Design Patterns Explained: A New Perspective on Object-Oriented Design

Relating the Adapter Pattern to the CAD/CAM Problem

In the CAD/CAM problem (Chapter 3, “A Problem That Cries Out for Flexible Code”), the features in the V2 model will be represented by OOGFeature objects. Unfortunately, these objects do not have the correct interface (from my perspective) because I did not design them. I cannot make them derive from the Feature classes, yet, when I use the V2 system, they would do our job perfectly.

In this case, the option of writing new classes to implement this function is not even present—I must communicate with the OOGFeature objects. The easiest way to do this is with the Adapter pattern.