Decouple an abstraction from its implementation so that the two can vary independently
Bridge pattern allows us to vary both the implementation and the abstraction by placing both in seperate class hierachies.
The Abstraction defines the abstraction, and maintains the reference to the implementor. RefinedAbstraction provides an extension to the Abstraction, usually adding extra methods that provide different ways of getting at the same functionality.
RefinedAbstractions are implemented in terms of the abstraction, and not that implementation interface.This means that the implementation details are hidden from the client. The pattern is similar to the Adapter pattern, except the Bridge pattern separates the interface from implementation.
http://www.codeproject.com/Articles/183655/Bridge-Design-Pattern
Bridge pattern allows you to develop the Abstraction and the Implementation parts independently. It also cuts down on the number of classes that you need to create to fulfill all the possible combinations of the Abstractions (user interface concepts) and the Implementations (actual actions behind the scene).
When to Use
The Bridge pattern should be used when both the class as well as what it does vary often. The bridge pattern can also be thought of as two layers of abstraction. When the abstractions and implementations should not be bound at compile time, and should be independently extensible the pattern should be used.
http://sourcemaking.com/design_patterns/bridge
Check list
in AWT, where a component has a component peer which does the OS specific operations. Also the Collections framework has examples of the bridge interface: ArrayList and LinkedList are implement List. And List provides common methods to add, remove or check size.
The Bridge design pattern proposes refactoring this exponentially explosive inheritance hierarchy into two orthogonal hierarchies – one for platform-independent abstractions, and the other for platform-dependent implementations.
On/Off Switch
Remote control which can turn on and off different kinds of device.
The concept of turning the appliance on or off is the Abstraction part, and the user only needs to know the Abstraction part.
the left side represents controls that can turn appliances on or off, such as the on/off switch, the pull switch, or the remote control, while the right side represents the actual appliances that performs the action, such as the TV or the VacuumCleaner.
Copy and paste function in many applications. The copy and paste function is the abstraction, where the user only needs to know how to use it, and the actual action of transferring the information into the memory and transferring the information onto the application is the implementation.
Watch Out for the Downsides
One of the major drawbacks of this pattern is that, in providing flexibility, it increases complexity. There's also possible performance issues with the indirection of messages - the abstraction needs to pass messages along to the implementator for the operation to get executed.
Read full article from Design Patterns Uncovered: The Bridge Pattern | Javalobby
Bridge pattern allows us to vary both the implementation and the abstraction by placing both in seperate class hierachies.
The Abstraction defines the abstraction, and maintains the reference to the implementor. RefinedAbstraction provides an extension to the Abstraction, usually adding extra methods that provide different ways of getting at the same functionality.
RefinedAbstractions are implemented in terms of the abstraction, and not that implementation interface.This means that the implementation details are hidden from the client. The pattern is similar to the Adapter pattern, except the Bridge pattern separates the interface from implementation.
http://www.codeproject.com/Articles/183655/Bridge-Design-Pattern
Bridge pattern allows you to develop the Abstraction and the Implementation parts independently. It also cuts down on the number of classes that you need to create to fulfill all the possible combinations of the Abstractions (user interface concepts) and the Implementations (actual actions behind the scene).
When to Use
The Bridge pattern should be used when both the class as well as what it does vary often. The bridge pattern can also be thought of as two layers of abstraction. When the abstractions and implementations should not be bound at compile time, and should be independently extensible the pattern should be used.
http://sourcemaking.com/design_patterns/bridge
Check list
- Decide if two orthogonal dimensions exist in the domain. These independent concepts could be: abstraction/platform, or domain/infrastructure, or front-end/back-end, or interface/implementation.
- Design the separation of concerns: what does the client want, and what do the platforms provide.
- Design a platform-oriented interface that is minimal, necessary, and sufficient. Its goal is to decouple the abstraction from the platform.
- Define a derived class of that interface for each platform.
- Create the abstraction base class that "has a" platform object and delegates the platform-oriented functionality to it.
- Define specializations of the abstraction class if desired.
- Adapter makes things work after they're designed; Bridge makes them work before they are.
- Bridge is designed up-front to let the abstraction and the implementation vary
- If interface classes delegate the creation of their implementation classes (instead of creating/coupling themselves directly), then the design usually uses the Abstract Factory pattern to create the implementation objects.
in AWT, where a component has a component peer which does the OS specific operations. Also the Collections framework has examples of the bridge interface: ArrayList and LinkedList are implement List. And List provides common methods to add, remove or check size.
The Bridge design pattern proposes refactoring this exponentially explosive inheritance hierarchy into two orthogonal hierarchies – one for platform-independent abstractions, and the other for platform-dependent implementations.
On/Off Switch
Remote control which can turn on and off different kinds of device.
The concept of turning the appliance on or off is the Abstraction part, and the user only needs to know the Abstraction part.
the left side represents controls that can turn appliances on or off, such as the on/off switch, the pull switch, or the remote control, while the right side represents the actual appliances that performs the action, such as the TV or the VacuumCleaner.
Copy and paste function in many applications. The copy and paste function is the abstraction, where the user only needs to know how to use it, and the actual action of transferring the information into the memory and transferring the information onto the application is the implementation.
Watch Out for the Downsides
One of the major drawbacks of this pattern is that, in providing flexibility, it increases complexity. There's also possible performance issues with the indirection of messages - the abstraction needs to pass messages along to the implementator for the operation to get executed.
Read full article from Design Patterns Uncovered: The Bridge Pattern | Javalobby
