Facade

Provide a unified interface to a set of interfaces in a subsystem. Facade defines a higher-level interface that makes the subsystem easier to use.

Applicability

• Need to provide a simple interface to a complex system
• Need to decouple a subsystem from its clients
• Need to provide an interface to a software layer

Consequences

• Shields clients from subsystem components
• Promotes weak coupling between the subsystem and its clients
• Facade doesn't prevent clients from using subsystem classes if they need to