Question

I have a simple bean, i.e.:

public class MyBean {

  private boolean selected;

  private String someString;

  ...
}

So if selected is true, I want someString to be @NotNull etc. .

Any hints, links how to achieve this behaviour?

Thanks
Jonny

Answer 1

You could do this by annotating MyBean with a custom validator, for example:

@ValidMyBean
public class MyBean {

  private boolean selected;

  private String someString;

  ...
}

ValidMyBean:

@Target({ ElementType.FIELD })
@Retention(RetentionPolicy.RUNTIME)
@Constraint(validatedBy = MyBeanValidator.class)
public @interface ValidMyBean {

    boolean allViolationMessages() default true;

    Class<?>[] constraints() default {};

    Class<?>[] groups() default {};

    String message() default "{ValidMyBean.message}";

    Class<? extends Payload>[] payload() default {};
}

MyBeanValidator:

public final class MyBeanValidator implements
        ConstraintValidator<ValidMyBean, MyBean> {

    @Override
    public void initialize(
            @SuppressWarnings("unused") final ValidMyBean constraintAnnotation) {
    }

    @Override
    public boolean isValid(final MyBean value,
            final ConstraintValidatorContext context) {

        boolean isValid = true;
        //your validation here

        return isValid;
    }
}