Java: GroupSequenceProvider for Validation, object is null in getValidationGroups method - spring

Question

This is what I am trying to achieve:
I have an update request object and user is allowed to do Partial Updates. But I want to validate the field only if it is in the request body. Otherwise, it is OK to be null. To achieve this, I am using GroupSequenceProvider to let the Validator know what groups to validate. What am I doing wrong here? If there is a blunder, how do I fix it?
Documentation: https://docs.jboss.org/hibernate/validator/5.1/reference/en-US/html/chapter-groups.html#example-implementing-using-default-group-sequence-provider
#GroupSequenceProvider(UpdateUserRegistrationGroupSequenceProvider.class)
public class UpdateUserRegistrationRequestV1 {
#NotBlank(groups = {EmailExistsInRequest.class})
#Email(groups = {EmailExistsInRequest.class})
#SafeHtml(whitelistType = SafeHtml.WhiteListType.NONE, groups = {EmailExistsInRequest.class})
private String email;
#NotNull(groups = {PasswordExistsInRequest.class})
#Size(min = 8, max = 255, groups = {PasswordExistsInRequest.class})
private String password;
#NotNull(groups = {FirstNameExistsInRequest.class})
#Size(max = 255, groups = {FirstNameExistsInRequest.class})
#SafeHtml(whitelistType = SafeHtml.WhiteListType.NONE, groups = {FirstNameExistsInRequest.class})
private String firstName;
// THERE ARE GETTERS AND SETTERS BELOW
}
Group Sequence Provider Code:
public class UpdateUserRegistrationGroupSequenceProvider implements DefaultGroupSequenceProvider<UpdateUserRegistrationRequestV1> {
public interface EmailExistsInRequest {}
public interface PasswordExistsInRequest {}
public interface FirstNameExistsInRequest {}
#Override
public List<Class<?>> getValidationGroups(UpdateUserRegistrationRequestV1 updateUserRegistrationRequestV1) {
List<Class<?>> defaultGroupSequence = new ArrayList<Class<?>>();
defaultGroupSequence.add(Default.class);
defaultGroupSequence.add(UpdateUserRegistrationRequestV1.class);
if(StringUtils.hasText(updateUserRegistrationRequestV1.getEmail())) {
defaultGroupSequence.add(EmailExistsInRequest.class);
}
if(StringUtils.hasText(updateUserRegistrationRequestV1.getPassword())) {
defaultGroupSequence.add(PasswordExistsInRequest.class);
}
if(StringUtils.hasText(updateUserRegistrationRequestV1.getFirstName())) {
defaultGroupSequence.add(FirstNameExistsInRequest.class);
}
return defaultGroupSequence;
}
}
I am using Spring MVC, so this is how my controller method looks,
#RequestMapping(value = "/{userId}", method = RequestMethod.PUT, consumes = MediaType.APPLICATION_JSON_VALUE)
#ResponseStatus(HttpStatus.NO_CONTENT)
public void updateUser(#PathVariable("userId") Long userId,
#RequestBody #Valid UpdateUserRegistrationRequestV1 request) {
logger.info("Received update request = " + request + " for userId = " + userId);
registrationService.updateUser(userId, conversionService.convert(request, User.class));
}
Now the problem is, the parameter "updateUserRegistrationRequestV1" in the UpdateUserRegistrationGroupSequenceProvider.getValidationGroups method is null. This is the request object that I am sending in the request body and I am sending email field with it.
What am I doing wrong?

Answer 1

I too went through the same issue ,and hopefully solved it
You just have to check the object is null and put all your conditions inside it.
public List<Class<?>> getValidationGroups(Employee object) {
List<Class<?>> sequence = new ArrayList<>();
//first check if the object is null
if(object != null ){
if (!object.isDraft()) {
sequence.add(Second.class);
}
}
// Apply all validation rules from default group
sequence.add(Employee.class);
return sequence;
}