design patterns in PHP

This is a collection of known design patterns and some sample code how to implement them in PHP. Every pattern has a small list of examples (most of them from Zend Framework, Symfony2 or Doctrine2 as I'm most familiar with this software).

I think the problem with patterns is that often people do know them but don't know when to apply which.

The patterns can be structured in roughly three different categories:

Creational

• (AbstractFactory)[tree/master/AbstractFactory]
• (Builder)[tree/master/Builder]
• (SimpleFactory)[tree/master/SimpleFactory]
• (FactoryMethod)[tree/master/FactoryMethod]
• (StaticFactory)[tree/master/StaticFactory]
• (Prototype)[tree/master/Prototype]
• (Singleton)[tree/master/Singleton] (is considered an anti-pattern! ⛔)
• (Multiton)[tree/master/Multiton] (is considered an anti-pattern! ⛔)

Structural

• (Adapter)[tree/master/Adapter]
• (Composite)[tree/master/Composite]
• (Decorator)[tree/master/Decorator]
• (Facade)[tree/master/Facade]
• (Proxy)[tree/master/Proxy]
• (Registry)[tree/master/Registry]
• (FluentInterface)[tree/master/FluentInterface]
• (DataMapper)[tree/master/DataMapper]
• (DependencyInjection)[tree/master/DependencyInjection]

Behavioral

• (ChainOfResponsibilities)[tree/master/ChainOfResponsibilities]
• (Command)[tree/master/Command]
• (Iterator)[tree/master/Iterator]
• (Mediator)[tree/master/Mediator]
• (NullObject)[tree/master/NullObject]
• (Observer)[tree/master/Observer]
• (StatusPattern)[tree/master/StatusPattern]
• (Strategy)[tree/master/Strategy]
• (TemplateMethod)[tree/master/TemplateMethod]
• (Visitor)[tree/master/Visitor]

Please feel free to fork and extend existing or add your own examples!