Communication Diagram - Multiplicity - It is wrong

[Miguel Gonzalez]

Hello,

I have been creating a Communication Diagram and I see that the tool allows you to add multiplicity on the object associations.

UML does not allow this, from a formal point of view, multiplicity is not correct on interaction diagram; these diagrams model the system at a given time, like taking a snapshot of the system. These diagrams do not show classes but object.

One of the advantages of UML is the flexibility it gives for us to add functionality and so I guess that you guys probably want to allow multiplicity on Communication Diagram for a special purpose.

I also see that it allows specifying operations within the object while these operations should be shown as the messages the objects send to each other.

I have been thinking that perhaps you want to show properties of the static class diagram on the interaction Communication Diagram.

What is the reason for multiplicity on this diagram?

Thank you.

[Miguel Gonzalez]

I guess this is a question for the most rigorousness guys out there.

Guys, from a strict UML point of view... Is multiplicity incoherent with object and so it shouldn't be allowed on Communication diagrams?

Miguel.