Object Oriented Software Engineering   View all facts   Glossary   Help

subject > pattern > design pattern > adapter

adapter
subject			fact

adapter	has definition A pattern found in class diagrams in which you are able to reuse an 'adaptee' class by providing a class, (the adapter) that delegates to the adaptee
	has context You are building an inheritance hierarchy and you want to incorporate into it a class written by somebody else - i.e. you want to reuse an existing class. Typically the methods of the reused class do not have the same name or argument types as the methods in the hierarchy you are creating. The reused class is also often already part of its own inheritance hierarchy.
	has forces You do not have access to multiple inheritance or you do not want to use it.
	has problem How do you obtain the power of polymorphism when reusing a class whose methods have the same function but do not have the same signature as the other methods in the hierarchy?
	has references one of the Gang of Four patterns.
	has related patterns facade, read-only interface, proxy
	has solution Rather than directly incorporating the reused class into your inheritance hierarchy, instead incorporate an «Adapter» class. The «Adapter»is connected by an association to the reused class, which we will call the «Adaptee». The polymorphic methods of the «Adapter» delegate to methods of the «Adaptee». The delegate method in the «Adaptee» may or may not have the same name as the delegating polymorphic method.
	is a subtopic of 6.8 - The Adapter Pattern
	is an instance of design pattern
design pattern	has antipatterns zero or more antipatterns - solutions that are inferior or do not work in this context with the reason for their rejection
	has name
	should be illustrated using a simple diagram
	should be written using a narrative writing style
pattern	should be as general as possible
	should be described in an easy-to-understand form so that people can determine when and how to use it
	should contain a solution that has been proven to effectively solve the problem in the indicated context

Next design pattern: antipattern    Up: design pattern    Previous design pattern: abstraction-occurrence