Doubt in the Representation of Use Cases

Question

Of the link Abstraction Difficulty in Use Cases, I made the following interpretation:

"Only the attendant can confirm the dispatch of the order, but for this it is necessary to have the completion of the order, which can only be made by the pizzaiolo. But to finalize a request it is necessary for the customer to make the payment and in turn it is necessary to make the request for it". Is the reading shown in the diagram correct? If correct, this confuses me a lot because the function of the Use Case Diagram is to represent the objectives of each actor, and should not represent those objectives in a sequence of steps to be done as in the Activity Diagram, but we can notice in this example that there is a flow to be followed.

Answer 1

The diagram documents what the system does from a user’s point of view. It describes the main functionalities of the system and the interaction of these functionalities with the users of the same system. In this type of diagram it is not necessary to delve into the technical details that tell how the system does the actions(Language, DBMS etc).

In this case, is represented all that the Customer User can do, that is to register, place order and pay. The Attendant user can only confirm the Shipping of the order. The User Pizzaiolo, can consult order and finalize order.

The whole system flow is represented, but also the actions of each actor, which can be analyzed both individually and together, so the representation is correct. The activity diagram is different from this, because it includes a logic to represent the flow of activities, it is usually closer to an algorithm.

In Summary: Use Case Diagram is a representation in a System User’s View, with simple explanations and no technical details. Activity Diagram is a representation of the flow, containing logic, next to an algorithmic representation of the system.