public function get($hydratorType)
    {
        if (self::TO_ARRAY == $hydratorType) {
            return new ArrayHydrator();
        } elseif (self::TO_OBJECT == $hydratorType) {
            return new LdapObjectHydrator();
        } else {
            throw new InvalidArgumentException(sprintf('Unknown hydrator type "%s".', $hydratorType));
        }
    }