Multiplicity on Objects or Classes (in CSD) ?

[Marc2]

Hi,

I would like to model (in an Composite Structure Diagram (CSD)) a machine platform. This platform consists of 3 types of blocks/elements (say elements of Block A, Block B and Block C). This is modelled in a Logical View. However, when modelling (in a Physical View) the 'concrete machine' (so a 'derivative' of the platform) the number of Blocks B may vary between 1 and 15. This variation should be visible in the Logical View too. How should I do this?


[glb][Edit: please skip the rest of this topic and read the possible solutions in the 2nd reply to this topic][/glb]

a) drag-and-drop Block A, Block B and Block C to the "Machine Platform (Logical View) (CS)" and select "New Child (Generalization)"; and specify for Block B a multiplicity of "1..15" ?
b) drag-and-drop Block A, Block B and Block C to the "Machine Platform (Logical View) (CS)" and select "Simple Link"; and then specify for Block B a multiplicity of "1..15" ?
c) ...

The problem I see with solution (a) is that (afaik) a 'new child' is already an instantiation, while specifying a multiplicity should be done on a block/class, not on an instance/object.

The problem I see with solution (b) is that (as far as I know) in a CSD normally instances/objects are modelled, not the blocks/classes themselves. This could also imply that for some other elements in the CSD objects are modelled, which are then coupled with blocks/classes. This seems not correct to me.


Could you please give your thoughts on this?


Thanks,

Marc

[thomaskilian]

I'd create instances for the physical machines. That should reflect your case most adequate.

[Marc2]

Thanks for your reaction. However, I made a mistake describing the possible solutions for the problem . What I meant was the following:

In a Composite Structure Diagram one should model the instances/objects, not the classes. However, in this case in the Logic View I want to model 1 instance (of class B) and set the multiplicity to "1..15" (i.e. in the Physical View there could be 1..15 physical instances of this single logical instance). But this seems contradicting, as I modelled only 1 instance.

Another solution would be that I model a class in a Composite Structure Diagram and set the multiplicity to "1..15". Multiplicity-wise this seems better, but a class in a CSD is not correct neither.


Sorry for the mistake; could you please give your view on this problem?


Thanks,

Marc

[thomaskilian]

Pass :-/

[jeshaw2]

Does UML 2.0 Composition Model, Bock help?  Take a look at how the wheels on a car are handled.

-Jim

[Marc2]

Hi Jim,

Yes, this makes sense. Thank you for the URL!


Regards,

Marc