Java Request Date Validation: For any class with two variable parameters

Java Request Date Validation: For any class with two variable parameters - java

I am creating a shared component for Request Date constraints, Begin Date is before End Date.
I want to take my current Validation request, and make it common, so I type in the (Begin and EndDate class members for any Class), and it will work. How can this be done? I use annotations above the request class, in ProductRequest below .
Note: How do I set Start and End date parameters in the annotation; they may not always be "Start/End" field members, sometimes they could be "Begin/Finish" in another class .
#DatesRequestConstraint
public class ProductRequest {
private Long productId;
private DateTime startDate;
private DateTime EndDate;
private List<String> productStatus;
}
#Target({ TYPE, ANNOTATION_TYPE })
#Retention(RUNTIME)
#Constraint(validatedBy = ProductValidator.class)
#Documented
public #interface DatesRequestConstraint {
String message() default "Invalid dates request.";
Class <?> [] groups() default {};
Class <? extends Payload> [] payload() default {};
}
public class ProductValidator implements ConstraintValidator<DatesRequestConstraint, ProductRequest> {
#Override
public void initialize(DatesRequestConstraint constraintAnnotation) {
ConstraintValidator.super.initialize(constraintAnnotation);
}
#Override
public boolean isValid(ProductRequest productRequest, ConstraintValidatorContext constraintValidatorContext) {
if (productRequest.getStartDate() != null &&
productRequest.getEndDate() != null &&
productRequest.getStartDate().isAfter(productRequest.getEndDate())) {
return false;
}
else return true;
}

You can:
Implement ConstraintValidator<DatesMatch, Object> so that you can apply the #DatesMatch annotation on any type;
Add custom String fields to the #DatesMatch annotation where you can specify the names of the fields you want to validate;
Use reflection at runtime to access the field values by their specified name.
There's a similar example of class-level validation over multiple custom fields here: Baeldung: Spring MVC Custom Validation (scroll down to "9. Custom Class Level Validation").
Customized to your example, something like this should work:
#Constraint(validatedBy = DatesMatchValidator.class)
#Target({ElementType.TYPE})
#Retention(RetentionPolicy.RUNTIME)
public #interface DatesMatch {
String message() default "The dates don't match.";
String startField();
String endField();
Class<?>[] groups() default {};
Class<? extends Payload>[] payload() default {};
#Target({ElementType.TYPE})
#Retention(RetentionPolicy.RUNTIME)
#interface List {
DatesMatch[] value();
}
}
// Accept a list of items so that you can validate more than one pair of dates on the same object if needed
#DatesMatch.List({
#DatesMatch(
startField = "startDate",
endField = "endDate",
message = "The end date must be after the start date."
)
})
public class ProductRequest {
private Long productId;
private Instant startDate;
private Instant endDate;
private List<String> productStatus;
/* Getters and setters omitted */
}
public class DatesMatchValidator implements ConstraintValidator<DatesMatch, Object> {
private String startField;
private String endField;
public void initialize(DatesMatch constraintAnnotation) {
this.startField = constraintAnnotation.startField();
this.endField = constraintAnnotation.endField();
}
public boolean isValid(Object value, ConstraintValidatorContext context) {
Instant startFieldValue = (Instant) new BeanWrapperImpl(value)
.getPropertyValue(startField);
Instant endFieldValue = (Instant) new BeanWrapperImpl(value)
.getPropertyValue(endField);
if (startFieldValue == null || endFieldValue == null) {
return true;
}
return endFieldValue.isAfter(startFieldValue);
}
}
Update: (in response to comment):
this answer is great, allows multiple pair of dates, however isn't type-string safe, person can type in whatever for the fields in the product fields
Implementing ConstraintValidator<DatesMatch, Object> is meant as an easy catch-all solution you can apply to any class.
But you can absolutely do it in a more type-safe way by implementing a separate ConstraintValidator for each type you want to validate (i.e. ConstraintValidator<DatesMatch, ProductRequest>, ConstraintValidator<DatesMatch, AnotherRequest>, ...) and then specify all of them in the #Constraint(validatedBy={...}) attribute:
#Constraint(validatedBy = {ProductRequestDatesMatchValidator.class, AnotherRequestDatesMatchValidator.class})
#Target({ElementType.TYPE})
#Retention(RetentionPolicy.RUNTIME)
public #interface DatesMatch {
String message() default "Invalid dates request.";
Class<?>[] groups() default {};
Class<? extends Payload>[] payload() default {};
}
#DatesMatch(message = "Start and end dates do not match!")
public class ProductRequest {
private Long productId;
private Instant startDate;
private Instant endDate;
private List<String> productStatus;
/* Getters and setters omitted */
}
#DatesMatch(message = "Begin and finish dates do not match!")
public class AnotherRequest {
private Long productId;
private Instant beginDate;
private Instant finishDate;
private List<String> productStatus;
/* Getters and setters omitted */
}
public class ProductRequestDatesMatchValidator implements ConstraintValidator<DatesMatch, ProductRequest> {
#Override
public boolean isValid(ProductRequest value, ConstraintValidatorContext context) {
// No need to cast here
Instant startDate = value.getStartDate();
Instant endDate = value.getEndDate();
// You could reuse this logic between each implementation by putting it in a parent class or a utility method
if (startDate == null || endDate == null) {
return true;
}
return startDate.isBefore(endDate);
}
}
public class AnotherRequestDatesMatchValidator implements ConstraintValidator<DatesMatch, AnotherRequest> {
#Override
public boolean isValid(AnotherRequest value, ConstraintValidatorContext context) {
Instant beginDate = value.getBeginDate();
Instant finishDate = value.getFinishDate();
if (beginDate == null || finishDate == null) {
return true;
}
return beginDate.isBefore(finishDate);
}
}
Do note, however, that this is still not compile-time type-safe, as you could put the #DatesMatch annotation on a class for which you haven't written an implementation and the validation will only fail at runtime.
(You could achieve compile-time type-safety using annotation processing, but this another topic for another time.)

