setLength([6, 7, 8]); $this->setCharacters('0123456789'); $this->setChecksum('gtin'); } /** * Overrides parent checkLength * * @param string $value Value * @return bool */ public function hasValidLength($value) { if (strlen($value) != 8) { $this->useChecksum(false); } else { $this->useChecksum(true); } return parent::hasValidLength($value); } }