messageEventReceived before process has reached Message Catching Event

[boekhold]

Hi,

Let's say I start a process instance that does some processing, possibly involving user tasks, and then uses a Message Catching Event at one point in the flow. The process is not supposed to continue processing beyond that Message Catching Event before the specific message is 'caught'.

The actual delivery of the message is triggered by some external process (for sake of argument: the REST API), and uses Runtime.messageEventReceived().

What will happen if messageEventReceived() is called before the Message Catching Event is reached. Will the process then just be stuck on the Message Catching Event, or does Activiti somehow 'buffer up' unconsumed messages?

Maarten

[boekhold]

Hmmm, seems like I am confused about what an "executionId" really is. I understand now that it actually refers to a specific execution of a specific task/activiti. For me that means that what I really want to do is something like:

• find a specific ProcessInstance
• For that ProcessInstance, find the Execution that's waiting for this specific message
• deliver to that execution

So I suppose the real question is: how do I handle the case where (1) I know that eventually there will be an execution listening to this message, but (2) that point has not been reached yet.

[trademak]

Yes you are correct about the Execution id. This does however also mean that the message catching event should already be reached in the process instance. Is it not possible to create the Message catching event earlier on in the process definition to make sure it's reached, by using a parallel gateway or so?

Best regards,

[boekhold]

Hi Tijs, yes, I had not thought of using a parallel gateway for this. I think this will work. There's still a tiny opportunity for a message to arrive before the Message Catching event has been reached, but that's mostly theoretical I suppose.

Thanks for the suggestion.

Maarten