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Convert the interface of a class into another interface clients expect. Adapter lets classes work together that couldn't otherwise because of incompatible interfaces.

Class Diagram



  • Target
    • defines the domain-specific interface that Client uses.
  • Client
    • collaborates with objects conforming to the Target interface.
  • Adaptee.
    • defines an existing interface that needs adapting.
  • Adapter.
    • adapts the interface Adaptee to the Target interface.


  • Allow two or more incompatible objects to communicate and interact.
  • Improves reusability of older functionality.


  • When you want to use an existing class, and its interface does not match the interface you need.
  • When you want to create a reusable class that cooperates with unrelated or onforeseen classes, classes that don't necesarily have compatible interfaces.
  • When you want to use an object in an environment that expects an interface that is diferent from the object's interface.
  • When you must ensure interface translation among multiple sources.