You can annotate startDate and endDate with custom annotations something like:
#StartDateField
private DateTime startDate;
#EndDateField
private DateTime endDate;
Then in your isValid(), you can access both startDate and endDate fields by their annotations by iterating over all class fields (in your case, all ProductRequest fields) and checking the following:
field.isAnnotationPresent(StartDateField.class)
field.isAnnotationPresent(EndDateField.class)
The complete code could be as follows:
import javax.validation.Constraint;
import javax.validation.ConstraintValidator;
import javax.validation.ConstraintValidatorContext;
import javax.validation.Payload;
import java.lang.annotation.*;
import java.util.Arrays;
import java.util.List;
import static java.lang.annotation.ElementType.ANNOTATION_TYPE;
import static java.lang.annotation.RetentionPolicy.RUNTIME;
#Target({ ANNOTATION_TYPE.TYPE })
#Retention(RUNTIME)
#Constraint(validatedBy = ProductValidator.class)
#Documented
#interface DatesRequestConstraint {
String message() default "Invalid dates request.";
Class <?> [] groups() default {};
Class <? extends Payload> [] payload() default {};
}
#DatesRequestConstraint
class ProductRequest {
private Long productId;
#StartDateField
private DateTime startDate;
#EndDateField
private DateTime EndDate;
private List<String> productStatus;
}
#Target({ ElementType.FIELD })
#Retention(RUNTIME)
#Documented
#interface StartDateField {
}
#Target({ ElementType.FIELD })
#Retention(RUNTIME)
#Documented
#interface EndDateField {
}
public class ProductValidator implements ConstraintValidator<DatesRequestConstraint, Object> {
#Override
public void initialize(DatesRequestConstraint constraintAnnotation) {
ConstraintValidator.super.initialize(constraintAnnotation);
}
#Override
public boolean isValid(Object requestObject, ConstraintValidatorContext constraintValidatorContext) {
DateTime startDate = getDateFieldByAnnotation(requestObject, StartDateField.class);
DateTime endDate = getDateFieldByAnnotation(requestObject, EndDateField.class);
if (startDate != null &&
endDate != null &&
startDate.isAfter(endDate)) {
return false;
} else return true;
}
private DateTime getDateFieldByAnnotation(Object requestObject, Class<? extends Annotation> annotationClass) {
return Arrays.stream(requestObject.getClass().getDeclaredFields()).filter(field -> field.isAnnotationPresent(annotationClass)).map(field -> {
try {
return field.get(requestObject);
} catch (IllegalAccessException e) {
e.printStackTrace();
}
return null;
}).map(DateTime.class::cast).findAny().orElse(null);
}
}

Related

spring boot validation - at least one of cross fields

I have some trouble using cross field validation in Spring Boot. For example there is a class with four fields. The first field is mandatory, all others are optional, but at least one of optional fields must exist.
public class DataContainer {
#NotNull
private String provider;
#Valid
private List<Client> clients;
#Valid
private List<Item> items;
#Valid
private List<Order> orders;
// Getter and setter omitted for simplicity
}
Now I'm looking for a dynamic solution because I need to extend the class easily. How can I do it?

Using Ishikawa Yoshi's hint, I found the solution myself. Here is my implementation for all who are interested.
First I created a new annotation
#Target({ElementType.TYPE, ElementType.ANNOTATION_TYPE})
#Retention(RetentionPolicy.RUNTIME)
#Constraint(validatedBy = {AtLeastOneOfValidator.class})
public #interface AtLeastOneOf {
String message() default "{one.of.message}";
Class<?>[] groups() default {};
Class<? extends Payload>[] payload() default {};
String[] fields();
int max() default 2147483647;
}
And then the related validator
public class AtLeastOneOfValidator implements ConstraintValidator<AtLeastOneOf, Object> {
private String[] fields;
private int max;
#Override
public void initialize(AtLeastOneOf annotation) {
this.fields = annotation.fields();
this.max = annotation.max();
}
#Override
public boolean isValid(Object value, ConstraintValidatorContext context) {
BeanWrapper wrapper = PropertyAccessorFactory.forBeanPropertyAccess(value);
int matches = countNumberOfMatches(wrapper);
if (matches > this.max) {
setValidationErrorMessage(context, "one.of.too.many.matches.message");
return false;
} else if (matches == 0) {
setValidationErrorMessage(context, "one.of.no.matches.message");
return false;
}
return true;
}
private int countNumberOfMatches(BeanWrapper wrapper) {
int matches = 0;
for (String field : this.fields) {
Object value = wrapper.getPropertyValue(field);
boolean isPresent = detectOptionalValue(value);
if (value != null && isPresent) {
matches++;
}
}
return matches;
}
#SuppressWarnings("rawtypes")
private boolean detectOptionalValue(Object value) {
if (value instanceof Optional) {
return ((Optional) value).isPresent();
}
return true;
}
private void setValidationErrorMessage(ConstraintValidatorContext context, String template) {
context.disableDefaultConstraintViolation();
context.buildConstraintViolationWithTemplate("{" + template + "}").addConstraintViolation();
}
}
Now the annotation can be used
#AtLeastOneOf(fields = {"clients", "items", "orders"})
public class DataContainer {
#NotNull
private String provider;
#Valid
private List<Client> clients;
#Valid
private List<Item> items;
#Valid
private List<Order> orders;
// Getter and setter omitted for simplicity
}

javax validation greater or less than from other property

with respect to javax.validation
#NotNull(message = "From can't be null")
#Min(value = 1, message = "From must be greater than zero")
private Long from;
#NotNull(message = "To can't be null")
#Min(value = 1, message = "To must be greater than zero")
private Long to;
I want to also validate that FROM should be less than TO and TO should be greater than FROM ? how we can do this using javax validation's annotation ?

You need a custom cross field validation annotation.
One way is to annotate your custom class with #YourCustomAnnotation.
In YourCustomAnnotationValidator you have access to your value, hence you can implement your logic there:
#Retention(RetentionPolicy.RUNTIME)
#Target(ElementType.TYPE)
#Constraint(validatedBy = DateValidator.class)
public #interface RangeCheck {
String message();
Class<?>[] groups() default {};
Class<? extends Payload>[] payload() default {};
}
public class RangeCheckValidtor implements ConstraintValidator<RangeCheck, YourDto> {
#Override
public void initialize(RangeCheck date) {
// Nothing here
}
#Override
public boolean isValid(YourDto dto, ConstraintValidatorContext constraintValidatorContext) {
if (dto.getFrom() == null || dto.getTo() == null) {
return true;
}
return from < to;
}
}
Then mark your YourDto class with #RangeCheck:
#RangeCheck(message = "your messgae")
public class YourDto {
// from
// to
}
Or simply manually validate the relation of two fields.

Best practice for using date parameters in Spring controllers?

After written several backend APIs, I found that the following code duplicates in almost every method which needs to filter data by dates:
#GetMapping(value="/api/test")
#ResponseBody
public Result test(#RequestParam(value = "since", required = false) #DateTimeFormat(iso = DateTimeFormat.ISO.DATE) LocalDate since,
#RequestParam(value = "until", required = false) #DateTimeFormat(iso = DateTimeFormat.ISO.DATE) LocalDate until) {
// Date validation code I want to eliminate
since = ObjectUtils.defaultIfNull(since, DEFAULT_SINCE_DATE);
until = ObjectUtils.defaultIfNull(until, LocalDate.now().plusDays(1));
if(since.isAfter(until)) {
throw new SinceDateAfterUntilDateException();
}
// Do stuff
}
Obviously this is some kind of code smell. But, since I do need to validate since and until before using them to query the service/DAO, I am not sure where should I extract these code to?
Any advice?

