Singleton

From Open Pattern Repository for Online Learning Systems
Jump to navigation Jump to search


Singleton
Contributors Erich Gamma, Richard Helm, Ralph Johnson, John Vlissides
Last modification June 6, 2017
Source Gamma, Helm, Johnson & Vlissides (1995)[1], Singleton Pattern (2016)[2]
Pattern formats OPR Alexandrian
Usability
Learning domain
Stakeholders

If a system only needs one instance of a class, and that instance needs to be accessible in many different parts of a system, you control both instantiation and access by making that class a singleton.[1][2]


Context

Problem

Forces

Solution

Consequences

Benefits

Liabilities

Evidence

Literature

Discussion

Data

Applied evaluation

Related patterns

Example

References

  1. 1.0 1.1 Gamma, E., Helm, R., Johnson, R. & Vlissides, J. (1995). Design Patterns: elements of reusable object-oriented software. Addison-Wesley: Boston, MA. ISBN 0-201-63361-2.
  2. 2.0 2.1 Singleton Pattern. (2016). Retrieved October 4, 2016 from http://c2.com/cgi/wiki?SingletonPattern.