Using Jakarta Been Validation https://hibernate.org/validator/ to validate Java code, I annotate a Classes property by a default #NotEmpty validation anotaton
#Validate
public class A {
..
#NotEmpty
private List<String> myList;
..
}
In a Test I set myList to an empty List, validate that List and expect the violation "must not be empty", which is the default violation message for the standard #NotEmpty annotation. I found that by printing it, but also here https://github.com/hibernate/hibernate-validator/blob/main/engine/src/main/resources/org/hibernate/validator/ValidationMessages.properties
Set<ConstraintViolation<A>> violations = validator.validate(A);
assertThat(violations).anyMatch(having Message("must not be empty", A.class));
This works, but I would like to replace the expected Message string with a reference to the default-string like jakarta.validation.constraints.Null.message, avoiding duplication of Strings. This however does not work:
assertThat(violations).anyMatch(having Message(jakarta.validation.constraints.Null.message, A.class));
Is there any validation expert around, that can show me what I am missing?
one has to load it from the classpath, if provided by /ValidationMessages.properties (or language specific ValidationMessages_<x>(_<y>).properties):
Properties ps = new Properties() ;
ps.load( getClass().getResourceAsStream("/ValidationMessages.properties") ) ;
assertThat(violations).anyMatch(having Message(
ps.getProperty( "jakarta.validation.constraints.Null.message"),
A.class))
if provided/overridden by direct class annotation, one has to use reflection on the specific classes field or method and get its annotation.
Related
I'm using Jackson's readValue() method on an object mapper to read from a JSON file and convert it into my java object.
eg.
mapperObject.readValue( node, MyTargetClass.class )
Are there any annotations that I can set on MyTargetClass to enforce required attributes? For example, if I have a JSON object with properties ABC,DEF and GHI, and my Json is the following
{
"ABC" : "somevalue"
"DEF" : "someothervalue"
}
I want it to fail somehow, and only succeed on the readValue if it contained ABC, DEF and GHI.
You can mark a property as required with the #JsonProperty(required = true) annotation, and it will throw a JsonMappingException during deserialization if the property is missing or null.
Edit: I received a downvote for this without comment. I'd love to know why, since it does exactly the right thing.
Jackson does not include validation functionality, and this is by design (i.e. that is considered out-of-scope). But what is usually used is Bean Validation API implementation.
The nice thing about this is decoupling between data format handling, and validation logic.
This is what frameworks like DropWizard use; and it's the direction JAX-RS (like Jersey) are taking things for JAX-RS 2.0.
If you want to make sure a json field is provided, you have to use the #JsonProperty(value = "fieldName", required = true) annotation as a parameter to the constructor. But this is not enough, also the Constructor should have #JsonCreator annotation.
For example, if you have a field named 'endPoint' and you want o make sure it is provided in the JSON file, then the following code will throw an exception if it is not provided.
#JsonCreator
public QuerySettings(#JsonProperty(value = "endPoint", required = true) String endPoint) {
this.endPoint = endPoint;
}
I found this link helpful to understand the Jackson annotations. It also well explains why required=true is not enough and counter-intuitive to its name.
If you are neither satisfied with using #JsonProperty(required = true) as it works only with #JsonCreator nor with the use of bean validation then one more way of tackling it would be to catch this in your setter methods for the relevant variables.
You can simply check if the variable is null before setting it and throw an IllegalArgumentException or NullPointerException (as preferred by few people)
Note: It depends on how your POJO is defined too, so please make sure that it is going the setter method route for this solution to work.
In a Java (+ Spring Boot) project, there is a notation using javax.validation as shown below:
#NotEmpty(message = "validation.product.notEmpty")
private String product;
#NotEmpty(message = "validation.username.password")
private String password;
I have a look at the usage of them, but there are some points that I could not understand:
1. Is there a special usage e.g. conditional message displaying for validation.username.password? For example if username field is null, then display this message? Or is it completely the same manner as the product field?
2. I search the project, but could not find validation.product.notEmpty or validation.username.password. So, how do they work? I think there should be a definition for these messages, but as I did not find, is it come from default messages of javax.validation?
