Bank Automation Teller Machine (ATM) use-case diagram, is "Login" is a "use-case"

Question

This is a simple ATM use-case diagram: I think it missed something like Login (authentication) and Print (after Transfer, Withdraw... we will be asked for selecting print bill or not). So are they use-case?

Answer 1

When trying to decide if a certain piece of behavior should be a use case you should look to the "observable result" for the main actor. Does "login" yield such a result?

It depends on the system you are developing, the complexity of the authentication system etc. It might be a mere step in the use case scenario or it might become a (secondary) use case.

Another tool I teach my students is the BOSS test. You have to ask yourself:

Will my boss be happy when I 100 times today?

Usually usecases like "Login" fail the BOSS test. Things like "Create Order" or "Pay Invoice" usually pass the BOSS test.

But again whether or not to make a use case depends on your methodology (granularity of your use cases), on your system, and on the complexity. There is no YES/NO answer.

Answer 2

Yes, Login is a use case. If Login doesn't happen, then none of the other use cases can happen.

Answer 3

A use-case is a process where an actor interacts with the system. Now map this with Login. Login is a user authentication process where the customer inputs the card and PIN. Then the system carries out the authentication. So this is by all means a use-case.

Answer 4

No absolutely not. "Login" and "Print" are not usecases of ATM. User must by identified before use of ATM services as describe usecase diagram you provide. But, user does not use ATM for LOGIN service. It is not meaningful service. Print is not a UseCase as well. Print is one of step of processes within some of usecases of ATM.

Your UseCase diagram is correct.