Reuse auto-configured `Validator` in WebFlux

This commit makes sure that if a `Validator` is auto-configured, it is
reused as the `webFluxValidator`. This is pretty much the same thing as
what was done recently for Spring MVC.

Since the infrastructure is now shared, the package protected class has
been published in the `.validation` package.

Closes gh-8400

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

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package org.springframework.boot.autoconfigure.web;
+package org.springframework.boot.autoconfigure.validation;
 
 import org.springframework.beans.BeansException;
 import org.springframework.beans.factory.DisposableBean;
@@ -38,19 +38,19 @@ import org.springframework.validation.beanvalidation.SpringValidatorAdapter;
  * @author Stephane Nicoll
  * @author Phillip Webb
  */
-class WebMvcValidator implements SmartValidator, ApplicationContextAware,
+public class SpringValidator implements SmartValidator, ApplicationContextAware,
 		InitializingBean, DisposableBean {
 
 	private final SpringValidatorAdapter target;
 
 	private final boolean existingBean;
 
-	WebMvcValidator(SpringValidatorAdapter target, boolean existingBean) {
+	public SpringValidator(SpringValidatorAdapter target, boolean existingBean) {
 		this.target = target;
 		this.existingBean = existingBean;
 	}
 
-	SpringValidatorAdapter getTarget() {
+	public final SpringValidatorAdapter getTarget() {
 		return this.target;
 	}
 
@@ -131,10 +131,10 @@ class WebMvcValidator implements SmartValidator, ApplicationContextAware,
 	private static Validator wrap(Validator validator, boolean existingBean) {
 		if (validator instanceof javax.validation.Validator) {
 			if (validator instanceof SpringValidatorAdapter) {
-				return new WebMvcValidator((SpringValidatorAdapter) validator,
+				return new SpringValidator((SpringValidatorAdapter) validator,
 						existingBean);
 			}
-			return new WebMvcValidator(
+			return new SpringValidator(
 					new SpringValidatorAdapter((javax.validation.Validator) validator),
 					existingBean);
 		}

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

@@ -43,6 +43,7 @@ import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean
 import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication.Type;
+import org.springframework.boot.autoconfigure.validation.SpringValidator;
 import org.springframework.boot.autoconfigure.validation.ValidationAutoConfiguration;
 import org.springframework.boot.autoconfigure.web.ResourceProperties.Strategy;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
@@ -404,7 +405,7 @@ public class WebMvcAutoConfiguration {
 					getClass().getClassLoader())) {
 				return super.mvcValidator();
 			}
-			return WebMvcValidator.get(getApplicationContext(),
+			return SpringValidator.get(getApplicationContext(),
 					getValidator());
 		}
 

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/webflux/WebFluxAnnotationAutoConfiguration.java

@@ -32,6 +32,7 @@ import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication;
+import org.springframework.boot.autoconfigure.validation.SpringValidator;
 import org.springframework.boot.autoconfigure.web.ConditionalOnEnabledResourceChain;
 import org.springframework.boot.autoconfigure.web.ResourceProperties;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
@@ -45,6 +46,8 @@ import org.springframework.core.convert.converter.GenericConverter;
 import org.springframework.format.Formatter;
 import org.springframework.format.FormatterRegistry;
 import org.springframework.http.CacheControl;
+import org.springframework.util.ClassUtils;
+import org.springframework.validation.Validator;
 import org.springframework.web.reactive.config.DelegatingWebFluxConfiguration;
 import org.springframework.web.reactive.config.EnableWebFlux;
 import org.springframework.web.reactive.config.ResourceChainRegistration;
@@ -71,15 +74,14 @@ import org.springframework.web.reactive.result.view.ViewResolver;
 @Configuration
 @ConditionalOnWebApplication(type = ConditionalOnWebApplication.Type.REACTIVE)
 @ConditionalOnClass(WebFluxConfigurer.class)
-@ConditionalOnMissingBean(RouterFunction.class)
+@ConditionalOnMissingBean({ WebFluxConfigurationSupport.class, RouterFunction.class })
 @AutoConfigureAfter(ReactiveWebServerAutoConfiguration.class)
 @AutoConfigureOrder(Ordered.HIGHEST_PRECEDENCE + 10)
 public class WebFluxAnnotationAutoConfiguration {
 
