Author Topic: Operations in class diagram +use case realisations  (Read 767 times)


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Operations in class diagram +use case realisations
« on: April 30, 2006, 02:54:47 am »
Hi everyone!

I work as a bussines analyst and I'm new in OOAD and UML language and I have two questions:

1. I have prepeared the sequence diagrams for the illustration of the work flow for use cases (I know, it would perhaps be better to use activity diagrams for this...). In the literature I have read, that each message in the sequence diagram represents one operation in the class diagram. Now I'm questioning myselphe, if I understood this right - is this really a general rule?  

2. What would you understand uder "use case realisations"? I imagine, that this is demonstration of how every funktional requirement will be realised by each use case. For example, I have a requirement "Prepeare a report" and use case "Prepearing a report". If I draw a "realise" connection from use case to requirement, is this use case realisation? I'm confused, because I heard, that use case realisation is actually demonstration of how use cases will be realised with entities? If this last is correct, how should I draw this?

Thanks for answers.
« Last Edit: April 30, 2006, 03:01:22 am by analyst »


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Re: Operations in class diagram +use case realisat
« Reply #1 on: May 01, 2006, 04:02:14 pm »
1.  You can just use generic timelines and not instances of classes to show whatever you want in the sequence diagram.  The problem with sequence diagrams is that it becomes difficult to show decision points.  So they are not as easily understood by the intended audience of the Use Case.  This is why activity diagrams are better.  (IMHO).  Sequence diagrams can be used later in your design process to show how your domain objects interact to implement your use case.  When you start diagramming at this low level you can use actual class instances for your timelines, via drag and drop,  and begin to actually correlate messages with class operations.

2.  I am not the best one to answer this because I never show Use Case Realizations in my diagrams.  Instead, I just make my Use a Composite Element and create any diagrams that realize the Use underneath it.  Thus, my basic model organization relates this information.  


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Re: Operations in class diagram +use case realisat
« Reply #2 on: May 02, 2006, 03:36:33 am »
See here and search for "collaboration" in this forum.