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

    /**
     * Determines if the given value is a valid cron expression.
     * @param value the value to validate
     * @return true if valid, false otherwise
     */
    protected boolean determineValid(final String value) {
        if (StringUtil.isNotBlank(value) && !LaCronUtil.isCronExpValid(value)) {