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How to set validation groups dynamically

I have a Spring Boot application where I want to validate a request body object with the #valid annotation.
#PostMapping("update")
public void upateSnippet(#Valid #RequestBody MyDto dto)
This works as expected. But I need to do the validation based on session specific informations. So I created validation groups which should be set dynamically. I don´t want to call the validator manually in the controller. The validation logic should be completely outside of the controller.
So what I´m trying to do is to register a custom MethodValidationInterceptor where I can specify the groups in determineValidationGroups().
public class SessionAwareValidationInterceptor extends MethodValidationInterceptor
{
#Autowired
public SessionAwareValidationInterceptor(Validator validator)
{
super(validator);
}
#Override
protected Class<?>[] determineValidationGroups(MethodInvocation invocation)
{
ServletRequestAttributes requestAttributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
HttpSession session = requestAttributes.getRequest().getSession();
//return groups from session
}
}
In my configuration I register the interceptor as any other bean:
#Bean
public MethodValidationInterceptor methodValidationInterceptor(Validator validator)
{
return new SessionAwareValidationInterceptor(validator);
}
But I have serveral problems with this:
The #Valid annotation works on its own, but the MethodValidationInterceptor is only called when I add a #Validated annotation on the controller class.
But even when I use both annotations combined, Spring does not use my custom interceptor.
How do I register my custom MethodValidationInterceptor? Or is there maybe an other way to register the validation groups dynamically? Plan B would be some custom constraint validators which get the necessary informations out of the session, but I would prefer the group approach.

I figured it out how to do it. I had to create a custom MethodValidationPostProcessor that returns my SessionAwareValidationInterceptor.
public class CustomMethodValidationPostProcessor extends MethodValidationPostProcessor {
#Override
#NotNull
protected Advice createMethodValidationAdvice(Validator validator) {
return validator != null ? new SessionAwareValidationInterceptor(validator) : new SessionAwareValidationInterceptor();
}
}
Then I simply registered it as bean. This way, I was able to use my solution from above. To make it work, I have to use the #Validated annotation on class level and the #Valid annotation on the method parameter.

Can I explicitly call custom validator from service in Spring Boot?

I have a custom validator class that implements Validator, like this:
public class MyCustomValidator implements Validator
I want to be able to call its validate() method from a Service.
This is how this method looks:
#Override
public void validate(Object target, Errors errors) {
// validation goes here
MyClass request = (MyClass) target;
if (request.getId() == null) {
errors.reject("content.id", "Id is missing";
}
}
I don't want to have this validator in my endpoint, because I need to fetch the object to be validated from the database and then call the validation on it, so I need to do it from my service.
Can you please guide me on how to achieve this?

Use validation annotations in class but don't use #Valid on request body, then spring won't validate your class.
public class MyClass{
#NotNull
private Integer id;
#NotBlank
private String data;
}
Autowired Validator first
#Autowired
private final Validator validator;
Then for class validate using the validator conditionally when needed.
if(isValidate) {
Set<ConstraintViolation<MyClass>> violations = validator.validate(myClassObj);
if (!violations.isEmpty()) {
throw new ConstraintViolationException(new HashSet<ConstraintViolation<?>>(violations));
}
}

The Validator interface is, as far as i understand it, called as soon as a matching object (determined by the public boolean Validator.supports(Class clazz) method).
However, your goal seems to be to validate an object of MyClass only at a specific time, coming from your persistence layer to your service layer.
There are multiple ways to achieve this.
The first and most obvious one is to not extend any classes, but to use a custom component with some notion of a validation function:
#Component
public class CustomValidator{
public void validate(MyClass target) throws ValidationException {
// validation goes here
if (target.getId() == null) {
throw new ValidationException("Id is missing");
}
}
}
And inject/autowire it into your service object:
#Component
public class MyClassService{
// will be injected in first instance of this component
#Autowired
private CustomValidator validator
public MyClass get(MyClass target) {
try {
validator.validate(target);
return dao.retrieve(target);
} catch (ValidationException) {
// handle validation error
} catch (DataAccessException) {
// handle dao exception
}
}
}
This has the benefit that you yourself can control the validation, and error handling.
The negative side is the relatively high boilerplate.
However, if you want different Validators for different CRUD-Operations (or Service Methods), you may be interested in the Spring Validation Groups Feature.
First, you create a simple marker interface for each Operation you want to differ:
interface OnCreate {};
interface OnUpdate {};
Then, all you need to do is use the marker interfaces in the fields of your entity class,
using the Bean Validation Annotations:
public class MyClass{
#Null(groups = OnCreate.class)
#NotNull(groups = OnUpdate.class)
String id;
}
In order to use those groups in your Service Class, you will have to use the #Validated annotation.
#Validated
#Service
public class MyService {
#Validated(OnCreate.class)
void validateForCreate(#Valid InputWithGroups input){
// do something
}
#Validated(OnUpdate.class)
void validateForUpdate(#Valid InputWithGroups input){
// do something
}
}
Note that #Validated is applied to the service class as well as the methods. You can also set the group for the whole service, if you plan on using multiple services.
I for once mostly use the built-in Jakarta Bean Validation annotations in combination with marker interfaces, because of their ease of use and almost no boilerplate, while staying somewhat flexible and adjustable.

