AHMAD ASJAD – احمد اسجد

Singleton pattern

is a creational pattern – one of the three basic design pattern.

As the name describes, it’s something which deals with a single value or it works as a unique thing.

In programming, it’s a class which have only one object in the entire execution process.

According to a programming language, you’ll have to set up the class in such a way that only one object will be created in the entire process.

Prerequisites:

• Basic programming knowledge.
• A basic oops concept like what is class, method, property, etc.
• More understandable if you know PHP

In this, I’m going to use PHP as a programming language to implement the singleton pattern.

• Make constructor – __contruct method – private.
• Make __clone method private or keep it public, but let you always return $this variable.
• Define a public static method to create an object of the same class.
• Define a private static variable to check if the object created or not. Or keep the created object in that variable and return the same value if requested – I’m going to return the same object created in the previous call. I’ll create one if it’s called first time, and I’ll store it in the static variable.

SingletonPattern

<?php
 
/**
 * Description of SingletonPattern
 *
 * @author Ahmad Asjad <ahmadcimage@gmail.com>
 */
class SingletonPattern {
 
    public $param1;
    public $param2;
    private static $selfInstance;
 
    private function __construct($param1, $param2) {
        $this->param1 = $param1;
        $this->param2 = $param2;
    }
 
    public function __clone() {
        return $this;
    }
 
    /**
     * @param string $param1
     * @param string $param2
     * @return SingletonPattern
     */
    public static function getInstance($param1, $param2) {
        if (empty(self::$selfInstance)) {
            //Pass params to be passed to the constructor
            self::$selfInstance = new static($param1, $param2);
        }
        return self::$selfInstance;
    }
 
}