Bean Validation List<?> on static method or getters - java

I have a problem of triggering the custom constraint validation on jersey. I would like to activate the constraint on a method or a static method. What I have tried is putting a custom annotation and #ValidateOnExecution on top of the method, but the custom validator class still was not triggered.
#LocationIsValid
#ValidateOnExecution
public static List<Double> getLocation(String location) {
...
}
I suspected that the problem is bean annotation did not support static method, so I removed the static keyword and accessing the method by creating a new object. However the custom LocationIsValid validator still was not activated.
As a result I ended up placing a validator factory to validate this variable manually.
public static List<Double> getLocation(String location) {
...
// split the location string into a list of double
...
ValidatorFactory factory = Validation.buildDefaultValidatorFactory();
validator = factory.getValidator();
validator.validate(location, LocationIsValid.class);
}
But yet the custom constraints won't budge. I hope that someone can give me a clue on what to do next, or other suggestion on solving this issue.
More Info
It works properly when the annotation is placed on top of the resource field.
public class Product {
...
#LocationIsValid
private List<Double> location;
...
}
Updated
Even I have changed the method to normal instance method, it still doesn't work. Note that I have two overloaded methods, one is the resource getter, the other one is for converting the string to locations.
Product model
public class Product {
#Id
#JsonSerialize(using = ObjectIdSerializer.class)
private ObjectId id;
#Size(min = 5)
private String name;
#NotNull
#LocationIsValid
private List<Double> location;
private Date dateCreated;
private Date dateModified;
public Product() {
}
public List<Double> getLocation() {
return location;
}
#ValidateOnExecution
#LocationIsValid
public List<Double> getLocation(String location) {
String[] locationString = location.split(";");
if (locationString.length != 2) {
return null;
}
List<Double>locations = new ArrayList<Double>();
for (int i = 0; i < locationString.length; i++) {
locations.add(Double.parseDouble(locationString[i]));
}
return locations;
}
// Other setters getters
}
Product resource
#GET
public ProductList getProducts(#QueryParam("near") String location) {
// parse the locations variable
Product product = new Product();
// did not work
// I have placed a breakpoint on the LocationIsValid
List<Double> locations = product.getLocation(location);
}
Note: I am pretty sure the problem is not located in LocationIsValid, as it works correctly when I validated it as an entity #Valid Product product I am using Jersey 2.4.1 with jersey-bean-validation 2.4.1 dependency

As you say validation of static methods is not supported by the Bean Validation specification. The validation of instance methods should work though, can you post the entire code of your JAX-RS resource? Is getLocation() defined on that resource? JAX-RS should trigger the validation of method constraints (be it parameter or return value constraints) on the methods of resource classes.

The problem is I did not actually invoke the validator using #Valid at the Product object in the controller. The reason is I only need to validate the location variable and not the whole Product object. So I guess the only way to solve it is to invoke the validator factory programatically inside the resource function. Note that the reason I did not success validate the property using the validator before is because I never call the correct method. Below is the code that make use of validation factory to validate a specific property in a resource object.
#GET
public ProductList getProducts(#QueryParam("near") String location) {
// parse the locations variable
List<Double> locations = Product.getLocation(location);
// validate the value
Set<ConstraintViolation<Product>> constraints = Validation
.buildDefaultValidatorFactory()
.getValidator()
.validateValue(Product.class, "location", locations, Default.class);
if (locations == null || locations.size() != 2
|| constraints.size() > 0) {
throw new ConstraintViolationException(constraints);
}
}
If someone has better ideas or suggestions to workaround with this issue, please let me know.

