Can the actor in a use case diagram be the system, for example I have a use case for checking the username and password for the system user ,, then the actor for this use case is the system itself,, so is this right?
Hi John,
I'm not sure I understand your exact example but "Yes" - a system an be an actor (and actor can be a system).
If you are using use cases to model the functional requirements for a shopping cart system then the "Login" use case might have the customer as the primary actor and an "Entitlements" system which is used by the shopping cart to check the user's credentials.
- Adrian
To be clear, I am working on a registration system which can be used to cover different areas (schools, universities, events managements, etc), so there are processes such as checking if the registered user is in considered a VIP person or not, this is done by comparing his information to a predefined VIP list, those processes are performed automatically by the system without user evolvement , then after those processes are completed the system user will be informed by the results of those processes, so my question is that when I write the user case diagrams, can I say that the system is the actor for the “checking VIP list” use case?
Thanks
the process of checking if the user is a VIP is done in response to something - and that something will be initiated by the actor. So the system for which you are developing the use case can't really be an actor.
I would suggest the scenario documented in the user case might be something like:
"Pre condition: user wishes to make booking
Post condition: user informed of VIP status, booking details, etc
This use case starts when the user wants to use the solution to make a booking.
1.The user supplies a user name and password
2.The system informs them if they hold VIP status or not
3.The user selects a date...
Etc"
You might want some exception/alternatives around statement 2 for user name and password not found and another for if they don't have a valid status.
The key thing here is that as the use case defines the user/solution interaction having the solution as an actor just wouldn't work.
Hope this helps.
Guy
Thanks for response, but my question is regarding the use case diagram and not the use case details, the use case diagram usually consists of all the use cases in the system and the actors plus showing the actor/s who interacts with each one of the use cases
brought to you by enabling practitioners & organizations to achieve their goals using: