<?php
class Singleton {
  // object instance
  private static $instance;
 
  private function __construct() {}
 
  private function __clone() {}
 
  public static function getInstance() {
    if (self::$instance === null) {
      self::$instance = new Singleton();
    }
    return self::$instance;
  }
 
  public function doAction() {
    ...
  }
}
 
//usage
Singleton::getInstance()->doAction();
 
?>