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Design pattern reading group – decorator pattern
The document discusses the decorator design pattern. It defines the decorator pattern as allowing behavior to be added to individual objects without affecting other objects from the same class. It describes how the decorator pattern works by subclassing the original component class into a decorator class and redirecting component methods to the underlying component pointer. Examples of using the decorator pattern for a coffee shop and beauty salon are provided, with pros and cons discussed.
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Design pattern reading group – decorator pattern
- 1. DESIGN PATTERN READING GROUP– DECORATOR PATTERN 2014/May/30 Vincent Chu
- 2. AGENDA What is DecoratorPattern? Examples Conclusion
- 3. WHAT IS DECORATOR PATTERN? Definition Inobject-oriented programming, the decorator pattern (also known as Wrapper, an alternative naming shared with the Adapter pattern) is a design pattern that allows behavior to be added to an individual object, either statically or dynamically, without affecting the behavior of other objects from the same class. UML
- 4. WHAT IS DECORATOR PATTERN? Implementation 1.Subclass the original "Component" class into a "Decorator" class (see UML diagram); 2. In the Decorator class, add a Component pointer as a field; 3. Pass a Component to the Decorator constructor to initialize the Component pointer; 4. In the Decorator class, redirect all "Component" methods to the "Component" pointer; and 5. In the ConcreteDecorator class, override any Component method(s) whose behavior needs to be modified.
- 5. EXAMPLES Cup of JoeBeauty Salon
- 6.
- 7. EXAMPLE – BEAUTYSALON http://www.slideshare.net/eolexe/omg-patterns- ltdecorator-by-max-titov Page 3
- 8. CONCLUSION Consider following patternbefore you choice Decorator Adapter Proxy Strategy Composite
- 9. CONCLUSION Pros 1) The cureof ugly code 2) Composition over inheritance 3) Add behavior at runtime without class modification 4) Behavior can be reuse Cons 1) Tons of small classes 2) Could be not obvious for other developers
- 10. REFERENCE Wikipedia - http://en.wikipedia.org/wiki/Decorator_pattern Photo &Conclusion - http://www.slideshare.net/eprafulla/01-introduction- and-decorator-pattern Beauty Salon - http://www.slideshare.net/eolexe/omg- patterns-ltdecorator-by-max-titov Cup of Joe - http://www.slideshare.net/melbournepatterns/phani- kumar-decorator-pattern Coffee - http://internshipblogg.wordpress.com/2012/06/13/dec orator-pattern-power-of-extension/
- 11. THANKS FOR YOURTIME!