Bridge

Bridge design pattern

Intend

• Separate an abstraction from its implementation.
• The abstraction is an interface or abstract class and the implementor is also an interface or abstract class

The bridge is a structure design pattern which allow to the abstraction and the implementation can be developed independently and the client code can access only the abstraction level without being concerned about implementation level.

This pattern involves an interface which acts as a bridge which makes the functionality of concrete classes independent from interface implementer classes.

Example

Mostly bridge design pattern we use when we have some complex class or set of closely related classes and we want to split them into two separated hierarchies, abstraction and implementation. In concrete case we want to draw two independent circles, red and green, with concerning only abut circle center, radius and type.

To solve this task:

1. Create CircleInterface which will be a bridge between implementation and abstraction level.
2. Create implementation later with two classes RedCircleClass and GreenCircleClass
3. Create abstraction layer with SharpClass as abstract class
4. Create client class CircleClass which inherits SharpClass