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class diagram how?

 
Christian Sell
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Hello,
I just got my results from part II - 68 of 70 required, arggh. As seems to be common, I failed on the class diagram (17 of 40), the rest almost perfect. It also seems to be common to have 12 7f 12 in the sequence diagram.
Now, even though I am not a beginner in UML/J2EE, I am still clueless how to come up with a class diagram that fulfills Sun's requirements. Heres the model I initially submitted:
I took the provided business model, split the Itinerary into One-Way/Roundtrip subclasses, and combined flight and segment into one ConnectingFlight class.
Therefore, an Itinerary references a collection of ConnectingFlights between main origin and main destination (Roundtrip has another collection for the way back).
When a reservation is made, the available seats in the ConnectingFlight objects are decreased. I really had no need for the "Equipment" and "Seat" things, so I removed them (maybe that was my mistake) and ended up with only 7 classes (added user and travelagent).
I consciously did not want to include implementation and infrastructure artifacts (such as EJBs, ValueHolders, Controllers, etc.).
Does anyone (preferrably with experience and success record) have comments/good clues how to improve on this?
thanks,
Christian
 
Robin Zhang
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Christian ,sorry to hear that.
I am struggling to do my part2 now. Can you tell me if you followed the design of the petStore?
 
Christian Sell
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Originally posted by Robin Zhang:
Christian ,sorry to hear that.
I am struggling to do my part2 now. Can you tell me if you followed the design of the petStore?

no, I did not follow the petstore. I dont think that mattered, however, as my other diagram scores were pretty good (39 and 12). Something threw that grader off on my class diagram, and I am trying to understand what...
 
Ian B Anderson
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Christian,
Have you seen the class diagram in the guide book? I know the assignment is different from the example but it should give you an idea of what they expect. One thing I noticed was they put value objects, DAO's in their sequence diagrams but kept their class diagrams really simple, about 10-12 classes if I remember correctly.
Good luck for the future
Ian
[ May 13, 2002: Message edited by: Ian B Anderson ]
 
Christian Sell
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no, I haven't looked at the guide book (I assume you mean the one by some Cade?). However, the number of 10-12 classes shows that I may not be too far off. I deviated pretty much from the business domain model - I wonder to what extent that is permissible.
thanks,
Christian
 
Ian B Anderson
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Christian,
Just thinking out loud here but it seems stange to score so well in the other areas but so poorly in the class diagram. Have you asked Sun for an explanation (I don't know if its possible to get one).
The class diagram in the Cade book doesn't have any attributes or method names shown, don't know if that helps.
Ian
 
Mon Mayor
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Hi,
Sorry to hear that. My take would be that your architecture was right on but your design might not be complete. The contradiction to that assumption would be your score on the sequence diagram, which is not explainable.
Out of 17 you can remove 10 for uml standards, then you have 7 and which might correspond to 7 classes and which would point to an incomplete design. Did you capture all the requirements in your design.
 
Jaspreet Singh UK
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Hi,
Sorry to hear about your result.
Just a guess, but it may be that you so drastically changed the orginal domain model, it seems from your description you only left a couple of classes in there for the original model. How did you document this fact.
I have assummed I am to build on top of the domain model unless I feel it is really incorrect. This maybe a case of (like scjd) how well you can work with a given model.
Did you change the terminology used in the Use cases or use the same terminology?
Just a guess ... since I haven't passed it is a guess
Jas
[ May 13, 2002: Message edited by: Jaspreet Singh UK ]
 
Christian Sell
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well, thanks for everybodys hints and condolences. Looking at my class diagram one more time, I guess I was a little sloppy in doing it. I had spent so much time on the other diagrams, and had gotten so frustrated with the questionable merits of sequence diagrams and the poor support for them in most UML tools. There really may be a few requirements I missed (e.g., seat reservation). I will throw in a few more classes and hope to get over the 2 missing points, and some more ..
BTW, my evaluation of usable UML tools turned out MagicDraw as winner. It does all one can expect (including generate HTML), and is quite affordable if you need to go commercial aferwards.
thanks again,
Christian
 
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