Leslie Munday wrote: > 1) What is the difference between showing, all transitions coming from the > initial activity and flowing into each of the subsequent parallel activities, > and > showing a single transition from the initial activity as entering a > synchronization bar and then several transitions exiting the synchonization bar > and entering my parallel activities?
I haven't done enough with activity diagrams, but here's how it looks to me: The initial activity executes in 1 "tick" so the multiple transitions out of it are simulaneous. A synchronization bar in the diagram is harmless but redundant. If you have an initial state, instead of an activity, the state can use an indeterminate number of ticks (including 0) between the transitions, so the parallel threads may be *launched* asynchronously, and a synchronization bar is very significant. > 2) What is the difference between showing, all transition from parallel > activities entering my single terminal activity, and > all transitions from parallel activities entering a synchronization bar and a > single transition from the synchronization bar entering my terminal activity? If it is a terminal activity with multiple, asynchronous, incoming transitions, I would expect it to take the first event from any thread and execute in 1 tick. This is probably a design flaw, since it may not be clear what is intended from the system when the subsequent events arrive. A synchronization bar certainly makes a difference. A terminal state would be capable of collecting the incoming events, thus getting the whole system back to a single thread. A synchrononization bar here tells you that the state will wait for synchronization before completing a response to the collection of events. (It bugs me a little that the notation puts this characteristic of the state outside of its icon.) -Eric ************************************************************************ * 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 *************************************************************************
