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poutsmapoutsma
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Polish contribution
- Split Validator::of into two factory methods: - forInstanceOf using Class::isAssignableFrom - forType using Class::equals - Moved anonymous implementation into TypedValidator with default access Closes gh-30341
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‎spring-context/src/main/java/org/springframework/validation/TypedValidator.java

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/*
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* Copyright 2002-2023 the original author or authors.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* https://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package org.springframework.validation;
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import java.util.function.BiConsumer;
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import java.util.function.Predicate;
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import org.springframework.util.Assert;
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/**
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* Validator instance returned by {@link Validator#forInstanceOf(Class, BiConsumer)}
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* and {@link Validator#forType(Class, BiConsumer)}.
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*
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* @author Toshiaki Maki
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* @author Arjen Poutsma
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* @since 6.1
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* @param <T> the target object type
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*/
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final class TypedValidator<T> implements Validator {
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private final Class<T> targetClass;
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private final Predicate<Class<?>> supports;
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private final BiConsumer<T, Errors> validate;
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public TypedValidator(Class<T> targetClass, Predicate<Class<?>> supports, BiConsumer<T, Errors> validate) {
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Assert.notNull(targetClass, "TargetClass must not be null");
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Assert.notNull(supports, "Supports function must not be null");
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Assert.notNull(validate, "Validate function must not be null");
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this.targetClass = targetClass;
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this.supports = supports;
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this.validate = validate;
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}
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@Override
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public boolean supports(Class<?> clazz) {
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return this.supports.test(clazz);
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}
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@Override
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public void validate(Object target, Errors errors) {
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this.validate.accept(this.targetClass.cast(target), errors);
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}
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}

‎spring-context/src/main/java/org/springframework/validation/Validator.java

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import java.util.function.BiConsumer;
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import org.springframework.util.Assert;
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/**
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* A validator for application-specific objects.
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*
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* of an application, and supports the encapsulation of validation
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* logic as a first-class citizen in its own right.
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*
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* <p>Find below a simple but complete {@code Validator}
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* implementation, which validates that the various {@link String}
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* properties of a {@code UserLogin} instance are not empty
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* (that is they are not {@code null} and do not consist
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* <p>Implementations can be created via the static factory methods
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* {@link #forInstanceOf(Class, BiConsumer)} or
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* {@link #forType(Class, BiConsumer)}.
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* Below is a simple but complete {@code Validator} that validates that the
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* various {@link String} properties of a {@code UserLogin} instance are not
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* empty (they are not {@code null} and do not consist
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* wholly of whitespace), and that any password that is present is
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* at least {@code 'MINIMUM_PASSWORD_LENGTH'} characters in length.
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*
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* <pre class="code">public class UserLoginValidator implements Validator {
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*
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* private static final int MINIMUM_PASSWORD_LENGTH = 6;
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*
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* public boolean supports(Class clazz) {
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* return UserLogin.class.isAssignableFrom(clazz);
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* }
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*
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* public void validate(Object target, Errors errors) {
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* ValidationUtils.rejectIfEmptyOrWhitespace(errors, "userName", "field.required");
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* ValidationUtils.rejectIfEmptyOrWhitespace(errors, "password", "field.required");
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* UserLogin login = (UserLogin) target;
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* if (login.getPassword() != null
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* &amp;&amp; login.getPassword().trim().length() &lt; MINIMUM_PASSWORD_LENGTH) {
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* errors.rejectValue("password", "field.min.length",
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* new Object[]{Integer.valueOf(MINIMUM_PASSWORD_LENGTH)},
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* "The password must be at least [" + MINIMUM_PASSWORD_LENGTH + "] characters in length.");
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* }
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* }
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* }</pre>
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* <pre class="code">Validator userLoginValidator = Validator.forInstance(UserLogin.class, (login, errors) -> {
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* ValidationUtils.rejectIfEmptyOrWhitespace(errors, "userName", "field.required");
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* ValidationUtils.rejectIfEmptyOrWhitespace(errors, "password", "field.required");
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* if (login.getPassword() != null
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* &amp;&amp; login.getPassword().trim().length() &lt; MINIMUM_PASSWORD_LENGTH) {
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* errors.rejectValue("password", "field.min.length",
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* new Object[]{Integer.valueOf(MINIMUM_PASSWORD_LENGTH)},
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* "The password must be at least [" + MINIMUM_PASSWORD_LENGTH + "] characters in length.");
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* }
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* });</pre>
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*
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* <p>See also the Spring reference manual for a fuller discussion of
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* the {@code Validator} interface and its role in an enterprise
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* application.
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*
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* @author Rod Johnson
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* @author Toshiaki Maki
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* @author Arjen Poutsma
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* @see SmartValidator
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* @see Errors
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* @see ValidationUtils
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*/
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void validate(Object target, Errors errors);
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/**
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* Takes the {@link BiConsumer} containing the validation logic for the specific type
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* <code>&lt;T&gt;</code> and returns the {@link Validator} instance.<br>
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* This validator implements the <i>typical</i> {@link #supports(Class)} method
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* for the given <code>&lt;T&gt;</code>.<br>
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*
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* By using this method, a {@link Validator} can be implemented as follows:
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* Return a {@code Validator} that checks whether the target object
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* {@linkplain Class#isAssignableFrom(Class) is an instance of}
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* {@code targetClass}, resorting to {@code delegate} to populate
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* {@link Errors} if it is.
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*
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* <pre class="code">Validator passwordEqualsValidator = Validator.of(PasswordResetForm.class, (form, errors) -> {
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* if (!Objects.equals(form.getPassword(), form.getConfirmPassword())) {
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* errors.rejectValue("confirmPassword",
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* "PasswordEqualsValidator.passwordResetForm.password",
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* "password and confirm password must be same.");
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* }
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* });</pre>
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* @param targetClass the class of the object that is to be validated
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* @param delegate the validation logic to delegate for the specific type <code>&lt;T&gt;</code>
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* @param <T> the type of the object that is to be validated
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* @return the {@link Validator} instance
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* <p>For instance:
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* <pre class="code">Validator passwordEqualsValidator = Validator.forInstanceOf(PasswordResetForm.class, (form, errors) -> {
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* if (!Objects.equals(form.getPassword(), form.getConfirmPassword())) {
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* errors.rejectValue("confirmPassword",
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* "PasswordEqualsValidator.passwordResetForm.password",
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* "password and confirm password must be same.");
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* }
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* });</pre>
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* @param targetClass the class supported by the returned validator
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* @param delegate function invoked with the target object, if it is an
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* instance of type T
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* @param <T> the target object type
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* @return the created {@code Validator}
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* @since 6.1
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*/
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static <T> Validator of(Class<T> targetClass, BiConsumer<T, Errors> delegate) {
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Assert.notNull(targetClass, "'targetClass' must not be null.");
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return new Validator() {
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@Override
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public boolean supports(Class<?> clazz) {
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return targetClass.isAssignableFrom(clazz);
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}
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static <T> Validator forInstanceOf(Class<T> targetClass, BiConsumer<T, Errors> delegate) {
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return new TypedValidator<>(targetClass, targetClass::isAssignableFrom, delegate);
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}
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@Override
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public void validate(Object target, Errors errors) {
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delegate.accept(targetClass.cast(target), errors);
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}
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};
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/**
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* Return a {@code Validator} that checks whether the target object's class
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* is identical to {@code targetClass}, resorting to {@code delegate} to
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* populate {@link Errors} if it is.
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*
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* <p>For instance:
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* <pre class="code">Validator passwordEqualsValidator = Validator.forType(PasswordResetForm.class, (form, errors) -> {
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* if (!Objects.equals(form.getPassword(), form.getConfirmPassword())) {
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* errors.rejectValue("confirmPassword",
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* "PasswordEqualsValidator.passwordResetForm.password",
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* "password and confirm password must be same.");
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* }
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* });</pre>
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* @param targetClass the exact class supported by the returned validator (no subclasses)
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* @param delegate function invoked with the target object, if it is an
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* instance of type T
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* @param <T> the target object type
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* @return the created {@code Validator}
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* @since 6.1
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*/
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static <T> Validator forType(Class<T> targetClass, BiConsumer<T, Errors> delegate) {
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return new TypedValidator<>(targetClass, targetClass::equals, delegate);
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}
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}

