A sequence graph

I want to learn something about UML graphs and I just have a case that I can express in a sequence chart. I go Violet and create this graph.

The graph tells about how the JGSS GSSName is created with the API and SPI things. It looks pretty but I'm sure it's very non-standard. I especially don't know how to express an abstract class, a static method, calls and returns, and I don't know how to tell who implements who and who extends who in a formal way. I am also curious why Violet automatically create another vertical box of GSSManagerImpl when GSSNameImpl call its getNameElement() method.
Comments:

I'm no expert on sequence diagrams, but I think that the reason a second vertical box is created in GSSManagerImpl is because the <<create>> call is blocking that thread of execution. Thus, the call to getNameElement is (in theory) calling back into another thread of GSSManagerImpl. The second vertical box therefore represents a second (logical) thread of execution.

Posted by Trevor Watson on July 27, 2005 at 01:54 PM CST #

Then I must be wrong somwhere. It's the <<create>> method that calls getNameElement into GSSManagerImpl, in the same thread, and the same GSSManagerImpl object.

Posted by Weijun Wang on July 28, 2005 at 02:48 AM CST #

Hmm, having looked at my book, I think I may be wrong in thinking that the second box indicates a separate thread. I think what it really indicates is a procedural call into the GssManagerImpl object (ie getNameElement()) which is taking place during another call which starts with the call to create the GssNameImpl.

So, the boxes represent procedural activity rather than thread activity.

By the way, thanks for pointing out Violet - I've been looking for a simply UML diagram editor for a long time now, and this is great for the job.

Posted by Trevor Watson on July 28, 2005 at 11:36 AM CST #

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