static function lessenAsEncoding($str, $length = 255, $tail = '...')
 {
     $context = \CADB\Model\Context::getInstance();
     if ($context->getProperty('database.utf8') != true) {
         return UTF8::lessen($str, $length, $tail);
     } else {
         return UTF8::lessenAsByte($str, $length, $tail);
     }
 }