java-design-patterns/decorator/index.md

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layout	title	folder	permalink	categories	tags
pattern	Decorator	decorator	/patterns/decorator/	pattern_cat	pattern_tag

Intent: Attach additional responsibilities to an object dynamically. Decorators provide a flexible alternative to subclassing for extending functionality.

Applicability: Use Decorator

• to add responsibilities to individual objects dynamically and transparently, that is, without affecting other objects
• for responsibilities that can be withdrawn
• 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