I'm trying to implement a custom annotation to validate my fields. The idea is that the validation fails whenever the annotated field is null. Something like this.
#RequiredProperty
public abstract Person getPerson();
Now if this returns a null Person, I'd like the validation to fail (ideally with a custom message "Person field is null").
I tried to do it like this.
#Documented
#Constraint(validatedBy = RequiredPropertyValidator.class)
#Retention(RetentionPolicy.RUNTIME)
#Target({FIELD, METHOD, PARAMETER, ANNOTATION_TYPE, TYPE_USE})
#ReportAsSingleViolation
public #interface RequiredProperty {
String message() default "{javax.validation.constraints.RequiredProperty.message}";
Class<?>[] groups() default {};
Class<? extends Payload>[] payload() default {};
}
And validator.
public class RequiredPropertyValidator implements ConstraintValidator<RequiredProperty, Object> {
#Override
public void initialize(RequiredProperty constraintAnnotation) {
}
#Override
public boolean isValid(Object property, ConstraintValidatorContext context) {
return property != null;
}
}
However this won't work. It doesn't validate at all. Object property is never even passed to the isValid method. Any advice on how to get it working?
UPDATE
Removing the empty initialize method got it working. However, I'm not sure how to create a custom error message that the "Person" field is null. Is that possible?
I created a custom message in .properties file, but this is just a static message, and I'd like to capture the actual field from runtime.
Related
I have a custom annotation called Matches which has a default value for message. This is essentially a class-level custom constraint validator but that's not part of the problem.
#Constraint(validatedBy = MatchesValidator.class)
#Documented
#Target({ElementType.TYPE, ElementType.ANNOTATION_TYPE})
#Retention(RetentionPolicy.RUNTIME)
#Repeatable(Matches.List.class)
public #interface Matches {
String field();
String otherField();
String message() default "{com.example.api.validation.constraints.Matches.message}";
Class<?>[] groups() default {};
Class<? extends Payload>[] payload() default {};
#Documented
#Target({ElementType.TYPE, ElementType.ANNOTATION_TYPE})
#Retention(RetentionPolicy.RUNTIME)
#interface List {
Matches[] value();
}
}
This is a simple constraint that will be applied on a class to validate if two fields have the same value:
#Matches(field = "password", otherField = "confirmPassword")
class UserRegistration {
private String password;
private String confirmPassword;
// Getters
}
I'm writing a test using JUnit and Mockito and and I'm trying to mock the Matches annotation:
#Test
void isValid_whenFieldsDoNotMatch_thenReturnsFalse() {
Matches invalidPropertyMatches = Mockito.mock(Matches.class);
when(invalidPropertyMatches.field()).thenReturn("password");
when(invalidPropertyMatches.field()).thenReturn("confirmPassword");
when(invalidPropertyMatches.message()).thenCallRealMethod(); // This throws
}
I want that when the Matches.message() value is called, I get back the default defined value "{com.example.api.validation.constraints.Matches.message}", so I added:
when(invalidPropertyMatches.message()).thenCallRealMethod();
However, this throws the following exception:
org.mockito.exceptions.base.MockitoException:
Cannot call abstract real method on java object!
Calling real methods is only possible when mocking non abstract method.
//correct example:
when(mockOfConcreteClass.nonAbstractMethod()).thenCallRealMethod();
It essentially says that Matches.message() is abstract and cannot be called. Are annotation properties in Java abstract? Is there a way to fix this?
I'm trying to make a custom java validation annotation and returns me
Request processing failed; nested exception is javax.validation.ConstraintDeclarationException: HV000144: Cross parameter constraint com.my.company.CustomConstraint is illegally placed on field 'private java.util.List com.my.company.ElementOfTheList'."
the code is really naive
#Documented
#Retention(RUNTIME)
#Target({ FIELD, METHOD})
#Constraint(validatedBy = ConstraintValidation.class)
public #interface CustomConstraint {
String message() default "this is the default message";
Class<?>[] groups() default {};
Class<? extends Payload>[] payload() default {};
}
#SupportedValidationTarget(ValidationTarget.PARAMETERS)
public class ConstraintValidationimplements ConstraintValidator<CustomConstraint , List<ElementOfTheList>> {
public boolean isValid(List<ElementOfTheList> value, ConstraintValidatorContext context) {
System.out.println("only a sysout to test");
return true;
}
}
And in the rest object model
#JsonProperty("ElementOfTheList")
#Valid
#NotNull(message ="not null message")
#NotEmpty(message = "not empty message")
#CustomConstraint
private List<ElementOfTheList> list = null;
change
#SupportedValidationTarget(ValidationTarget.PARAMETERS)
to
#SupportedValidationTarget(ValidationTarget.ANNOTATED_ELEMENT)
since you want to validate and element (here is List list)
and not the parameters of a method or a constructor
A custom enum validator annotation interface:
#Target({METHOD, FIELD, ANNOTATION_TYPE, CONSTRUCTOR, PARAMETER, TYPE_USE})
#Retention(RUNTIME)
#Documented
#Constraint(validatedBy = PanTypeSubSetValidator.class)
public #interface PanTypeSubset {
PanType[] anyOf();
String message() default "must be any of {anyOf}";
Class<?>[] groups() default {};
Class<? extends Payload>[] payload() default {};
}
and the actual implementation:
public class PanTypeSubSetValidator implements ConstraintValidator<PanTypeSubset, PanType> {
private PanType[] subset;
#Override
public void initialize(PanTypeSubset constraint) {
this.subset = constraint.anyOf();
}
#Override
public boolean isValid(PanType value, ConstraintValidatorContext context) {
return value == null || Arrays.asList(subset).contains(value);
}
}
and the usage inside a request DTO:
#SuperBuilder
#Data
#NoArgsConstructor
public class PanBaseRequestDto {
#NotNull(message = "'PANTYPE' cannot be empty or null")
#PanTypeSubset(anyOf = {PanType.PAN, PanType.TOKEN}, message = "yesssss")
private PanType panType;
}
The problem is that this annotation never seems to be triggered. I get another exception kick in in the #RestControllerAdvice DefaultExceptionHandler implementation before this actual validation:
Handling generic exception: (Invalid JSON input: Cannot deserialize value of type `...pantoken.PanType` from String "PAN1": not one of the values accepted for Enum class: [TOKEN, PAN]; nested exception is com.fasterxml.jackson.databind.exc.InvalidFormatException: Cannot deserialize value of type `...pantoken.PanType` from String "PAN1": not one of the values accepted for Enum class: [TOKEN, PAN]
Solved it by creating a custom #JsonCreator function inside the ENUM class. Not the best approach, as we loose the value that user has submitted when displaying error to the end client, but it's ok for me.
