[Modeling] Modeling an Agent Class- composition
Thu, 26 Jun 2003 10:19:58 +0200
> Hong Zhu wrote (on 19 June):
>> We have a agent that represents a department in a university,
>> and a number of agents as members of the department. When the
>> department is destroyed, ...
> Composition seems to work perfectly well to me.
Yes, I don't see any problem either.
And contrary to Hong's appeal, we cannot rely on the UML2 spec for
the semantics of aggregation/composition (especially wrt lifetime
dependency), because it is unclear/confused and not well-defined.
They say themselves:
Semantic Variation Points (p.40 of the current UML2 document)
The precise lifecycle semantics of aggregation is a semantic
Semantic Variation Points (p.75 of the current UML2 document)
Precise semantics of shared aggregation varies by application
area and modeler.
So we better rely on well-justified theories of the part-whole
relationsip, such as sketched in my paper
Towards Ontological Foundations for UML Conceptual Models
which is also a recommended reading in OMG's RFP for an Ontology