Related

Spring REST partial update with #PATCH method

I'm trying to implement a partial update of the Manager entity based in the following:
Entity
public class Manager {
private int id;
private String firstname;
private String lastname;
private String username;
private String password;
// getters and setters omitted
}
SaveManager method in Controller
#RequestMapping(value = "/save", method = RequestMethod.PATCH)
public #ResponseBody void saveManager(#RequestBody Manager manager){
managerService.saveManager(manager);
}
Save object manager in Dao impl.
#Override
public void saveManager(Manager manager) {
sessionFactory.getCurrentSession().saveOrUpdate(manager);
}
When I save the object the username and password has changed correctly but the others values are empty.
So what I need to do is update the username and password and keep all the remaining data.
If you are truly using a PATCH, then you should use RequestMethod.PATCH, not RequestMethod.POST.
Your patch mapping should contain the id with which you can retrieve the Manager object to be patched. Also, it should only include the fields with which you want to change. In your example you are sending the entire entity, so you can't discern the fields that are actually changing (does empty mean leave this field alone or actually change its value to empty).
Perhaps an implementation as such is what you're after?
#RequestMapping(value = "/manager/{id}", method = RequestMethod.PATCH)
public #ResponseBody void saveManager(#PathVariable Long id, #RequestBody Map<Object, Object> fields) {
Manager manager = someServiceToLoadManager(id);
// Map key is field name, v is value
fields.forEach((k, v) -> {
// use reflection to get field k on manager and set it to value v
Field field = ReflectionUtils.findField(Manager.class, k);
field.setAccessible(true);
ReflectionUtils.setField(field, manager, v);
});
managerService.saveManager(manager);
}
Update
I want to provide an update to this post as there is now a project that simplifies the patching process.
The artifact is
<dependency>
<groupId>com.github.java-json-tools</groupId>
<artifactId>json-patch</artifactId>
<version>1.13</version>
</dependency>
The implementation to patch the Manager object in the OP would look like this:
Controller
#Operation(summary = "Patch a Manager")
#PatchMapping("/{managerId}")
public Task patchManager(#PathVariable Long managerId, #RequestBody JsonPatch jsonPatch)
throws JsonPatchException, JsonProcessingException {
return managerService.patch(managerId, jsonPatch);
}
Service
public Manager patch(Long managerId, JsonPatch jsonPatch) throws JsonPatchException, JsonProcessingException {
Manager manager = managerRepository.findById(managerId).orElseThrow(EntityNotFoundException::new);
JsonNode patched = jsonPatch.apply(objectMapper.convertValue(manager, JsonNode.class));
return managerRepository.save(objectMapper.treeToValue(patched, Manager.class));
}
The patch request follows the specifications in RFC 6092, so this is a true PATCH implementation. Details can be found here
With this, you can patch your changes
1. Autowire `ObjectMapper` in controller;
2. #PatchMapping("/manager/{id}")
ResponseEntity<?> saveManager(#RequestBody Map<String, String> manager) {
Manager toBePatchedManager = objectMapper.convertValue(manager, Manager.class);
managerService.patch(toBePatchedManager);
}
3. Create new method `patch` in `ManagerService`
4. Autowire `NullAwareBeanUtilsBean` in `ManagerService`
5. public void patch(Manager toBePatched) {
Optional<Manager> optionalManager = managerRepository.findOne(toBePatched.getId());
if (optionalManager.isPresent()) {
Manager fromDb = optionalManager.get();
// bean utils will copy non null values from toBePatched to fromDb manager.
beanUtils.copyProperties(fromDb, toBePatched);
updateManager(fromDb);
}
}
You will have to extend BeanUtilsBean to implement copying of non null values behaviour.
public class NullAwareBeanUtilsBean extends BeanUtilsBean {
#Override
public void copyProperty(Object dest, String name, Object value)
throws IllegalAccessException, InvocationTargetException {
if (value == null)
return;
super.copyProperty(dest, name, value);
}
}
and finally, mark NullAwareBeanUtilsBean as #Component
or
register NullAwareBeanUtilsBean as bean
#Bean
public NullAwareBeanUtilsBean nullAwareBeanUtilsBean() {
return new NullAwareBeanUtilsBean();
}
First, you need to know if you are doing an insert or an update. Insert is straightforward. On update, use get() to retrieve the entity. Then update whatever fields. At the end of the transaction, Hibernate will flush the changes and commit.
You can write custom update query which updates only particular fields:
#Override
public void saveManager(Manager manager) {
Query query = sessionFactory.getCurrentSession().createQuery("update Manager set username = :username, password = :password where id = :id");
query.setParameter("username", manager.getUsername());
query.setParameter("password", manager.getPassword());
query.setParameter("id", manager.getId());
query.executeUpdate();
}
ObjectMapper.updateValue provides all you need to partially map your entity with values from dto.
As an addition, you can use either of two here: Map<String, Object> fields or String json, so your service method may look like this:
#Autowired
private ObjectMapper objectMapper;
#Override
#Transactional
public Foo save(long id, Map<String, Object> fields) throws JsonMappingException {
Foo foo = fooRepository.findById(id)
.orElseThrow(() -> new ResourceNotFoundException("Foo not found for this id: " + id));
return objectMapper.updateValue(foo , fields);
}
As a second solution and addition to Lane Maxwell's answer you could use Reflection to map only properties that exist in a Map of values that was sent, so your service method may look like this:
#Override
#Transactional
public Foo save(long id, Map<String, Object> fields) {
Foo foo = fooRepository.findById(id)
.orElseThrow(() -> new ResourceNotFoundException("Foo not found for this id: " + id));
fields.keySet()
.forEach(k -> {
Method method = ReflectionUtils.findMethod(LocationProduct.class, "set" + StringUtils.capitalize(k));
if (method != null) {
ReflectionUtils.invokeMethod(method, foo, fields.get(k));
}
});
return foo;
}
Second solution allows you to insert some additional business logic into mapping process, might be conversions or calculations ect.
Also unlike finding reflection field Field field = ReflectionUtils.findField(Foo.class, k); by name and than making it accessible, finding property's setter actually calls setter method that might contain additional logic to be executed and prevents from setting value to private properties.

