[Modeling] agents vs actors

James Odell email@jamesodell.com
Wed, 17 Sep 2003 21:58:46 -0400

Vivek ,

This discussion would benefit greatly by a clarification of what an actor
is. The following three sentences are all taken from the UML2.0 spec:

"An actor specifies a role played by a user or any other system that
interacts with the subject."

"An Actor models a type of role played by an entity that interacts with the

"Actors model entities external to the subject. Each actor represents a
coherent set of roles that users of the subject can play when interacting
with it. When an external entity interacts with the subject, it plays the
role of a specific actor."

As you see, the three sentences define actor completely different: a role, a
type of role and an entity/set of roles - the last one is the Semantics
text. (This should in fact be registered as an FTF issue to be fixed in the
coming year.)



On 9/17/03 12:36 PM, "Vivek Kumar Singh" indited:

> Hello all,
> I'm a student of Mtech ICT, DA-IICT, india. I'm working on modelling of
> a project on agents. But I'm finding it very diffiult to categorize my
> agents as either actors or use cases. According to books on UML
> modeling, and actor is an external entity interacting with our system.
> If I consider this then agents can't be actors. But also it is said
> that actor can initiate processes (use cases). So according to this, my
> agents become actors.
> My project idea is to develop intelligent agents for every student in
> institution and also to have intelligent library agents. Then students
> can just order their agents to search for a book on a particular topic.
> The agents who will be knowing about his master's interests and
> knowledge level and will intelligently search for most suitable book
> for his master from a big list of books. The library will also have
> intelligents on particular subjects. The project also have many adjunct
> features.
> But the problem is identifying agents as actors or use cases. I've seen
> extended form of UML for this, but what can be done with UML's present
> form and Rational rose. Kindly give suggestions.
> With regards,
> Vivek Kumar Singh
> Vivek Kumar Singh
> Mtech ICT, DA-IICT
> Gandhinagar 
> MOB : 09426374152
> http://intranet.da-iict.org
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