RE: (ROSE) Question About Actors

[Crain, Anthony R.]

Actors are outside the system.  The whole purpose of identifying actors is to show the boundary of what is in the system and what is outside of the system.

 

The "of value" part of your explanation is good though.  And it does not conflict with the idea that actors are external.

 

Stakeholders in RUP are anyone who would be materially affected by the system if it were built correctly.  But not all stakeholders are actors.  The difference?  Some stakeholders interact with the system, others do not.  The ones that do are actors, the ones that do not are not.  The actor name may match up with the stakeholder name, but often do not.

 

Jane runs a university, and if we build a registration system, she is materially affected, thus is a stakeholder.  However, there may be no requirements that the system directly help her run the university, so there would be no use cases for her.  Thus she would not be an actor.

 

Fred is a professor.  He hopes to use the system to see what courses he can teach next semester and to see what students he has and to grade and evaluate their performance.  He is a stakeholder, and since there are use cases for him, he is also an actor, possibly named Professor.

 

Fred also hopes to use the system to register for the courses he plans to take to improve himself as a professor.  This would result in more use cases for him, but this time the actor would be more appropriately named Student.

 

In all cases, the actors are external to the system.  And they always will be.

 

    --anthony

-----Original Message-----
From: Colin Gourlay [mailto:[EMAIL PROTECTED]]
Sent: Wednesday, February 07, 2001 2:15 AM
To: 'Pankaj Chatterjee'; Rational Rose Forum (E-mail)
Subject: RE: (ROSE) Question About Actors

Well I am fairly new to the UML world so the following may not be 100% accurate!

 

My understanding of an Actor is that it is something or someone that either gives value to or gets value from say a use case in which it is associated.

 

The actor may be a primary actor in that it initiates actions within the system under discussion or it may be a stakeholder (whereby it has a vested interested in the value of a given use case).

 

IMHO an actor need not necessarily be an entity outside the scope of the system - they may in fact be part of it. 

 

Hope this helps

 

Regards

 

Colin

 

 

 

-----Original Message-----
From: Pankaj Chatterjee [mailto:[EMAIL PROTECTED]]
Sent: 06 February 2001 10:20
To: 'Rose Forum'
Subject: (ROSE) Question About Actors

Hello,

 

My understanding is that an Actor is an entity that is outside the scope of the system under consideration. They help us to define the scope that is outside the system as well as what is inside. Actors act upon the system but are not acted upon.

 

Is this a correct description or is there some thing untrue? Please also add the missing parts

 

Thanks

 

Pankaj