Singleton.php

<?php

class Singleton {
  private static $uniqueInstance = NULL;
  protected function __construct() {
  }
  private final function __clone() {
  }
  public static function getInstance() {
    if (self::$uniqueInstance === NULL) {
      self::$uniqueInstance = new Singleton();
    }
    return self::$uniqueInstance;
  }

}