Validation of one attribute with Hibernate validator

Good evening, I'm trying to use Hibernate Validator, in the following scenario:
public class Car {
#NotNull
private String manufacturer;
#NotNull
#Size(min = 2, max = 14)
private String licensePlate;
#Min(2)
private int seatCount;
//setters and getters....
}
and I am trying to validate its attributes as follows:
public class CarMain {
public static Validator validator;
public static void main(String[] args) {
ValidatorFactory factory = Validation. buildDefaultValidatorFactory() ;
validator = factory. getValidator();
Car car = new Car(null,null,0);
Set<ConstraintViolation<Car>> st= validator.validate(car);
while(st.iterator.hasNext()){
ConstraintViolation<Car> cv = st.iterator.next();
System.out.println("Value: ("+cv.getInvalidValue()+") -->"+cv.getMessage());
System.out.println("Attribute: "+cv.getPropertyPath());
}
}
Here the whole entity is validated and the invalid values with the validation message and property path are displayed.
My question is:"Is it possible to validate only one attribute at a time with Hibernate Validator? Like I don't have to work with the whole object to validate it.
The Validator interface defines also a [Validator.validateProperty][1] method where you explicitly specify the property to validate. Mind you, you still need the object instance and you need to know the property you want to validate. This method is for example used by the integration of Bean Validation into JSF. Whether it makes sense to use it inm your case, will depend on your use case? Why don't you want to validate the whole object?
BTW, there is also Validator.validateValue which does not require an actual bean instance.

How to implement Jackson custom serialization outside a domain bean?

I have a Spring managed bean...
#Component("Foobean")
#Scope("prototype")
public class foobean {
private String bar1;
private String bar2;
public String getBar1() {
return bar1;
}
public void setBar1(String bar1) {
this.bar1 = bar1;
}
public String getBar2() {
return bar2;
}
public void setBar2(String bar2) {
this.bar2 = bar2;
}
}
...and because I am using Dojo Dgrid to display an ArrayList of this bean, I am returning it into the controller as a JSON string:
#Controller
#RequestMapping("/bo")
public class FooController {
#Autowired
private FooService fooService
#RequestMapping("action=getListOfFoos*")
#ResponseBody
public String clickDisplayFoos(
Map<String, Object> model) {
List<Foobean> foobeans = fooService.getFoobeans();
ObjectMapper objMapper = new ObjectMapper();
String FooJson = null;
try {
FooJson = objMapper.writeValueAsString(foobeans);
} catch (JsonGenerationException e) {
etc.
}
However, my grid needs an additional column which will contain a valid action for each Foo; that action is not really dependent on any data in individual Foos -- they'll all have the same valid action -- repeated on each line of the resulting DGrid -- but that value is actually dependent upon security roles on the session...which can't be sent to the front end in a Json. So, my solution is twofold:
First I need to add a "virtual" Json property to the bean... which I can do in the bean with #JsonProperty on a method...
#JsonProperty("validActions")
public String writeValidActions {
return "placeHolderForSerializerToChange";
}
...but it just generates a placeholder. To really generate a valid value,
I need to reference the security role of the session,
which I am very reluctant to code in the above method. (A service call in
the domain bean itself? Seems very wrong.) I
think I should create a custom serializer and put the logic -- and the reference
to the Session.Security role in there. Are my instincts right, not to
inject session info into a domain bean method? And if so, what would such a
custom serializer look like?
Yes, I wouldn't put Session Info in to the domain or access session directly in my domain.
Unless there is a specific reason, you could simply add the logic in your action class.
public String clickDisplayFoos(){
List<Foo> foos = service.getFoos();
for(iterate through foos){
foo.setValidAction(session.hasSecurityRole())
}
String json = objMapper.writeValueAsString(foobeans);
return json;
}
I don't like the idea of setting new values as part of the serialization process. I feel custom serializers are meant to transform the representation of a particular property rather than add new values to a property.

How can I programmatically call the same validator that runs on a #RequestMethod method with a #Valid parameter in Spring?

