I am pleased to announce the availability of Spring Integration 4.3.0.RC1 - the first (and final) release candidate; it is available from the spring milestone repo The GA release should follow shortly after the GA release of Spring Framework 4.3.

4.2.6.RELEASE is also available in the spring release repo as well as maven central. This release includes a few important bug fixes and all users are encouraged to upgrade to it.

4.3 is only a minor release with a few new features and improvements over 4.2 and will close out the 4.x line. Meanwhile we are looking forward to embrace the Reactive Foundation for the JVM in Spring Integration 5.0. We have yet to determine exactly what that means, so stay tuned! In addition, 5.0 (2017) will include the (currently separate) Spring Integration Java DSL.

Here are some highlights of the release (some of which were previously announced in earlier milestones):

Previously announced:

• A negate option for HeaderMappers to allow the exclusion of request and/or reply headers with logical NOT !. (e.g. !foo,* - map all headers except foo).

• Exception superclass mappings for the ErrorMessageExceptionTypeRouter to avoid mapping duplications for different inheritors.

• null Remote Directory support for the list() and listNames() functions in the FTP adapters to meet the standard FTP protocol support when listing the current working directory .

• An option to change the direction of Redis List Push/Pop operations in the Redis Queue Adapters.

• FileWritingMessageHandler sub-path support in the file name to allow restoration of the directory structure locally, e.g. after unzipping.

• Upgrade to Smack-4.1.x.

• Upgrade to Spring Amqp 1.6 with support for its new features such as Delayed Message Exchange.

• The Spring Integration runtime object model, together with Component Metrics, can now be exposed as a graph, which may be used to visualize the current state of the integration application. When running in a web container, the @EnableIntegrationGraphController annotation, together with an IntegrationGraphServer bean, creates a service to retrieve the model and state over the REST protocol, e.g. in JSON notation:

{
  "nodes": [
    {
      "nodeId": 1,
      "name": "nullChannel",
      "componentType": "channel",
    },
    {
      "nodeId": 2,
      "name": "errorChannel",
      "componentType": "publish-subscribe-channel",
    },
    {
      "nodeId": 3,
      "name": "_org.springframework.integration.errorLogger",
      "componentType": "logging-channel-adapter",
      "output": null,
      "input": "errorChannel"
    }
  ],
  "links": [
    {
      "from": 2,
      "to": 3
    }
  ]
}

Continuing the tradition of Spring Integration, message channels are represented as first class citizens (nodes) in this model, and are not simply links between nodes. Also, when statistics are enabled (@EnableIntegrationManagement or <int:management />), each node in the object graph contains those statistics (message counts, response times etc). (Some improvements have been made to the graph since it was announced in the last milestone, including: support for chains - list of handlers,

• Persistent MessageStores now support a Lazy-Load algorithm (enabled by default) for MessageGroup retrieval. When dealing with large, persisted, groups with operations such as aggregation, this produces significant performance benefits.

• The Service Activator now supports an async option. If the service returns a ListenableFuture<?> and async is true, the calling thread is released immediately, and the reply message is sent on the thread (from within your service) that completes the future. Based on this foundation we also provide an AsyncAmqpOutboundGateway and async mode for the JmsOutboundGateway where the downstream flow runs on the reply listener container thread.

• The XMPP Adapters now support Extensions (XEP). So, for example, you can more easily interact with Google Cloud Messaging (GCM):

<int-xmpp:inbound-channel-adapter id="xmppInboundAdapter"
    payload-expression="getExtension('google:mobile:data').json"/>
...
<bean id="gcmExtensionProvider" class="org.jivesoftware.smackx.gcm.provider.GcmExtensionProvider"/>

<int-xmpp:outbound-channel-adapter id="xmppOutboundAdapter"
    extension-provider="gcmExtensionProvider"/>

• Groovy scripts can now be configured with the compile-static or compiler-configuration to achieve improved performance or provide some exotic customization to the target AST.

• The WatchServiceDirectoryScanner has undergone several improvements. Its logic has been moved to the FileReadingMessageSource directly via the use-watch-service flag. In addition, we can specify the WatchEventTypes to listen for on the directory tree. Also the StandardWatchEventKinds.ENTRY_DELETE event is treated as a ResettableFileListFilter.remove() operation, for example to remove a file from an AcceptOnceFilteListFilter.

• Several more cases for channel late binding have been implemented. For example in the was WireTap, which led to the

MessageChannelSpec.wireTap() feature in the Spring Integration Java DSL.

New in this RC:

• FTP/SFTP inbound channel adapters can now support direct streaming of file contents, avoiding a copy to the local file system.

• TCP deserializers can now be configured to use a buffer pool.

• Various minor fixes and improvements.

The release addresses over 125 JIRA issues. Also see the What's New for a summary of the major changes. We are very grateful for a number of external contributions to the project - thank you all!.

Project Page | JIRA | [Contributions] (https://github.com/spring-projects/spring-integration/blob/master/CONTRIBUTING.md) | StackOverflow (spring-integration tag)

If you are attending Spring IO in Barcelona, I will be talking about Spring Integration and Spring AMQP on Friday, May 20. There are many other great talks from the Spring team members, so check the agenda.

This is also a reminder that Spring One Platform will be taking place in Las Vegas between August 1-4 this year, and you should consider getting your ticket if you haven’t done so already.