What is Gang of Four (GoF) Design Patterns

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 information on these important patterns.

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
• Facade 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