2. What’s new in Spring Integration 4.2?

This chapter provides an overview of the new features and improvements that have been introduced with Spring Integration 4.1. If you are interested in more details, please see the Issue Tracker tickets that were resolved as part of the 4.1 development process.

2.1 New Components

2.1.1 Major Management/JMX Rework

A new MetricsFactory strategy interface has been introduced. This, together with other changes in the JMX and management infrastructure provides much more control over management configuration and runtime performance.

However, this has some important implications for (some) user environments.

For complete details, see Section 9.1, “Metrics and Management” and the section called “JMX Improvements”.

2.1.2 MongoDB Metadata Store

The MongoDbMetadataStore is now available. For more information, see Section 22.3.2, “MongoDB Metadata Store”.

2.1.3 SecuredChannel Annotation

The @SecuredChannel annotation has been introduced, replacing the deprecated ChannelSecurityInterceptorFactoryBean. For more information, see Appendix D, Security in Spring Integration.

2.1.4 SecurityContext Propagation

The SecurityContextPropagationChannelInterceptor has been introduced for the SecurityContext propagation from one message flow’s Thread to another. For more information, see Appendix D, Security in Spring Integration.

2.1.5 FileSplitter

The FileSplitter, which splits text files into lines, was added in 4.1.2. It now has full support in the int-file: namespace; see Section 14.5, “File Splitter” for more information.

2.1.6 Zookeeper Support

Zookeeper support has been added to the framework to assist when running on a clustered/multi-host environment.

  • ZookeeperMetadataStore
  • ZookeeperLockRegistry
  • Zookeeper Leadership

See Chapter 37, Zookeeper Support for more information.

2.1.7 Thread Barrier

A new thread <int:barrier/> component is available allowing a thread to be suspended until some asynchronous event occurs.

See Section 6.8, “Thread Barrier” for more information.

2.1.8 STOMP Support

STOMP support has been added to the framework as inbound and outbound channel adapters pair. See Chapter 28, STOMP Support for more information.

2.1.9 Codec

A new Codec abstraction has been introduced, to encode/decode objects to/from byte[]. An implementation that uses Kryo is provided. Codec-based transformers and message converters are also provided.

See Section 7.4, “Codec” for more information.

2.1.10 Message PreparedStatement Setter

A new MessagePreparedStatementSetter functional interface callback is available for the JdbcMessageHandler (<int-jdbc:outbound-gateway> and <int-jdbc:outbound-channel-adapter>) as an alternative to the SqlParameterSourceFactory to populate parameters on the PreparedStatement with the requestMessage context.

See Section 18.2, “Outbound Channel Adapter” for more information.

2.2 General Changes

2.2.1 Wire Tap

As an alternative to the existing selector attribute, the <wire-tap/> now supports the selector-expression attribute.

2.2.2 File Changes

See Chapter 14, File Support for more information about these changes.

Appending New Lines

The <int-file:outbound-channel-adapter> and <int-file:outbound-gateway> now support an append-new-line attribute. If set to true, a new line is appended to the file after a message is written. The default attribute value is false.

Ignoring Hidden Files

The ignore-hidden attribute has been introduced for the <int-file:inbound-channel-adapter> to pick up or not the hidden files from the source directory. It is true by default.

Writing InputStream Payloads

The FileWritingMessageHandler now also accepts InputStream as a valid message payload type.


The HeadDirectoryScanner can now be used with other FileListFilter s.

Last Modified Filter

The LastModifiedFileListFilter has been added.

WatchService Directory Scanner

The WatchServiceDirectoryScanner is now available.

Persistent File List Filter Changes

The AbstractPersistentFileListFilter has a new property flushOnUpdate which, when set to true, will flush() the metadata store if it implements Flushable (e.g. the PropertiesPersistingMetadataStore).

2.2.3 Class Package Change

The ScatterGatherHandler class has been moved from the org.springframework.integration.handler to the org.springframework.integration.scattergather.

2.2.4 TCP Changes

TCP Serializers

The TCP Serializers no longer flush() the OutputStream; this is now done by the TcpNxxConnection classes. If you are using the serializers directly within user code, you may have to flush() the OutputStream.

