Question

I am reverse engineering some Java code into a class diagram. Now I’m wondering how to model classes that are from a library that I didn’t design. If I’m writing them down as classes, I should maybe also know what interfaces they implement, etc, and put that in the diagram. How far do I go with this? Is it better to write them down as attributes of my own classes?

Answer 1

Include whatever classes and interfaces your code uses in the diagram for your code.

Place the elements from the library into a package which represents the library’s package.

Use whatever level of detail is sufficient for what the diagram represents.

• If you only want to record that your code uses the library, a «uses» relationship to the package representing the library

• If you have associations to elements in the library, model the elements you relate to but no detail in them.

• If you or extend or implement classes or interfaces, model the attributes and operations of those elements.

• If your code relies on a sequence of operations on elements in the library, you may model the operations, or may just use messages which are not directly linked to them, depending what your tool allows.