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I'm currently learning object-oriented programming and we have moved on to UML. We are learning about use cases and actors currently and we need to create a list of actors and use cases initiated by each actor for a given problem.

I understand what each of the individual components are but we haven't been given any examples. I've looked up examples but it only seems to give the final result of the use case diagram. What I am struggling with is using a problem statement ( the requirements of the system) to then create and find the actors and use cases.

Here's the domain to model: https://www.scribd.com/document/401208954/Pms

And this is my example of what I think I have to do (but not sure if I'm on the right track)

2.2 MONITOR:

Each bed has a separate monitor that collects patient data, sends information to the display, and response to user commands and queries.

My assumptions:

The requirement is going to be: collects patient data. The goal: sends info to the display and the owner: the patient

Do am I approaching the analysis from the right side? How can I identify the Use Case of a given statement and the actors involved?

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  • What actually is the question here?
    – Simon B
    Commented Mar 11, 2019 at 16:22
  • Whether or not what I am doing is anywhere near correct. I need to identify the use cases and actors using the requirements within the link attached. But I don't know how to find the actors and use cases so attempted what i think is right
    – RHH
    Commented Mar 11, 2019 at 16:26

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You need to step back a bit and look at the system as a whole.

An actor is anyone who interacts with the system. Users are always actors (hint: read the last sentence of "1. Purpose"). Other people can also be actors where they need to interact with the system - for instance if the system asks them to do something. I am not sure that the "patient" is even an actor in this example - they don't seem to do anything but be monitored.

Other computer systems that are outside the system you are modelling can also be actors. For example, if two computers communicate over a network, but you are only responsible for one of them, then the other must be an actor.

A use case represents a series of interactions between the user and the system, to achieve a specific purpose. So you have to think about all the things that the users will do with the system. It sounds like you are only being asked to identify what the use cases are at this stage, not actually write them out in full.

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  • I think the next stage afterwards is choose two of the use cases and describe them. The first stage is: list of actors and use cases initiated by each actor. My problem is i dont have a clue where to start with the whole requirements list and how each differs
    – RHH
    Commented Mar 11, 2019 at 16:59
  • @RHH Bear in mind that requirements aren't use cases. You need to read them, then work out who the actors must be - what people will be interacting with the system. That's the easy bit. Teasing out the use cases is more difficult. You need to look at what the system is supposed to do, from the requirements, and then work out how the people will need to interact with the system to achieve that. That is entirely down to you working out what the system is for, and then teasing out what the users will do. The question writers aren't making it easy for you here.
    – Simon B
    Commented Mar 11, 2019 at 22:50
  • So where do i begin with this then... I need to read through the requirements and pick out elements of what the system needs to do. Then see who interacts with them. And then what do you mean by teasing? Also, say when i actually understsnd and begin to document it... what will i need to document. Just a list of actors and use cases linked to them. Or the actual diagram, and if so a diagram for each of the 5 seperate areas of the requirements or all together
    – RHH
    Commented Mar 12, 2019 at 13:23
  • By "teasing", I just mean that some use cases are more obvious than others. 3.1.8 looks like a use case to me. 3.2.2 isn't a use case at all. There might be one or even two use cases implied by 3.2.7.
    – Simon B
    Commented Mar 12, 2019 at 16:01
  • I think I'm starting to get it a bit more, so basically I've just got to go through the requirements and determine which are actual things the system needs to do
    – RHH
    Commented Mar 12, 2019 at 16:08

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