What is the difference between #EmailRegex and #Email? And is there
any need to also use #NotEmpty with these #EmailRegex or #Email
annotations?
#Email will not throw error for an empty String. So you need #NotEmpty to be sure that this String is not empty if you always require an email to be there.
#Email will consider valid everything that is in the form blabla#blabla.blabla. If you want to further constraint this you can use #EmailRegex so that you allow only blabla#blabla.eu by defining your own regular expression.
#EmailRegex does not seem to be included in hibernate annotations or spring annotations. So it is either a custom annotation imported from somewhere else or just a custom annotation of your application. Inspect the code to see how it actually behaves but from it's name I suppose it behaves as I have explained above.
I search the project, but could not find validation.product.notEmpty
or validation.username.password. So, how do they work? I think there
should be a definition for these messages, but as I did not find, is
it come from default messages of javax.validation?
It should be with {....} so like #NotEmpty(message = "{validation.username.password}") private String password;. In that case Spring will automatically read properties from the property files and apply the value for the property validation.username.password. If it does not exist then go to either application.properties or application.yaml and add that property.
Some more notes on this last one. I have seen some strange cases in backend-frontend applications which might be your case here.
#NotEmpty(message = "validation.username.password")
The actual message thrown here when the validation fails is validation.username.password. I have seen cases where the frontend then reads that message and binds a value to this one. I have seen this to be used when frontend supports multiple languages and binds another value for each language each time. This would explain why you don't have { } or such a property in your application.
#NotEmpty(message = "{validation.username.password}")
with an existing property validation.username.password= password can not be empty
will have as a result when the validation fails the message password can not be empty to be delivered.
I'm implementing an in-memory API gateway to a SOAP service utilizing JAXB. One of the schema elements is a "choice", and there are several elements in the choice block.
I'm attempting to mirror the generated JAXB classes in the client namespace, so for this "choice" scenario I have a bean class with several properties, only one of which will be non-null.
I'm attempting to use the #NotNull annotation from javax.validation, along with the ValidatorFactory and Validator. However, a "choice" scenario makes this a little more complicated. I'm guessing this would call for a custom ConstraintValidator, along with a custom annotation to refer to the custom ConstraintValidator.
For instance, here's some fake code that resembles a part of my structure:
public class InquireRandomInformationRequest {
#NotNull(message ="subscriberSelector cannot be null")
#Valid
private SubscriberSelector subscriberSelector; // required
private SelectorMode mode; // optional
...
}
public class SubscriberSelector {
// Choice 1
private String billingAccountNumber; // \d{8,9,12,13}; required
private MarketInfo billingMarket; // optional
// Choice 2
private String subscriberNumber; // \d{10}; required
private ValidationCriteria validationCriteria; // optional
private BillingAccountInformation billingAccountInformation; // optional
private MemoProductType memoProductType; // optional
// Choice 3
private String unifiedBillingAccountNumber; // [0-9A-Za-z]{13}; required
...
}
I understand that I need the #Valid annotation on the "subscriberSelector" property for the validator to validate the sub-object. Past that, I'm not quite sure what I need to do to handle the choices problem.
To fit my example, I will need exactly one of "billingAccountNumber", "subscriberNumber", or "unifiedBillingAccountNumber" to be non-null (although I could compromise on simply taking the first non-null one in a particular sequence). In each "choice group", the other properties are optional, but it's possible that another property could be "required" if that particular choice group is selected (the selector property is non-null, in other words).
I've looked through the Hibernate Validator documentation, but I'm not sure exactly how to apply that for this situation.
If I define a custom annotation and a custom ConstraintValidator, where is the annotation referenced? On the class (like "SubscriberSelector") or on the "subscriberSelector" property (the former seems more logical to me).
You can define constraints on the class or on the property depending on your requirements.
Usually, the constraints are placed on the property but, in the case you mention, as multiple properties are concerned and interdependent, you should place the constraint at the class level.
See https://docs.jboss.org/hibernate/stable/validator/reference/en-US/html_single/#section-declaring-bean-constraints in our documentation.
