Spring MVC Validation for list and reporting the invalid value - spring

Question

I have a list of strings which should be of a specific format. I need to return the error message with the strings which are not of the format specified. How to do this with spring validation(I am using the hibernate validator).
The annotation:
#Documented
#Retention(RUNTIME)
#Target({FIELD, METHOD})
#Constraint(validatedBy = HostsValidator.class)
public #interface HostsConstraint {
String message();
Class<?>[] groups() default {};
Class<? extends Payload>[] payload() default {};
}
The implementation:
public class HostsValidator implements ConstraintValidator<HostsConstraint, List<String>>{
#Override
public void initialize(OriginHostsConstraint constraintAnnotation) {
}
#Override
public boolean isValid(List<String> strings, ConstraintValidatorContext context) {
for (String s : strings) {
if (!s.matches("[0-9]+") {
//How do I say: Invalid string <s> ?
return false;
}
}
}
}
The usage:
public class Test {
#HostsConstraint(message="Invalid string ")
private List<String> hosts;
}
Using validatedValue will give the entire list.

Answer 1

Use JSR 380 validation, it allows container element constraints.
Here is a link to the container element section in the Hibernate Validator 6.0.6.FINAL Document

Answer 2

I think I found a solution but it is coupled to hibernate validator. May be it is even a hacky implementation.
The usage:
public class Test {
#HostsConstraint(message="Invalid string : ${invalidStr}")
private List<String> hosts;
}
The implementation
public class HostsValidator implements ConstraintValidator<HostsConstraint, List<String>>{
#Override
public void initialize(OriginHostsConstraint constraintAnnotation) {}
#Override
public boolean isValid(List<String> strings, ConstraintValidatorContext context) {
for (String s : strings) {
if (!s.matches("[0-9]+") {
ConstraintValidatorContextImpl contextImpl =
(ConstraintValidatorContextImpl) context
.unwrap(HibernateConstraintValidatorContext.class);
contextImpl.addExpressionVariable("invalidStr", s);
return false;
}
}
}
}