Tom, I think that message flow and associations are typical constructs that are used by a business analist. I am not sure they are that important to the execution. Of course if message flows are added to the GPD at some point in time and the GPD is to operate on the same model as the runtime engine, it would make sense to add these capabilities to the core model. As for the question what a message flow would mean in jPDL, I think it could be used to somehow limit the visibility of the variables contained in this flow to all the nodes that are connected by the flow. Regards, Koen View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3982373#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...