analysis

drak3 · 30 Oct 2007 at 18:11

Hello,

I was wondering if any members are into analysis. I am preparing a UML use case diagram for the visa paywave cashless payment system as part of an exercise.

The problem is, I am not sure if the scanner interface and the online management of the card (web site) are outside of system boundary and act upon the system as actors?

Any help appreciated

Dj_Jestar · 30 Oct 2007 at 18:54

Actors are users, or external systems that interact with the system you are analysing through a controlled interface. The scanner interface would not be an actor, it would be an active part of the system, like wise for the online management - the UI is simply that, a User Interface. The model for the systembehind it will remain unchanged, with the UI having simple tie-ins to the data it is permitted to manipulate.

drak3 · 30 Oct 2007 at 19:13

My thinking was that, users will be actors on the scanner and online interface. Then, the scanner and online interfaces will be actors on the internal system.

For example, a user can trigger the use case "purchase" on the scanner subsystem. Then, in turn, the scanner (which is a subsystem) will trigger the use case "process payment" on another subsystem.

Working together the subsystems achieve the goal of the system.

I am on the right track you think?

edit:
The confusing bit is how you model an interface in a system. An online account management website is part of the system, however, the web site just communicates with the server. The user acts on the web site, and then is the web site that acts on the server.

this is what confuses me

thanks for any help

RobH · 30 Oct 2007 at 20:01

Look up the notation for a UML use case diagram. You'll see that using the arrows you can indicate what part of the system initiates another or vice versa. The book 'Software Development with UML' by Ken Lunn is a great book if your just starting to learn about software development, it has a running case study throughout the book. We used this as our course book for the Uni Module.

You'll find that there is no single correct answer in design, it can be done multiple ways.