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67 lines
1.5 KiB
ReStructuredText
67 lines
1.5 KiB
ReStructuredText
`Facade`_
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=========
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Purpose
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-------
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The primary goal of a Facade Pattern is not to avoid you to read the
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manual of a complex API. It's only a side-effect. The first goal is to
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reduce coupling and follow the Law of Demeter.
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A Facade is meant to decouple a client and a sub-system by embedding
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many (but sometimes just one) interface, and of course to reduce
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complexity.
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- A facade does not forbid you the access to the sub-system
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- You can (you should) have multiple facades for one sub-system
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That's why a good facade has no ``new`` in it. If there are multiple
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creations for each method, it is not a Facade, it's a Builder or a
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[Abstract\|Static\|Simple] Factory [Method].
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The best facade has no ``new`` and a constructor with
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interface-type-hinted parameters. If you need creation of new instances,
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use a Factory as argument.
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UML Diagram
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-----------
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.. image:: uml/uml.png
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:alt: Alt Facade 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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OsInterface.php
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.. literalinclude:: OsInterface.php
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:language: php
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:linenos:
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Facade.php
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.. literalinclude:: Facade.php
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:language: php
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:linenos:
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BiosInterface.php
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.. literalinclude:: BiosInterface.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/FacadeTest.php
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.. literalinclude:: Tests/FacadeTest.php
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:language: php
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:linenos:
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.. _`GitHub`: https://github.com/domnikl/DesignPatternsPHP/tree/master/Structural/Facade
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.. _`Facade`: http://en.wikipedia.org/wiki/Facade_pattern
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