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You can grasp the idea of bridge pattern and see real life examples in code and class diagrams.
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BRIDGE PATTERN“ decoupling an abstraction from its implementation ”
Jang, Taeksoon (NHN NEXT)
Wednesday, March 26, 14
MOTIVATION- Suppose an abstraction should have different implementation
- Simple implementation would just extend the object itself
- Then, inheritance binds an implementation to the abstraction
- When a class changes often, you should change all classes
“ Bridge Pattern helps minimize changes in class ”
Wednesday, March 26, 14
BRIDGE PATTERN DEFINED
- Separate abstraction and implementation
Class itself : AbstractionWhat class can do : Implementation
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PARTICIPANT
Abstraction : defines abstract interface and maintains the implementor referenceRefined Abstraction : extends the interface defined by abstractionImplementor : defines the interface for implementation classesConcrete Implementor : implements the Implementor interface
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EXAMPLE & CODE
[ Requirement 1 ]
“ I need a programthat can draw circles and rectangles. “
Wednesday, March 26, 14
EXAMPLE & CODE[ What You Do ]
Wednesday, March 26, 14
EXAMPLE & CODE
[ Requirement 2 ]
“ I want shapes to be colorful, blue and red! ”
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EXAMPLE & CODE[ What You Do ]
in progress....
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HERE COMESBRIDGE PATTERN !!!
Wednesday, March 26, 14
EXAMPLE & CODE[ What You Do ]
Wednesday, March 26, 14
EXAMPLE & CODE
[ Requirement 3 ]
“ I honestly want Green color and Triangle. “(oh yes....)
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EXAMPLE & CODE[ What You Do ]
Wednesday, March 26, 14
EXAMPLE & CODEAbstraction
Implementation Client
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REAL WORLD EXAMPLE
- GUI FrameworkSeparate Window abstraction from
Window implementationfor Linux, Windows, or Mac OS.
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REAL WORLD EXAMPLEex) Java AWT (Abstract Window Toolkit)
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BENEFIT OF BRIDGE PATTERN
- Avoid binding between abstraction and implementation => Able to select implementation at run time
- Reduction in the number of sub classes
- Abstraction and Implementation can be varied independently
- Cleaner code without ‘if ’ or ‘switch’ statement
Wednesday, March 26, 14
ADAPTER VS BRIDGE
Adapter- meant to change the interface of an existing object- intended to make unrelated classes work together- My Code + Someone else’s Code
Bridge- intended to decouple abstraction from its implementation- Entirely My Code and My Structure
Wednesday, March 26, 14