Implement org.springframework.core.convert.converter.Converter; interface.
Register with spring conversion service.
Use in you controller
Sharing sample code below :
public class MyCustomDateTypeConverter implements Converter<String, LocalDate> {
#Override
public LocalDate convert(String param) {
//convert string to DateTime
return dateTiemObjectCreatedfromParam;
}
}
<bean id="conversionService" class="org.springframework.context.support.ConversionServiceFactoryBean"> <property name="converters"> <list>
<bean class="com.x.y.z.web.converters.MyCustomDateTypeConverter"/> </list> </property>
</bean>
<mvc:annotation-driven conversion-service="conversionService">
</mvc:annotation-driven>
public Result test(LocalDate since,LocalDate until) {
since = ObjectUtils.defaultIfNull(since, DEFAULT_SINCE_DATE);
until = ObjectUtils.defaultIfNull(until, LocalDate.now().plusDays(1));
if(since.isAfter(until)) {
throw new SinceDateAfterUntilDateException();
}
// Do stuff
}

As ol' gud-procedural approach suggests:
public Result test(#RequestParam(value = "since", required = false) #DateTimeFormat(iso = DateTimeFormat.ISO.DATE) LocalDate since,
#RequestParam(value = "until", required = false) #DateTimeFormat(iso = DateTimeFormat.ISO.DATE) LocalDate until) {
checkInputDates();
// Do stuff
}
private checkInputDates(LocalDate since, LocalDate until) {
since = ObjectUtils.defaultIfNull(since, DEFAULT_SINCE_DATE);
until = ObjectUtils.defaultIfNull(until, LocalDate.now().plusDays(1));
if(since.isAfter(until)) {
throw new SinceDateAfterUntilDateException();
}
}
//so on..

If you have request params received from object then you can do it by using Bean level Validation(JSR 303) and custom Date Deserializer by extending Jackson serializers. This way you dont have check the params for null.
public class yourBeanName{
public LocalDate since;
public LocalDate until;
#JsonDeserialize(using = CustomDateDeserializer.class)
public void setSince(LocalDate since) {
this.since = since;
}
// same for until
}
// Custom jackson Desealizer
#Component
public class CustomDateDeserializer extends StdDeserializer<Date> {
#Override
public Date deserialize(JsonParser jsonparser, DeserializationContext
context)
throws IOException, JsonProcessingException {
// Here check the date for null and assign default with your dateTimeFormat
}
}

I would suggest a model type holding the parameters since and until with a custom bean validation (using Lombok but you can also write getters and setters). The defaults are now field initializers:
#Ordered({"since", "until"})
#Data
public class DateRange {
#NotNull
#PastOrPresent
private LocalDate since = DEFAULT_SINCE_DATE;
#NotNull
private LocalDate until = LocalDate.now().plusDays(1);
}
#GetMapping(value="/api/test")
#ResponseBody
public Result test(#Valid DateRange dateFilter) {
// Do stuff
}
To make the validation work, you need a custom bean validation constraint:
#Target(ElementType.TYPE)
#Retention(RetentionPolicy.RUNTIME)
#Documented
#Constraint(validatedBy = OrderedValidator.class)
public #interface Ordered {
/** The property names with comparable values in the expected order. **/
String[] value();
String message() default "{com.stackoverflow.validation.Ordered.message}";
Class<?>[] groups() default {};
Class<? extends Payload>[] payload() default {};
}
And the validator to check the constraint (sorry, litte generics hell to make it work for any kind of Comparable values instead of LocaleDate only):
public class OrderedValidator implements ConstraintValidator<Ordered, Object>
{
private String[] properties;
#Override
public void initialize(Ordered constraintAnnotation) {
if (constraintAnnotation.value().length < 2) {
throw new IllegalArgumentException("at least two properties needed to define an order");
}
properties = constraintAnnotation.value();
}
#Override
public boolean isValid(Object value, ConstraintValidatorContext context) {
return isValid(value));
}
private <T extends Comparable<? super T>> boolean isValid(Object value)
{
List<T> values = getProperties(value);
return isSorted(values);
}
private <T extends Comparable<? super T>> List<T> getProperties(Object value)
{
BeanWrapperImpl bean = new BeanWrapperImpl(value);
return Stream.of(properties)
.map(bean::getPropertyDescriptor)
.map(pd -> this.<T>getProperty(pd, value))
.filter(Objects::nonNull)
.collect(Collectors.toList());
}
// See https://stackoverflow.com/a/3047160/12890
private <T extends Comparable<? super T>> boolean isSorted(Iterable<T> iterable) {
Iterator<T> iter = iterable.iterator();
if (!iter.hasNext()) {
return true;
}
T t = iter.next();
while (iter.hasNext()) {
T t2 = iter.next();
if (t.compareTo(t2) > 0) {
return false;
}
t = t2;
}
return true;
}
#SuppressWarnings("unchecked")
private <T extends Comparable<? super T>> T getProperty(PropertyDescriptor prop, Object bean) {
try {
return prop.getReadMethod() == null ? null : (T)prop.getReadMethod().invoke(bean);
} catch (ReflectiveOperationException noAccess) {
return null;
}
}
}

Bean validation based on another field value using hibernate validator and javax.validation [duplicate]

Is there an implementation of (or third-party implementation for) cross field validation in Hibernate Validator 4.x? If not, what is the cleanest way to implement a cross field validator?
As an example, how can you use the API to validate two bean properties are equal (such as validating a password field matches the password verify field).
In annotations, I'd expect something like:
public class MyBean {
#Size(min=6, max=50)
private String pass;
#Equals(property="pass")
private String passVerify;
}

Each field constraint should be handled by a distinct validator annotation, or in other words it's not suggested practice to have one field's validation annotation checking against other fields; cross-field validation should be done at the class level. Additionally, the JSR-303 Section 2.2 preferred way to express multiple validations of the same type is via a list of annotations. This allows the error message to be specified per match.
For example, validating a common form:
#FieldMatch.List({
#FieldMatch(first = "password", second = "confirmPassword", message = "The password fields must match"),
#FieldMatch(first = "email", second = "confirmEmail", message = "The email fields must match")
})
public class UserRegistrationForm {
#NotNull
#Size(min=8, max=25)
private String password;
#NotNull
#Size(min=8, max=25)
private String confirmPassword;
#NotNull
#Email
private String email;
#NotNull
#Email
private String confirmEmail;
}
The Annotation:
package constraints;
import constraints.impl.FieldMatchValidator;
import javax.validation.Constraint;
import javax.validation.Payload;
import java.lang.annotation.Documented;
import static java.lang.annotation.ElementType.ANNOTATION_TYPE;
import static java.lang.annotation.ElementType.TYPE;
import java.lang.annotation.Retention;
import static java.lang.annotation.RetentionPolicy.RUNTIME;
import java.lang.annotation.Target;
/**
* Validation annotation to validate that 2 fields have the same value.
* An array of fields and their matching confirmation fields can be supplied.
*
* Example, compare 1 pair of fields:
* #FieldMatch(first = "password", second = "confirmPassword", message = "The password fields must match")
*
* Example, compare more than 1 pair of fields:
* #FieldMatch.List({
* #FieldMatch(first = "password", second = "confirmPassword", message = "The password fields must match"),
* #FieldMatch(first = "email", second = "confirmEmail", message = "The email fields must match")})
*/
#Target({TYPE, ANNOTATION_TYPE})
#Retention(RUNTIME)
#Constraint(validatedBy = FieldMatchValidator.class)
#Documented
public #interface FieldMatch
{
String message() default "{constraints.fieldmatch}";
Class<?>[] groups() default {};
Class<? extends Payload>[] payload() default {};
/**
* #return The first field
*/
String first();
/**
* #return The second field
*/
String second();
/**
* Defines several <code>#FieldMatch</code> annotations on the same element
*
* #see FieldMatch
*/
#Target({TYPE, ANNOTATION_TYPE})
#Retention(RUNTIME)
#Documented
#interface List
{
FieldMatch[] value();
}
}
The Validator:
package constraints.impl;
import constraints.FieldMatch;
import org.apache.commons.beanutils.BeanUtils;
import javax.validation.ConstraintValidator;
import javax.validation.ConstraintValidatorContext;
public class FieldMatchValidator implements ConstraintValidator<FieldMatch, Object>
{
private String firstFieldName;
private String secondFieldName;
#Override
public void initialize(final FieldMatch constraintAnnotation)
{
firstFieldName = constraintAnnotation.first();
secondFieldName = constraintAnnotation.second();
}
#Override
public boolean isValid(final Object value, final ConstraintValidatorContext context)
{
try
{
final Object firstObj = BeanUtils.getProperty(value, firstFieldName);
final Object secondObj = BeanUtils.getProperty(value, secondFieldName);
return firstObj == null && secondObj == null || firstObj != null && firstObj.equals(secondObj);
}
catch (final Exception ignore)
{
// ignore
}
return true;
}
}