 	@Configuration
-	@ConditionalOnMissingBean(WebFluxConfigurationSupport.class)
 	@EnableConfigurationProperties({ResourceProperties.class, WebFluxProperties.class})
-	@Import(DelegatingWebFluxConfiguration.class)
+	@Import(EnableWebFluxConfiguration.class)
 	public static class WebFluxConfig implements WebFluxConfigurer {
 
 		private static final Log logger = LogFactory.getLog(WebFluxConfig.class);
@@ -178,6 +180,26 @@ public class WebFluxAnnotationAutoConfiguration {
 		}
 	}
 
+	/**
+	 * Configuration equivalent to {@code @EnableWebFlux}.
+	 */
+	@Configuration
+	public static class EnableWebFluxConfiguration
+			extends DelegatingWebFluxConfiguration {
+
+		@Override
+		@Bean
+		public Validator webFluxValidator() {
+			if (!ClassUtils.isPresent("javax.validation.Validator",
+					getClass().getClassLoader())) {
+				return super.webFluxValidator();
+			}
+			return SpringValidator.get(getApplicationContext(),
+					getValidator());
+		}
+
+	}
+
 	@Configuration
 	@ConditionalOnEnabledResourceChain
 	static class ResourceChainCustomizerConfiguration {

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/validation/SpringValidatorTests.java

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package org.springframework.boot.autoconfigure.web;
+package org.springframework.boot.autoconfigure.validation;
 
 import java.util.HashMap;
 
@@ -37,11 +37,11 @@ import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
 
 /**
- * Tests for {@link WebMvcValidator}.
+ * Tests for {@link SpringValidator}.
  *
  * @author Stephane Nicoll
  */
-public class WebMvcValidatorTests {
+public class SpringValidatorTests {
 
 	private AnnotationConfigApplicationContext context;
 
@@ -54,7 +54,7 @@ public class WebMvcValidatorTests {
 
 	@Test
 	public void wrapLocalValidatorFactoryBean() {
-		WebMvcValidator wrapper = load(
+		SpringValidator wrapper = load(
 				LocalValidatorFactoryBeanConfig.class);
 		assertThat(wrapper.supports(SampleData.class)).isTrue();
 		MapBindingResult errors = new MapBindingResult(new HashMap<String, Object>(),
@@ -89,12 +89,12 @@ public class WebMvcValidatorTests {
 		verify(validator, times(0)).destroy();
 	}
 
-	private WebMvcValidator load(Class<?> config) {
+	private SpringValidator load(Class<?> config) {
 		AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext();
 		ctx.register(config);
 		ctx.refresh();
 		this.context = ctx;
-		return this.context.getBean(WebMvcValidator.class);
+		return this.context.getBean(SpringValidator.class);
 	}
 
 	@Configuration
@@ -106,8 +106,8 @@ public class WebMvcValidatorTests {
 		}
 
 		@Bean
-		public WebMvcValidator wrapper() {
-			return new WebMvcValidator(validator(), true);
+		public SpringValidator wrapper() {
+			return new SpringValidator(validator(), true);
 		}
 
 	}
@@ -119,8 +119,8 @@ public class WebMvcValidatorTests {
 				LocalValidatorFactoryBean.class);
 
 		@Bean
-		public WebMvcValidator wrapper() {
-			return new WebMvcValidator(this.validator, false);
+		public SpringValidator wrapper() {
+			return new SpringValidator(this.validator, false);
 		}
 
 	}
@@ -132,8 +132,8 @@ public class WebMvcValidatorTests {
 				LocalValidatorFactoryBean.class);
 
 		@Bean
-		public WebMvcValidator wrapper() {
-			return new WebMvcValidator(this.validator, true);
+		public SpringValidator wrapper() {
+			return new SpringValidator(this.validator, true);
 		}
 
