {@link Zip}.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link ZipBuilder} to create {@link Zip}.
 		 */
 		public static ZipBuilder arrayOf(AggregationExpression expression) {
 
@@ -1544,7 +1592,7 @@ public class ArrayOperators {
 		/**
 		 * Create new {@link Zip} and set the {@code useLongestLength} property to {@literal true}.
 		 *
-		 * @return
+		 * @return new instance of {@link Zip}.
 		 */
 		public Zip useLongestLength() {
 			return new Zip(append("useLongestLength", true));
@@ -1554,7 +1602,7 @@ public class ArrayOperators {
 		 * Optionally provide a default value.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Zip}.
 		 */
 		public Zip defaultTo(String fieldReference) {
 
@@ -1566,7 +1614,7 @@ public class ArrayOperators {
 		 * Optionally provide a default value.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Zip}.
 		 */
 		public Zip defaultTo(AggregationExpression expression) {
 
@@ -1578,7 +1626,7 @@ public class ArrayOperators {
 		 * Optionally provide a default value.
 		 *
 		 * @param array must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Zip}.
 		 */
 		public Zip defaultTo(Object[] array) {
 
@@ -1602,7 +1650,7 @@ public class ArrayOperators {
 			 * array, etc.
 			 *
 			 * @param arrays arrays to zip the referenced one with. must not be {@literal null}.
-			 * @return
+			 * @return new instance of {@link Zip}.
 			 */
 			public Zip zip(Object... arrays) {
 
@@ -1616,7 +1664,7 @@ public class ArrayOperators {
 					}
 				}
 
-				return new Zip(Collections.<String, Object> singletonMap("inputs", sourceArrays));
+				return new Zip(Collections.<String, Object>singletonMap("inputs", sourceArrays));
 			}
 		}
 	}
@@ -1627,7 +1675,7 @@ public class ArrayOperators {
 	 * @author Christoph Strobl
 	 * @author Shashank Sharma
 	 * @see <a href=
-	 *      "https://docs.mongodb.com/manual/reference/operator/aggregation/in/">https://docs.mongodb.com/manual/reference/operator/aggregation/in/</a>
+	 * "https://docs.mongodb.com/manual/reference/operator/aggregation/in/">https://docs.mongodb.com/manual/reference/operator/aggregation/in/</a>
 	 * @since 2.2
 	 */
 	public static class In extends AbstractAggregationExpression {
@@ -1645,7 +1693,7 @@ public class ArrayOperators {
 		 * Start creating {@link In}.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link InBuilder} to create {@link In}.
 		 */
 		public static InBuilder arrayOf(String fieldReference) {
 
@@ -1662,7 +1710,7 @@ public class ArrayOperators {
 		 * Start creating {@link In}.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link InBuilder} to create {@link In}.
 		 */
 		public static InBuilder arrayOf(AggregationExpression expression) {
 
@@ -1704,7 +1752,7 @@ public class ArrayOperators {
 			 * Set the {@literal value} to check for existence in the array.
 			 *
 			 * @param value must not be {@literal value}.
-			 * @return
+			 * @return new instance of {@link In}.
 			 */
 			In containsValue(Object value);
 		}
@@ -1716,7 +1764,7 @@ public class ArrayOperators {
 	 *
 	 * @author Christoph Strobl
 	 * @see <a href=
-	 *      "https://docs.mongodb.com/manual/reference/operator/aggregation/arrayToObject/">https://docs.mongodb.com/manual/reference/operator/aggregation/arrayToObject/</a>
+	 * "https://docs.mongodb.com/manual/reference/operator/aggregation/arrayToObject/">https://docs.mongodb.com/manual/reference/operator/aggregation/arrayToObject/</a>
 	 * @since 2.1
 	 */
 	public static class ArrayToObject extends AbstractAggregationExpression {

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

@@ -34,7 +34,7 @@ public class BooleanOperators {
 	 * Take the array referenced by given {@literal fieldReference}.
 	 *
 	 * @param fieldReference must not be {@literal null}.
-	 * @return
+	 * @return new instance of {@link BooleanOperatorFactory}.
 	 */
 	public static BooleanOperatorFactory valueOf(String fieldReference) {
 		return new BooleanOperatorFactory(fieldReference);
@@ -44,7 +44,7 @@ public class BooleanOperators {
 	 * Take the value resulting of the given {@link AggregationExpression}.
 	 *
 	 * @param fieldReference must not be {@literal null}.
-	 * @return
+	 * @return new instance of {@link BooleanOperatorFactory}.
 	 */
 	public static BooleanOperatorFactory valueOf(AggregationExpression fieldReference) {
 		return new BooleanOperatorFactory(fieldReference);
@@ -55,7 +55,7 @@ public class BooleanOperators {
 	 * opposite boolean value.
 	 *
 	 * @param fieldReference must not be {@literal null}.
-	 * @return
+	 * @return new instance of {@link Not}.
 	 */
 	public static Not not(String fieldReference) {
 		return Not.not(fieldReference);
@@ -66,7 +66,7 @@ public class BooleanOperators {
 	 * and returns the opposite boolean value.
 	 *
 	 * @param expression must not be {@literal null}.
-	 * @return
+	 * @return new instance of {@link Not}.
 	 */
 	public static Not not(AggregationExpression expression) {
 		return Not.not(expression);
@@ -109,7 +109,7 @@ public class BooleanOperators {
 		 * all of the expressions are {@literal true}.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link And}.
 		 */
 		public And and(AggregationExpression expression) {
 