I suggest you another possible solution. Perhaps less elegant, but easier!
public class MyBean {
#Size(min=6, max=50)
private String pass;
private String passVerify;
#NotNull
private LocalDate passExpiry;
#NotNull
private LocalDate dateOfJoining;
#AssertTrue(message = "Fields `pass` and `passVerify` should be equal")
// Any method name is ok als long it begins with `is`
private boolean isValidPass() {
//return pass == null && passVerify == null || pass.equals(passVerify);
// Since Java 7:
return Objects.equals(pass, passVerify);
}
#AssertTrue(message = "Field `passExpiry` should be later than `dateOfJoining`")
// Other rules can also be validated in other methods
private boolean isPassExpiryAfterDateOfJoining() {
return dateOfJoining.isBefore(passExpiry);
}
}
The isValid() and isPassExpiryAfterDateOfJoining() methods are invoked automatically by the validator. The property paths reported in the ConstraintViolations will be extracted from the method names: valid and passExpiryAfterDateOfJoining.

I'm surprised this isn't available out of the box. Anyway, here is a possible solution.
I've created a class level validator, not the field level as described in the original question.
Here is the annotation code:
package com.moa.podium.util.constraints;
import static java.lang.annotation.ElementType.*;
import static java.lang.annotation.RetentionPolicy.*;
import java.lang.annotation.Documented;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;
import javax.validation.Constraint;
import javax.validation.Payload;
#Target({TYPE, ANNOTATION_TYPE})
#Retention(RUNTIME)
#Constraint(validatedBy = MatchesValidator.class)
#Documented
public #interface Matches {
String message() default "{com.moa.podium.util.constraints.matches}";
Class<?>[] groups() default {};
Class<? extends Payload>[] payload() default {};
String field();
String verifyField();
}
And the validator itself:
package com.moa.podium.util.constraints;
import org.mvel2.MVEL;
import javax.validation.ConstraintValidator;
import javax.validation.ConstraintValidatorContext;
public class MatchesValidator implements ConstraintValidator<Matches, Object> {
private String field;
private String verifyField;
public void initialize(Matches constraintAnnotation) {
this.field = constraintAnnotation.field();
this.verifyField = constraintAnnotation.verifyField();
}
public boolean isValid(Object value, ConstraintValidatorContext context) {
Object fieldObj = MVEL.getProperty(field, value);
Object verifyFieldObj = MVEL.getProperty(verifyField, value);
boolean neitherSet = (fieldObj == null) && (verifyFieldObj == null);
if (neitherSet) {
return true;
}
boolean matches = (fieldObj != null) && fieldObj.equals(verifyFieldObj);
if (!matches) {
context.disableDefaultConstraintViolation();
context.buildConstraintViolationWithTemplate("message")
.addNode(verifyField)
.addConstraintViolation();
}
return matches;
}
}
Note that I've used MVEL to inspect the properties of the object being validated. This could be replaced with the standard reflection APIs or if it is a specific class you are validating, the accessor methods themselves.
The #Matches annotation can then be used used on a bean as follows:
#Matches(field="pass", verifyField="passRepeat")
public class AccountCreateForm {
#Size(min=6, max=50)
private String pass;
private String passRepeat;
...
}
As a disclaimer, I wrote this in the last 5 minutes, so I probably haven't ironed out all the bugs yet. I'll update the answer if anything goes wrong.

With Hibernate Validator 4.1.0.Final I recommend using #ScriptAssert. Exceprt from its JavaDoc:
Script expressions can be written in any scripting or expression
language, for which a JSR 223 ("Scripting for the JavaTM Platform")
compatible engine can be found on the classpath.
Note: the evaluation is being performed by a scripting "engine" running in the Java VM, therefore on Java "server side", not on "client side" as stated in some comments.
Example:
#ScriptAssert(lang = "javascript", script = "_this.passVerify.equals(_this.pass)")
public class MyBean {
#Size(min=6, max=50)
private String pass;
private String passVerify;
}
or with shorter alias and null-safe:
#ScriptAssert(lang = "javascript", alias = "_",
script = "_.passVerify != null && _.passVerify.equals(_.pass)")
public class MyBean {
#Size(min=6, max=50)
private String pass;
private String passVerify;
}
or with Java 7+ null-safe Objects.equals():
#ScriptAssert(lang = "javascript", script = "Objects.equals(_this.passVerify, _this.pass)")
public class MyBean {
#Size(min=6, max=50)
private String pass;
private String passVerify;
}
Nevertheless, there is nothing wrong with a custom class level validator #Matches solution.

