Allow body of JmsListener annotated method to define returned Message Destination [SPR-13133]

[spring-projects-issues]

Bart Prokop opened SPR-13133 and commented

There are three possible use-cases for JmsListener annotated method processing:

1. request-reply scenario. The request have a JMSReplyTo set. Supported.
2. processing messages and sending result back to predefined queue. Supported with SendTo annotation.
3. processing message but the destination where to send response is determined during request processing. In most trivial case it can be forwarding incoming message to various destination, based on incoming message evaluation. There is no elegant solution to do this.

Please note that elegant solution would allow for implementing very rich/advance functionality inside listeners including dispatching multiple replies, dynamic destinations.

Some workaround for point 3 exists like returning void and use JMSTemplate or hacking request JMSReplyTo - but they are not elegant solution and not intended to use patterns.

The solution would require to inspect returning object that could be placeholder for both Message and Destination. There was some discussion around it that excluded using Message properties for this as JMS non compliant solution (see the ref URL). Alternatively a Map<Message, Destination> could be passed as parameter (or returned from listener method).

---

Reference URL: #817

Referenced from: commits be43295, bd093eb, c8fcdad

[spring-projects-issues]

Stéphane Nicoll commented

Add JmsResponse that you can use in any message listener method to not only indicate the reply but also the destination to wich the response should be sent.

Assume the following situation

@JmsListener(destination = "myQueue")
@SendTo("queueOut")
public MyObject process(MyRequest request) {
    // processing
    return myObject;
}

If you need to be able to change the reply destination at runtime, you can rewrite the example above as follows:

@JmsListener(destination = "myQueue")
public JmsResponse<MyObject> process(MyRequest request) {
    // processing
    // this particular response should be sent to a queue with name "fooBar"
    return JmsResponse.forQueue(myObject, "fooBar");
}

Bart Prokop could you please try this out? (a SNAPSHOT should be available in the next couple of hours or you can build locally). Let me know if that works out for you.

[spring-projects-issues]

Bart Prokop commented

Hi Stéphane, I've tried to write simple test app, but SNAPSHOTS are still not available. Shall I get them from that repo?

url("http://repo.spring.io/snapshot")
compile("org.springframework:spring-context:4.1.0.BUILD-SNAPSHOT")
compile("org.springframework:spring-jms:4.1.0.BUILD-SNAPSHOT")

The test stuff is on github: https://github.com/bartprokop/sandbox/blob/master/jms-reply-poc/src/main/java/jms001/ExampleListener.java
I will try to validate this as soon as get the SNAPSHOT.

[spring-projects-issues]

Stéphane Nicoll commented

You're using the wrong version (see the fix version). 4.2.0.BUILD-SNAPSHOT.

[spring-projects-issues]

Bart Prokop commented

Thanks for pointing this out. I've tested the feature and it seems to work as expected:

@JmsListener(destination = "INBOUND")
public JmsResponse inbound(Message message, Session s) throws JMSException {
    String dst = "D" + (1 + message.hashCode() % 3); // mock dynamic targeting
    System.out.println("sending to: " + dst);
    return JmsResponse.forQueue(s.createTextMessage("What a beautiful world!"), dst);
}

[spring-projects-issues]

Stéphane Nicoll commented

okay, thanks. For the record, you could rewrite that code as follows:

@JmsListener(destination = "INBOUND")
public JmsResponse inbound(Message message) throws JMSException {
    String dst = "D" + (1 + message.hashCode() % 3); // mock dynamic targeting
    System.out.println("sending to: " + dst);
    return JmsResponse.forQueue("What a beautiful world!", dst);
}

[spring-projects-issues]

Stéphane Nicoll commented

documentation has been updated as well.