3 Replies Latest reply on Dec 6, 2007 3:37 PM by burrsutter

    fork in jBPM and asynchronously called services in fork

    kadlecp Dec 6, 2007 11:34 AM

      Hello,

      I know that this question should go to jBPM forum, nevertheless I will try to ask here, maybe somebody has already solved it.

      In bpm_orchestration2 example is fork of execution. But the executions of services in fork are called synchronously, one after another. The result from previous service is input of next service in fork....

      I want to call the services in fork concurrently, and in join node I would have my custom action where I would assemble the results from the services.

      Is that possible? Do you know how to configure it?

      Thanks for help, advice
      Regards
      Pavel

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        • 1. Re: fork in jBPM and asynchronously called services in fork
          kadlecp Dec 6, 2007 12:46 PM (in response to kadlecp)

          Maybe it will be better not to use jBPM's fork and join. I can use topic and aggregator instead, or static router and aggregator...

          But still I am wonder how to implement that in jBPM's fork and join....

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          • 2. Re: fork in jBPM and asynchronously called services in fork
            kconner
            kconner Dec 6, 2007 1:36 PM (in response to kadlecp)

            There is no reason why you could not have the services called concurrently, using the jBPM fork/join mechanism. This is as valid a solution as using split/aggregator within the bus.

            The answer to the question really depends on which part of your process is the most natural place to host this functionality, whether it is in the business process or the implementation of an ESB service.

            The current jBPM integration code will handle this using synchronous invocations on the ESB bus, therefore blocking a jBPM thread. Kurt is currently rewriting this code so that it uses asynchronous messaging on the ESB side, resuming the jBPM process through a subsequent signal. This will no longer block threads while still providing the semantics of synchronous invocations to the jBPM process.

            The new integration code will also support a timeout mechanism specified within the jBPM process definition, allowing the process definition to control each aspect of the invocation.

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            • 3. Re: fork in jBPM and asynchronously called services in fork
              burrsutter
              burrsutter Dec 6, 2007 3:37 PM (in response to kadlecp)

              This is something that I've not tried (caution)...

              jBPM by default actually processes all transitions out of a fork
              synchronously. They have an async continuation feature:
              http://docs.jboss.com/jbpm/v3/userguide/graphorientedprogramming.html#asynchronouscontinuations

              Which I think is keyed by async=true on the fork node.

              However, as Kevin pointed out, our ESBActionHandler that is invoking the actual ESB Service needs to properly handle the async call down into the ESB.

              bpm_orchestration3 illustrates what the jboss-esb.xml and the jpdl need to look like in 4.2.1, after we get this new capability/fix in place this may change slightly.

              Burr

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