Further rework Spring MVC JSR-303 validation

Rework Spring MVC JSR-303 validation support a little more to move
most of the creation logic to the wrapper class. Also rename
`SpringValidatorAdapterWrapper` -> `WebMvcValidator`.

See gh-8223

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/SpringValidatorAdapterWrapper.java

@@ -1,84 +0,0 @@
-/*
- * Copyright 2012-2017 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
- *
- *      http://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.autoconfigure.web;
-
-import org.springframework.beans.BeansException;
-import org.springframework.beans.factory.DisposableBean;
-import org.springframework.beans.factory.InitializingBean;
-import org.springframework.context.ApplicationContext;
-import org.springframework.context.ApplicationContextAware;
-import org.springframework.validation.Errors;
-import org.springframework.validation.Validator;
-import org.springframework.validation.beanvalidation.SpringValidatorAdapter;
-
-/**
- * Wraps a {@link SpringValidatorAdapter} so that only the Spring's {@link Validator} type
- * is exposed. This prevents such a bean to expose both the Spring and JSR-303 validator
- * contract at the same time.
- *
- * @author Stephane Nicoll
- */
-class SpringValidatorAdapterWrapper
-		implements Validator, ApplicationContextAware, InitializingBean, DisposableBean {
-
-	private final SpringValidatorAdapter target;
-
-	private final boolean managed;
-
-	SpringValidatorAdapterWrapper(SpringValidatorAdapter target, boolean managed) {
-		this.target = target;
-		this.managed = managed;
-	}
-
-	public SpringValidatorAdapter getTarget() {
-		return this.target;
-	}
-
-	@Override
-	public boolean supports(Class<?> clazz) {
-		return this.target.supports(clazz);
-	}
-
-	@Override
-	public void validate(Object target, Errors errors) {
-		this.target.validate(target, errors);
-	}
-
-	@Override
-	public void setApplicationContext(ApplicationContext applicationContext)
-			throws BeansException {
-		if (!this.managed && this.target instanceof ApplicationContextAware) {
-			((ApplicationContextAware) this.target)
-					.setApplicationContext(applicationContext);
-		}
-	}
-
-	@Override
-	public void afterPropertiesSet() throws Exception {
-		if (!this.managed && this.target instanceof InitializingBean) {
-			((InitializingBean) this.target).afterPropertiesSet();
-		}
-	}
-
-	@Override
-	public void destroy() throws Exception {
-		if (!this.managed && this.target instanceof DisposableBean) {
-			((DisposableBean) this.target).destroy();
-		}
-	}
-
-}

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/WebMvcAutoConfiguration.java

@@ -45,11 +45,9 @@ import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplicat
 import org.springframework.boot.autoconfigure.validation.ValidationAutoConfiguration;
 import org.springframework.boot.autoconfigure.web.ResourceProperties.Strategy;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
-import org.springframework.boot.validation.MessageInterpolatorFactory;
 import org.springframework.boot.web.filter.OrderedHiddenHttpMethodFilter;
 import org.springframework.boot.web.filter.OrderedHttpPutFormContentFilter;
 import org.springframework.boot.web.filter.OrderedRequestContextFilter;
-import org.springframework.context.ApplicationContext;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.Import;
@@ -69,8 +67,6 @@ import org.springframework.util.StringUtils;
 import org.springframework.validation.DefaultMessageCodesResolver;
 import org.springframework.validation.MessageCodesResolver;
 import org.springframework.validation.Validator;
-import org.springframework.validation.beanvalidation.OptionalValidatorFactoryBean;
-import org.springframework.validation.beanvalidation.SpringValidatorAdapter;
 import org.springframework.web.accept.ContentNegotiationManager;
 import org.springframework.web.bind.support.ConfigurableWebBindingInitializer;
 import org.springframework.web.context.request.RequestContextListener;
@@ -133,8 +129,6 @@ public class WebMvcAutoConfiguration {
 
 	public static String DEFAULT_SUFFIX = "";
 