You could inject Validator and call validate
#Autowired
Validator validator;
And then call validate:
Set<ConstraintViolation<Driver>> violations = validator.validate(yourObjectToValidate);

How to propagate same instance using CDI

I have a web application with JAX-RS, CDI and EJB. In each resource I inject a Stateless SessionBean, and my question is whether it is possible to inject the same instances into a provider of JAX-RS and the Stateless SesionBean. I am trying to pass some data that come in each request to the Stateless SesionBean from a ContainerRequestFilter. All EJB components are accessed only by jax rs resources.
Example:
public class Bean {
private String attr;
// getter and setter
}
#Stateless
public class BeanService {
#Inject
Bean bean;
public void doStuff() {
bean.getAttr();
// do something with bean.attr
}
}
#Path("/bean")
public class BeanResource {
#Inject
BeanService service;
#GET
public void doStuff() {
service.doStuff():
}
}
#Provider
public class BeanRequestFilter implements ContainerRequestFilter {
#Inject
Bean bean;
#Override
public void filter(ContainerRequestContext containerRequestContext) throws IOException {
String data = null; // <- get data from request
bean.setAttr(data);
}
}
Update
Change the Bean for Pojo, my only intention is use a class that hold some state that come in every request and can be transmited in each invocation, since the PojoResource to PojoService. I want to do it in this way because all the services retrive this data and I don't want to pass this as parameter on every method.

This looks like your Bean class is essentially request scoped, so changing it to:
#RequestScoped
public class Bean {
...
}
should have the desired effect. The same instance will be injected in both the BeanRequestFilter and the BeanService.
However, I think you may also get what you're looking for by injecting the ContainerRequestContext directly into the BeanService and forgetting about Bean altogether.
#Stateless
public class BeanService {
#Context
ContainerRequestContext containerRequestContext;
public void doStuff() {
// <- get data from request
}
}

If you want the Bean to be a kind of singleton using CDI see the #ApplicationScoped annotation (in that case Bean should be Sersializable)
Or if you want the EJB BeanService to be a singleton see the #Singleton annotation

Before answering the question, Bean should never be updated. A concept of bean is that which provides a service, and uses data to process a request.
That said, you can of course provide data as bean, but then the data needs to be produced at one point to be used, and not to be updated.
I would therefore use the BeanRequestFilter to produce the bean, and let the BeanService inject the produced bean.
This notwithstanding however, i see that this is a request based data? is it a header data?, request parameter? Then i would suggest that you use the jax-rs #QueryParam or #HeaderParam or #PathParam or #FormParam or #CookieParam within the jax-rs resource class, and then provide the data as a domain object parameter to your BeanService thus:
#Path("/api/resource-path")
public class MyResource {
public void processSomething(#QueryParam("qparam") String param, #HeaderParam("hparam") String hParam) {
MyDomain domain = new MyDomain(qParam, hParam);
myService.process(domain);
}
}

Spring #Validated in service layer

Hej,
I want to use the #Validated(group=Foo.class) annotation to validate an argument before executing a method like following:
public void doFoo(Foo #Validated(groups=Foo.class) foo){}
When i put this method in the Controller of my Spring application, the #Validated is executed and throws an error when the Foo object is not valid. However if I put the same thing in a method in the Service layer of my application, the validation is not executed and the method just runs even when the Foo object isn't valid.
Can't you use the #Validated annotation in the service layer ? Or do I have to do configure something extra to make it work ?
Update:
I have added the following two beans to my service.xml:
<bean id="validator" class="org.springframework.validation.beanvalidation.LocalValidatorFactoryBean"/>
<bean class="org.springframework.validation.beanvalidation.MethodValidationPostProcessor"/>
and replaced the #Validate with #Null like so:
public void doFoo(Foo #Null(groups=Foo.class) foo){}
I know it is a pretty silly annotation to do but I wanted to check that if I call the method now and passing null it would throw an violation exception which it does. So why does it execute the #Null annotation and not the #Validate annotation ? I know one is from javax.validation and the other is from Spring but I do not think that has anything to do with it ?

