/**
  * Returns a unique instance of the Singleton object. Use this method instead of the private/protected class constructor.
  * 
  * @param   void
  * @return  Tx_PtExtbase_Registry_Registry      unique instance of the Singleton object
  * @author 	Fabrizio Branca <*****@*****.**>
  */
 public static function getInstance()
 {
     if (self::$uniqueInstance === null) {
         self::$uniqueInstance = new Tx_PtExtbase_Registry_Registry();
     }
     return self::$uniqueInstance;
 }