Editing Design Patterns (section)

== Patterns by type ==

===Creational===
{{main|Creational pattern}}
[[Creational pattern]]s are ones that create objects, rather than having to instantiate objects directly. This gives the program more flexibility in deciding which objects need to be created for a given case.
* [[Abstract factory pattern|Abstract factory]] groups object factories that have a common theme.
* [[Builder pattern|Builder]] constructs complex objects by separating construction and representation.
* [[Factory method pattern|Factory method]] creates objects without specifying the exact class to create.
* [[Prototype pattern|Prototype]] creates objects by cloning an existing object.
* [[Singleton pattern|Singleton]] restricts object creation for a class to only one instance.

===Structural===
[[Structural pattern]]s concern class and object composition. They use inheritance to compose interfaces and define ways to compose objects to obtain new functionality.
* [[Adapter pattern|Adapter]] allows classes with incompatible interfaces to work together by wrapping its own interface around that of an already existing class.
* [[Bridge pattern|Bridge]] decouples an abstraction from its implementation so that the two can vary independently.
* [[Composite pattern|Composite]] composes zero-or-more similar objects so that they can be manipulated as one object.
* [[Decorator pattern|Decorator]] dynamically adds/overrides behavior in an existing method of an object.
* [[Facade pattern|Facade]] provides a simplified interface to a large body of code.
* [[Flyweight pattern|Flyweight]] reduces the cost of creating and manipulating a large number of similar objects.
* [[Proxy pattern|Proxy]] provides a placeholder for another object to control access, reduce cost, and reduce complexity.

===Behavioral===
Most [[Behavioral pattern|behavioral design patterns]] are specifically concerned with communication between objects.
* [[Chain-of-responsibility pattern|Chain of responsibility]] delegates commands to a chain of processing objects.
* [[Command pattern|Command]] creates objects that encapsulate actions and parameters.
* [[Interpreter pattern|Interpreter]] implements a specialized language.
* [[Iterator pattern|Iterator]] accesses the elements of an object sequentially without exposing its underlying representation.
* [[Mediator pattern|Mediator]] allows [[loose coupling]] between classes by being the only class that has detailed knowledge of their methods.
* [[Memento pattern|Memento]] provides the ability to restore an object to its previous state (undo).
* [[Observer pattern|Observer]] is a publish/subscribe pattern, which allows a number of observer objects to see an event.
* [[State pattern|State]] allows an object to alter its behavior when its internal state changes.
* [[Strategy pattern|Strategy]] allows one of a family of algorithms to be selected on-the-fly at runtime.
* [[Template method pattern|Template method]] defines the skeleton of an algorithm as an abstract class, allowing its subclasses to provide concrete behavior.
* [[Visitor pattern|Visitor]] separates an algorithm from an object structure by moving the hierarchy of methods into one object.