Software Design Patterns

Design patterns are recurring solutions to software design problems you find again and again in real-world application development. Design patterns are about design and interaction of objects, as well as providing a communication platform concerning elegant, reusable solutions to commonly encountered programming challenges.

The Gang of Four (GOF) patterns are generally considered the foundation for all other patterns. They are categorized in three groups: Creational, Structural, and Behavioral. Here you will find the source code for these patterns in Java.

  Creational Patterns
  Abstract Factory   Creates an instance of several families of classes
  Builder   Separates object construction from its representation
  Factory Method   Creates an instance of several derived classes
  Prototype   A fully initialized instance to be copied or cloned
  Singleton   A class of which only a single instance can exist

  Structural Patterns
  Adapter   Match interfaces of different classes
  Bridge   Separates an object’s interface from its implementation
  Composite   A tree structure of simple and composite objects
  Decorator   Add responsibilities to objects dynamically
  Façade   A single class that represents an entire subsystem
  Flyweight   A fine-grained instance used for efficient sharing
  Proxy   An object representing another object

  Behavioral Patterns
  Chain of Resp.   A way of passing a request between a chain of objects
  Command   Encapsulate a command request as an object
  Interpreter   A way to include language elements in a program
  Iterator   Sequentially access the elements of a collection
  Mediator   Defines simplified communication between classes
  Memento   Capture and restore an object's internal state
  Observer   A way of notifying change to a number of classes
  State   Alter an object's behavior when its state changes
  Strategy   Encapsulates an algorithm inside a class
  Template Method   Defer the exact steps of an algorithm to a subclass
  Visitor   Defines a new operation to a class without change


For more details and code in C#, please refer to the website
http://www.dofactory.com/patterns/patterns.aspx