I'm using Jackson's readValue() method on an object mapper to read from a JSON file and convert it into my java object.
eg.
mapperObject.readValue( node, MyTargetClass.class )
Are there any annotations that I can set on MyTargetClass to enforce required attributes? For example, if I have a JSON object with properties ABC,DEF and GHI, and my Json is the following
{
"ABC" : "somevalue"
"DEF" : "someothervalue"
}
I want it to fail somehow, and only succeed on the readValue if it contained ABC, DEF and GHI.
You can mark a property as required with the #JsonProperty(required = true) annotation, and it will throw a JsonMappingException during deserialization if the property is missing or null.
Edit: I received a downvote for this without comment. I'd love to know why, since it does exactly the right thing.
Jackson does not include validation functionality, and this is by design (i.e. that is considered out-of-scope). But what is usually used is Bean Validation API implementation.
The nice thing about this is decoupling between data format handling, and validation logic.
This is what frameworks like DropWizard use; and it's the direction JAX-RS (like Jersey) are taking things for JAX-RS 2.0.
If you want to make sure a json field is provided, you have to use the #JsonProperty(value = "fieldName", required = true) annotation as a parameter to the constructor. But this is not enough, also the Constructor should have #JsonCreator annotation.
For example, if you have a field named 'endPoint' and you want o make sure it is provided in the JSON file, then the following code will throw an exception if it is not provided.
#JsonCreator
public QuerySettings(#JsonProperty(value = "endPoint", required = true) String endPoint) {
this.endPoint = endPoint;
}
I found this link helpful to understand the Jackson annotations. It also well explains why required=true is not enough and counter-intuitive to its name.
If you are neither satisfied with using #JsonProperty(required = true) as it works only with #JsonCreator nor with the use of bean validation then one more way of tackling it would be to catch this in your setter methods for the relevant variables.
You can simply check if the variable is null before setting it and throw an IllegalArgumentException or NullPointerException (as preferred by few people)
Note: It depends on how your POJO is defined too, so please make sure that it is going the setter method route for this solution to work.
Is there a way to use JSR-303 (hibernate) annotations and modify the Message using {0} {1} syntax? It seem that using a Spring Validator gets you this:
String args[] = {"mark", "is", "cool"};
ValidationUtils.rejectIfEmptyOrWhitespace(errors, "aboutYou", "aboutYou.required", args);
So I can change the message. However, if I use annotations, I cannot use the message args. I understand that there are limited (min, max, etc.) args to use, but we want to make a generic statement and add some text.
java:
#NotEmpty (message="validation.name.required")
private String name;
properties
validation.name.required={0} is required...
Output:
Full name is required.
In your interface:
public #interface Test{
int value() default 7;
String message() default "{MESSAGE}";
}
In your messages file:
MESSAGE=Testing param {value}
Output:
Testing param 7
As found here and here, works for validators which do not use hibernate also.
As it seems you're using Spring, this might help: http://blog.inflinx.com/2010/03/10/jsr-303-bean-validation-using-spring-3/
You can also get the annotation-parameters (like min- and max- annotation-values for #Size) from ConstraintViolation< Object> -object (javax.validation.Validator.validate(Object) -method returns a Set< ConstraintViolation< Object>>) with .getConstraintDescriptor.getAttributes(), if you want to parameterize them to the messages with the {0} {1} etc. -notation (the numbers might be something else than 0 and 1 for #Size for example, I don't have the code at hand, but I seem to recall that there was some other data "in between" in the Map that getAttributes returned).
Note that in my case I used programmatic validation (getting Validator-object from Validation.buildDefaultValidatorFactory().getValidator() and using it to validate an object with JSR-303 -annotations), extracted the needed data from the Set of ConstraintViolations (if the Set was not empty), put the data in a custom Exception-class and threw it out of the service, all the way to a org.springframework.web.servlet.HandlerExceptionResolver -implementation, that would gather the localization keys and message parameters from the exception object and localize the messages via MessageSource, so this might not be exactly what you're looking for.