21.1 Facade Design Pattern

Facade:

• Simpler interface to a complex subsystem.
• communication between complex objects

Facade pattern hides the complexities of the system and provides an interface to the client using which the client can access the system. This type of design pattern comes under structural pattern as this pattern adds an interface to existing system(legacy code) to hide its complexities.

This pattern involves a single class which provides simplified methods required by client and delegates calls to methods of existing system classes.

http://www.tutorialspoint.com/design_pattern/facade_pattern.htm

Factory: for creating objects