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

Summary

The Facade pattern is so named because it puts up a new front (a facade) in front of the original system.

The Facade pattern applies when

• You do not need to use all of the functionality of a complex system and can create a new class that contains all of the rules for accessing that system. If this is a subset of the original system, as it usually is, the API that you create in new class should be much simpler than the original system's API.

• You want to encapsulate or hide the original system.

• You want to use the functionality of the original system and want to add some new functionality as well.

• The cost of writing this new class is less than the cost of everybody learning how to use the original system or is less than you would spend on ...