[rules-users] Keeping track of sessions and their process instances

[Gustavo Tenrreiro]

Hi,

I am working on a flow that uses flow events.
I send the event from a rule, and the only way I know to send an event
requires that I know the processId as well as the sessionId. Which
means I need to be able to keep track of both those two values so that
I can later use them to send the event.

So the question is what is the best strategy to keep track of the
sessions and the processes ?
The following is what I do; please comment on it, and feel free to
suggest a better way.

I ve created a class called WorkflowInfo that has two members (
processId, and sessionId )
When I start the process I create a WorkflowInfo, I set the processId,
and the sessionId then I insert it into the working memory:

     WorkflowInfo info = new WorkflowInfo();
     info.setProcessId(instance.getId());
     info.setSessionId(ksession.getId());
     ksession.insert(info);

In one of the rules I check for a condition, and when it is met I send
the flow event:


rule "sendEvent"
when
       $info : WorkflowInfo()
       <something is true>
then
      DroolsEventsManager.getInstance().sendEvent($info.getProcessId(),
$info.getSessionId(), "someEvent");
end



Now to send the event this is what I do ( from a java class ):

public void sendEvent(long processId, int sessionId, String eventType)
	{

		StatefulKnowledgeSession session =
JPAKnowledgeSessionLookup.getInstance().loadSession(sessionId);

		try {
			
			SignalEventCommand command = new SignalEventCommand();
			command.setProcessInstanceId(processId);
			command.setEventType(eventType);
			command.setEvent(true);
			session.execute(command);
		} catch (Exception e) {
			Logger.getInstance().error(this.getClass(), e.getMessage());
			e.printStackTrace();
		}
		finally{
			session.dispose();
		}
		
	}


Does this approach make sense ?

Thanks