Java Design Patterns: A Hands-On Experience with Real-World Examples

© Vaskaran Sarcar 2019

Vaskaran SarcarJava Design Patternshttps://doi.org/10.1007/978-1-4842-4078-6_1

1. Singleton Pattern

Vaskaran Sarcar¹ 

(1)

Bangalore, Karnataka, India

 

This chapter covers the singleton pattern.

GoF Definition

Ensure a class only has one instance, and provide a global point of access to it.

Concept

A class cannot have multiple instances. Once created, the next time onward, you use only the existing instance. This approach helps you restrict unnecessary object creations in a centralized system. The approach also promotes easy maintenance.

Real-World Example

Let’s assume that you are a member of a sports team, and your team is participating in a tournament. Your team needs to play against multiple opponents throughout the tournament. ...