Bridge is a structural design pattern that divides business logic or huge class into separate class hierarchies that can be developed independently.
One of these hierarchies (0often called the Abstraction) will get a reference to an object of the second hierarchy (Implementation). The abstraction will be able to delegate some (sometimes, most) of its calls to the implementations object. Since all implementations will have a common interface, they would be interchangeable inside the abstraction.
Usage examples: The Bridge pattern is especially useful when dealing with cross-platform apps, supporting multiple types of database servers or working with several API providers of a certain kind (for example, cloud platforms, social networks, etc.)
Identification: Bridge can be recognized by a clear distinction between some controlling entity and several different platforms that it relies on.
Example: Structure of the Pattern
This example illustrates the structure of the Bridge design pattern. It focuses on answering these questions:
What classes does it consists of?
What roles do these classes play?
In what way the elements of the pattern are related?