protected function processValue()
    {
        $form = $this->getForm();

        $data = &$form->getFormData();
        if (!isset($data[$this->id])) {
            return false;
        }

        if ($this->serialize_values) {
            $salt = $form->getSalt();
            $this->value = SwatString::signedUnserialize(
                $data[$this->id],
                $salt
            );
        } else {
            $this->value = (string) $data[$this->id];
        }

        return true;
    }