At first sight, the Bridge pattern looks much like the Adapter pattern in that a class is used to convert one kind of interface to another. However, the Adapter pattern is intended to make one or more classes' interfaces look the same as that of a particular class. By contrast, the Bridge pattern is designed to separate a class's interface from its implementation so that you can vary or replace the implementation without changing the client code.
The participants in the Bridge pattern are
the Abstraction, which defines the class's interface,
the Refined Abstraction, which extends and implements that interface,
the Implementor, which defines the interface for the implementation classes, and
the ConcreteImplementors, which ...