protected function applyLengthValidators(ValidatorManagerInterface $manager)
    {
        $minimum = $this->getMinimumRequirement();
        $maximum = $this->getMaximumRequirement();
        $this->applyMinMaxStrings($minimum, $maximum);

        // Set validators
        if ($maximum) {
            $manager->setValidator('maximum_length', $maximum);
        }
        if ($minimum) {
            $manager->setValidator('minimum_length', $minimum);
        }
    }