20 lines
1.2 KiB
Text
20 lines
1.2 KiB
Text
Jakarta Commons Chain of Responsibility library.
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The Chain API models a computation as a series of "commands" that can be
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combined into a "chain". The API for a command consists of a single method
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(execute()), which is passed a "context" parameter containing the dynamic state
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of the computation, and whose return value is a boolean that determines whether
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or not processing for the current chain has been completed (true), or whether
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processing should be delegated to the next command in the chain (false).
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Given that command implementations are designed to conform with these
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recommendations, it should be feasible to utilize the Chain of Responsibility
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APIs in the "front controller" of a web application framework (such as Struts),
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but also be able to use it in the business logic and persistence tiers to model
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complex computational requirements via composition. In addition, separation of a
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computation into discrete commands that operate on a general purpose context
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allows easier creation of commands that are unit testable, because the impact of
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executing a command can be directly measured by observing the corresponding
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state changes in the context that is supplied.
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WWW: http://jakarta.apache.org/commons/chain/
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