 	}

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

@@ -39,6 +39,7 @@ import org.junit.rules.ExpectedException;
 import org.springframework.beans.DirectFieldAccessor;
 import org.springframework.beans.factory.NoSuchBeanDefinitionException;
 import org.springframework.boot.autoconfigure.context.PropertyPlaceholderAutoConfiguration;
+import org.springframework.boot.autoconfigure.validation.SpringValidator;
 import org.springframework.boot.autoconfigure.web.WebMvcAutoConfiguration.WebMvcAutoConfigurationAdapter;
 import org.springframework.boot.autoconfigure.web.WebMvcAutoConfiguration.WelcomePageHandlerMapping;
 import org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext;
@@ -674,8 +675,8 @@ public class WebMvcAutoConfigurationTests {
 				.isEmpty();
 		assertThat(this.context.getBeansOfType(Validator.class)).hasSize(1);
 		Validator validator = this.context.getBean(Validator.class);
-		assertThat(validator).isInstanceOf(WebMvcValidator.class);
-		assertThat(((WebMvcValidator) validator).getTarget())
+		assertThat(validator).isInstanceOf(SpringValidator.class);
+		assertThat(((SpringValidator) validator).getTarget())
 				.isSameAs(this.context.getBean(MvcJsr303Validator.class).validator);
 	}
 
@@ -687,8 +688,8 @@ public class WebMvcAutoConfigurationTests {
 				.hasSize(1);
 		assertThat(this.context.getBeansOfType(Validator.class)).hasSize(2);
 		Validator validator = this.context.getBean("mvcValidator", Validator.class);
-		assertThat(validator).isInstanceOf(WebMvcValidator.class);
-		assertThat(((WebMvcValidator) validator).getTarget())
+		assertThat(validator).isInstanceOf(SpringValidator.class);
+		assertThat(((SpringValidator) validator).getTarget())
 				.isSameAs(this.context.getBean(javax.validation.Validator.class));
 	}
 
@@ -700,8 +701,8 @@ public class WebMvcAutoConfigurationTests {
 				.hasSize(1);
 		assertThat(this.context.getBeansOfType(Validator.class)).hasSize(1);
 		Validator validator = this.context.getBean(Validator.class);
-		assertThat(validator).isInstanceOf(WebMvcValidator.class);
-		SpringValidatorAdapter target = ((WebMvcValidator) validator)
+		assertThat(validator).isInstanceOf(SpringValidator.class);
+		SpringValidatorAdapter target = ((SpringValidator) 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/webflux/WebFluxAnnotationAutoConfigurationTests.java

@@ -16,8 +16,14 @@
 
 package org.springframework.boot.autoconfigure.webflux;
 
+import java.util.Optional;
+
+import javax.validation.ValidatorFactory;
+
 import org.junit.Test;
 
+import org.springframework.beans.DirectFieldAccessor;
+import org.springframework.boot.autoconfigure.validation.SpringValidator;
 import org.springframework.boot.context.GenericReactiveWebApplicationContext;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.boot.test.util.EnvironmentTestUtils;
@@ -28,9 +34,13 @@ import org.springframework.core.Ordered;
 import org.springframework.core.annotation.Order;
 import org.springframework.core.io.ClassPathResource;
 import org.springframework.http.server.reactive.HttpHandler;
+import org.springframework.validation.Validator;
+import org.springframework.validation.beanvalidation.LocalValidatorFactoryBean;
+import org.springframework.validation.beanvalidation.SpringValidatorAdapter;
 import org.springframework.web.reactive.HandlerMapping;
 import org.springframework.web.reactive.accept.CompositeContentTypeResolver;
 import org.springframework.web.reactive.config.WebFluxConfigurationSupport;
+import org.springframework.web.reactive.config.WebFluxConfigurer;
 import org.springframework.web.reactive.handler.SimpleUrlHandlerMapping;
 import org.springframework.web.reactive.resource.CachingResourceResolver;
 import org.springframework.web.reactive.resource.CachingResourceTransformer;
@@ -41,7 +51,6 @@ import org.springframework.web.reactive.result.method.annotation.RequestMappingH
 import org.springframework.web.reactive.result.method.annotation.RequestMappingHandlerMapping;
 import org.springframework.web.reactive.result.view.ViewResolutionResultHandler;
 import org.springframework.web.reactive.result.view.ViewResolver;
-import org.springframework.web.server.adapter.HttpWebHandlerAdapter;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.mockito.Mockito.mock;
@@ -152,6 +161,68 @@ public class WebFluxAnnotationAutoConfigurationTests {
 		);
 	}
 
