Bridge By online-example

The Bridge pattern allows to vary both the implementation and the abstraction by placing both in separate class hierarchies. Abstraction defines the abstract interface and maintains the Implementor reference. RefinedAbstraction extends the interface defined by Abstraction. Implementor defines the interface for implementation classes. ConcreteImplementor implements the Implementor interface According to "Design Patterns" by Helm and Johnson, the use of the bridge pattern means to "decouple an abstraction from its implementation so that the two can vary independently".