I would like to understand when shall I use the Call activity to link another process and when shall I use a collaboration diagram with "black box" pool representing another model? I am tring to decide on conventions for our company and we came across this topic, we would like to follow BPMN rules and at the same time make it as easy to use as possible for our modelers. Are there any reccomendations?
Klemens Hauk on
Hello Joanna,
Pools are used as container to represent participants which interact by message flows. Pools can be "black box pools" without a process (container is empty) typically used for external partners like a customer or a supplier or "white box pools" used for the internal ("private") process of the own organization. Between pools there are only message flows allowed (no sequence flows) starting or ending at the edge of the pool, if a pool contains no process. If the pool containes a process, message flows can also start or end at tasks or events. So there is no link by sequence flows between pools allowed but "only" message flows.
Call activities are reusable sub-processes to model processes with standard flows called by reference from any point of other processes. They are no alternative and do not replace the pool concept.
So you need both.
That`s a very short explanation. Feel free to ask for further details may be based on use cases you have in mind.
Regards
Klemens