Spring - Validation of custom constraints - java

I have a custom annotation #UniqueModel, which is validated by a ConstraintValidator:
#Component
public class UniquePlaceValidator implements ConstraintValidator<UniqueModel, Model> {
#Autowired
private ModelRepository repository;
public UniqueModelValidator() {
}
public void initialize(UniqueModel constraint) {
}
#Override
public boolean isValid(Model model, ConstraintValidatorContext context) {
if (repository == null)
return true;
Model dbModel = repository.findByNameAndMail(model.getName(), model.getMail());
return dbModel == null;
}
The problem is, that I need to do the validation before the safe()-method of the repository is called, otherwise the field injection won't work.
I therefor created a delegate-method with a #Valid-annotation, in order to force the unique-validation before:
Model save(#Valid Model model {
return repository.save(model);
}
Unfortunately this doesn't work, it seems like the #Valid-annotation is ignored by Spring.
How can I assure the correct timing of validation?

Depending on your Bean validation configuration you may need to annotate your repository bean with #ValidateOnExecution.
But I'm not sure if Spring does support this annoation (see SPR-10641) hence I'm using Spring's own #Validated annotation in my repository and service interfaces and method level validation works fine!
See also this question and have a look into MethodValidationPostProcessor which clearly states "Target classes with such annotated methods need to be annotated with Spring's #Validated annotation at the type level". So it seems to be pretty clear that you have to use #Validated instead of #ValidateOnExecution until SPR-10641 is fixed.

Related

Use Spring dependency injection on a custom Hibernate validator

I want to create my own Hibernate custom Validator and what I would like to do is to add custom logic based on some information gathered from a different context (a different Spring bean)
On my custom implementation, I have tried to both add a constructor and define the validator in a spring bean, or to use the Autowire annotation and none of them worked
Autowire example:
public class MyCustomValidator implements ConstraintValidator<CustomConstraint, String> {
#Autowired
private MyCustomChecker customChecker;
#Override
public void initialize(CustomConstraint constraintAnnotation) {
}
#Override
public boolean isValid(String value, ConstraintValidatorContext context) {
if (null == value) {
return true;
}
//get user authenticated properties to perform validation based on the user
AuthenticatedIdentity identity = Context.getAuthenticatedIdentity();
return customChecker.isWhitelisted(identity);
}
}
Constructor example:
public class MyCustomValidator implements ConstraintValidator<CustomConstraint, String> {
private MyCustomChecker customChecker;
public MetricDataSizeValidator(MyCustomChecker customChecker) {
this.customChecker = customChecker;
}
#Override
public void initialize(CustomConstraint constraintAnnotation) {
}
#Override
public boolean isValid(String value, ConstraintValidatorContext context) {
if (null == value) {
return true;
}
//get user authenticated properties to perform validation based on the user
AuthenticatedIdentity identity = Context.getAuthenticatedIdentity();
return customChecker.isWhitelisted(identity);
}
}
I've read around on the official Hibernate doc but that doesn't quite answer my question.
I am pretty sure this is a common issue when you want to validate based on some information based from a different context, however I didn't find around an answer for this.
My app is using Spring DI, where my bean is already initialized like this
<bean id="customChecker" class="com.mycomp.CustomChecker">
<constructor-arg>
<value>arg</value>
</constructor-arg>
</bean>
Is there any example around of how to achieve this?
Update
If I configure my Validator to be:
<bean id="validatorFactory" class="org.springframework.validation.beanvalidation.LocalValidatorFactoryBean"/>
<bean id="validator" factory-bean="validatorFactory"
factory-method="getValidator" />
Now I can see the validation is wired up correctly using spring beans. However, now I'm doubtful whether I'm using HibernateValidator (I think I'm not). Is there any way to achieve the same but configure HibernateValidator factory to use Spring beans?
I assume your MyCustomValidator is not recognized as a managed spring bean, so no autowiring will occur.
The easiest way to make your MyCustomValidator a spring bean is to add the #Component annotation at the class level.
You can use InitBinder in case of Spring MVC where your custom validator will automatically called by the RequestMappingHandlerAdapter.
Simply annotate your method in the controller with #InitBinder and inside the method provide your validator and provide the your validator class to WebDataBinder by calling webDataBinder.setValidator()

