topic Sending a message to cancel a usertask within same process in Alfresco Archive

Sending a message to cancel a usertask within same process

jkuehn — Tue, 08 Oct 2013 14:42:23 GMT

Hi,we have a process with two usertasks spawning after a parallel gateway. As long as usertask 1 is not completed, the user should be able to complete usertask 2. Once usertask 1 is completed, usertask 2 should be removed.How would you model this? Our current approach:[img]http://picture.ms/images/2

Re: Sending a message to cancel a usertask within same process

jkuehn — Tue, 08 Oct 2013 15:21:11 GMT

Small update:

ActivitiOptimisticLockingException is caught correctly, i was logging to std out and misinterpreted the output.

The ActivitiOptimisticLockingException occurs after recieving the message and executing "Do some stuff" service task. After the exception, the usertask 2 remains active. On a retry to send the message again, no exception occurrs and the process ends as desired. But the "Do some stuff" servicetask has been executed 2 times in that case.

Gateway->usertask1->servicetask send message->endevent
message event->servicetask do some stuff->endevent –> ActivitiOptimisticLockingException triggers retry –>message event->servicetask do some stuff->endevent

Can i implement some sort of queue, to avoid concurrent modifications? How to check whether a process is locked? Is there a better way to model this use case?

Re: Sending a message to cancel a usertask within same process

trademak — Tue, 08 Oct 2013 17:08:28 GMT

When using the parallel gateway you should make sure that you have a joining parallel gateway before you end the process. So instead of having 3 end events you should include a joining parallel gateway and 1 end event. Also instead of using a message event I think it would be better to use a boundary and a throw signal event.

Best regards,

Re: Sending a message to cancel a usertask within same process

jkuehn — Wed, 09 Oct 2013 08:14:26 GMT

Hi Tijs,

thank you very much for your feedback. The following model works like a charm (signal is sent using signalEventReceived(signalName, executionId) to deliver signal to the specific execution):

[img]http://picture.ms/images/2013/10/09/parallelSignal.png[/img]

Greetings,
Juri

Re: Sending a message to cancel a usertask within same process

trademak — Wed, 09 Oct 2013 08:35:41 GMT

Hi Juri,

Great, you could even use a signal throw event element instead of a service task to send the signal event.

Best regards,

Re: Sending a message to cancel a usertask within same process

jkuehn — Wed, 09 Oct 2013 09:20:32 GMT

Hi Tijs,

great to know. A good modelling can save a lot of implementation In our case we want to send the signal to the usertask in the current process only. As far as i understand the intermediate signal throwing event would not suit this case, as it sends a global event. We are quite happy with your suggested solution: no async executions, no retries, clear process.

Thanks again,
Juri