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  Wikipedia: Design pattern (computer science)

Wikipedia: Design pattern (computer science)
Design pattern (computer science)
From Wikipedia, the free encyclopedia.

Design patterns are recurring solutions to problems in object-oriented design. The phrase was introduced to computer science in the 1990s by the text Design Patterns: elements of reusable object-oriented software. The scope of the term remained a matter of dispute into the next decade. Algorithms are not thought of as design patterns, since they solve implementation problems rather than design ones. Typically, a design pattern is thought to encompass a tight interaction of a few classes and objects.

Professor Christopher Alexander's work on a pattern language, for designing buildings and communities, was the inspiration for the design patterns of software.

Interest in sharing patterns in the software community has led to a number of books, symposiums, and the formation of Ward Cunningham's original wiki. The goal of pattern literature is to make the experience of past designers accessible to beginners and others in the field. A book of design patterns presents different solutions in a common format, to provide a language for discussing design issues.

Pattern Format

The design pattern format has four essential parts, although names and ordering differ by source:


Every pattern needs a name, to provide a language for design discussion.


Recurring circumstances lead to the discovery of this pattern by multiple persons. A primary goal of design is to limit the amount of source change needed to change a program's observed behavior, but this can be difficult to achieve if a designer does not understand the implications of a design.


The solution is described sufficiently for implementation by novices, although the implementation is usually given in general enough terms that it can be adapted to different projects.


Applying this solution will effect the rest of the project in certain ways, so it is important to mention any common negative or serendipitous side-effects.

Similar Terms

Poor (yet unfortunately common) solutions to common problems are sometimes known as anti-patterns.

See also amelioration pattern

A List of Design Patterns

Fundamental patterns

Creational patterns

Structural patterns

Behavioral patterns

Concurrency patterns

RealTime patterns

Related Topics


External links


From Wikipedia, the free encyclopedia. 
Modified by Geona