View source for Chain-of-responsibility pattern

In [[object-oriented programming]], the '''chain-of-responsibility pattern''' is a [[software design pattern]] consisting of a source of [[Command pattern|command objects]] and a series of processing objects.

== Description ==

Each processing object contains logic that defines the types of command objects that it can handle; the rest are passed to the next processing object in the chain. A mechanism also exists for adding new processing objects to the end of this chain.

In a variation of the standard chain-of-responsibility model, some handlers may act as dispatchers, capable of sending commands out in a variety of directions, forming a tree of responsibility.

In some cases, this can occur recursively, with processing objects calling higher-up processing objects with commands that attempt to solve some smaller part of the problem; in this case recursion continues until the command is processed, or the entire tree has been explored. An XML interpreter might work in this manner.

This pattern promotes the idea of [[loose coupling]].

== See also ==

* [[Command pattern]]
* [[Loose coupling]]
* [[Object-oriented programming]]
* [[Software design pattern]]
* [[Software engineering]]
* [[Single responsibility principle]]

== External links ==

* [https://en.wikipedia.org/wiki/Chain-of-responsibility_pattern Chain-of-responsibility pattern] @ Wikipedia.org 

[[Category:Computer science]]
[[Category:Software design patterns]]
[[Category:Software engineering]]