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