import jakarta.validation.ConstraintValidatorContext;

/**
 * Validator implementation for the CronExpression constraint.
 */
public class CronExpressionValidator implements ConstraintValidator<CronExpression, String> {

    /**
     * Default constructor.
     */
    public CronExpressionValidator() {
        // Empty constructor
    }

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

/**
 * Validation constraint to ensure that a string is a valid cron expression.
 */
@Target({ METHOD, FIELD, ANNOTATION_TYPE, CONSTRUCTOR, PARAMETER })
@Retention(RUNTIME)
@Documented
@Constraint(validatedBy = CronExpressionValidator.class)
public @interface CronExpression {

    /**
     * The error message when validation fails.
     * @return the error message
     */