Chapter 4
Wouldn't it be ideal to extend the functionality of an object or plug in to the existing services of a legacy system without any disruption to that system whatsoever? The Adapter design pattern described in this chapter allows you to accomplish just that by advocating loose coupling of a class's interface to its implementation.
NOTE
Coupling is a measure of how closely related modules or classes are to each other. Loose coupling implies that the modules aren't restrictively interdependent.