Why does validation not work on objects of type DTO, but only on entities

I have an annotation set over objects of type dto, the same as over objects of type Entity. The annotation works on entities, but it does not work on objects of type dto.
I work in SpringBoot.
application.properties
validate.packageid.size = "The field 'PACKAGEID' can contain only {max} symbols.";
config file
#Configuration
public class ServiceConfig implements WebMvcConfigurer {
#Bean
public MessageSource messageSource() {
ResourceBundleMessageSource source = new ResourceBundleMessageSource();
source.setDefaultEncoding("UTF-8");
source.setBasename("classpath:ValidationMessages");
return source;
}
#Nullable
#Override
public Validator getValidator() {
LocalValidatorFactoryBean validator = new LocalValidatorFactoryBean();
validator.setValidationMessageSource(messageSource());
return validator;
}
}
dto
#Size(message = "{validate.packageid.size}", max = 36)
private String documentId
entity
#Column(name = "DOCUMENTID")
#Size(message = "{validate.packageid.size}", max = 36)
private String documentId;
I cannot use the annotation #Valid because I fill an object of dto type with reflection technology.
public static <S> S fillData (S object, List<Object> values){
return obtainMetadataOfObject(object, values);
}
I need to be able to get the constraint annotation, or rather its parameters, set on the fields of the dto object (but in the case of the dto object I get null, since Spring may not know what to use the constraint annotations set on the fields of the dto object), in the case of entity - it turns out, but the entity validator is engaged by Spritg, since it manages the entity as a component from the Application context.
To validate the dto on the web client side, I use the #Valid annotation in the parameters of the method that handles the request from the client
For validation dto from
Update
I put the annotation #Validation over dto and after that I got the data I need.
It work for classes that don't have classes-heir.
I get data of annotation #Size
private static int getMaxLimitSize(Field field){
field.setAccessible(true);
Size annotation = field.getAnnotation(Size.class);
int zero = 0;
if(annotation == null) return zero;
return annotation.max();
}
But this does not work for objects whose fields are split into several classes : several abstract and one produce.
Validation does not work for composite objects of type DTO, Any help is appreciated?
The validation needs to be triggered somewhere, for entities in your case the spring framework does it (or jpa perhaps). DTOs never make it there. So you have to trigger the validation (validator.validate) on your own, as per the documentation. Here's a related question asking at which application layer to do it.
#PostMapping("/test")
public void test( #RequestBody #Valid final UserDto dto) {
// logic
}
u should add #Valid annotation in controller.
If u want validate dto in service layers u should add #Validate and #Valid :
#Service
#Validated
public class Service {
public void test(#Valid UserDto dto){
// logic
}
}

