Singleton

namespaces\Singleton.php

<?php
namespace namespaces;
abstract class Singleton
{
    // an array of instances. this will keep track of objects already created
    private static $instances = [];

    abstract protected function __construct();

    // this function gets called whenever there is a request for a static function
    // that is not present.
    // here we assume that the application is looking for the particular service
    public static function __callStatic($name, $args)
    {
        // if no reader is defined yet. set it
        if (!isset(self::$instances[$name])) {
            $c = "\\namespaces\\Singleton\\{$name}";
            self::$instances[$name] = new $c;
        }

        return self::$instances[$name];
    }
}