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hasa in UML

From: Francis McCabe <fgm@fla.fujitsu.com>
Date: Fri, 30 May 2003 14:42:22 -0700
To: www-ws-arch@w3.org
Message-Id: <9882C99A-92E7-11D7-BA7E-000393A3327C@fla.fujitsu.com>

UML does not, in fact, has a direct notion of aggregation.

There are three concepts that might be pressed into the service of 

Association (3.41 and following)
Composite Object (3.40)
Collaboration diagrams (3.65 and following)

Association is simply a relationship. There is no additional semantics 
built-in. We can define our own form of association called has-a (but 
we are trying to avoid that right?)

"A composite object represents a high-level object made of tightly 
bound parts. This is an instance of a composite class, which implies 
the composition aggregation between the class and its parts. A 
composite object is similar to (but simpler and more restricted than) a 
collaboration; ..."

I do not think that this meets our needs. It is not accurate to say 
that a service is composed of X + an identifier.

Collaborations on the other hand are not what is going on either:

"A collaboration is used for describing the realization of an Operation 
or Classifier."


On Friday, May 30, 2003, at 02:10  PM, Cutler, Roger (RogerCutler) 

> Well, that's progress of a sort.  Now what do "generalization" and
> "aggregation" mean, and how does this differ from the current
> definition?
Received on Friday, 30 May 2003 17:42:31 UTC

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