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Adapter pattern

In computer programming, the adapter design pattern 'adapts' one interface for a class into one that a client expects. An adapter allows classes to work together that normally could not because of incompatible interfaces by wrapping its own interface around that of an already existing class.

There are two types of adapter patterns:

The adapter pattern is useful in situations where an already existing class provides some or all of the services you need but does not use the interface you need. A good real life example is an adapter that converts the interface of a Document Object Model of an XML document into a tree structure that can be displayed. A link to a tutorial that uses the adapter design pattern is listed in the links below.

External Links


 * Java code sample 

interface Stack { public void push (Object); public Object pop (); public Object top (); }

/* DoubleLinkedList */ class DList { public void insert (DNode pos, Object o) { ... } public void remove (DNode pos, Object o) { ... } public void insertHead (Object o) { ... } public void insertTail (Object o) { ... } public Object removeHead () { ... } public Object removeTail () { ... } public Object getHead () { ... } public Object getTail () { ... } }

/* Adapt DList class to Stack interface */ class DListImpStack extends DList implements Stack { public void push (Object o) { insertTail (o); } public Object pop () { return removeTail (); }

public Object top () { return getTail (); } }