Editing Adapter pattern (section)

==Overview==
The adapter<ref name="GoF"/> design pattern is one of the twenty-three well-known [[Gang of Four (software)|Gang of Four]] design patterns that describe how to solve recurring design problems to design flexible and reusable object-oriented software, that is, objects that are easier to implement, change, test, and reuse.

The adapter design pattern solves problems like:<ref name="Adapter_Design_Pattern"/>
* How can a class be reused that does not have an interface that a client requires?
* How can classes that have incompatible interfaces work together?
* How can an alternative interface be provided for a class?

Often an (already existing) class can not be reused only because its interface does not conform to the interface clients require.

The adapter design pattern describes how to solve such problems:
* Define a separate <code>adapter</code> class that converts the (incompatible) interface of a class (<code>adaptee</code>) into another interface (<code>target</code>) clients require.
* Work through an <code>adapter</code> to work with (reuse) classes that do not have the required interface.

The key idea in this pattern is to work through a separate <code>adapter</code> that adapts the interface of an (already existing) class without changing it.

Clients don't know whether they work with a <code>target</code> class directly or through an <code>adapter</code> with a class that does not have the <code>target</code> interface.

See also the UML class diagram below.