extension points and guard

[kamil.svoboda]

Hi,
How can I specify which extension point is used by the relation <<extend>> between two use cases?
Jim Arlow in 'UML and the Unified Process' shows name of the extension point under the stereotyp in curve, like this:
UseCase1 -------<<extend>>------>UseCase2
                     (extension point)
                            [guard]

Shall I use the relation name?
Thanx Kamil
BTW: Can I use relation constraint for the guard?

[thomaskilian]

Hi Kamil,
guards are used within status diagrams.  You find the guard description in a status transition between two states. An association between to use cases does not have a guard. You could use a pre-condition instead.

As it comes to use case modeling I would like to promote http://www.usecasemodeling.com/ which in my opinion is an excellent description of an use case modeling methodology. This methodology is based on text templates (sounds strange to prefer this method if you are used to work with tools like EA).  With a few constraints you can use this method with EA and it really brings you forward!

[angel-o-sphere]

The problem with http://www.usecasemodeling.com is that all links are currently broken and lead to the same page at IBM.

So better post a link to amazon or to a different book, e.g. "Advanced UseCase Modelling" or the book from Ivar Jacobson himslef.

I have links to UseCase books on my web site: www.oomentor.de

To your question:
I use the relation name for extension points and place '(' and ')' around it. However you could select the relation and choose attach note. Then you write the extension points in () and if needed constraints in {} into that note.

angel'o'sphere

[thomaskilian]

The problem with http://www.usecasemodeling.com is that all links are currently broken and lead to the same page at IBM.

The "Purchase" button directly brings you to Amazon. Of course there are many more books about use case modeling (you can search here in the forum also). The real problem with these books is simply: they are awfully expensive  

[kamil.svoboda]

Thank you for your advise! I will use relation name for extension point specifing.
Kamil