Author Topic: Sequence Diagrams  (Read 1975 times)

bundy115

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Sequence Diagrams
« on: July 13, 2003, 12:58:52 pm »
This is a newbie question so I'll apologize in advance if I'm missing the point here.

I'm reading a book in an effort to learn the UML.  The book is based on UML version 1.4 and at the moment I'm interested in sequence diagrams.

The book makes reference to several items that don't appear to be available in EA sequence diagrams (or at least I can't find them).

The items that I can't find are...
1. Branching (for messages)
2. Alternative flows (for objects)
3. Object states
4. Time changes

Am I missing the point or is there an easy explanation for what I'm seeing (or not as the case may be).  Perhaps the reference I'm using is not correct.

Any help would be greatly appreciated.

Thanks

jps

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Re: Sequence Diagrams
« Reply #1 on: July 17, 2003, 09:29:58 am »
You’ve probably found this by now… but just in case!

If you have two messages on a sequence diagram, right click the bottom one, and choose the option to “Branch with Previous Message.”

Regards,

James

bundy115

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Re: Sequence Diagrams
« Reply #2 on: July 17, 2003, 01:38:24 pm »
Thanks for the info.

Yes I had discovered how to initiate branching but still have not found anything on alternative flows.  I have also since found a topic further down in this forum that asks the same question.

Andrew

jdbaker

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Re: Sequence Diagrams
« Reply #3 on: July 21, 2003, 12:44:39 pm »
Hi,

It would help to know what book you are reading.   That would help me to determine what kind of alternate flows you have questions about.  For example, object flows are shown on activity diagrams.  An alternate flow of a use case would/could be modeled with a sequence diagram.  Give me the book title and I'll try to give you an answer in context.

J.D.

J.D. Baker
BAE SYSTEMS

bundy115

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Re: Sequence Diagrams
« Reply #4 on: July 23, 2003, 07:58:10 pm »
The book is called "UML A Beginner's Guide"

The alternate flow idea goes something like this...

1. A web interface object is created and its lifeline begins.

2. An actor sends a message to the web interface to login.

3. At this point the web interface object lifeline splits into 2 lifelines; the first lifeline is for a successful login with the second for a failed attempt.

4. The 2 lifelines continue sending messages pertinent to the scenario they represent; for instance the failed login atempt displays a message box while the successful atempt notifies a database object,

Hope this helps.

As a note I have seen this notation refered to in the UML specification.