Cross fields validations can be done by creating custom constraints.
Example:- Compare password and confirmPassword fields of User instance.
CompareStrings
#Target({TYPE})
#Retention(RUNTIME)
#Constraint(validatedBy=CompareStringsValidator.class)
#Documented
public #interface CompareStrings {
String[] propertyNames();
StringComparisonMode matchMode() default EQUAL;
boolean allowNull() default false;
String message() default "";
Class<?>[] groups() default {};
Class<? extends Payload>[] payload() default {};
}
StringComparisonMode
public enum StringComparisonMode {
EQUAL, EQUAL_IGNORE_CASE, NOT_EQUAL, NOT_EQUAL_IGNORE_CASE
}
CompareStringsValidator
public class CompareStringsValidator implements ConstraintValidator<CompareStrings, Object> {
private String[] propertyNames;
private StringComparisonMode comparisonMode;
private boolean allowNull;
#Override
public void initialize(CompareStrings constraintAnnotation) {
this.propertyNames = constraintAnnotation.propertyNames();
this.comparisonMode = constraintAnnotation.matchMode();
this.allowNull = constraintAnnotation.allowNull();
}
#Override
public boolean isValid(Object target, ConstraintValidatorContext context) {
boolean isValid = true;
List<String> propertyValues = new ArrayList<String> (propertyNames.length);
for(int i=0; i<propertyNames.length; i++) {
String propertyValue = ConstraintValidatorHelper.getPropertyValue(String.class, propertyNames[i], target);
if(propertyValue == null) {
if(!allowNull) {
isValid = false;
break;
}
} else {
propertyValues.add(propertyValue);
}
}
if(isValid) {
isValid = ConstraintValidatorHelper.isValid(propertyValues, comparisonMode);
}
if (!isValid) {
/*
* if custom message was provided, don't touch it, otherwise build the
* default message
*/
String message = context.getDefaultConstraintMessageTemplate();
message = (message.isEmpty()) ? ConstraintValidatorHelper.resolveMessage(propertyNames, comparisonMode) : message;
context.disableDefaultConstraintViolation();
ConstraintViolationBuilder violationBuilder = context.buildConstraintViolationWithTemplate(message);
for (String propertyName : propertyNames) {
NodeBuilderDefinedContext nbdc = violationBuilder.addNode(propertyName);
nbdc.addConstraintViolation();
}
}
return isValid;
}
}
ConstraintValidatorHelper
public abstract class ConstraintValidatorHelper {
public static <T> T getPropertyValue(Class<T> requiredType, String propertyName, Object instance) {
if(requiredType == null) {
throw new IllegalArgumentException("Invalid argument. requiredType must NOT be null!");
}
if(propertyName == null) {
throw new IllegalArgumentException("Invalid argument. PropertyName must NOT be null!");
}
if(instance == null) {
throw new IllegalArgumentException("Invalid argument. Object instance must NOT be null!");
}
T returnValue = null;
try {
PropertyDescriptor descriptor = new PropertyDescriptor(propertyName, instance.getClass());
Method readMethod = descriptor.getReadMethod();
if(readMethod == null) {
throw new IllegalStateException("Property '" + propertyName + "' of " + instance.getClass().getName() + " is NOT readable!");
}
if(requiredType.isAssignableFrom(readMethod.getReturnType())) {
try {
Object propertyValue = readMethod.invoke(instance);
returnValue = requiredType.cast(propertyValue);
} catch (Exception e) {
e.printStackTrace(); // unable to invoke readMethod
}
}
} catch (IntrospectionException e) {
throw new IllegalArgumentException("Property '" + propertyName + "' is NOT defined in " + instance.getClass().getName() + "!", e);
}
return returnValue;
}
public static boolean isValid(Collection<String> propertyValues, StringComparisonMode comparisonMode) {
boolean ignoreCase = false;
switch (comparisonMode) {
case EQUAL_IGNORE_CASE:
case NOT_EQUAL_IGNORE_CASE:
ignoreCase = true;
}
List<String> values = new ArrayList<String> (propertyValues.size());
for(String propertyValue : propertyValues) {
if(ignoreCase) {
values.add(propertyValue.toLowerCase());
} else {
values.add(propertyValue);
}
}
switch (comparisonMode) {
case EQUAL:
case EQUAL_IGNORE_CASE:
Set<String> uniqueValues = new HashSet<String> (values);
return uniqueValues.size() == 1 ? true : false;
case NOT_EQUAL:
case NOT_EQUAL_IGNORE_CASE:
Set<String> allValues = new HashSet<String> (values);
return allValues.size() == values.size() ? true : false;
}
return true;
}
public static String resolveMessage(String[] propertyNames, StringComparisonMode comparisonMode) {
StringBuffer buffer = concatPropertyNames(propertyNames);
buffer.append(" must");
switch(comparisonMode) {
case EQUAL:
case EQUAL_IGNORE_CASE:
buffer.append(" be equal");
break;
case NOT_EQUAL:
case NOT_EQUAL_IGNORE_CASE:
buffer.append(" not be equal");
break;
}
buffer.append('.');
return buffer.toString();
}
private static StringBuffer concatPropertyNames(String[] propertyNames) {
//TODO improve concating algorithm
StringBuffer buffer = new StringBuffer();
buffer.append('[');
for(String propertyName : propertyNames) {
char firstChar = Character.toUpperCase(propertyName.charAt(0));
buffer.append(firstChar);
buffer.append(propertyName.substring(1));
buffer.append(", ");
}
buffer.delete(buffer.length()-2, buffer.length());
buffer.append("]");
return buffer;
}
}
User
#CompareStrings(propertyNames={"password", "confirmPassword"})
public class User {
private String password;
private String confirmPassword;
public String getPassword() { return password; }
public void setPassword(String password) { this.password = password; }
public String getConfirmPassword() { return confirmPassword; }
public void setConfirmPassword(String confirmPassword) { this.confirmPassword = confirmPassword; }
}
Test
public void test() {
User user = new User();
user.setPassword("password");
user.setConfirmPassword("paSSword");
Set<ConstraintViolation<User>> violations = beanValidator.validate(user);
for(ConstraintViolation<User> violation : violations) {
logger.debug("Message:- " + violation.getMessage());
}
Assert.assertEquals(violations.size(), 1);
}
Output Message:- [Password, ConfirmPassword] must be equal.
By using the CompareStrings validation constraint, we can also compare more than two properties and we can mix any of four string comparison methods.
ColorChoice
#CompareStrings(propertyNames={"color1", "color2", "color3"}, matchMode=StringComparisonMode.NOT_EQUAL, message="Please choose three different colors.")
public class ColorChoice {
private String color1;
private String color2;
private String color3;
......
}
Test
ColorChoice colorChoice = new ColorChoice();
colorChoice.setColor1("black");
colorChoice.setColor2("white");
colorChoice.setColor3("white");
Set<ConstraintViolation<ColorChoice>> colorChoiceviolations = beanValidator.validate(colorChoice);
for(ConstraintViolation<ColorChoice> violation : colorChoiceviolations) {
logger.debug("Message:- " + violation.getMessage());
}
Output Message:- Please choose three different colors.
Similarly, we can have CompareNumbers, CompareDates, etc cross-fields validation constraints.
P.S. I have not tested this code under production environment (though I tested it under dev environment), so consider this code as Milestone Release. If you find a bug, please write a nice comment. :)

If you’re using the Spring Framework then you can use the Spring Expression Language (SpEL) for that. I’ve wrote a small library that provides JSR-303 validator based on SpEL – it makes cross-field validations a breeze! Take a look at https://github.com/jirutka/validator-spring.
This will validate length and equality of the password fields.
#SpELAssert(value = "pass.equals(passVerify)",
message = "{validator.passwords_not_same}")
public class MyBean {
#Size(min = 6, max = 50)
private String pass;
private String passVerify;
}
You can also easily modify this to validate the password fields only when not both empty.
#SpELAssert(value = "pass.equals(passVerify)",
applyIf = "pass || passVerify",
message = "{validator.passwords_not_same}")
public class MyBean {
#Size(min = 6, max = 50)
private String pass;
private String passVerify;
}

