bridge - Harsh4999/Design-Patterns GitHub Wiki

Bridge

##Use

• Using bridge pattern we can decouple the abstraction so they can both change without affecting eachother
• We achieve it by creating 2 seperate inheritance hierarchies one for implementation and another for abstraction
• We use composition for bridge

##UML

• Abstraction class = defines the abstraction interface, it has refrenece to implementor
• Refind abstraction = child of Abstraction it defines the specified abstraction
• Implementor = Its base interface which provides methods to Abstraction, methods are unrelated to abstraction and typically represent smaller steps needed bridge is called the relationship between the Abstraction and Implementor
• Concrete Implementors = they implement Implementor

##Implementation

• We determine common base operations and define them in abstraction
• We can optionally also define abstraction & provide more specialized operations
• Implementor methods do not have to match with abstractor however abstraction can carry out its work by using implementor methods
• We write one or more concrete implementor providing implementation
• Abstraction are created by composiing with an instance of concrete implementor which is used by methods in abstraction
• It reduces the dependencies and make both classes and interface indepenedent we can change any methods anywhere without worrying about errors of methods not implemented
• It allows great flexiblity in between of abstraction and implementor
• Eg: DriverManger of JDBC