Author Topic: Activity Diagrams and Actors  (Read 2659 times)


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Activity Diagrams and Actors
« on: November 21, 2003, 08:32:54 am »

I am using activity diagrams to model processes. I am making use of swimlanes to reflect responsibility for activities. No problem so far.

However I am also documenting process roles using actors. These actors are being used within class diagrams to reflect the relationships between roles and the data being produced/manipulated by the process.

I would also like to show the interaction between the actors and the activities in my process model. I realise I could start to show actors on the activity diagram. The problem with this is
a. I am not sure what the UML convention/rule for using actors in an activity diagram is
b. this makes the diagrams very noisy - simplicity is important as not all my users are UML savvy

Any suggestions ?.



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Re: Activity Diagrams and Actors
« Reply #1 on: November 21, 2003, 09:22:55 am »
Hi Andy,

I've just done something similar to model software development processes using activity diagrams. I modelled roles such as 'Project Engineer', 'Test Developer', 'GUI Designer', 'SW developer' as actors. Processes such as 'GUI Design', 'Schedule Generation', 'Test Development' were modelled as activities.

I then created new stereotypes <<work product>> and <<tool>>. A work product resulting from activities are simply Objects with the stereotype <<work product>> and tools used in the activities are Objects with the stereotype <<tool>>.

A work product might be a Statement of Work, a Software Requirements Specification, Source code, Test Description, etc.

I used the 'Flow' linkage to link the process flow between activitites, and pretty much dependency links everywhere else. For example, a dependency link between an actor and activity with the stereotype <<performs>>.
I also modelled links from one workproduct to another with a <<trace>> dependency indicating that a trace needs to exists between one workproduct to another. For exampe, SRS to Test cases.

For clarity, I colored <<tools>> and <<work products>> differently so they distinguish themselves from one another better.



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Re: Activity Diagrams and Actors
« Reply #2 on: November 25, 2003, 01:59:08 am »

I've ust solved the same problem by using swimlanes named after the Actors.  Keep the Actors themselves off the Activity diagram!

Instead, use the Relationships matrix to create links between the Actors and the Activities.

This keeps the relationship diagram clean.  If you now drop an Actor onto the diagram, the links you've created in the realtionships matrix will indeed show up, but there's little point: the swimlanes convey very clearly who's doing what.

Hope this helps,

Andrew Webster