-	private static final String JSR303_VALIDATOR_CLASS = "javax.validation.Validator";
-
 	@Bean
 	@ConditionalOnMissingBean(HiddenHttpMethodFilter.class)
 	public OrderedHiddenHttpMethodFilter hiddenHttpMethodFilter() {
@@ -405,17 +399,12 @@ public class WebMvcAutoConfiguration {
 		@Bean
 		@Override
 		public Validator mvcValidator() {
-			if (isJsr303Present()) {
+			if (!ClassUtils.isPresent("javax.validation.Validator",
-				Validator userDefinedValidator = getValidator();
+					getClass().getClassLoader())) {
-				return new Jsr303ValidatorHandler(getApplicationContext(),
+				return super.mvcValidator();
-						userDefinedValidator).wrapJsr303Validator();
 			}
-			return super.mvcValidator();
+			return WebMvcValidator.get(getApplicationContext(),
-		}
+					getValidator());
-
-		private boolean isJsr303Present() {
-			return ClassUtils.isPresent(JSR303_VALIDATOR_CLASS,
-					getApplicationContext().getClassLoader());
 		}
 
 		@Override
@@ -559,62 +548,4 @@ public class WebMvcAutoConfiguration {
 
 	}
 
-	static class Jsr303ValidatorHandler {
-
-		private final ApplicationContext applicationContext;
-
-		private final Validator userDefinedValidator;
-
-		Jsr303ValidatorHandler(ApplicationContext applicationContext,
-				Validator userDefinedValidator) {
-			this.applicationContext = applicationContext;
-			this.userDefinedValidator = userDefinedValidator;
-		}
-
-		public Validator wrapJsr303Validator() {
-			try {
-				if (this.userDefinedValidator != null) {
-					if (this.userDefinedValidator instanceof javax.validation.Validator) {
-						return wrap(
-								(javax.validation.Validator) this.userDefinedValidator,
-								false);
-					}
-					else {
-						return this.userDefinedValidator;
-					}
-				}
-				else {
-					return wrap(this.applicationContext
-							.getBean(javax.validation.Validator.class), true);
-				}
-			}
-			catch (NoSuchBeanDefinitionException ex) {
-				OptionalValidatorFactoryBean factory = new OptionalValidatorFactoryBean();
-				MessageInterpolatorFactory interpolatorFactory = new MessageInterpolatorFactory();
-				factory.setMessageInterpolator(interpolatorFactory.getObject());
-				return new SpringValidatorAdapterWrapper(factory, false);
-			}
-
-		}
-
-		/**
-		 * Wrap the specified {@code validator}.
-		 * @param validator the validator to wrap
-		 * @param bean {@code true} if the specified {@code validator} is a bean managed
-		 * in the context
-		 * @return a {@link Validator} wrapping the specified argument
-		 */
-		private Validator wrap(javax.validation.Validator validator, boolean bean) {
-			if (validator instanceof SpringValidatorAdapter) {
-				return new SpringValidatorAdapterWrapper(
-						(SpringValidatorAdapter) validator, bean);
-			}
-			else {
-				return new SpringValidatorAdapterWrapper(
-						new SpringValidatorAdapter(validator), false);
-			}
-		}
-
-	}
-
 }