Server Socket Exceptions

TcpConnectionServerExceptionEvent s are now published whenever an unexpected exception occurs on a TCP server socket (also added to 4.1.3, 4.0.7). See Section 31.5, “TCP Connection Events” for more information.

TCP Server Port

If a TCP server socket factory is configured to listen on a random port, the actual port chosen by the OS can now be obtained using getPort(). getServerSocketAddress() is also available.

See Section 31.3, “TCP Connection Factories” for more information.

TCP Gateway Remote Timeout

The TcpOutboundGateway now supports remote-timeout-expression as an alternative to the existing remote-timeout attribute. This allows setting the timeout based on each message.

Also, the remote-timeout no longer defaults to the same value as reply-timeout which has a completely different meaning.

See Table 31.7, “TCP Outbound Gateway Attributes” for more information.

TCP SSLSession Available for Header Mapping

TcpConnection s now support getSslSession() to enable users to extract information from the session to add to message headers.

See Section 31.12, “IP Message Headers” for more information.

TCP Events

New events are now published whenever a correlation exception occurs - for example sending a message to a non-existent socket.

The TcpConnectionEventListeningMessageProducer is deprecated; use the generic event adapter instead.

See Section 31.5, “TCP Connection Events” for more information.

2.2.5 @InboundChannelAdapter

Previously, the @Poller on an inbound channel adapter defaulted the maxMessagesPerPoll attribute to -1 (infinity). This was inconsistent with the XML configuration of <inbound-channel-adapter/> s, which defaults to 1. The annotation now defaults this attribute to 1.

2.2.6 API Changes

o.s.integration.util.FunctionIterator now requires a o.s.integration.util.Function instead of a reactor.function.Function. This was done to remove an unnecessary hard dependency on Reactor. Any uses of this iterator will need to change the import.

Of course, Reactor is still supported for functionality such as the Promise gateway; the dependency was removed for those users who don’t need it.

2.2.7 JMS Changes

Reply Listener Lazy Initialization

It is now possible to configure the reply listener in JMS outbound gateways to be initialized on-demand and stopped after an idle period, instead of being controlled by the gateway’s lifecycle.

See Section 20.5, “Outbound Gateway” for more information.

Conversion Errors in Message-Driven Endpoints

The error-channel now is used for the conversion errors, which have caused a transaction rollback and message redelivery previously.

See Section 20.2, “Message-Driven Channel Adapter” and Section 20.4, “Inbound Gateway” for more information.

Default Acknowledge Mode

When using an implicitly defined DefaultMessageListenerContainer, the default acknowledge is now transacted. transacted is recommended when using this container, to avoid message loss. This default now applies to the message-driven inbound adapter and the inbound gateway, it was already the default for jms-backed channels.

See Section 20.2, “Message-Driven Channel Adapter” and Section 20.4, “Inbound Gateway” for more information.

Shared Subscriptions

Namespace support for shared subscriptions (JMS 2.0) has been added to message-driven endpoints and the <int-jms:publish-subscribe-channel>. Previously, you had to wire up listener containers as <bean/> s to use shared connections.

See Chapter 20, JMS Support for more information.

2.2.8 Conditional Pollers

Much more flexibility is now provided for dynamic polling.

See Section 4.2.3, “Conditional Pollers for Message Sources” for more information.

2.2.9 AMQP Changes

Publisher Confirms

The <int-amqp:outbound-gateway> now supports confirm-correlation-expression and confirm-(n)ack-channel attributes with similar purpose as for <int-amqp:outbound-channel-adapter>.

Correlation Data

For both the outbound channel adapter and gateway, if the correlation data is a Message<?>, it will be the basis of the message on the ack/nack channel, with the additional header(s) added. Previously, any correlation data (including Message<?>) was returned as the payload of the ack/nack message.

The Inbound Gateway properties

The <int-amqp:inbound-gateway> now exposes the amqp-template attribute to allow more control over an external bean for the reply RabbitTemplate or even provide your own AmqpTemplate implementation. In addition the default-reply-to is exposed to be used if request message doesn’t have replyTo property.

See Chapter 11, AMQP Support for more information.

