layout	title	folder	permalink	pumlid	categories	tags
pattern	Adapter	adapter	/patterns/adapter/	DSR14S8m30J0Lg20M7-wEMnDOiPMFDA9j0yyUEtUkzMHJTF7xI1NF4GSLzaxZtncgDVJgCPIpobzv0N2vOKtjgRHTziMI7KBcOXl10thfxB-Nz9dMJd71m00	Structural	Java Gang Of Four Difficulty-Beginner

Also known as

Wrapper

Intent

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

Applicability

Use the Adapter pattern when

• you want to use an existing class, and its interface does not match the one you need
• you want to create a reusable class that cooperates with unrelated or unforeseen classes, that is, classes that don't necessarily have compatible interfaces
• you need to use several existing subclasses, but it's impractical to adapt their interface by subclassing every one. An object adapter can adapt the interface of its parent class.

Real world examples

• java.util.Arrays#asList()
• java.util.Collections#list()
• java.util.Collections#enumeration()
• javax.xml.bind.annotation.adapters.XMLAdapter

Credits

• Design Patterns: Elements of Reusable Object-Oriented Software
• J2EE Design Patterns