I have tried Alberthoven's example (hibernate-validator 4.0.2.GA) and i get an ValidationException: „Annotated methods must follow the JavaBeans naming convention. match() does not.“ too. After I renamed the method from „match“ to "isValid" it works.
public class Password {
private String password;
private String retypedPassword;
public Password(String password, String retypedPassword) {
super();
this.password = password;
this.retypedPassword = retypedPassword;
}
#AssertTrue(message="password should match retyped password")
private boolean isValid(){
if (password == null) {
return retypedPassword == null;
} else {
return password.equals(retypedPassword);
}
}
public String getPassword() {
return password;
}
public String getRetypedPassword() {
return retypedPassword;
}
}

I like the idea from Jakub Jirutka to use Spring Expression Language. If you don't want to add another library/dependency (assuming that you already use Spring), here is a simplified implementation of his idea.
The constraint:
#Constraint(validatedBy=ExpressionAssertValidator.class)
#Target({ElementType.TYPE})
#Retention(RetentionPolicy.RUNTIME)
public #interface ExpressionAssert {
String message() default "expression must evaluate to true";
Class<?>[] groups() default {};
Class<? extends Payload>[] payload() default {};
String value();
}
The validator:
public class ExpressionAssertValidator implements ConstraintValidator<ExpressionAssert, Object> {
private Expression exp;
public void initialize(ExpressionAssert annotation) {
ExpressionParser parser = new SpelExpressionParser();
exp = parser.parseExpression(annotation.value());
}
public boolean isValid(Object value, ConstraintValidatorContext context) {
return exp.getValue(value, Boolean.class);
}
}
Apply like this:
#ExpressionAssert(value="pass == passVerify", message="passwords must be same")
public class MyBean {
#Size(min=6, max=50)
private String pass;
private String passVerify;
}

I made a small adaptation in Nicko's solution so that it is not necessary to use the Apache Commons BeanUtils library and replace it with the solution already available in spring, for those using it as I can be simpler:
import org.springframework.beans.BeanWrapper;
import org.springframework.beans.PropertyAccessorFactory;
import javax.validation.ConstraintValidator;
import javax.validation.ConstraintValidatorContext;
public class FieldMatchValidator implements ConstraintValidator<FieldMatch, Object> {
private String firstFieldName;
private String secondFieldName;
#Override
public void initialize(final FieldMatch constraintAnnotation) {
firstFieldName = constraintAnnotation.first();
secondFieldName = constraintAnnotation.second();
}
#Override
public boolean isValid(final Object object, final ConstraintValidatorContext context) {
BeanWrapper beanWrapper = PropertyAccessorFactory.forBeanPropertyAccess(object);
final Object firstObj = beanWrapper.getPropertyValue(firstFieldName);
final Object secondObj = beanWrapper.getPropertyValue(secondFieldName);
boolean isValid = firstObj == null && secondObj == null || firstObj != null && firstObj.equals(secondObj);
if (!isValid) {
context.disableDefaultConstraintViolation();
context.buildConstraintViolationWithTemplate(context.getDefaultConstraintMessageTemplate())
.addPropertyNode(firstFieldName)
.addConstraintViolation();
}
return isValid;
}
}

I don't have the reputation for commenting on the first answer but wanted to add that I have added unit tests for the winning answer and have the following observations:
If you get the first or field names wrong then you get a validation error as though the values don't match. Don't get tripped up by spelling mistakes e.g.
#FieldMatch(first="invalidFieldName1", second="validFieldName2")
The validator will accept equivalent data types i.e. these will all pass with FieldMatch:
private String stringField = "1";
private Integer integerField = new Integer(1)
private int intField = 1;
If the fields are of an object type which does not implement equals, the validation will fail.

Very nice solution bradhouse. Is there any way to apply the #Matches annotation to more than one field?
EDIT:
Here's the solution I came up with to answer this question, I modified the Constraint to accept an array instead of a single value:
#Matches(fields={"password", "email"}, verifyFields={"confirmPassword", "confirmEmail"})
public class UserRegistrationForm {
#NotNull
#Size(min=8, max=25)
private String password;
#NotNull
#Size(min=8, max=25)
private String confirmPassword;
#NotNull
#Email
private String email;
#NotNull
#Email
private String confirmEmail;
}
The code for the annotation:
package springapp.util.constraints;
import static java.lang.annotation.ElementType.*;
import static java.lang.annotation.RetentionPolicy.*;
import java.lang.annotation.Documented;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;
import javax.validation.Constraint;
import javax.validation.Payload;
#Target({TYPE, ANNOTATION_TYPE})
#Retention(RUNTIME)
#Constraint(validatedBy = MatchesValidator.class)
#Documented
public #interface Matches {
String message() default "{springapp.util.constraints.matches}";
Class<?>[] groups() default {};
Class<? extends Payload>[] payload() default {};
String[] fields();
String[] verifyFields();
}
And the implementation:
package springapp.util.constraints;
import javax.validation.ConstraintValidator;
import javax.validation.ConstraintValidatorContext;
import org.apache.commons.beanutils.BeanUtils;
public class MatchesValidator implements ConstraintValidator<Matches, Object> {
private String[] fields;
private String[] verifyFields;
public void initialize(Matches constraintAnnotation) {
fields = constraintAnnotation.fields();
verifyFields = constraintAnnotation.verifyFields();
}
public boolean isValid(Object value, ConstraintValidatorContext context) {
boolean matches = true;
for (int i=0; i<fields.length; i++) {
Object fieldObj, verifyFieldObj;
try {
fieldObj = BeanUtils.getProperty(value, fields[i]);
verifyFieldObj = BeanUtils.getProperty(value, verifyFields[i]);
} catch (Exception e) {
//ignore
continue;
}
boolean neitherSet = (fieldObj == null) && (verifyFieldObj == null);
if (neitherSet) {
continue;
}
boolean tempMatches = (fieldObj != null) && fieldObj.equals(verifyFieldObj);
if (!tempMatches) {
addConstraintViolation(context, fields[i]+ " fields do not match", verifyFields[i]);
}
matches = matches?tempMatches:matches;
}
return matches;
}
private void addConstraintViolation(ConstraintValidatorContext context, String message, String field) {
context.disableDefaultConstraintViolation();
context.buildConstraintViolationWithTemplate(message).addNode(field).addConstraintViolation();
}
}

You need to call it explicitly. In the example above, bradhouse has given you all the steps to write a custom constraint.
Add this code in your caller class.
ValidatorFactory factory = Validation.buildDefaultValidatorFactory();
validator = factory.getValidator();
Set<ConstraintViolation<yourObjectClass>> constraintViolations = validator.validate(yourObject);
in the above case it would be
Set<ConstraintViolation<AccountCreateForm>> constraintViolations = validator.validate(objAccountCreateForm);

Why not try Oval: http://oval.sourceforge.net/
I looks like it supports OGNL so maybe you could do it by a more natural
#Assert(expr = "_value ==_this.pass").

