> > > I gather the consensus in my own simplistic terms, is that > > transitions from an activity occur asynchronously, whereas > > transitions from a fork occur in parallel. > > The latter is true, the former is probably true (but doesn't seem > to have been nailed down for certain). >
If the former turns out to be true, then I believe that the latter is unnecessary, because the equivalent situation can occur by indicating that all transitions occur simultaneously. (For eg, activity 'A' has steps 1 and 2, occuring in this sequence. I can indicate asynchronous transitions by labeling my transitions '1 is complete' and '2 is complete' .. or .. I could indicate parallel transitions by labelling both exits from the activity with the same name.) > > > On the receiving end, a transtion into an activity causes that > > activity to fire. If you wish for muliple activities to complete > > before exercising a subsequent activity then you must use > > a synchronization bar in order to wait for completion. > > It woulds appear so. > > > So, one more brief simple question, if a transition activates > > an activity, and while that activity is exercising it receives a > > subsequent transition, > > > > 1) does the activity reset and start again, > > 2) does it complete before addressing the new stimulus, > > 3) does it ignore the subsequent stimulus or > > 4) is the behaviour customisable based upon the specification > > of the activity? > > We must first question how such a precondition could arise. > For each instantiation of an Activity Diagram, if the only > way that we can get activities happening in parallel is via > a fork, then this precondition can only occur between > a fork and a join. > > If I were writing an activity diagram where there could be > more than one transition into an activity after a fork, > but without a join, then I would expect this occurrence > to cause a new instantiation of the activity that may be > proceeding in parallel with another instantiation of the > activity from another thread derived from the fork. > > OTOH, what I expect may not be what other folk expect; > the situation is a bit ambiguous for my purposes and I'd > want to state clearly and unambiguously what I expect > to happen. > > I guess UML is like any other language - you can write > a sentence that is grammatically and syntactically > correct, but it may still be nonsense. > > So my (tentative) answer is :- > > 5) It starts a separate instantiation of the activity that may run > in parallel with other instantiations. > > But don't take my word on this; I admit that I may well be wrong. > I thought of this option on the way home. So the question becomes: "Is it feasible to be able to indicate that several instances of an activity may execute in parallel, in a single activity diagram?". Les. ________________________________________________ Get your own "800" number Voicemail, fax, email, and a lot more http://www.ureach.com/reg/tag ************************************************************************ * Rose Forum is a public venue for ideas and discussions. * For technical support, visit http://www.rational.com/support * * Post or Reply to: [EMAIL PROTECTED] * Subscription Requests: [EMAIL PROTECTED] * Archive of messages: * http://www.rational.com/support/usergroups/rose/rose_forum.jsp * Other Requests: [EMAIL PROTECTED] * * To unsubscribe from the list, please send email * To: [EMAIL PROTECTED] * Subject: <BLANK> * Body: unsubscribe rose_forum *************************************************************************
