In 1994–95, four Is
—Erich Gamma, Richard Helm, Ralph Johnson and John Vlissides
—published Design Patterns—Elements of Reusable Object-Oriented Software (Addison-Wesley, 1995) in which they initiated the concept of design patterns for software development.
These Is became known as the Gang of Four (GoF).
They introduced 23 patterns which were developed by experienced software engineers over a very long period of time. As a result, now if any new member joins a development team and he knows that the new system is following some specific design patterns, he can actively participate in the development process with the other members of the team within a very short period of time.
1, Creational Design Patterns
1, Abstract Factory Pattern
2, Builder Pattern
3, Factory Method Pattern
4, Prototype Pattern
5, Singleton Pattern
2, Structural Design Patterns
6, Adapter Pattern
7, Bridge Pattern
8, Composite Pattern
9, Decorator Pattern
10, Facade Pattern
11, Flyweight Pattern
12, Proxy Pattern
3, Behavioral Design Patterns
13, Chain Of Responsibility Pattern
14, Command Pattern
15, Interpreter Pattern
16, Iterator Pattern
17, Mediator Pattern
18, Memento Pattern
19, Observer Pattern
20, State Pattern
21, Strategy Pattern
22, Template Method Pattern
23, Visitor Pattern