The Facade Pattern

You may have had occasion to stitch third-party systems into your own projects in the past. Whether or not the code is object oriented, it will often be daunting, large, and complex. Your own code, too, may become a challenge to the client programmer who needs only to access a few features. The Facade pattern is a way of providing a simple, clear interface to complex systems.

The Problem

Systems tend to evolve large amounts of code that is really only useful within the system itself. Just as classes define clear public interfaces and hide their guts away from the rest of the world, so should well-designed systems. However, it is not always clear which parts of a system are designed to be used by client code and which are best hidden.