public static function initializeStaticData()
 {
     static $run = false;
     if ($run === false) {
         self::$reflection = new ReflectionClass(__CLASS__);
         foreach (self::$reflection->getConstants() as $cname => $cval) {
             list($ctype, $ctypeid) = explode('_', $cname, 2);
             switch ($ctype) {
                 case 'ATTR':
                     self::$attr_values[] = $cval;
                     break;
                 case 'PROPERTY':
                     self::$meta_values[] = $cval;
                     break;
             }
         }
         $run = true;
     }
 }