Facade Pattern




The facade pattern (or façade pattern) is a software design pattern commonly used with object-oriented programming. The name is by analogy to an architectural facade.

A facade is an object that provides a simplified interface to a larger body of code, such as a class library. A facade can:
• make a software library easier to use, understand and test, since the facade has convenient methods for common tasks;
• make the library more readable, for the same reason;
• reduce dependencies of outside code on the inner workings of a library, since most code uses the facade, thus allowing more flexibility in developing the system;
• wrap a poorly designed collection of APIs with a single well-designed API.

The Facade design pattern is often used when a system is very complex or difficult to understand because the system has a large number of interdependent classes or its source code is unavailable.


This pattern hides the complexities of the larger system and provides a simpler interface to the client. It typically involves a single wrapper class which contains a set of members required by client. These members access the system on behalf of the facade client and hide the implementation details.




A Facade is used when an easier or simpler interface to an underlying object is desired.[1] Alternatively, an adapter can be used when the wrapper must respect a particular interface and must support polymorphicbehavior. A decorator makes it possible to add or alter behavior of an interface at run-time.





Converts one interface to another so that it matches what the client is expecting


Dynamically adds responsibility to the interface by wrapping the original code


Provides a simplified interface


The facade pattern is typically used when:


  • a simple interface is required to access a complex system;
  • the abstractions and implementations of a subsystem are tightly coupled;
  • need an entry point to each level of layered software; or
  • a system is very complex or difficult to understand






     The facade class abstracts Packages 1, 2, and 3 from the rest of the application.


    The objects are using the Facade Pattern to access resources from the Packages