In the eyes of a Spring MVC stack, there is no such thing as a service layer. The reason it works for #Controller class handler methods is that Spring uses a special HandlerMethodArgumentResolver called ModelAttributeMethodProcessor which performs validation before resolving the argument to use in your handler method.
The service layer, as we call it, is just a plain bean with no additional behavior added to it from the MVC (DispatcherServlet) stack. As such you cannot expect any validation from Spring. You need to roll your own, probably with AOP.
With MethodValidationPostProcessor, take a look at the javadoc
Applicable methods have JSR-303 constraint annotations on their
parameters and/or on their return value (in the latter case specified
at the method level, typically as inline annotation).
Validation groups can be specified through Spring's Validated
annotation at the type level of the containing target class, applying
to all public service methods of that class. By default, JSR-303 will
validate against its default group only.
The #Validated annotation is only used to specify a validation group, it doesn't itself force any validation. You need to use one of the javax.validation annotations like #Null or #Valid. Remember that you can use as many annotations as you would like on a method parameter.

As a side note on Spring Validation for methods:
Since Spring uses interceptors in its approach, the validation itself is only performed when you're talking to a Bean's method:
When talking to an instance of this bean through the Spring or JSR-303 Validator interfaces, you'll be talking to the default Validator of the underlying ValidatorFactory. This is very convenient in that you don't have to perform yet another call on the factory, assuming that you will almost always use the default Validator anyway.
This is important because if you're trying to implement a validation in such a way for method calls within the class, it won't work. E.g.:
#Autowired
WannaValidate service;
//...
service.callMeOutside(new Form);
#Service
public class WannaValidate {
/* Spring Validation will work fine when executed from outside, as above */
#Validated
public void callMeOutside(#Valid Form form) {
AnotherForm anotherForm = new AnotherForm(form);
callMeInside(anotherForm);
}
/* Spring Validation won't work for AnotherForm if executed from inner method */
#Validated
public void callMeInside(#Valid AnotherForm form) {
// stuff
}
}
Hope someone finds this helpful. Tested with Spring 4.3, so things might be different for other versions.

#pgiecek You don't need to create a new Annotation. You can use:
#Validated
public class MyClass {
#Validated({Group1.class})
public myMethod1(#Valid Foo foo) { ... }
#Validated({Group2.class})
public myMethod2(#Valid Foo foo) { ... }
...
}

Be careful with rubensa's approach.
This only works when you declare #Valid as the only annotation. When you combine it with other annotations like #NotNull everything except the #Valid will be ignored.
The following will not work and the #NotNull will be ignored:
#Validated
public class MyClass {
#Validated(Group1.class)
public void myMethod1(#NotNull #Valid Foo foo) { ... }
#Validated(Group2.class)
public void myMethod2(#NotNull #Valid Foo foo) { ... }
}
In combination with other annotations you need to declare the javax.validation.groups.Default Group as well, like this:
#Validated
public class MyClass {
#Validated({ Default.class, Group1.class })
public void myMethod1(#NotNull #Valid Foo foo) { ... }
#Validated({ Default.class, Group2.class })
public void myMethod2(#NotNull #Valid Foo foo) { ... }
}