Spring Managed Custom Validator not being used from endpoint

I've been at this for a while, but I have a Spring managed custom validator that looks like the below, I have some print statements in there which I'll get to later
#Component
public class BulkUpdateValidator implements ConstraintValidator<ValidBulkUpdate, BulkUpdate> {
#Autowired
ObjectMapper mapper;
public BulkUpdateValidator(){
System.out.println(this.toString());
}
#PostConstruct
public void post(){
System.out.println(mapper);
System.out.println(this.toString());
}
public boolean isValid(BulkUpdate update, ConstraintValidatorContext context){
System.out.println(this.toString());
System.out.println(mapper);
}
... other validator methods ...
}
My controller method: (NOTE: my controller class is annotated with #Validated at the top)
#RequestMapping(...)
public #ResponseBody RestResponse bulkUpdate(#Valid #ValidBulkUpdate Bulkupdate bulkUpdate){
... stuff here ...
}
My Bean:
public class BulkUpdate {
#NotEmpty
public List<String> recordIds;
#NotEmpty
#Valid
public List<FieldUpdate> updates;
.... getters and setters ....
}
Here's my problem, when I execute the endpoint it get a NullPointerException when I attempt to use the autowired mapper. The output from the print statements I posted above are quite telling. In both the constructor and the #PostConstruct sections I get the same Object ID for the validator and I also get an ID for the mapper. However, once isValid is called, it prints out a different Object ID. I know the spring managed validator is being created, but it's not being used.
Furthermore, I've tried to remove the #ValidBulkUpdate annotation from the REST endpoint and put it inside a wrapper object, thinking that maybe #Valid was necessary to get spring to take over, like below:
public #ResponseBody RestResponse bulkUpdate(#Valid BulkupdateWrapper bulkUpdate){
... stuff here ...
}
And wrapper
public class BulkUpdateWrapper {
#ValidBulkUpdate
private BulkUpdate update;
.... getter and setter ....
}
This leaves me with a whole new error which is even weirder:
"JSR-303 validated property 'update.org.hibernate.validator.internal.engine.ConstraintViolationImpl' does not have a corresponding accessor"
I'm not sure where to turn, hopefully someone has an idea. Either how to get it to use the Spring managed validator, or how to remove that vague error when I use the object wrapper;
What's worse, is I have MockMvc based Integration tests for this that run flawlessly, this only happens when I deploy it.
UPDATE
So I kept my wrapper and changed #Valid to #Validated and now my error is the following: "NotReadablePropertyException: Bean property 'update.field' does not have a corresponding accessor for Spring data binding"
Fun fact, there is no property called "field"

Java Spring #Valid on a method call [duplicate]

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) { ... }
...
}

Discovering annotated methods

In my Spring application, I have components that use Spring's caching mechanism. Each #Cacheable annotation specifies the cache that is to be used. I'd like to autodiscover all the caches that are needed at startup so that they can be automatically configured.
The simplest approach seemed to create a marker interface (ex: CacheUser) to be used by each caching component:
#Component
public class ComponentA implements CacheUser {
#Cacheable("dictionaryCache")
public String getDefinition(String word) {
...
}
}
I would then have Spring autodiscover all the implementations of this interface and autowire them to a configuration list that can be used when configuring the cache manager(s). This works.
#Autowired
private Optional<List<CacheUser>> cacheUsers;
My plan was to take each discovered class and find all methods annotated with #Cacheable. From there I would access the annotation's properties and obtain the cache name. I'm using AnnotationUtils.findAnnotation() to get the annotation declaration.
That's where the plan falls apart. Spring actually wires proxies instead of the raw component, and the annotations aren't copied over to the proxies' methods. The only workaround I've found exploits the fact that the proxy implements Advised which provides access to the proxied class:
((Advised)proxy).getTargetSource().getTargetClass().getMethods()
From there I can get the original annotations, but this approach is clearly brittle.
So two questions, really:
Is there a better way to get to the annotations defined by the proxied class?
Can you suggest any other way to discover all uses of #Cacheable in my project? I'd love to do without a marker interface.
Thanks!
Spring has a lot of infrastructure interfaces which can help you tap into the lifecycle of the container and/or beans. For your purpose you want to use a BeanPostProcessor and the SmartInitializingSingleton.
The BeanPostProcessor will get a callback for all the beans constructed, you will only need to implement the the postProcessAfterInitialization method. You can in that method detect the annotations and fill a list of caches.
Then in the SmartInitializingSingletons afterSingletonsInstantiated method you use this list to bootstrap/init your caches.
Something like the following (it is untested but should give you an idea).
public class CacheInitialingProcessor implements BeanPostProcessor, SmartInitializingSingleton {
private final Set<String> caches = new HashSet<String>();
#Override
public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
return bean;
}
#Override
public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
Class<?> targetClass = AopUtils.getTargetClass(bean);
ReflectionUtils.doWithMethods(targetClass, new ReflectionUtils.MethodCallback() {
#Override
public void doWith(Method method) throws IllegalArgumentException, IllegalAccessException {
Cacheable cacheable = AnnotationUtils.getAnnotation(method, Cacheable.class);
if (cacheable != null) {
caches.addAll(Arrays.asList(cacheable.cacheNames()));
}
}
});
return bean;
}
#Override
public void afterSingletonsInstantiated() {
for (String cache : caches) {
// inti caches.
}
}
}

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