About Design Patterns

This article gives a basic introduction to design patterns and talks about the classification of design patterns namely creational design patterns, structural design patterns and behavioral design patterns.

Design Patterns Introduction

• Design patterns describe recurring software design problems and their solutions.
• Design patterns assign in reuse of software architectures.
• Design patterns are independent of any programming language and they don't talk about code re-use.
• The book "Design Patterns: Elements of Reusable Object-Oriented Software" also referred as "GoF (Gang of Four) Book" started the design patterns. Enrich Gamma, Richard Helm, Ralph Johnson and John Vlissides are the authors of this book.
  
• Design patterns are classified into various categories:-

1. Creational patterns,
2. Structural patterns and
3. Behavioral patterns.

• Creational patterns deal with instantiation. Some examples include:-

1. Singleton,
2. Abstract Factory,
3. Factory,
4. Builder and
5. Prototype patterns.

• Structural patterns deal with ways of class composition to add new functionality. Some examples include:-

1. Adapter,
2. Bridge,
3. Composite,
4. Decorator,
5. Facade,
6. Flyweight and
7. Proxy patterns.

• Behavioral patterns deal with object communication. Some examples include:-

1. Chain of responsibility,
2. Command,
3. Interpreter,
4. Iterator,
5. Mediator,
6. Memento,
7. Observer,
8. State and
9. Visitor patterns.