Chain-of-responsibility pattern: Difference between revisions

Revision as of 17:46, 28 October 2006

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In [[computer programming]], the '''chain-of-responsibility pattern''' is a [[design pattern (computer science)|design pattern]] consisting of a source of [[Command pattern|command objects]] and a series of '''processing objects'''. Each processing object contains a set of logic that describes the types of command objects that it can handle, and how to pass off those that it cannot 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 [[dynamic dispatch|dispatcher]]s, capable of sending commands out in a variety of directions, forming a ''tree of responsibility''. RecursionIn couldsome continuecases, 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 (parsed, but not yet executed) might be a fitting example.

This pattern promotes the idea of [[loose coupling]], a common programming practice.