‎spring-context/src/test/java/org/springframework/validation/DataBinderTests.java

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*/
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class DataBinderTests {
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Validator spouseValidator = Validator.of(TestBean.class, (tb, errors) -> {
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private final Validator spouseValidator = Validator.forInstanceOf(TestBean.class, (tb, errors) -> {
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if (tb == null || "XXX".equals(tb.getName())) {
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errors.rejectValue("", "SPOUSE_NOT_AVAILABLE");
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return;

‎spring-context/src/test/java/org/springframework/validation/ValidationUtilsTests.java

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*/
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public class ValidationUtilsTests {
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Validator emptyValidator = Validator.of(TestBean.class, (testBean, errors) -> ValidationUtils.rejectIfEmpty(errors, "name", "EMPTY", "You must enter a name!"));
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private final Validator emptyValidator = Validator.forInstanceOf(TestBean.class, (testBean, errors) -> ValidationUtils.rejectIfEmpty(errors, "name", "EMPTY", "You must enter a name!"));
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Validator emptyOrWhitespaceValidator = Validator.of(TestBean.class, (testBean, errors) -> ValidationUtils.rejectIfEmptyOrWhitespace(errors, "name", "EMPTY_OR_WHITESPACE", "You must enter a name!"));
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private final Validator emptyOrWhitespaceValidator = Validator.forInstanceOf(TestBean.class, (testBean, errors) -> ValidationUtils.rejectIfEmptyOrWhitespace(errors, "name", "EMPTY_OR_WHITESPACE", "You must enter a name!"));
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@Test
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public void testInvokeValidatorWithNullValidator() throws Exception {

‎spring-context/src/test/java/org/springframework/validation/ValidatorTests.java

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/*
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* Copyright 2002-2023 the original author or authors.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* https://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package org.springframework.validation;
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import org.junit.jupiter.api.Test;
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import org.springframework.beans.testfixture.beans.TestBean;
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import static org.assertj.core.api.Assertions.assertThat;
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/**
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* @author Arjen Poutsma
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*/
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class ValidatorTests {
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@Test
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public void testSupportsForInstanceOf() {
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Validator validator = Validator.forInstanceOf(TestBean.class, (testBean, errors) -> {});
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assertThat(validator.supports(TestBean.class)).isTrue();
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assertThat(validator.supports(TestBeanSubclass.class)).isTrue();
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}
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@Test
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public void testSupportsForType() {
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Validator validator = Validator.forType(TestBean.class, (testBean, errors) -> {});
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assertThat(validator.supports(TestBean.class)).isTrue();
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assertThat(validator.supports(TestBeanSubclass.class)).isFalse();
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}
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private static class TestBeanSubclass extends TestBean {
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}
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}

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