4 Replies Latest reply on Nov 4, 2011 1:41 PM by dme

Using Timers to Interrupt Synchronous Process in jBPM5

dme Oct 28, 2011 2:56 PM

Hi,

How can I use an event timer to interrupt a synchronous process in jBPM5? I have created a process which has a subprocess that performs a task (say MyCustomTask). I have a boundary event timer set to 500ms. I observe the following behaviour:

1. If in MyCustomTask if I do not call "completeWorkItem", the event timer fires correctly after 500ms

2. If in MyCustomTask if I make a call to "completeWorkItem" as the only thing the task does, the event timer does not fire which is as expected, as the sub-process has completed before the timer got a chance to fire

3. If in MyCustomTask if I sleep for 1sec (1000ms) and then make call "completeWorkItem", the event timer does not fire. How can I get the timer to fire in this case?

It seems that the timer is using the same thread as the MyCustomTask and for synchronous task it will not fire? How can I make the timer to fire when if a sub-process does not complete within "x" seconds?

Attached is the process file and Java (Handler and Driver) code for my test.

Thanks.

TimerTestWorkItemHandler.java.zip 544 bytes
Timer3.java.zip 721 bytes
Timer3.bpmn2.zip 1.2 KB

1. Re: Using Timers to Interrupt Synchronous Process in jBPM5

dme Oct 28, 2011 2:55 PM (in response to dme)
I tried a couple of scenarios to test how timeouts are handled in jBPM5.
- In the first test I added a delay timer (of 1 ms) between 2 sync process calls, once the first process is done, the boundary timer is invoked (probably because there is a delay timer) and timeout is handled correctly
- In the second test I have 3 sync processes in the sub-process. In this case after the first process goes to sleep, the second process is started in another thread which also goes to sleep when the 3rd process is started in a third thread, eventually all 3 processes complete, but the boundary timer is never fired. I was expecting the boundary timer to fire and interrput the processing. Why is the boundary timer not getting fired?

Can someone please help me understand how boundary timers are implemented in jBPM5?

Thanks.

Timer_MultipleSyncProcesses.bpmn2.zip 1.3 KB

Timer_SyncProcessWithDelayTimer.bpmn2.zip 1.4 KB

Timer_MultipleSyncProcesses.java.zip 791 bytes

Timer_SyncProcessWithDelayTimer.java.zip 802 bytes
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2. Re: Using Timers to Interrupt Synchronous Process in jBPM5

dme Nov 3, 2011 10:26 AM (in response to dme)

Hi,

Could someone with jBPM expertise please advise me if the ability to not interrupt a synchronous process is by design, or if this is a limitation which would be addressed in a future release? This will help me in designing my process flows a number of which require some kind of timeout interrupts.

Thanks.
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3. Re: Using Timers to Interrupt Synchronous Process in jBPM5

swiderski.maciej Nov 4, 2011 7:21 AM (in response to dme)
Hi,

issue you are facing is due to thread synchronization. You start a process on a thread that does not complete when timer is fired. Timer is executed on separate thread but it cannot continue because it waits until the first operation will release process instance which does not happen so the sleeping time expires in your work item handler and timer does not have opportunity to complete.

Please find attached modified work item handler that moves the work to be done on separate thread and releases the main thread that started the process. With this timer is fired properly and activity is aborted.

HTH

TimerTestWorkItemHandler.java.zip 630 bytes
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4. Re: Using Timers to Interrupt Synchronous Process in jBPM5

dme Nov 4, 2011 1:41 PM (in response to swiderski.maciej)

Hi Maciej,

Thanks for the solution. It works well for me.
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