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) {
    }

import jakarta.validation.ConstraintValidatorContext;

public class CronExpressionValidatorTest extends UnitFessTestCase {

    public CronExpressionValidator validator;

    @Override
    public void setUp() throws Exception {
        super.setUp();
        validator = new CronExpressionValidator();
    }

    public void test_isValid_nullValue() {
        final ConstraintValidatorContext context = null;

/**
 * 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
     */

        assertNotNull(constraint);
        Class<?>[] validators = constraint.validatedBy();
        assertEquals(1, validators.length);
        assertEquals(CronExpressionValidator.class, validators[0]);
    }

    // Test validation with valid cron expressions
    public void test_validCronExpressions() {
        TestBean bean = new TestBean();