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/WebMvcValidator.java

@@ -0,0 +1,144 @@
+/*
+ * Copyright 2012-2017 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
+ *
+ *      http://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.autoconfigure.web;
+
+import org.springframework.beans.BeansException;
+import org.springframework.beans.factory.DisposableBean;
+import org.springframework.beans.factory.InitializingBean;
+import org.springframework.beans.factory.NoSuchBeanDefinitionException;
+import org.springframework.boot.validation.MessageInterpolatorFactory;
+import org.springframework.context.ApplicationContext;
+import org.springframework.context.ApplicationContextAware;
+import org.springframework.validation.Errors;
+import org.springframework.validation.SmartValidator;
+import org.springframework.validation.Validator;
+import org.springframework.validation.beanvalidation.OptionalValidatorFactoryBean;
+import org.springframework.validation.beanvalidation.SpringValidatorAdapter;
+
+/**
+ * A {@link SmartValidator} exposed as a bean for WebMvc use. Wraps existing
+ * {@link SpringValidatorAdapter} instances so that only the Spring's {@link Validator}
+ * type is exposed. This prevents such a bean to expose both the Spring and JSR-303
+ * validator contract at the same time.
+ *
+ * @author Stephane Nicoll
+ * @author Phillip Webb
+ */
+class WebMvcValidator implements SmartValidator, ApplicationContextAware,
+		InitializingBean, DisposableBean {
+
+	private final SpringValidatorAdapter target;
+
+	private final boolean existingBean;
+
+	WebMvcValidator(SpringValidatorAdapter target, boolean existingBean) {
+		this.target = target;
+		this.existingBean = existingBean;
+	}
+
+	SpringValidatorAdapter getTarget() {
+		return this.target;
+	}
+
+	@Override
+	public boolean supports(Class<?> clazz) {
+		return this.target.supports(clazz);
+	}
+
+	@Override
+	public void validate(Object target, Errors errors) {
+		this.target.validate(target, errors);
+	}
+
+	@Override
+	public void validate(Object target, Errors errors, Object... validationHints) {
+		this.target.validate(target, errors, validationHints);
+	}
+
+	@Override
+	public void setApplicationContext(ApplicationContext applicationContext)
+			throws BeansException {
+		if (!this.existingBean && this.target instanceof ApplicationContextAware) {
+			((ApplicationContextAware) this.target)
+					.setApplicationContext(applicationContext);
+		}
+	}
+
+	@Override
+	public void afterPropertiesSet() throws Exception {
+		if (!this.existingBean && this.target instanceof InitializingBean) {
+			((InitializingBean) this.target).afterPropertiesSet();
+		}
+	}
+
+	@Override
+	public void destroy() throws Exception {
+		if (!this.existingBean && this.target instanceof DisposableBean) {
+			((DisposableBean) this.target).destroy();
+		}
+	}
+
+	public static Validator get(ApplicationContext applicationContext,
+			Validator validator) {
+		if (validator != null) {
+			return wrap(validator, false);
+		}
+		return getExistingOrCreate(applicationContext);
+	}
+
+	private static Validator getExistingOrCreate(ApplicationContext applicationContext) {
+		Validator existing = getExisting(applicationContext);
+		if (existing != null) {
+			return wrap(existing, true);
+		}
+		return create();
+	}
+
+	private static Validator getExisting(ApplicationContext applicationContext) {
+		try {
+			javax.validation.Validator validator = applicationContext
+					.getBean(javax.validation.Validator.class);
+			if (validator instanceof Validator) {
+				return (Validator) validator;
+			}
+			return new SpringValidatorAdapter(validator);
+		}
+		catch (NoSuchBeanDefinitionException ex) {
+			return null;
+		}
+	}
+
+	private static Validator create() {
+		OptionalValidatorFactoryBean validator = new OptionalValidatorFactoryBean();
+		validator.setMessageInterpolator(new MessageInterpolatorFactory().getObject());
+		return wrap(validator, false);
+	}
+
+	private static Validator wrap(Validator validator, boolean existingBean) {
+		if (validator instanceof javax.validation.Validator) {
+			if (validator instanceof SpringValidatorAdapter) {
+				return new WebMvcValidator((SpringValidatorAdapter) validator,
+						existingBean);
+			}
+			return new WebMvcValidator(
+					new SpringValidatorAdapter((javax.validation.Validator) validator),
+					existingBean);
+		}
+		return validator;
+	}
+
+}

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/web/WebMvcAutoConfigurationTests.java

@@ -674,8 +674,8 @@ public class WebMvcAutoConfigurationTests {
 				.isEmpty();
 		assertThat(this.context.getBeansOfType(Validator.class)).hasSize(1);
 		Validator validator = this.context.getBean(Validator.class);
-		assertThat(validator).isInstanceOf(SpringValidatorAdapterWrapper.class);
+		assertThat(validator).isInstanceOf(WebMvcValidator.class);
-		assertThat(((SpringValidatorAdapterWrapper) validator).getTarget())
+		assertThat(((WebMvcValidator) validator).getTarget())
 				.isSameAs(this.context.getBean(MvcJsr303Validator.class).validator);
 	}
 
