29 lines
1012 B
Markdown
29 lines
1012 B
Markdown
---
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layout: pattern
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title: Decorator
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folder: decorator
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permalink: /patterns/decorator/
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categories: Structural
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tags:
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- Java
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- Gang Of Four
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---
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**Also known as:** Wrapper
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**Intent:** Attach additional responsibilities to an object dynamically.
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Decorators provide a flexible alternative to subclassing for extending
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functionality.
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**Applicability:** Use Decorator
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* to add responsibilities to individual objects dynamically and transparently, that is, without affecting other objects
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* for responsibilities that can be withdrawn
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* when extension by subclassing is impractical. Sometimes a large number of independent extensions are possible and would produce an explosion of subclasses to support every combination. Or a class definition may be hidden or otherwise unavailable for subclassing
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**Credits**
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* [Design Patterns: Elements of Reusable Object-Oriented Software](http://www.amazon.com/Design-Patterns-Elements-Reusable-Object-Oriented/dp/0201633612)
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