#JsonCreator
public static PanType create(String value) {
if (Objects.isNull(value)) {
return null;
}
return Arrays.stream(PanType.values())
.filter(v -> value.equals(v.getType()))
.findFirst()
.orElse(PanType.UNKNOWN);
}
I have List of Objects that I need to run some validation on
#KeyValid
#Valid
protected List<KeyValue> keyValues;
and I have a the following annotation created for it:
#Target({ElementType.TYPE, ElementType.FIELD})
#Retention(RetentionPolicy.RUNTIME)
#Constraint(validatedBy = KeyValidator.class)
public #interface KeyValid{
String message() default "invalid_parameter_default_message";
String[] checks() default {};
Class<?>[] groups() default {};
Class<? extends Payload>[] payload() default {};
}
And this is my validator:
public class KeyValidator implements ConstraintValidator<KeyValid, KeyValue> {
#Override
public void initialize(KeyValid keyValid) {
}
#Override
public boolean isValid(KeyValue keyValue, ConstraintValidatorContext constraintValidatorContext) {
return true;
}
}
I had read somewhere that collections can be validated in bulk if the list or map or set is annotated by custom constraint then all of the elements of the collection call the validator but the above code throws the following error
javax.validation.UnexpectedTypeException: HV000030: No validator could be found for constraint 'com.util.Validators.KeyValid' validating type 'java.util.List<com.model.KeyValue>'. Check configuration for 'keyValue'
Your constraint would get the actual List passed not its elements. If you are using Java 8 and the latest version of Hibernate Validator, you can use type argument constraints. You just have to make sure to also add ElementType.TYPE_USE to #Target in your constraint. Type argument constraints are not yet official part of Bean Validation, but will be in the next version of it (BV 2.0).
You would have something like this:
protected List<#KeyValid KeyValue> keyValues;
Alternatively, could you not put the #KeyValid constraint as class level constraint on KeyValue?
I'm working with bean validations and I'm searching for a possibility to set a default group of my own bean validation annotation.
I have something (working) like this:
Application.class (calling validate on MyBean)
public class Application {
public static void main(String[] args) {
Validator validator = Validation.buildDefaultValidatorFactory().getValidator();
Set<ConstraintViolation<MyBean>> violations =
validator.validate(new MyBean(), SecondStep.class);
}
}
MyBean.class (the bean itself; here is what I want to prevent)
public class MyBean {
// I don't want to write this "groups" attribute every time, because it's very clear,
// that this should only be validated for the second step, isn't it?
#RequiredBySecondStep(groups=SecondStep.class)
private Object myField;
}
RequiredBySecondStep.class (the bean validation annotation)
#Documented
#Target(FIELD)
#Retention(RUNTIME)
#Constraint(validatedBy = RequiredBySecondStepValidator.class)
public #interface RequiredBySecondStep {
String message() default "may not be null on the second step";
Class<?>[] groups() default {}; // <-- here I want to set SecondStep.class
Class<? extends Payload>[] payload() default {};
}
RequiredBySecondStepValidator.class (an implemented constraint validator)
public class RequiredBySecondStepValidator implements ConstraintValidator<RequiredBySecondStep, Object> {
public void initialize(RequiredBySecondStep constraintAnnotation) {
}
public boolean isValid(Object object, ConstraintValidatorContext constraintContext) {
return object != null;
}
}
SecondStep.class (the bean validation group)
public interface SecondStep {
}
Unfortunately, it's not possible by specification, to set the default group in the RequiredBySecondStep annotation like this:
Class<?>[] groups() default SecondStep.class;
// and using just the following in the bean:
#RequiredBySecondStep
private Object myField;
This will result in a RuntimeException:
javax.validation.ConstraintDefinitionException: Default value for
groups() must be an empty array
Furthermore, there is not only a SecondStep. There are probably 5 different groups which I want to annotate directly with a #RequiredByFirstStep or #RequiredByFifthStep.
Is there a good way to implement this?
I think you got it all a bit wrong. There is indeed to way to do what you want and that's because the aspect of constraints and their validation via a ConstraintValidator is orthogonal to groups and groups sequences. Per design a constraint (annotation and its validator) should be independent of the group getting validated. Even if you would get this to work, it would not be portable constraints. Personally, I would re-think what you want to achieve. #RequiredByFirstStep does not tell you what the requirement is. You should develop constraints which imply what they are valiating (a string length, not null, etc), when or better in which condition they are executed is a then controlled by group interfaces.