Re: OCL challenge



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stuart kent (stuart@mclellankent.com)
Wed, 06 Dec 2000 17:14:06 +0000


Daniel I am following this discussion with interest. Just a couple of brief comments... > 1. presumably the structuring sublanguage in which you declare classes and > relations is not official OCL? i've criticized this feature of UML/OCL > before, as it seems to me essential to be able to have a fully textual spec, > as you do. is this USE syntax? I don't see why the spec needs to be textual. What is essential of course is to have a precise language capturing these structural aspects. It does not follow that that language needs to be textual (I can imagine parsing a diagram). One could also use the XMI format defined for UML. > on the diagram question: your correction to my diagram seems necessary from > what i understand of UML. what i try to do in the paper i mentioned is to > allow this situation without having to make every class a subclass of > object, which for a large diagram would be a big nuisance. i also allow uses > of lists in different contexts to be distinguished (as different boxes). Actually you can achieve the same in UML by using dynamic subclasses, which one can consider to be the same as states (as in a state diagram). In this case, one can consider that list has two states, Empty and NonEmpty, which could be represented as dynamic subclasses of List. Then the diagram is as you have it. You might also like to take a look at my constraint diagram notation which allows a significant subset of a constraint language to be expressed visually, and allows 'uses' of classes to be distinguished in quite a fine-grained manner. See http://www.cs.ukc.ac.uk/people/staff/sjhk/cds.html Stuart -- ukc home - http://www.cs.ukc.ac.uk/people/staff/sjhk uml'2000 - http://www.cs.york.ac.uk/uml2000 puml group - http://www.puml.org/


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