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21 lines
867 B
Markdown
21 lines
867 B
Markdown
# Facade
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## Purpose
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The primary goal of a Facade Pattern is not to avoid you to read the manual of a complex API. It's only a side-effect.
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The first goal is to 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 many (but sometimes just one) interface, and of course to reduce 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 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 interface-type-hinted parameters.
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If you need creation of new instances, use a Factory as argument.
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## UML Diagram
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