Use Cases for a Simple Library System
Now that we have defined our business object and
Use cases are an extremely important aspect of UML modeling. They allow developers to understand software systems from the user's perspective, and cause the whole system architecture to be driven by what the
The use cases in our example describe a simple software application for a library. This example is a variation along the classic theme of use case examples and works well because it's simple enough to model in a chapter this
The following image contains a high-level overview use case diagram containing most of the main use cases in this application:
As you can see in this diagram, there are three actors - the
(as you might imagine) represents people who
searches for media, but also
Notice our use case diagram identifies three "uses" relationships, indicating places where application functionality is reused from multiple use cases. Both the Check in Media and Daily Processing use the Calculate Overdue Amount use case. Check Out Media and Apply Payments use the Display Borrower Account use case.
We won't perform object modeling on all these use cases, but we'll pick a few key use cases so you get a feel for how it's done.
Modeling the Check Out Media Use Case
The first use case we'll model is " Check Out Media ". Here is a more detailed explanation of this use case: