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77 lines
1.7 KiB
ReStructuredText
77 lines
1.7 KiB
ReStructuredText
`Command`__
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===========
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Purpose
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-------
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To encapsulate invocation and decoupling.
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We have an Invoker and a Receiver. This pattern uses a "Command" to
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delegate the method call against the Receiver and presents the same
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method "execute". Therefore, the Invoker just knows to call "execute" to
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process the Command of the client. The Receiver is decoupled from the
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Invoker.
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The second aspect of this pattern is the undo(), which undoes the method
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execute(). Command can also be aggregated to combine more complex
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commands with minimum copy-paste and relying on composition over
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inheritance.
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Examples
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--------
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- A text editor : all events are Command which can be undone, stacked
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and saved.
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- Symfony2: SF2 Commands that can be run from the CLI are built with
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just the Command pattern in mind
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- big CLI tools use subcommands to distribute various tasks and pack
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them in "modules", each of these can be implemented with the Command
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pattern (e.g. vagrant)
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UML Diagram
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-----------
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.. image:: uml/uml.png
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:alt: Alt Command UML Diagram
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:align: center
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Code
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----
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You can also find these code on `GitHub`_
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CommandInterface.php
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.. literalinclude:: CommandInterface.php
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:language: php
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:linenos:
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HelloCommand.php
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.. literalinclude:: HelloCommand.php
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:language: php
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:linenos:
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Receiver.php
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.. literalinclude:: Receiver.php
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:language: php
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:linenos:
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Invoker.php
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.. literalinclude:: Invoker.php
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:language: php
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:linenos:
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Test
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----
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Tests/CommandTest.php
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.. literalinclude:: Tests/CommandTest.php
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:language: php
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:linenos:
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.. _`GitHub`: https://github.com/domnikl/DesignPatternsPHP/tree/master/Behavioral/Command
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.. __: http://en.wikipedia.org/wiki/Command_pattern |