Re: activity diagram



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robert france (france@bach.cs.colostate.edu)
Fri, 10 Dec 1999 17:37:28 -0700 (MST)


> I have a question about the activity diagram. Is it >possible for a transition leaving from an subactivity >node A nested in an activity node B to enter another subactivity C >node nested in another activity node D? If this is legal, when >the envent associated with this transition happens, what will >happen? Thanks a lot. >Best, >Wuwei What is the context for this question? I assume that B and D are subactivity states. Are A and C both action states or are they both subactivity states (or some combination)? If they are both action states then it means that they represent atomic (non-interuptible) actions. If they are subactivity states then they represent execution flows of non-atomic activities. Given all that, the above does not seem to be generally allowed for subactivity states. A subactivity state is exited under the following conditions (UML1.3, pg. 2-163): 1) when the final state of the nested graph is reached (normal termination) 2) when the explicit event of an outgoing transition shown at the subactivity state level occurs. So in the above, the transition must be shown at the level of B and D, C must be a start state in D (execution of a subactivity state machine always starts at the start state) and A must be a terminal state in B. But I may be missing something in the UML documentation ... Robert ==================================================================== Robert B. France, Assoc Professor | Tel: 970-491-6356 Computer Science Department | Fax: 970-491-2466 Colorado State University | Email: france@cs.colostate.edu Fort Collins, CO 80523 | www.cs.colostate.edu/~france/


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