@@ -122,7 +122,7 @@ public class BooleanOperators {
 		 * all of the expressions are {@literal true}.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link And}.
 		 */
 		public And and(String fieldReference) {
 
@@ -139,7 +139,7 @@ public class BooleanOperators {
 		 * any of the expressions are {@literal true}.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Or}.
 		 */
 		public Or or(AggregationExpression expression) {
 
@@ -152,7 +152,7 @@ public class BooleanOperators {
 		 * any of the expressions are {@literal true}.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Or}.
 		 */
 		public Or or(String fieldReference) {
 
@@ -167,7 +167,7 @@ public class BooleanOperators {
 		/**
 		 * Creates new {@link AggregationExpression} that evaluates a boolean and returns the opposite boolean value.
 		 *
-		 * @return
+		 * @return new instance of {@link Not}.
 		 */
 		public Not not() {
 			return usesFieldRef() ? Not.not(fieldReference) : Not.not(expression);
@@ -198,8 +198,8 @@ public class BooleanOperators {
 		 * Creates new {@link And} that evaluates one or more expressions and returns {@literal true} if all of the
 		 * expressions are {@literal true}.
 		 *
-		 * @param expressions
-		 * @return
+		 * @param expressions must not be {@literal null}.
+		 * @return new instance of {@link And}.
 		 */
 		public static And and(Object... expressions) {
 			return new And(Arrays.asList(expressions));
@@ -209,7 +209,7 @@ public class BooleanOperators {
 		 * Creates new {@link And} with all previously added arguments appending the given one.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link And}.
 		 */
 		public And andExpression(AggregationExpression expression) {
 
@@ -221,7 +221,7 @@ public class BooleanOperators {
 		 * Creates new {@link And} with all previously added arguments appending the given one.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link And}.
 		 */
 		public And andField(String fieldReference) {
 
@@ -233,7 +233,7 @@ public class BooleanOperators {
 		 * Creates new {@link And} with all previously added arguments appending the given one.
 		 *
 		 * @param value must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link And}.
 		 */
 		public And andValue(Object value) {
 
@@ -263,7 +263,7 @@ public class BooleanOperators {
 		 * expressions are {@literal true}.
 		 *
 		 * @param expressions must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Or}.
 		 */
 		public static Or or(Object... expressions) {
 
@@ -275,7 +275,7 @@ public class BooleanOperators {
 		 * Creates new {@link Or} with all previously added arguments appending the given one.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Or}.
 		 */
 		public Or orExpression(AggregationExpression expression) {
 
@@ -287,7 +287,7 @@ public class BooleanOperators {
 		 * Creates new {@link Or} with all previously added arguments appending the given one.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Or}.
 		 */
 		public Or orField(String fieldReference) {
 
@@ -299,7 +299,7 @@ public class BooleanOperators {
 		 * Creates new {@link Or} with all previously added arguments appending the given one.
 		 *
 		 * @param value must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Or}.
 		 */
 		public Or orValue(Object value) {
 
@@ -329,7 +329,7 @@ public class BooleanOperators {
 		 * value.
 		 *
 		 * @param fieldReference must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Not}.
 		 */
 		public static Not not(String fieldReference) {
 
@@ -342,7 +342,7 @@ public class BooleanOperators {
 		 * returns the opposite boolean value.
 		 *
 		 * @param expression must not be {@literal null}.
-		 * @return
+		 * @return new instance of {@link Not}.
 		 */
 		public static Not not(AggregationExpression expression) {
 

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

@@ -15,12 +15,11 @@
  */
 package org.springframework.data.mongodb.core.aggregation;
 
+import org.bson.Document;
 import org.springframework.data.mongodb.core.aggregation.BucketAutoOperation.BucketAutoOperationOutputBuilder;
 import org.springframework.data.mongodb.core.aggregation.BucketOperationSupport.OutputBuilder;
 import org.springframework.util.Assert;
 
