The Object-Oriented Thought Process, Fourth Edition

Using Abstract Thinking When Designing Interfaces

One of the main advantages of OO programming is that classes can be reused. In general, reusable classes tend to have interfaces that are more abstract than concrete. Concrete interfaces tend to be very specific, whereas abstract interfaces are more general. However, simply stating that a highly abstract interface is more useful than a highly concrete interface, although often true, is not always the case.

It is possible to write a very useful, concrete class that is not at all reusable. This happens all the time, and nothing is wrong with it in some situations. However, we are now in the design business and want to take advantage of what OO offers us. So our goal is to design abstract, highly ...