Links

• GoF - Design Patterns: Elements of Reusable Object-Oriented Software
• Java core libraries
• Cheat sheets

Patterns

• Creational patterns

  • Abstract factory (recognizeable by creational methods returning the factory itself which in turn can be used to create another abstract/interface type)
  • Builder (recognizeable by creational methods returning the instance itself)
  • Factory method (recognizeable by creational methods returning an implementation of an abstract/interface type)
  • Prototype (recognizeable by creational methods returning a different instance of itself with the same properties)
  • Singleton (recognizeable by creational methods returning the same instance (usually of itself) everytime)

• Structural patterns

  • Adapter (recognizeable by creational methods taking an instance of different abstract/interface type and returning an implementation of own/another abstract/interface type which decorates/overrides the given instance)
  • Bridge (recognizeable by creational methods taking an instance of different abstract/interface type and returning an implementation of own abstract/interface type which delegates/uses the given instance)
  • Composite (recognizeable by behavioral methods taking an instance of same abstract/interface type into a tree structure)
  • Decorator (recognizeable by creational methods taking an instance of same abstract/interface type which adds additional behaviour)
  • Facade (recognizeable by behavioral methods which internally uses instances of different independent abstract/interface types)
  • Flyweight (recognizeable by creational methods returning a cached instance, a bit the "multiton" idea)
  • Proxy (recognizeable by creational methods which returns an implementation of given abstract/interface type which in turn delegates/uses a different implementation of given abstract/interface type)

• Behavioral patterns

  • Chain of responsibility (recognizeable by behavioral methods which (indirectly) invokes the same method in another implementation of same abstract/interface type in a queue)
  • Command (recognizeable by behavioral methods in an abstract/interface type which invokes a method in an implementation of a different abstract/interface type which has been encapsulated by the command implementation during its creation)
  • Interpreter (recognizeable by behavioral methods returning a structurally different instance/type of the given instance/type; note that parsing/formatting is not part of the pattern, determining the pattern and how to apply it is)
  • Iterator (recognizeable by behavioral methods sequentially returning instances of a different type from a queue)
  • Mediator (recognizeable by behavioral methods taking an instance of different abstract/interface type (usually using the command pattern) which delegates/uses the given instance)
  • Memento (recognizeable by behavioral methods which internally changes the state of the whole instance)
  • Observer (or Publish/Subscribe) (recognizeable by behavioral methods which invokes a method on an instance of another abstract/interface type, depending on own state)
  • State (recognizeable by behavioral methods which changes its behaviour depending on the instance's state which can be controlled externally)
  • Strategy (recognizeable by behavioral methods in an abstract/interface type which invokes a method in an implementation of a different abstract/interface type which has been passed-in as method argument into the strategy implementation)
  • Template method (recognizeable by behavioral methods which already have a "default" behaviour definied by an abstract type)
  • Visitor (recognizeable by two different abstract/interface types which has methods definied which takes each the other abstract/interface type; the one actually calls the method of the other and the other executes the desired strategy on it)