As stated above to specify validation groups is possible only through #Validated annotation at class level. However, it is not very convenient since sometimes you have a class containing several methods with the same entity as a parameter but each of which requiring different subset of properties to validate. It was also my case and below you can find several steps to take to solve it.
1) Implement custom annotation that enables to specify validation groups at method level in addition to groups specified through #Validated at class level.
#Target({ElementType.METHOD})
#Retention(RetentionPolicy.RUNTIME)
#Documented
public #interface ValidatedGroups {
Class<?>[] value() default {};
}
2) Extend MethodValidationInterceptor and override determineValidationGroups method as follows.
#Override
protected Class<?>[] determineValidationGroups(MethodInvocation invocation) {
final Class<?>[] classLevelGroups = super.determineValidationGroups(invocation);
final ValidatedGroups validatedGroups = AnnotationUtils.findAnnotation(
invocation.getMethod(), ValidatedGroups.class);
final Class<?>[] methodLevelGroups = validatedGroups != null ? validatedGroups.value() : new Class<?>[0];
if (methodLevelGroups.length == 0) {
return classLevelGroups;
}
final int newLength = classLevelGroups.length + methodLevelGroups.length;
final Class<?>[] mergedGroups = Arrays.copyOf(classLevelGroups, newLength);
System.arraycopy(methodLevelGroups, 0, mergedGroups, classLevelGroups.length, methodLevelGroups.length);
return mergedGroups;
}
3) Implement your own MethodValidationPostProcessor (just copy the Spring one) and in the method afterPropertiesSet use validation interceptor implemented in step 2.
#Override
public void afterPropertiesSet() throws Exception {
Pointcut pointcut = new AnnotationMatchingPointcut(Validated.class, true);
Advice advice = (this.validator != null ? new ValidatedGroupsAwareMethodValidationInterceptor(this.validator) :
new ValidatedGroupsAwareMethodValidationInterceptor());
this.advisor = new DefaultPointcutAdvisor(pointcut, advice);
}
4) Register your validation post processor instead of Spring one.
<bean class="my.package.ValidatedGroupsAwareMethodValidationPostProcessor"/>
That's it. Now you can use it as follows.
#Validated(groups = Group1.class)
public class MyClass {
#ValidatedGroups(Group2.class)
public myMethod1(Foo foo) { ... }
public myMethod2(Foo foo) { ... }
...
}

Spring MVC customized method parameter binding

I'm looking for a way to customize the default Spring MVC parameter binding. Take this method as an example:
#RequestMapping(value="/index.html")
public ModelAndView doIndex(#RequestParam String param) {
...
This is easy, when I have just a Stringthat I want to extract from the request. However, I want to populate a more complete object, so that my method looks like this:
#RequestMapping(value="/index.html")
public ModelAndView doIndex(Foo bar) {
...
What I'm looking for is some way to declare a binding like this;
#RequestMapping(value="/index.html")
public ModelAndView doIndex(#FooPopulator Foo bar) {
...
And have some other kind of implementor (determined by the #FooPopulator annotation) that does this:
public void doBind(Foo target, ServletRequest originalRequest) {
target.setX(this.computeStuffBasedOn(originalRequest));
target.sety(y);
}
So far I've found out about the #InitBinderbinder annotaion but I'm unsure whether that's really the right choice for this scenarion.
What's the best way?

It is very easy. You can use Converters (that work like one way PropertyEditors but are stateless).
See chapter 5.5 Spring 3 Type Conversion in Spring reference.
If such an converter is registered once, you do not need any additional information, you can simply use
#RequestMapping(value="/index.html")
public ModelAndView doIndex(#RequestParam Foo param) {
For example a simple converter that load an object by its id:
#Component
#CustomConverter //custom qualifyer
public class BUdToUserConverter implements Converter<String, User> {
#Resource
private UserDao userDao;
#Override
public User convert(String source) {
Integer id = Integer.parse(source);
return this.userDao.getByBusinessId(id);
}
}
A "helper" that registers all Beans with #CustomConverter anntoation
public class ApplicationConversionServiceFactoryBean extends FormattingConversionServiceFactoryBean {
#Resource
#CustomConverter
private List<Converter<?, ?>> customConverter;
#Override
protected void installFormatters(final FormatterRegistry registry) {
super.installFormatters(registry);
for (Converter<?, ?> converter : customConverter) {
registry.addConverter(converter);
}
}
}
How to use it
UserController {
...
#RequestMapping(value = "/{id}", method = RequestMethod.GET)
public ModelAndView show(#PathVariable("id") User user) {
return new ModelAndView("users/show", "user", user);
}
}

just a quick thank you and the info, that I've found the "correct" solution to the problem. Spring already provides the WebArgumentResolver for this scenario.
http://sergialmar.wordpress.com/2011/03/29/extending-handler-method-argument-resolution-in-spring-mvc/
http://scottfrederick.blogspot.com/2011/03/customizing-spring-3-mvcannotation.html