Author Topic: Invoking an Extended use case with an actor.  (Read 556 times)

fluxtah

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Invoking an Extended use case with an actor.
« on: March 23, 2004, 01:11:42 am »
It seems extended use case can be used to extend the behaviour of a use case, now I think I have this use case that extends another use case, however I also need to invoke this use case directly by the actor...

Is this possible and how would this effect my use case description?  ???

regards

Fluxtah

Oscar

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Re: Invoking an Extended use case with an actor.
« Reply #1 on: March 23, 2004, 05:05:11 am »
Fluxtah,

An extended use case can be directly invoked by an actor.

How it affects your base use case description depends on the way you made description itself. An extending use case is (usually) an alternate couse of (a part of) the base use case. So I would expect a minor (or zero) effect on the base use case.


An alternative is to create another base use case (possible with a small description) and extend it with the existing extended use case. The new base use case then acts as a 'wrapper' for the direct invocation of your extended use case.


Hope this helps,
Oscar

fluxtah

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Re: Invoking an Extended use case with an actor.
« Reply #2 on: March 23, 2004, 05:46:59 am »
Cheers Oscar! I also have a similar problem with an Included use case, one called 'Log In' which is a popular use case to include in the scope of a web system...

I was thinking of using it at the pre-condition level, where the use case must be satisfied as a pre-condition.. or the post-condition of the included use case is a pre-condition of the base use case...

not sure :] any thoughts would be helpful

regards

Ian

Oscar

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Re: Invoking an Extended use case with an actor.
« Reply #3 on: March 23, 2004, 06:58:32 am »
Fluxtah,

I think you're thinking .. of using it at the pre-condition level, where the use case must be satisfied as a pre-condition.. is in the right direction  ;)

As the OMG UML specification (according to the EA help) states:  
"Include is a directed relationship between two use cases, implying that the behavior of the included use case is inserted into the behavior of the including use case. The including use case may only depend on the result (value) of the included use case. This value is obtained as a result of the execution of the included use case."

regards,
Oscar


fluxtah

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Re: Invoking an Extended use case with an actor.
« Reply #4 on: March 23, 2004, 08:36:38 am »
cheers! :]

regards

fluxtah