Dynamic fork

[mreiterer]

Hi all,

i have the following requirements (see my process in the attachment):

- The "Render" step calls an external resource via REST.
- The external system delivers x (unknown number) request which contain a file reference which should then be handled/stored in parallel.
  -> My solution is to call messageEventReceived for every on the boundary message event and do a callActivitiy in the concurrent flow.

-  Then the external system delivers a success message.
  -> upon delivery of the success message i do a signal on the wait state (Wait for render result).

- The boundary message event is configured as "cancel activitiy = false"

My current problem is that i get an ActivitiOptimisticLockingException, on messageEventReceived.

Is there a best practice how to model such an requirement?


Thanks
Markus

[mreiterer]

how do i add a png attachment ?

[mreiterer]

http://postimg.org/image/70mdfarbb

[jbarrez]

So basically you have multiple threads hitting the same receive task at the same time, right?
One option would be to use a multi instance receive task, potentially using an embedded subprocess with multi instance so you can correlate the execution id when you're request is sent back to Activiti.

[mreiterer]

Yes. Don't i have to know the exact number of incoming messages / threads for multi-instance ?

[jbarrez]

So how do you know in that case when to stop?

[mreiterer]

I get a "completed" message at the end. I already have a solution now. I have implemented a loop consisting of a message gateway and a parallel gateway.