Facade pattern

The facade pattern is designed to provide a simple interface to a complex system of components. The objects in this system may need to be interacted with directly for complex tasks and interactions. Often, however, there is 'typical' usage for the system, and these complicated interactions aren't necessary in that common scenario. The facade pattern allows us to define a new object that wraps this typical usage of the system. Any code that wants to use the typical functionality can use the single object's simplified interface. If another project or part of the project finds this interface is too simple and needs to access more complicated functionality, it is still able to interact with the system directly. The UML diagram for the facade pattern is really dependent on the subsystem, but in a cloudy way, it looks like this:

Facade is, in many ways, like adapter. The primary difference is that the facade is trying to abstract a simpler interface out of a complex system; the adapter...