The PHP Singleton Class

In this video we will show you how to create a PHP singleton class and why you may want to use it. We'll show you how to create a basic class and a similar implementation with a singleton class.

A Singleton class is instantiated by itself and does not have multiple instances like a normal class.

You can find the source code to the video here: https://github.com/thedevdojo/create-a-php-singleton-class

You can take a look at each of the singletons created in this video below:

Greeting.php (singleton)

<?php

class Greeting{

	private static $instance;
	public static $name;

	public static function singleton(){

		if( !isset(self::$instance) ){
			self::$instance = new Greeting;
		}

		return self::$instance;

	}

	public static function setname($name){
		self::$name = $name;
	}

	public static function greet(){
		return 'Hello ' . self::$name . ' from the Singleton Greeting Class';
	}

}

Calculator.php (singleton)

<?php

class Calculator{

	private static $instance;

	public static function singleton(){

		if( !isset(self::$instance) ){
			self::$instance = new Greeting;
		}

		return self::$instance;

	}

	public static function add($num1, $num2){
		return (int)$num1 + (int)$num2;
	}

}