1. defines a higher-level interface that makes a subsystem easier to use
Façade
simplifies access to a related set of objects by providing one object that all objects outside the set use to communicate with the set
defines a higher-level interface that makes a subsystem easier to use
Façade Class
subsystem
March 2007
ACS Ron McFadyen

2. Façade
Facade knows the subsystem classes and delegates requests to appropriate subsystem objects.
                                                         
facade
Façade Class
Facade
subsystem
Subsystem has no knowledge of the facade - has no reference of it
March 2007
ACS Ron McFadyen

3. Consider text example …
Façade
A Façade simplifies access to a related set of objects by providing one object that all objects outside the set use to communicate with the set.
This avoids the problem of having to reference many different, complicated interfaces to each object of that set.
Consider text example …
March 2007
ACS Ron McFadyen

4. Façade vs Adapter Adapter Façade
provides an object that acts as an intermediary for method calls between client objects and one other object not known to the client objects.
provides an object that acts as an intermediary for method calls between client objects and multiple objects not know to the client objects.
March 2007
ACS Ron McFadyen