You guys are awesome. Really amazing ideas. I like Alberthoven's and McGin's most, so I decided to combine both ideas. And develop some generic solution to cater all cases. Here is my proposed solution.
#Documented
#Constraint(validatedBy = NotFalseValidator.class)
#Target({ElementType.METHOD, ElementType.FIELD,ElementType.TYPE})
#Retention(RetentionPolicy.RUNTIME)
public #interface NotFalse {
String message() default "NotFalse";
String[] messages();
String[] properties();
String[] verifiers();
Class<?>[] groups() default {};
Class<? extends Payload>[] payload() default {};
}
public class NotFalseValidator implements ConstraintValidator<NotFalse, Object> {
private String[] properties;
private String[] messages;
private String[] verifiers;
#Override
public void initialize(NotFalse flag) {
properties = flag.properties();
messages = flag.messages();
verifiers = flag.verifiers();
}
#Override
public boolean isValid(Object bean, ConstraintValidatorContext cxt) {
if(bean == null) {
return true;
}
boolean valid = true;
BeanWrapper beanWrapper = PropertyAccessorFactory.forBeanPropertyAccess(bean);
for(int i = 0; i< properties.length; i++) {
Boolean verified = (Boolean) beanWrapper.getPropertyValue(verifiers[i]);
valid &= isValidProperty(verified,messages[i],properties[i],cxt);
}
return valid;
}
boolean isValidProperty(Boolean flag,String message, String property, ConstraintValidatorContext cxt) {
if(flag == null || flag) {
return true;
} else {
cxt.disableDefaultConstraintViolation();
cxt.buildConstraintViolationWithTemplate(message)
.addPropertyNode(property)
.addConstraintViolation();
return false;
}
}
}
#NotFalse(
messages = {"End Date Before Start Date" , "Start Date Before End Date" } ,
properties={"endDateTime" , "startDateTime"},
verifiers = {"validDateRange" , "validDateRange"})
public class SyncSessionDTO implements ControllableNode {
#NotEmpty #NotPastDate
private Date startDateTime;
#NotEmpty
private Date endDateTime;
public Date getStartDateTime() {
return startDateTime;
}
public void setStartDateTime(Date startDateTime) {
this.startDateTime = startDateTime;
}
public Date getEndDateTime() {
return endDateTime;
}
public void setEndDateTime(Date endDateTime) {
this.endDateTime = endDateTime;
}
public Boolean getValidDateRange(){
if(startDateTime != null && endDateTime != null) {
return startDateTime.getTime() <= endDateTime.getTime();
}
return null;
}
}

Solution realated with question:
How to access a field which is described in annotation property
#Target(ElementType.FIELD)
#Retention(RetentionPolicy.RUNTIME)
#Documented
public #interface Match {
String field();
String message() default "";
}
#Target(ElementType.TYPE)
#Retention(RetentionPolicy.RUNTIME)
#Constraint(validatedBy = MatchValidator.class)
#Documented
public #interface EnableMatchConstraint {
String message() default "Fields must match!";
Class<?>[] groups() default {};
Class<? extends Payload>[] payload() default {};
}
public class MatchValidator implements ConstraintValidator<EnableMatchConstraint, Object> {
#Override
public void initialize(final EnableMatchConstraint constraint) {}
#Override
public boolean isValid(final Object o, final ConstraintValidatorContext context) {
boolean result = true;
try {
String mainField, secondField, message;
Object firstObj, secondObj;
final Class<?> clazz = o.getClass();
final Field[] fields = clazz.getDeclaredFields();
for (Field field : fields) {
if (field.isAnnotationPresent(Match.class)) {
mainField = field.getName();
secondField = field.getAnnotation(Match.class).field();
message = field.getAnnotation(Match.class).message();
if (message == null || "".equals(message))
message = "Fields " + mainField + " and " + secondField + " must match!";
firstObj = BeanUtils.getProperty(o, mainField);
secondObj = BeanUtils.getProperty(o, secondField);
result = firstObj == null && secondObj == null || firstObj != null && firstObj.equals(secondObj);
if (!result) {
context.disableDefaultConstraintViolation();
context.buildConstraintViolationWithTemplate(message).addPropertyNode(mainField).addConstraintViolation();
break;
}
}
}
} catch (final Exception e) {
// ignore
//e.printStackTrace();
}
return result;
}
}
And how to use it...? Like this:
#Entity
#EnableMatchConstraint
public class User {
#NotBlank
private String password;
#Match(field = "password")
private String passwordConfirmation;
}

JSR 303 Validation, If one field equals "something", then these other fields should not be null

I'm looking to do a little custom validation with JSR-303 javax.validation.
I have a field. And If a certain value is entered into this field I want to require that a few other fields are not null.
I'm trying to figure this out. Not sure exactly what I would call this to help find an explanation.
Any help would be appreciated. I am pretty new to this.
At the moment I'm thinking a Custom Constraint. But I'm not sure how to test the value of the dependent field from within the annotation. Basically I'm not sure how to access the panel object from the annotation.
public class StatusValidator implements ConstraintValidator<NotNull, String> {
#Override
public void initialize(NotNull constraintAnnotation) {}
#Override
public boolean isValid(String value, ConstraintValidatorContext context) {
if ("Canceled".equals(panel.status.getValue())) {
if (value != null) {
return true;
}
} else {
return false;
}
}
}
It's the panel.status.getValue(); giving me trouble.. not sure how to accomplish this.

Define method that must validate to true and put the #AssertTrue annotation on the top of it:
#AssertTrue
private boolean isOk() {
return someField != something || otherField != null;
}
The method must start with 'is'.

In this case I suggest to write a custom validator, which will validate at class level (to allow us get access to object's fields) that one field is required only if another field has particular value. Note that you should write generic validator which gets 2 field names and work with only these 2 fields. To require more than one field you should add this validator for each field.
Use the following code as an idea (I've not test it).
Validator interface
/**
* Validates that field {#code dependFieldName} is not null if
* field {#code fieldName} has value {#code fieldValue}.
**/
#Target({TYPE, ANNOTATION_TYPE})
#Retention(RUNTIME)
#Repeatable(NotNullIfAnotherFieldHasValue.List.class) // only with hibernate-validator >= 6.x
#Constraint(validatedBy = NotNullIfAnotherFieldHasValueValidator.class)
#Documented
public #interface NotNullIfAnotherFieldHasValue {
String fieldName();
String fieldValue();
String dependFieldName();
String message() default "{NotNullIfAnotherFieldHasValue.message}";
Class<?>[] groups() default {};
Class<? extends Payload>[] payload() default {};
#Target({TYPE, ANNOTATION_TYPE})
#Retention(RUNTIME)
#Documented
#interface List {
NotNullIfAnotherFieldHasValue[] value();
}
}
Validator implementation
/**
* Implementation of {#link NotNullIfAnotherFieldHasValue} validator.
**/
public class NotNullIfAnotherFieldHasValueValidator
implements ConstraintValidator<NotNullIfAnotherFieldHasValue, Object> {
private String fieldName;
private String expectedFieldValue;
private String dependFieldName;
#Override
public void initialize(NotNullIfAnotherFieldHasValue annotation) {
fieldName = annotation.fieldName();
expectedFieldValue = annotation.fieldValue();
dependFieldName = annotation.dependFieldName();
}
#Override
public boolean isValid(Object value, ConstraintValidatorContext ctx) {
if (value == null) {
return true;
}
try {
String fieldValue = BeanUtils.getProperty(value, fieldName);
String dependFieldValue = BeanUtils.getProperty(value, dependFieldName);
if (expectedFieldValue.equals(fieldValue) && dependFieldValue == null) {
ctx.disableDefaultConstraintViolation();
ctx.buildConstraintViolationWithTemplate(ctx.getDefaultConstraintMessageTemplate())
.addNode(dependFieldName)
.addConstraintViolation();
return false;
}
} catch (NoSuchMethodException | InvocationTargetException | IllegalAccessException ex) {
throw new RuntimeException(ex);
}
return true;
}
}
Validator usage example (hibernate-validator >= 6 with Java 8+)
#NotNullIfAnotherFieldHasValue(
fieldName = "status",
fieldValue = "Canceled",
dependFieldName = "fieldOne")
#NotNullIfAnotherFieldHasValue(
fieldName = "status",
fieldValue = "Canceled",
dependFieldName = "fieldTwo")
public class SampleBean {
private String status;
private String fieldOne;
private String fieldTwo;
// getters and setters omitted
}
Validator usage example (hibernate-validator < 6; the old example)
#NotNullIfAnotherFieldHasValue.List({
#NotNullIfAnotherFieldHasValue(
fieldName = "status",
fieldValue = "Canceled",
dependFieldName = "fieldOne"),
#NotNullIfAnotherFieldHasValue(
fieldName = "status",
fieldValue = "Canceled",
dependFieldName = "fieldTwo")
})
public class SampleBean {
private String status;
private String fieldOne;
private String fieldTwo;
// getters and setters omitted
}
Note that validator implementation uses BeanUtils class from commons-beanutils library but you could also use BeanWrapperImpl from Spring Framework.
See also this great answer: Cross field validation with Hibernate Validator (JSR 303)