@@ -687,8 +687,8 @@ public class WebMvcAutoConfigurationTests {
 				.hasSize(1);
 		assertThat(this.context.getBeansOfType(Validator.class)).hasSize(2);
 		Validator validator = this.context.getBean("mvcValidator", Validator.class);
-		assertThat(validator).isInstanceOf(SpringValidatorAdapterWrapper.class);
+		assertThat(validator).isInstanceOf(WebMvcValidator.class);
-		assertThat(((SpringValidatorAdapterWrapper) validator).getTarget())
+		assertThat(((WebMvcValidator) validator).getTarget())
 				.isSameAs(this.context.getBean(javax.validation.Validator.class));
 	}
 
@@ -700,8 +700,8 @@ public class WebMvcAutoConfigurationTests {
 				.hasSize(1);
 		assertThat(this.context.getBeansOfType(Validator.class)).hasSize(1);
 		Validator validator = this.context.getBean(Validator.class);
-		assertThat(validator).isInstanceOf(SpringValidatorAdapterWrapper.class);
+		assertThat(validator).isInstanceOf(WebMvcValidator.class);
-		SpringValidatorAdapter target = ((SpringValidatorAdapterWrapper) validator)
+		SpringValidatorAdapter target = ((WebMvcValidator) validator)
 				.getTarget();
 		assertThat(new DirectFieldAccessor(target).getPropertyValue("targetValidator"))
 				.isSameAs(this.context.getBean(javax.validation.Validator.class));

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/web/WebMvcValidatorTests.java

@@ -37,11 +37,11 @@ import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
 
 /**
- * Tests for {@link SpringValidatorAdapterWrapper}.
+ * Tests for {@link WebMvcValidator}.
  *
  * @author Stephane Nicoll
  */
-public class SpringValidatorAdapterWrapperTests {
+public class WebMvcValidatorTests {
 
 	private AnnotationConfigApplicationContext context;
 
@@ -54,7 +54,7 @@ public class SpringValidatorAdapterWrapperTests {
 
 	@Test
 	public void wrapLocalValidatorFactoryBean() {
-		SpringValidatorAdapterWrapper wrapper = load(
+		WebMvcValidator wrapper = load(
 				LocalValidatorFactoryBeanConfig.class);
 		assertThat(wrapper.supports(SampleData.class)).isTrue();
 		MapBindingResult errors = new MapBindingResult(new HashMap<String, Object>(),
@@ -89,12 +89,12 @@ public class SpringValidatorAdapterWrapperTests {
 		verify(validator, times(0)).destroy();
 	}
 
-	private SpringValidatorAdapterWrapper load(Class<?> config) {
+	private WebMvcValidator load(Class<?> config) {
 		AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext();
 		ctx.register(config);
 		ctx.refresh();
 		this.context = ctx;
-		return this.context.getBean(SpringValidatorAdapterWrapper.class);
+		return this.context.getBean(WebMvcValidator.class);
 	}
 
 	@Configuration
@@ -106,8 +106,8 @@ public class SpringValidatorAdapterWrapperTests {
 		}
 
 		@Bean
-		public SpringValidatorAdapterWrapper wrapper() {
+		public WebMvcValidator wrapper() {
-			return new SpringValidatorAdapterWrapper(validator(), true);
+			return new WebMvcValidator(validator(), true);
 		}
 
 	}
@@ -119,8 +119,8 @@ public class SpringValidatorAdapterWrapperTests {
 				LocalValidatorFactoryBean.class);
 
 		@Bean
-		public SpringValidatorAdapterWrapper wrapper() {
+		public WebMvcValidator wrapper() {
-			return new SpringValidatorAdapterWrapper(this.validator, false);
+			return new WebMvcValidator(this.validator, false);
 		}
 
 	}
@@ -132,8 +132,8 @@ public class SpringValidatorAdapterWrapperTests {
 				LocalValidatorFactoryBean.class);
 
 		@Bean
-		public SpringValidatorAdapterWrapper wrapper() {
+		public WebMvcValidator wrapper() {
-			return new SpringValidatorAdapterWrapper(this.validator, true);
+			return new WebMvcValidator(this.validator, true);
 		}
 
 	}