[coder_pl]

Hello

I was wondering if someone could help my with designing the use-case diagram. I have indetified the actors but i dont know what next...

Actors:
Staff
Security Guard
Sensors (heat, smoke, movment)
Police
Fire Brigade

Can someone take me step-by-step through it please?

Attached File(s)

•  Proposed combined security and fire system.pdf (119.07K)
  Number of downloads: 45

[coder_pl]

My thinking:

Staff ---> Swipe card + enter password (but only outside normal hours, dont know if it changes anything in the diagram)


Staff ---> can push alarm button which will trigger the alarm

Security Guard ---> i assume he can do things as Staff plus more

Security Guard ---> test the whole system

Security Guard ---> reset alarms in case of false alarm after confirming it was false

Security Guard ---> can activate the sprinkler system if no one in the zone

Sensors ---> detect movment
Sensors ---> detect heat
Sensors ---> detect smoke
Sensors ---> trigger alarm

is this correct? looks a bit messed up...I have no idea how to put it into diagram Please help...

[tlhIn`toq]

Take a look at the Objects & Classes tutorial in my signature block. A large part of that tutorial is built specifically to help people think in an Object Oriented way. In other words it was built to help teach you how to do this for yourself.

[BobRodes]

You're on the right track, coder. Go through your problem statement (that's what your pdf file is, and well-written too--good professor), and pull out everything that the system does. Forget about the actors while you're doing this. Just pay attention to everything that the system is supposed to do. Each discrete behavior in the system is a use case. Note also that you have a "security subsystem", so you will have to put that in there too. Get that information down cold. Also, don't worry about when and how the use cases behave. That's for another level of detail. So, for example, "Reset Alarms" is a use case. The precondition that the use case can't be entered unless a false alarm is confirmed belongs in the "use case narrative", typically diagrammed with an activity diagram. So, leave that for later; no doubt you'll get to that.

If you don't know how to do a use case diagram, start googling. Here is a decent little reference from Microsoft of all places. There are plenty of other examples. Once you are clear on what your use cases are, what the actors are, and what their interactions are, the diagram is the easy part. If you have any questions, feel free to post back.

This post has been edited by BobRodes: 02 December 2012 - 09:01 PM