Hi
I am new in the BPMN field and I have a question regarding the use of sequence flows and message flows. Here is an example of a collaboration between 2 pools.
I wondere whether I should add a sequence flow between task A and Task B or not.
Could you please let me know what you think as well as explaining me the reason of your choice? I took a look at the specification but I did not find any clear explanation for such an example.
Thanks in advance
Regards
Dali
Sascha Schneider on
Hi,
you have to create the sequence flow between A and B, because it is the way BPMN works.
Otherwise the current process would stop with task A, which then must be an end event (this is forced by the spec: if a process starts with a start event, it must end with an end event, and vice versa. Task B then would instantiate a new process.
But this is probably not what you want. What you probably want is the following:
- Process Pool A starts, the process steps to the Task A, which sends a message to Task D (in this case A could be a send task, D could be a receive task).
- The process Pool B then starts with D and E. During processing D and E, the first process is waiting at Task B for receiving the message from B. This last step is only possible with the missing sequence flow.
Even a bit nicer would be to have the sequence flow from Task A into the start event, which then becomes an message start event automatically. The same works for the end event.
I hope I could help you a little bit to understand the BPMN. For further information see the BPMN spec: http://www.omg.org/spec/BPMN/2.0/PDF the chapter about "Sequence Flow Connections on page 153.