You should make use of custom DefaultGroupSequenceProvider<T>:
ConditionalValidation.java
// Marker interface
public interface ConditionalValidation {}
MyCustomFormSequenceProvider.java
public class MyCustomFormSequenceProvider
implements DefaultGroupSequenceProvider<MyCustomForm> {
#Override
public List<Class<?>> getValidationGroups(MyCustomForm myCustomForm) {
List<Class<?>> sequence = new ArrayList<>();
// Apply all validation rules from ConditionalValidation group
// only if someField has given value
if ("some value".equals(myCustomForm.getSomeField())) {
sequence.add(ConditionalValidation.class);
}
// Apply all validation rules from default group
sequence.add(MyCustomForm.class);
return sequence;
}
}
MyCustomForm.java
#GroupSequenceProvider(MyCustomFormSequenceProvider.class)
public class MyCustomForm {
private String someField;
#NotEmpty(groups = ConditionalValidation.class)
private String fieldTwo;
#NotEmpty(groups = ConditionalValidation.class)
private String fieldThree;
#NotEmpty
private String fieldAlwaysValidated;
// getters, setters omitted
}
See also related question on this topic.

Here's my take on it, tried to keep it as simple as possible.
The interface:
#Target({TYPE, ANNOTATION_TYPE})
#Retention(RUNTIME)
#Constraint(validatedBy = OneOfValidator.class)
#Documented
public #interface OneOf {
String message() default "{one.of.message}";
Class<?>[] groups() default {};
Class<? extends Payload>[] payload() default {};
String[] value();
}
Validation implementation:
public class OneOfValidator implements ConstraintValidator<OneOf, Object> {
private String[] fields;
#Override
public void initialize(OneOf annotation) {
this.fields = annotation.value();
}
#Override
public boolean isValid(Object value, ConstraintValidatorContext context) {
BeanWrapper wrapper = PropertyAccessorFactory.forBeanPropertyAccess(value);
int matches = countNumberOfMatches(wrapper);
if (matches > 1) {
setValidationErrorMessage(context, "one.of.too.many.matches.message");
return false;
} else if (matches == 0) {
setValidationErrorMessage(context, "one.of.no.matches.message");
return false;
}
return true;
}
private int countNumberOfMatches(BeanWrapper wrapper) {
int matches = 0;
for (String field : fields) {
Object value = wrapper.getPropertyValue(field);
boolean isPresent = detectOptionalValue(value);
if (value != null && isPresent) {
matches++;
}
}
return matches;
}
private boolean detectOptionalValue(Object value) {
if (value instanceof Optional) {
return ((Optional) value).isPresent();
}
return true;
}
private void setValidationErrorMessage(ConstraintValidatorContext context, String template) {
context.disableDefaultConstraintViolation();
context
.buildConstraintViolationWithTemplate("{" + template + "}")
.addConstraintViolation();
}
}
Usage:
#OneOf({"stateType", "modeType"})
public class OneOfValidatorTestClass {
private StateType stateType;
private ModeType modeType;
}
Messages:
one.of.too.many.matches.message=Only one of the following fields can be specified: {value}
one.of.no.matches.message=Exactly one of the following fields must be specified: {value}

A different approach would be to create a (protected) getter that returns an object containing all dependent fields. Example:
public class MyBean {
protected String status;
protected String name;
#StatusAndSomethingValidator
protected StatusAndSomething getStatusAndName() {
return new StatusAndSomething(status,name);
}
}
StatusAndSomethingValidator can now access StatusAndSomething.status and StatusAndSomething.something and make a dependent check.

Sample below:
package io.quee.sample.javax;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import javax.validation.ConstraintViolation;
import javax.validation.Valid;
import javax.validation.Validator;
import javax.validation.constraints.Pattern;
import java.util.Set;
/**
* Created By [**Ibrahim Al-Tamimi **](https://www.linkedin.com/in/iloom/)
* Created At **Wednesday **23**, September 2020**
*/
#SpringBootApplication
public class SampleJavaXValidation implements CommandLineRunner {
private final Validator validator;
public SampleJavaXValidation(Validator validator) {
this.validator = validator;
}
public static void main(String[] args) {
SpringApplication.run(SampleJavaXValidation.class, args);
}
#Override
public void run(String... args) throws Exception {
Set<ConstraintViolation<SampleDataCls>> validate = validator.validate(new SampleDataCls(SampleTypes.TYPE_A, null, null));
System.out.println(validate);
}
public enum SampleTypes {
TYPE_A,
TYPE_B;
}
#Valid
public static class SampleDataCls {
private final SampleTypes type;
private final String valueA;
private final String valueB;
public SampleDataCls(SampleTypes type, String valueA, String valueB) {
this.type = type;
this.valueA = valueA;
this.valueB = valueB;
}
public SampleTypes getType() {
return type;
}
public String getValueA() {
return valueA;
}
public String getValueB() {
return valueB;
}
#Pattern(regexp = "TRUE")
public String getConditionalValueA() {
if (type.equals(SampleTypes.TYPE_A)) {
return valueA != null ? "TRUE" : "";
}
return "TRUE";
}
#Pattern(regexp = "TRUE")
public String getConditionalValueB() {
if (type.equals(SampleTypes.TYPE_B)) {
return valueB != null ? "TRUE" : "";
}
return "TRUE";
}
}
}

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