21. MongoDb Support

As of version 2.1 Spring Integration introduces support for MongoDB: a "high-performance, open source, document-oriented database". This support comes in the form of a MongoDB-based MessageStore.

21.1 Introduction

To download, install, and run MongoDB please refer to the MongoDB documentation.

21.2 Connecting to MongoDb

To begin interacting with MongoDB you first need to connect to it. Spring Integration builds on the support provided by another Spring project, Spring Data MongoDB, which provides a factory class called MongoDbFactory that simplifies integration with the MongoDB Client API.


To connect to MongoDB you can use an implementation of the MongoDbFactory interface:

public interface MongoDbFactory {

	 * Creates a default {@link DB} instance.
	 * @return the DB instance
	 * @throws DataAccessException
	DB 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 the DB instance
	 * @throws DataAccessException
	DB getDb(String dbName) throws DataAccessException;

The example below shows SimpleMongoDbFactory, the out-of-the-box implementation:

In Java:

MongoDbFactory mongoDbFactory = new SimpleMongoDbFactory(new Mongo(), "test");

Or in Spring's XML configuration:

<bean id="mongoDbFactory" class="org.springframework.data.mongodb.core.SimpleMongoDbFactory">
        <bean class="com.mongodb.Mongo"/>
    <constructor-arg value="test"/>

As you can see SimpleMongoDbFactory takes two arguments: 1) a Mongo instance and 2) a String specifying the name of the database. If you need to configure properties such as host, port, etc, you can pass those using one of the constructors provided by the underlying Mongo class. For more information on how to configure MongoDB, please refer to the Spring-Data-Document reference.

21.3 MongoDB Message Store

As described in EIP, a Message Store allows you to persist Messages. This can be very useful when dealing with components that have a capability to buffer messages (QueueChannel, Aggregator, Resequencer, etc.) if reliability is a concern. In Spring Integration, the MessageStore strategy also provides the foundation for the ClaimCheck pattern, which is described in EIP as well.

Spring Integration's MongoDB module provides the MongoDbMessageStore which is an implementation of both the MessageStore strategy (mainly used by the QueueChannel and ClaimCheck patterns) and the MessageGroupStore strategy (mainly used by the Aggregator and Resequencer patterns).

<bean id="mongoDbMessageStore" class="org.springframework.integration.mongodb.store.MongoDbMessageStore">
    <constructor-arg ref="mongoDbFactory"/>

<int:channel id="somePersistentQueueChannel">
    <int:queue message-store="mongoDbMessageStore"/>

<int:aggregator input-channel="inputChannel" output-channel="outputChannel"

Above is a sample MongoDbMessageStore configuration that shows its usage by a QueueChannel and an Aggregator. As you can see it is a simple bean configuration, and it expects a MongoDbFactory as a constructor argument.