-import org.bson.Document;
-
 /**
  * Encapsulates the aggregation framework {@code $bucketAuto}-operation. <br />
  * Bucket stage is typically used with {@link Aggregation} and {@code $facet}. Categorizes incoming documents into a
@@ -106,14 +105,23 @@ public class BucketAutoOperation extends BucketOperationSupport<BucketAutoOperat
 
 		options.putAll(super.toDocument(context));
 
-		return new Document("$bucketAuto", options);
+		return new Document(getOperator(), options);
+	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperation#getOperator()
+	 */
+	@Override
+	public String getOperator() {
+		return "$bucketAuto";
 	}
 
 	/**
 	 * Configures a number of bucket {@literal buckets} and return a new {@link BucketAutoOperation}.
 	 *
 	 * @param buckets must be a positive number.
-	 * @return
+	 * @return new instance of {@link BucketAutoOperation}.
 	 */
 	public BucketAutoOperation withBuckets(int buckets) {
 
@@ -128,7 +136,7 @@ public class BucketAutoOperation extends BucketOperationSupport<BucketAutoOperat
 	 * Use either predefined {@link Granularities} or provide a own one.
 	 *
 	 * @param granularity must not be {@literal null}.
-	 * @return
+	 * @return new instance of {@link BucketAutoOperation}.
 	 */
 	public BucketAutoOperation withGranularity(Granularity granularity) {
 
@@ -209,7 +217,7 @@ public class BucketAutoOperation extends BucketOperationSupport<BucketAutoOperat
 		 *
 		 * @param expression must not be {@literal null}.
 		 * @param operation must not be {@literal null}.
-		 * @param parameters
+		 * @param parameters must not be {@literal null}.
 		 */
 		protected ExpressionBucketAutoOperationBuilder(String expression, BucketAutoOperation operation,
 				Object[] parameters) {

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

@@ -20,21 +20,19 @@ import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
 
+import org.bson.Document;
 import org.springframework.data.mongodb.core.aggregation.BucketOperation.BucketOperationOutputBuilder;
 import org.springframework.util.Assert;
 
-import org.bson.Document;
-
 /**
  * Encapsulates the aggregation framework {@code $bucket}-operation. <br />
- *
  * Bucket stage is typically used with {@link Aggregation} and {@code $facet}. Categorizes incoming documents into
  * groups, called buckets, based on a specified expression and bucket boundaries. <br />
- *
  * We recommend to use the static factory method {@link Aggregation#bucket(String)} instead of creating instances of
  * this class directly.
  *
- * @see <a href="https://docs.mongodb.org/manual/reference/aggregation/bucket/">https://docs.mongodb.org/manual/reference/aggregation/bucket/</a>
+ * @see <a href=
+ *      "https://docs.mongodb.org/manual/reference/aggregation/bucket/">https://docs.mongodb.org/manual/reference/aggregation/bucket/</a>
  * @see BucketOperationSupport
  * @author Mark Paluch
  * @since 1.10
@@ -103,14 +101,23 @@ public class BucketOperation extends BucketOperationSupport<BucketOperation, Buc
 
 		options.putAll(super.toDocument(context));
 
-		return new Document("$bucket", options);
+		return new Document(getOperator(), options);
+	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperation#getOperator()
+	 */
+	@Override
+	public String getOperator() {
+		return "$bucket";
 	}
 
 	/**
 	 * Configures a default bucket {@literal literal} and return a new {@link BucketOperation}.
 	 *
 	 * @param literal must not be {@literal null}.
-	 * @return
+	 * @return new instance of {@link BucketOperation}.
 	 */
 	public BucketOperation withDefaultBucket(Object literal) {
 
@@ -123,7 +130,7 @@ public class BucketOperation extends BucketOperationSupport<BucketOperation, Buc
 	 * preserved and the new {@literal boundaries} are appended.
 	 *
 	 * @param boundaries must not be {@literal null}.
-	 * @return
+	 * @return new instance of {@link BucketOperation}.
 	 */
 	public BucketOperation withBoundaries(Object... boundaries) {
 
@@ -204,12 +211,12 @@ public class BucketOperation extends BucketOperationSupport<BucketOperation, Buc
 			extends ExpressionBucketOperationBuilderSupport<BucketOperationOutputBuilder, BucketOperation> {
 
 		/**
-		 * Creates a new {@link ExpressionBucketOperationBuilderSupport} for the given value, {@link BucketOperation}
-		 * and parameters.
+		 * Creates a new {@link ExpressionBucketOperationBuilderSupport} for the given value, {@link BucketOperation} and
+		 * parameters.
 		 *
 		 * @param expression must not be {@literal null}.
 		 * @param operation must not be {@literal null}.
-		 * @param parameters
+		 * @param parameters must not be {@literal null}.
 		 */
 		protected ExpressionBucketOperationBuilder(String expression, BucketOperation operation, Object[] parameters) {
 			super(expression, operation, parameters);