/**
  * Get the current application url provider
  * @return string the name of the class
  */
 public static function GetUrlMakerClass()
 {
     if (is_null(self::$m_sUrlMakerClass)) {
         if (isset($_SESSION['UrlMakerClass'])) {
             self::$m_sUrlMakerClass = $_SESSION['UrlMakerClass'];
         } else {
             self::$m_sUrlMakerClass = 'iTopStandardURLMaker';
         }
     }
     return self::$m_sUrlMakerClass;
 }