23 lines
1.3 KiB
Markdown
23 lines
1.3 KiB
Markdown
---
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layout: pattern
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title: Bridge
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folder: bridge
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permalink: /patterns/bridge/
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categories: Structural
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tags: Java
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---
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**Intent:** Decouple an abstraction from its implementation so that the two can
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vary independently.
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**Applicability:** Use the Bridge pattern when
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* you want to avoid a permanent binding between an abstraction and its implementation. This might be the case, for example, when the implementation must be selected or switched at run-time.
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* both the abstractions and their implementations should be extensible by subclassing. In this case, the Bridge pattern lets you combine the different abstractions and implementations and extend them independently
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* changes in the implementation of an abstraction should have no impact on clients; that is, their code should not have to be recompiled.
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* you have a proliferation of classes. Such a class hierarchy indicates the need for splitting an object into two parts. Rumbaugh uses the term "nested generalizations" to refer to such class hierarchies
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* you want to share an implementation among multiple objects (perhaps using reference counting), and this fact should be hidden from the client. A simple example is Coplien's String class, in which multiple objects can share the same string representation.
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