}
  }

  /**
   * Determines whether {@code specifier} represents a valid {@link HostSpecifier} as described in
   * the documentation for {@link #fromValid(String)}.
   */
  public static boolean isValid(String specifier) {
    try {
      HostSpecifier unused = fromValid(specifier);
      return true;
    } catch (IllegalArgumentException e) {
      return false;
    }
  }

  @Override

public class CronExpressionValidator implements ConstraintValidator<CronExpression, String> {

    @Override
    public void initialize(final CronExpression constraintAnnotation) {
    }

    @Override
    public boolean isValid(final String value, final ConstraintValidatorContext context) {
        return determineValid(value);
    }

    protected boolean determineValid(final String value) {

        case FILE -> ComponentUtil.getFessConfig().getCrawlerFileProtocolsAsArray();
        default -> throw new ConstraintDefinitionException("protocolType is emtpy.");
        };
    }

    @Override
    public boolean isValid(final String value, final ConstraintValidatorContext context) {
        if (StringUtil.isNotBlank(value)) {
            return check(protocols, value);
        }
        return true;
    }

            max = Integer.parseInt(fessConfig.get(maxKey));
        }
        message = constraintAnnotation.message();
        validateParameters();
    }

    @Override
    public boolean isValid(final CharSequence value, final ConstraintValidatorContext context) {
        if (value == null) {
            return true;
        }