Extending Spring Integration while maintaining previous functionality?

Question

so I'm new to Spring Integration, and mostly to Spring as well, so I might not be up on all of the terminology, but I'm running across the following scenario:

I have a small Spring Integration application with three SI flows... each flow has its own Gateway, and each Gateway has its own request channel and reply channel. These flows receive a null invocation (for all intensive purposes... basically just a 'GO' signal / empty message) and reply with a status message, depending upon the (trivial) business logic results.

I would now like to wire each of these flows together to run in one 'master flow', given one request, without taking away their ability to run separately, and I'd like to wire it up completely through annotation / XML (IE. given a controller that invokes the main gateway's service interface, no additional code needs to be written outside of annotation / XML configuration.)

Is this feasible, what Integration components should I be using to do so, and/or should I just be adjusting the expected channels for each of these gateways to be meeting each other end-to-end (and if so, how would that strategy compensate to allow each of the flows to be called on a case-by-case basis)?

In addition, if this is not feasible, would it be appropriate to use a service activator to invoke each of the child flows? I wanted to avoid coding more, but if that is the only option, I guess that it'll have to do.

Thanks!

Answer 1

Probably the simplest way to do this is use Spring Profiles (a Spring 3.1 feature). When deployed in stand-alone mode, the final element can be a "bridge to nowhere"...

<int:bridge input-channel="app1Final" />

... when the final element in a flow has no output channel, the message is returned to the gateway's reply channel. If you prefer to explicitly configure the bridge to point to the gateway's reply-channel, that's ok too; it just not needed.

In the "linked" profile, you configure the bridge thus...

<int:bridge input-channel="app1Final" output-channel="app2Inbound"/>

...where app2Inbound is the same as that app's gateway's request-channel.

<beans profile="default">
    <int:bridge input-channel="app1Final" />
</beans>

<beans profile="linked">
    <int:bridge input-channel="app1Final" output-channel="app2Inbound"/>
</beans>

To run with the linked profile, set system property 'spring.profiles.active' to 'linked'