topic Re: Multi instance, add more element at runtime in Alfresco Archive

Multi instance, add more element at runtime

edgarjoao — Fri, 30 Oct 2015 05:42:36 GMT

Hi team,I have a muti instance "Call Activity", I was wondering if its possible to add more instances to the current activity? Regards

Re: Multi instance, add more element at runtime

dzj — Fri, 30 Oct 2015 10:09:23 GMT

good question!!!

Re: Multi instance, add more element at runtime

edgarjoao — Fri, 30 Oct 2015 19:03:11 GMT

Seems like that option won't work. I found a comment in the Activiti Book

Implementing the BPMN 2.0 multi-instance activity, pag 247

"The loop cardinality value is processed only once, when the multiinstance
activity is created. When the process variable value changes during
the multi-instance activity execution, this doesn’t result in another number of
instances."

Edgar

Re: Multi instance, add more element at runtime

edgarjoao — Mon, 02 Nov 2015 21:53:53 GMT

it's this possible to add this feature?

Re: Multi instance, add more element at runtime

martin_grofcik — Tue, 03 Nov 2015 08:50:01 GMT

Hi,

From my point of view it is not so big deal to implement this feature.
You can do it by yourselves. Just have a look on org.activiti.engine.impl.bpmn.behavior.ParallelMultiInstanceBehavior#createInstances org.activiti.engine.impl.bpmn.behavior.SequentialMultiInstanceBehavior#createInstances
Regards
Martin

Re: Multi instance, add more element at runtime

edgarjoao — Wed, 04 Nov 2015 06:53:19 GMT

Thanks Martin,
Just wonder what would be the way to accomplish this?

- Extending AbstractBpmnParseHandler<CallActivity> or
- Implementing BpmnParseHandler

After that, what would be the way to add a new instance, through Process Variables??

Edgar

Re: Multi instance, add more element at runtime

martin_grofcik — Wed, 04 Nov 2015 07:14:05 GMT

Hi,

I would expect that you want to add instances to the currently running multiinstance activity.
In that case I would implement new method to add executions to the currently running multiinstance execution (in parallel case). You can do it in the same way as Parallel Behavior is doing.

Regards
Martin

Re: Multi instance, add more element at runtime

edgarjoao — Thu, 05 Nov 2015 02:06:58 GMT

Hi Martin,
I tried to follow your recommendation, I made a CustomInstanceBehavior and CustomCallActivityParseHandler

<bean id="processEngineConfiguration" class="org.activiti.engine.impl.cfg.StandaloneInMemProcessEngineConfiguration">
<property name="databaseSchemaUpdate" value="true"/>
<property name="postBpmnParseHandlers">
<list>
<bean class="com.demo.listeners.CustomCallActivityParseHandler" />
</list>
</property>
</bean>

You are right I just want to add more executions not matter whether my initial list of elements was 5, just to say something more and more depending of the user.

In this case how can I call createInstances and then adding more executions?

Thanks,
Edgar

Re: Multi instance, add more element at runtime

edgarjoao — Thu, 05 Nov 2015 05:49:04 GMT

I don't know if I'm complicating at all, but is there a way to acomplish this using
Messages boundary event and Messages Catching event?
Just send any quantity of Messages to the subprocess and then wait for termination

Edgar

Re: Multi instance, add more element at runtime

martin_grofcik — Thu, 05 Nov 2015 10:25:58 GMT

Events -> Yes that's another possibility

behaviour implementation -> You do not need to make changes in the behaviour. What you have to do is to implement command which will create and add new executions to the multiinstance task execution.

Regards
Martin

Re: Multi instance, add more element at runtime

edgarjoao — Fri, 06 Nov 2015 06:28:52 GMT

Thanks for the advice, do you have some example of how to do it?
Edgar

Re: Multi instance, add more element at runtime

martin_grofcik — Fri, 06 Nov 2015 07:16:21 GMT

Hi Edgar,

From my point of view there are plenty of examples.
Basicly what you have to do is to take the logic from e.g. Multiinstance parallel activity behavior to your new command.

Regards
Martin

Re: Multi instance, add more element at runtime

edgarjoao — Sat, 09 Jan 2016 01:26:58 GMT

It is possible use MultiInstanceLoopCharacteristics for this?

Re: Multi instance, add more element at runtime

edgarjoao — Sat, 09 Jan 2016 01:39:03 GMT

I did some modifications to my current Multi-Instance adding a boundarymessage and I realize that every time that I was sending a message it was creating a new execution instead to add more instances to current one, I didn't found the way to add more instances

Re: Multi instance, add more element at runtime

edgarjoao — Sat, 09 Jan 2016 02:13:31 GMT

Once you call 6 times boundarymessage and you complete embedded subprocess, it will create 6 instances of "Procesar Notificación" this behavior its correct? I added a image diagram of this.

Thanks Edgar

Re: Multi instance, add more element at runtime

iam — Sat, 09 Jan 2016 10:26:41 GMT

I've added method addInstances to ParallelMultiInstanceBehavior and it works.
I've modified createInstances loop to retrieve nrOfInstances for each loop step:
[java]
nrOfInstances = (Integer) execution.getVariableLocal(NUMBER_OF_INSTANCES);
[/java]

And when I need it I just call addInstances for parent (scope) execution:
[java]
// executionEntity is a "ConcurrentExecution"
int additionalNrOfInstances = 5; // I want to add 5 more executions
ExecutionEntity parentExecution = executionEntity.getParent();
if (parentExecution.getActivity().getActivityBehavior() instanceof ParallelMultiInstanceBehavior) {
ParallelMultiInstanceBehavior behavior = ((ParallelMultiInstanceBehavior)parentExecution.getActivity().getActivityBehavior();
behavior.addInstances(parentExecution, additionalNrOfInstances);
}
[/java]

Re: Multi instance, add more element at runtime

iam — Sat, 09 Jan 2016 16:00:44 GMT

Hmm. It does not work for sub processes because of AtomicOperationAtivityEnd removes execution on eventNotificationsCompleted:
[java]execution.remove();[/java]
and after that execution.getExecutions() returns returns array without one element. Therefore ParallelMultiInstanceBehavior should have more complicated logic that I did.

Re: Multi instance, add more element at runtime

edgarjoao — Tue, 19 Jan 2016 14:01:40 GMT

Thanks iam, but seems like there isn't way to accomplish this

Edgar