2.2.10 XPath Splitter Improvements

The XPathMessageSplitter (<int-xml:xpath-splitter>) now allows the configuration of output-properties for the internal javax.xml.transform.Transformer and supports an Iterator mode (defaults to true) for the xpath evaluation org.w3c.dom.NodeList result.

See Section 35.5, “Splitting XML Messages” for more information.

2.2.11 HTTP Changes


The HTTP Inbound Endpoints (<int-http:inbound-channel-adapter> and <int-http:inbound-gateway>) now allow the configuration of Cross-Origin Resource Sharing (CORS).

See Section 17.4.4, “Cross-Origin Resource Sharing (CORS) Support” for more information.

Inbound Gateway Timeout

The HTTP inbound gateway can be configured as to what status code to return when a request times out. The default is now 500 Internal Server Error instead of 200 OK.

See Section 17.4.5, “Response StatusCode” for more information.

Form Data

Documentation is provided for when proxying multipart/form-data requests. See Chapter 17, HTTP Support for more information.

2.2.12 Gateway Changes

Gateway Methods can Return CompletableFuture<?>

When using Java 8, gateway methods can now return CompletableFuture<?>. See the section called “CompletableFuture” for more information.

MessagingGateway Annotation

The request and reply timeout properties are now String instead of Long to allow configuration with property placeholders or SpEL. See Section 8.3.6, “@MessagingGateway Annotation”.

2.2.13 Aggregator Changes

Aggregator Performance

This release includes some performance improvements for aggregating components (aggregator, resequencer, etc), by more efficiently removing messages from groups when they are released. New methods (removeMessagesFromGroup) have been added to the message store. Set the removeBatchSize property (default 100) to adjust the number of messages deleted in each operation. Currently, JDBC, Redis and MongoDB message stores support this property.

Output Message Group Processor

When using a ref or inner bean for the aggregator, it is now possible to bind a MessageGroupProcessor directly. In addition, a SimpleMessageGroupProcessor is provided that simply returns the collection of messages in the group. When an output processor produces a collection of Message<?>, the aggregator releases those messages individually. Configuring the SimpleMessageGroupProcessor makes the aggregator a message barrier, were messages are held up until they all arrive, and are then released individually. See Section 6.4, “Aggregator” for more information.

2.2.14 (S)FTP Changes

Inbound channel adapters

You can now specify a remote-directory-expression on the inbound channel adapters, to determine the directory at runtime. See Chapter 15, FTP/FTPS Adapters and Chapter 27, SFTP Adapters for more information.

Gateway Partial Results

When use FTP/SFTP outbound gateways to operate on multiple files (mget, mput), it is possible for an exception to occur after part of the request is completed. If such a condition occurs, a PartialSuccessException is thrown containing the partial results. See Section 15.6, “FTP Outbound Gateway” and Section 27.8, “SFTP Outbound Gateway” for more information.

Delegating Session Factory

A delegating session factory is now available, enabling the selection of a particular session factory based on some thread context value.

See Section 15.3, “Delegating Session Factory” and Section 27.3, “Delegating Session Factory” for more information.

Default Sftp Session Factory

Previously, the DefaultSftpSessionFactory unconditionally allowed connections to unknown hosts. This is now configurable (default false).

The factory now requires a configured knownHosts file unless the allowUnknownKeys property is true (default false).

See Section 27.2.1, “Configuration Properties” for more information.

Message Session Callback

The MessageSessionCallback<F, T> has been introduced to perform any custom Session operation(s) with the requestMessage context in the <int-(s)ftp:outbound-gateway/>.

See Section 15.9, “MessageSessionCallback” and Section 27.10, “MessageSessionCallback” for more information.

2.2.15 Websocket Changes

WebSocketHandlerDecoratorFactory support has been added to the ServerWebSocketContainer to allow chained customization for the internal WebSocketHandler. See Section 33.5, “WebSockets Namespace Support” for more information.

2.2.16 Application Event Adapters changes

The ApplicationEvent adapters can now operate with payload as event directly allow omitting custom ApplicationEvent extensions. The publish-payload boolean attribute has been introduced on the <int-event:outbound-channel-adapter> for this purpose. See Chapter 12, Spring ApplicationEvent Support for more information.