I have a class with hibernate's validation annotation on some fields (such as #NotNull and #Size(min = 4, max = 50), etc...)
public class MyClass {
Long id;
#NotEmpty
#Size(min = 4, max = 50)
String machineName;
#NotEmpty
#Size(min = 4, max = 50)
String humanName;
// Getters, setters, etc…
}
I also have a custom controller that acts as a JSON API, and a JSON deserializer that creates MyClass objects when API methods are called. In my custom controller I have a method to create a new object of that type:
#RequestMapping(method = RequestMethod.POST)
public long createMyObject(#RequestBody #Valid MyClass newObj) {
// Create the object in the database
return newObj.getId();
}
and another method that updates an existing object
#RequestMapping(method = RequestMethod.PUT)
public void updateMyObject(#RequestBody MyClass updatedObj) {
MyClass existingObj = // Get existing obj from DB by updatedObj.getId();
// Do some secondary validation, such as making sure that a specific
// field remains unchanged compared to the existing instance
if (existingObj.getMachineName() != null &&
!existingObj.getMachineName().equals(updatedObj.getMachineName())) {
throw new CannotChangeMachineNameException();
}
else {
updatedObj.setMachineName(existingObj.getMachineName());
}
// [HERE IS WHERE I WANT THE MAGIC TO HAPPEN]
// Save updatedObj to the database
}
While I can use #Valid in createMyObject, I cannot use it in updateMyObject because our API implementation requires that machineName remains unchanged - users can call the API with a JSON object that either excludes machineName entirely or populate it with the same value that exists in the database.*
Before saving the updated object to the database I want to call the same validator that having the #Valid annotation would cause to be called. How can I find this validator and use it?
Nothing says you need to use #Valid in your controller methods only. Why not make a validation method that accepts a parameter you annotate as #Valid, then just return that same parameter.
Like this:
public Book validateBook(#Valid Book book) {
return book;
}
Looks like an alternative would be to use Hibernate's validation package. Here's it's documentation.
Basically, you get a Validator from a ValidationFactory, and then use the validator like this:
#Test
public void manufacturerIsNull() {
Car car = new Car(null, "DD-AB-123", 4);
Set<ConstraintViolation<Car>> constraintViolations =
validator.validate(car);
assertEquals(1, constraintViolations.size());
assertEquals("may not be null", constraintViolations.iterator().next().getMessage());
}

Generating a error code per property in Hibernate Validator

I am looking at using Hibernate Validator for a requirement of mine. I want to validate a JavaBean where properties may have multiple validation checks. For example:
class MyValidationBean
{
#NotNull
#Length( min = 5, max = 10 )
private String myProperty;
}
But if this property fails validation I want a specific error code to be associated with the ConstraintViolation, regardless of whether it failed because of #Required or #Length, although I would like to preserve the error message.
class MyValidationBean
{
#NotNull
#Length( min = 5, max = 10 )
#ErrorCode( "1234" )
private String myProperty;
}
Something like the above would be good but it doesn't have to be structured exactly like that. I can't see a way to do this with Hibernate Validator. Is it possible?
You could create a custom annotation to get the behaviour you are looking for and then on validating and using refelection you could extract the value of the annotation. Something like the following:
#Target({ElementType.FIELD})
#Retention(RetentionPolicy.RUNTIME)
public #interface ErrorCode {
String value();
}
In your bean:
#NotNull
#Length( min = 5, max = 10 )
#ErrorCode("1234")
public String myProperty;
On validating your bean:
Set<ConstraintViolation<MyValidationBean>> constraintViolations = validator.validate(myValidationBean);
for (ConstraintViolation<MyValidationBean>cv: constraintViolations) {
ErrorCode errorCode = cv.getRootBeanClass().getField(cv.getPropertyPath().toString()).getAnnotation(ErrorCode.class);
System.out.println("ErrorCode:" + errorCode.value());
}
Having said that I probably would question the requirements for wanting error codes for these types of messages.
From the section 4.2. ConstraintViolation of the specification:
The getMessageTemplate method returns the non-interpolated error message (usually the message attribute on the constraint declaration). Frameworks can use this as an error code key.
I think this is your best option.
What I would try to do is isolate this behavior on the DAO Layer of the application.
Using your example we would have:
public class MyValidationBeanDAO {
public void persist(MyValidationBean element) throws DAOException{
Set<ConstraintViolation> constraintViolations = validator.validate(element);
if(!constraintViolations.isEmpty()){
throw new DAOException("1234", contraintViolations);
}
// it's ok, just persist it
session.saveOrUpdate(element);
}
}
And the following exception class:
public class DAOException extends Exception {
private final String errorCode;
private final Set<ConstraintViolation> constraintViolations;
public DAOException(String errorCode, Set<ConstraintViolation> constraintViolations){
super(String.format("Errorcode %s", errorCode));
this.errorCode = errorCode;
this.constraintViolations = constraintViolations;
}
// getters for properties here
}
You could add some annotation information based on what property has not validated from here, but always doing this on the DAO method.
I hope this helped.

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