Provide callback mechanism for customizing validation configuration

See gh-29429

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/validation/ValidationAutoConfiguration.java

@@ -16,8 +16,11 @@
 
 package org.springframework.boot.autoconfigure.validation;
 
+import java.util.List;
+
 import jakarta.validation.Validator;
 import jakarta.validation.executable.ExecutableValidator;
+import jakarta.validation.valueextraction.ValueExtractor;
 
 import org.springframework.beans.factory.ObjectProvider;
 import org.springframework.beans.factory.config.BeanDefinition;
@@ -28,8 +31,11 @@ import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean
 import org.springframework.boot.autoconfigure.condition.ConditionalOnResource;
 import org.springframework.boot.autoconfigure.condition.SearchStrategy;
 import org.springframework.boot.validation.MessageInterpolatorFactory;
+import org.springframework.boot.validation.beanvalidation.CustomizableLocalValidatorFactoryBean;
 import org.springframework.boot.validation.beanvalidation.FilteredMethodValidationPostProcessor;
 import org.springframework.boot.validation.beanvalidation.MethodValidationExcludeFilter;
+import org.springframework.boot.validation.beanvalidation.customize.AddValueExtractorCustomizer;
+import org.springframework.boot.validation.beanvalidation.customize.Customizer;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Import;
@@ -53,11 +59,20 @@ import org.springframework.validation.beanvalidation.MethodValidationPostProcess
 @Import(PrimaryDefaultValidatorPostProcessor.class)
 public class ValidationAutoConfiguration {
 
+	@Bean
+	public static AddValueExtractorCustomizer autoAddValueExtractorCustomizer(
+			@SuppressWarnings({ "rawtypes", "unchecked" }) List<ValueExtractor> valueExtractors) {
+
+		return new AddValueExtractorCustomizer(valueExtractors);
+	}
+
 	@Bean
 	@Role(BeanDefinition.ROLE_INFRASTRUCTURE)
 	@ConditionalOnMissingBean(Validator.class)
-	public static LocalValidatorFactoryBean defaultValidator(ApplicationContext applicationContext) {
-		LocalValidatorFactoryBean factoryBean = new LocalValidatorFactoryBean();
+	public static LocalValidatorFactoryBean defaultValidator(ApplicationContext applicationContext,
+			List<Customizer> customizers) {
+		CustomizableLocalValidatorFactoryBean factoryBean = new CustomizableLocalValidatorFactoryBean();
+		factoryBean.setCustomizers(customizers);
 		MessageInterpolatorFactory interpolatorFactory = new MessageInterpolatorFactory(applicationContext);
 		factoryBean.setMessageInterpolator(interpolatorFactory.getObject());
 		return factoryBean;

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/validation/beanvalidation/CustomizableLocalValidatorFactoryBean.java

@@ -0,0 +1,59 @@
+/*
+ * Copyright 2012-2020 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.validation.beanvalidation;
+
+import java.util.List;
+import java.util.Optional;
+
+import jakarta.validation.Configuration;
+
+import org.springframework.boot.validation.beanvalidation.customize.Customizer;
+import org.springframework.validation.beanvalidation.LocalValidatorFactoryBean;
+
+/**
+ * This class will callback the {@link Customizer} which supply by application. For
+ * example:
+ *
+ * <pre>{@code
+ * &#64;Bean
+ * public Customizer customizer() {
+ *		return configuration -> {
+ *			configuration.addValueExtractor(new CustomResultValueExtractor());
+ *			configuration.xxx
+ *			...
+ *		};
+ * }
+ * }</pre>
+ *
+ * @author Dang Zhicairang
+ * @since 2.6.2
+ */
+public class CustomizableLocalValidatorFactoryBean extends LocalValidatorFactoryBean {
+
+	private List<Customizer> customizers;
+
+	public void setCustomizers(List<Customizer> customizers) {
+		this.customizers = customizers;
+	}
+
+	@Override
+	protected void postProcessConfiguration(Configuration<?> configuration) {
+		Optional.ofNullable(this.customizers)
+				.ifPresent((list) -> list.forEach((customizer) -> customizer.customize(configuration)));
+	}
+
+}

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/validation/beanvalidation/customize/AddValueExtractorCustomizer.java

@@ -0,0 +1,54 @@
+/*
+ * Copyright 2012-2020 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.validation.beanvalidation.customize;
+
+import java.util.List;
+import java.util.Optional;
+
+import jakarta.validation.Configuration;
+import jakarta.validation.valueextraction.ValueExtractor;
+
+/**
+ * Add given collection of {@link ValueExtractor} into {@link Configuration}.
+ *
+ * @author Dang Zhicairang
+ * @since 2.6.2
+ */
+@SuppressWarnings({ "rawtypes", "unchecked" })
+public class AddValueExtractorCustomizer implements Customizer {
+
+	private List<ValueExtractor> valueExtractors;
+
+	public AddValueExtractorCustomizer(List<ValueExtractor> valueExtractors) {
+		this.valueExtractors = valueExtractors;
+	}
+
+	public List<ValueExtractor> getValueExtractors() {
+		return this.valueExtractors;
+	}
+
+	public void setValueExtractors(List<ValueExtractor> valueExtractors) {
+		this.valueExtractors = valueExtractors;
+	}
+
+	@Override
+	public void customize(Configuration<?> configuration) {
+		Optional.ofNullable(this.getValueExtractors())
+				.ifPresent((list) -> list.forEach(configuration::addValueExtractor));
+	}
+
+}

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/validation/beanvalidation/customize/Customizer.java

@@ -0,0 +1,33 @@
+/*
+ * Copyright 2012-2020 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.validation.beanvalidation.customize;
+
+import jakarta.validation.Configuration;
+
+/**
+ * Callback interface that can be used to customize {@link Configuration}.
+ *
+ * @author Dang Zhicairang
+ * @since 2.6.2
+ * @see AddValueExtractorCustomizer
+ */
+@FunctionalInterface
+public interface Customizer {
+
+	void customize(Configuration<?> configuration);
+
+}