Design Patterns

Design patterns are reusable solutions to the problems that we encounter in the day to day programming. They are generally targeted at solving the problems of object generation and integration. In other words, Design patterns acts as templates which can be applied to the real-world programming problems.

Design patterns are solutions to software design problems you find again and again in real-world application development. Patterns are about reusable designs and interactions of objects.

Types of Design Patterns

Gang of Four have categorised the design patterns in to 3 types based on different problems encountered in the real world applications. They are Creational, Structural and Behavioural.

Creational design patterns :

These patterns deal with object creation and initialization. Creational pattern gives the program more flexibility in deciding which objects need to be created for a given case.

Examples: Singleton , Factory and Abstract Factory etc.

Structural design patterns :

This pattern deals with class and object composition. In simple words, This pattern focuses on decoupling interface, implementation of classes and its objects.

Examples: Adapter,  Facade and Bridge etc.

Behavioural design patterns :

These patterns deal with communication between Classes and objects.

Examples: Chain of Responsibility, Command and Interpreter etc.

Design Pattern Sample with Real world examples