Access List index in customer hibernate validator message

Question

I am validating a list of vehicles, I want to provide a custom message to the user that describes the error a little better.

I can currently use

NotNull.vehicle.name = 'Vehicle name has not been filled in'

however if there were 10 vehicles in the list there is no indication of which vehicle was in error, I want to do something like this

NotNull.vehicle[0].name = 'Vehicle item {index + 1}: name has not been filled in'

Is something like this possible?

Answer 1

It's not possible out of the box, using the built-in constraints.

You could implement a custom constraint and validator for List<Car> and create the constraint violation and its message yourself. Using the node builder API you still could have the violation point the right element:

public class CarListValidator
    implements ConstraintValidator<ValidCarList, List<Car>> {

    @Override
    public void initialize(ValidCarList constraintAnnotation) {
    }

    @Override
    public boolean isValid(List<Car> cars, ConstraintValidatorContext constraintValidatorContext) {

        boolean isValid = ...;

        if ( !isValid ) {
            int invalidIndex = ...;

            constraintValidatorContext.disableDefaultConstraintViolation();
            constraintValidatorContext
                .buildConstraintViolationWithTemplate( 
                    "name missing for car #" + invalidIndex 
                )
                    .addPropertyNode( "name" )
                    .inIterable()
                    .atIndex( invalidIndex )
                .addConstraintViolation();             
        }

        return isValid;
    }
}