+	@Test
+	public void validationNoJsr303ValidatorExposedByDefault() {
+		load();
+		assertThat(this.context.getBeansOfType(ValidatorFactory.class)).isEmpty();
+		assertThat(this.context.getBeansOfType(javax.validation.Validator.class))
+				.isEmpty();
+		assertThat(this.context.getBeansOfType(Validator.class)).hasSize(1);
+	}
+
+	@Test
+	public void validationCustomConfigurerTakesPrecedence() {
+		load(WebFluxValidator.class);
+		assertThat(this.context.getBeansOfType(ValidatorFactory.class)).isEmpty();
+		assertThat(this.context.getBeansOfType(javax.validation.Validator.class))
+				.isEmpty();
+		assertThat(this.context.getBeansOfType(Validator.class)).hasSize(1);
+		Validator validator = this.context.getBean(Validator.class);
+		assertThat(validator)
+				.isSameAs(this.context.getBean(WebFluxValidator.class).validator);
+	}
+
+	@Test
+	public void validationCustomConfigurerTakesPrecedenceAndDoNotExposeJsr303() {
+		load(WebFluxJsr303Validator.class);
+		assertThat(this.context.getBeansOfType(ValidatorFactory.class)).isEmpty();
+		assertThat(this.context.getBeansOfType(javax.validation.Validator.class))
+				.isEmpty();
+		assertThat(this.context.getBeansOfType(Validator.class)).hasSize(1);
+		Validator validator = this.context.getBean(Validator.class);
+		assertThat(validator).isInstanceOf(SpringValidator.class);
+		assertThat(((SpringValidator) validator).getTarget())
+				.isSameAs(this.context.getBean(WebFluxJsr303Validator.class).validator);
+	}
+
+	@Test
+	public void validationJsr303CustomValidatorReusedAsSpringValidator() {
+		load(CustomValidator.class);
+		assertThat(this.context.getBeansOfType(ValidatorFactory.class)).hasSize(1);
+		assertThat(this.context.getBeansOfType(javax.validation.Validator.class))
+				.hasSize(1);
+		assertThat(this.context.getBeansOfType(Validator.class)).hasSize(2);
+		Validator validator = this.context.getBean("webFluxValidator", Validator.class);
+		assertThat(validator).isInstanceOf(SpringValidator.class);
+		assertThat(((SpringValidator) validator).getTarget())
+				.isSameAs(this.context.getBean(javax.validation.Validator.class));
+	}
+
+	@Test
+	public void validationJsr303ValidatorExposedAsSpringValidator() {
+		load(Jsr303Validator.class);
+		assertThat(this.context.getBeansOfType(ValidatorFactory.class)).isEmpty();
+		assertThat(this.context.getBeansOfType(javax.validation.Validator.class))
+				.hasSize(1);
+		assertThat(this.context.getBeansOfType(Validator.class)).hasSize(1);
+		Validator validator = this.context.getBean(Validator.class);
+		assertThat(validator).isInstanceOf(SpringValidator.class);
+		SpringValidatorAdapter target = ((SpringValidator) validator)
+				.getTarget();
+		assertThat(new DirectFieldAccessor(target).getPropertyValue("targetValidator"))
+				.isSameAs(this.context.getBean(javax.validation.Validator.class));
+	}
+
 	private void load(String... environment) {
 		load(null, environment);
 	}
@@ -216,4 +287,49 @@ public class WebFluxAnnotationAutoConfigurationTests {
 			return (serverHttpRequest, serverHttpResponse) -> null;
 		}
 	}
+
+	@Configuration
+	protected static class WebFluxValidator implements WebFluxConfigurer {
+
+		private final Validator validator = mock(Validator.class);
+
+		@Override
+		public Optional<Validator> getValidator() {
+			return Optional.of(this.validator);
+		}
+
+	}
+
+	@Configuration
+	protected static class WebFluxJsr303Validator implements WebFluxConfigurer {
+
+		private final LocalValidatorFactoryBean validator = new LocalValidatorFactoryBean();
+
+		@Override
+		public Optional<Validator> getValidator() {
+			return Optional.of(this.validator);
+		}
+
+	}
+
+	@Configuration
+	static class Jsr303Validator {
+
+		@Bean
+		public javax.validation.Validator jsr303Validator() {
+			return mock(javax.validation.Validator.class);
+		}
+
+	}
+
+	@Configuration
+	static class CustomValidator {
+
+		@Bean
+		public Validator customValidator() {
+			return new LocalValidatorFactoryBean();
+		}
+
+	}
+
 }