[Uml-devel] Bug or feature? Cant have same class appear more than once in class diagram

[Jonathan Riddell]

On Wed, 14 May 2003, Brian Thomas wrote:

>
> 	Hi all,
>
> 	The message below prompts me to remember an irritation that I
> 	have with Umbrello: You cant have the same class appear more
> 	than once in each class diagram. I find this a irriating because I
> 	may re-use a class many times in association with another class.
> 	Consider the following example:
>
> 	Sentence   -    <subject>  - Topic
>                |
>           <predicate>
>                |
>           Topic
>
> 	where lines are assoications between classes and brakets describe
>         the name of the associations ("Sentence" and "Topic" are the 2 classes).
>
> 	I can see a possible counterargument that it becomes hard to generate code
>         when a class appears more than one time in a diagram, but am not 100%
>         sure its so bad.
>
> 	Comments? I guess I lean towards removing this limitation in Umbrello
>         if its not too hairy. I dont see any problem with UML rules as to why this
>         cant happen.

I /think/ that UML does not allow classes to appear more than once in any
one diagram.  But it does allow class instances (i.e. objects) to appear
in class diagrams as many times as you want, something Umbrello does not
currently allow for.  Could be this is something that should be allowed
for.  Not sure how it would affect code generation though.

Jonathan Riddell