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.
You can also find this code on GitHub
.. literalinclude:: Facade.php :language: php :linenos:
.. literalinclude:: OsInterface.php :language: php :linenos:
.. literalinclude:: BiosInterface.php :language: php :linenos:
.. literalinclude:: Tests/FacadeTest.php :language: php :linenos: