2020-06-20 11:27:02 -03:00

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