LocalValidatorFactoryBean properly supports unwrap at ValidatorFactory level

Also documents limitation for Bean Validation 2.0's getClockProvider() method.

Issue: SPR-15561
Issue: SPR-13482

spring-context/src/main/java/org/springframework/validation/beanvalidation/LocalValidatorFactoryBean.java

@@ -30,6 +30,7 @@ import javax.validation.MessageInterpolator;
 import javax.validation.ParameterNameProvider;
 import javax.validation.TraversableResolver;
 import javax.validation.Validation;
+import javax.validation.ValidationException;
 import javax.validation.ValidationProviderResolver;
 import javax.validation.Validator;
 import javax.validation.ValidatorContext;
@@ -64,8 +65,12 @@ import org.springframework.util.ReflectionUtils;
  * you will almost always use the default Validator anyway. This can also be injected directly
  * into any target dependency of type {@link org.springframework.validation.Validator}!
  *
- * <p><b>As of Spring 5.0, this class requires Bean Validation 1.1, with special support
+ * <p><b>As of Spring 5.0, this class requires Bean Validation 1.1+, with special support
  * for Hibernate Validator 5.x</b> (see {@link #setValidationMessageSource}).
+ * This class is also runtime-compatible with Bean Validation 2.0 and Hibernate Validator 6.0,
+ * with one special note: If you'd like to call BV 2.0's {@code getClockProvider()} method,
+ * obtain the native {@code ValidatorFactory} through {@code #unwrap(ValidatorFactory.class)}
+ * and call the {@code getClockProvider()} method on the returned native reference there.
  *
  * <p>This class is also being used by Spring's MVC configuration namespace, in case of the
  * {@code javax.validation} API being present but no explicit Validator having been configured.
@@ -293,7 +298,6 @@ public class LocalValidatorFactoryBean extends SpringValidatorAdapter
 	}
 
 	private void configureParameterNameProviderIfPossible(Configuration<?> configuration) {
-		// TODO: inner class
 		final ParameterNameDiscoverer discoverer = this.parameterNameDiscoverer;
 		final ParameterNameProvider defaultProvider = configuration.getDefaultParameterNameProvider();
 		configuration.parameterNameProvider(new ParameterNameProvider() {
@@ -359,6 +363,32 @@ public class LocalValidatorFactoryBean extends SpringValidatorAdapter
 		return this.validatorFactory.getParameterNameProvider();
 	}
 
+	// Bean Validation 2.0: currently not implemented here since it would imply
+	// a hard dependency on the new javax.validation.ClockProvider interface.
+	// To be resolved once Spring Framework requires Bean Validation 2.0+.
+	// Obtain the native ValidatorFactory through unwrap(ValidatorFactory.class)
+	// instead which will fully support a getClockProvider() call as well.
+	/*
+	@Override
+	public javax.validation.ClockProvider getClockProvider() {
+		Assert.notNull(this.validatorFactory, "No target ValidatorFactory set");
+		return this.validatorFactory.getClockProvider();
+	}
+	*/
+
+	@Override
+	public <T> T unwrap(Class<T> type) {
+		if (type == null || !ValidatorFactory.class.isAssignableFrom(type)) {
+			try {
+				return super.unwrap(type);
+			}
+			catch (ValidationException ex) {
+				// ignore - we'll try ValidatorFactory unwrapping next
+			}
+		}
+		return this.validatorFactory.unwrap(type);
+	}
+
 	public void close() {
 		if (this.validatorFactory != null) {
 			this.validatorFactory.close();

spring-context/src/main/java/org/springframework/validation/beanvalidation/SpringValidatorAdapter.java

@@ -40,13 +40,16 @@ import org.springframework.validation.ObjectError;
 import org.springframework.validation.SmartValidator;
 
 /**
- * Adapter that takes a JSR-303 {@code javax.validator.Validator}
- * and exposes it as a Spring {@link org.springframework.validation.Validator}
+ * Adapter that takes a JSR-303 {@code javax.validator.Validator} and
+ * exposes it as a Spring {@link org.springframework.validation.Validator}
  * while also exposing the original JSR-303 Validator interface itself.
  *
  * <p>Can be used as a programmatic wrapper. Also serves as base class for
  * {@link CustomValidatorBean} and {@link LocalValidatorFactoryBean}.
  *
+ * <p>As of Spring Framework 5.0, this adapter is fully compatible with
+ * Bean Validation 1.1 as well as 2.0.
+ *
  * @author Juergen Hoeller
  * @since 3.0
  */

spring-context/src/test/java/org/springframework/validation/beanvalidation/SpringValidatorAdapterTests.java

@@ -27,6 +27,7 @@ import javax.validation.ConstraintValidator;
 import javax.validation.ConstraintValidatorContext;
 import javax.validation.Payload;
 import javax.validation.Validation;
+import javax.validation.Validator;
 import javax.validation.constraints.Pattern;
 import javax.validation.constraints.Size;
 
@@ -51,8 +52,9 @@ import static org.junit.Assert.*;
  */
 public class SpringValidatorAdapterTests {
 
-	private final SpringValidatorAdapter validatorAdapter = new SpringValidatorAdapter(
-			Validation.buildDefaultValidatorFactory().getValidator());
+	private final Validator nativeValidator = Validation.buildDefaultValidatorFactory().getValidator();
+
+	private final SpringValidatorAdapter validatorAdapter = new SpringValidatorAdapter(nativeValidator);
 
 	private final StaticMessageSource messageSource = new StaticMessageSource();
 
@@ -66,6 +68,12 @@ public class SpringValidatorAdapterTests {
 	}
 
 
+	@Test
+	public void testUnwrap() {
+		Validator nativeValidator = validatorAdapter.unwrap(Validator.class);
+		assertSame(this.nativeValidator, nativeValidator);
+	}
+
 	@Test  // SPR-13406
 	public void testNoStringArgumentValue() {
 		TestBean testBean = new TestBean();

spring-context/src/test/java/org/springframework/validation/beanvalidation/ValidatorFactoryTests.java

@@ -33,9 +33,12 @@ import javax.validation.ConstraintValidatorContext;
 import javax.validation.ConstraintViolation;
 import javax.validation.Payload;
 import javax.validation.Valid;
+import javax.validation.Validator;
+import javax.validation.ValidatorFactory;
 import javax.validation.constraints.NotNull;
 
 import org.hibernate.validator.HibernateValidator;
+import org.hibernate.validator.HibernateValidatorFactory;
 import org.junit.Test;
 
 import org.springframework.beans.factory.annotation.Autowired;
@@ -75,6 +78,12 @@ public class ValidatorFactoryTests {
 				fail("Invalid constraint violation with path '" + path + "'");
 			}
 		}
+
+		Validator nativeValidator = validator.unwrap(Validator.class);
+		assertTrue(nativeValidator.getClass().getName().startsWith("org.hibernate"));
+		assertTrue(validator.unwrap(ValidatorFactory.class) instanceof HibernateValidatorFactory);
+		assertTrue(validator.unwrap(HibernateValidatorFactory.class) instanceof HibernateValidatorFactory);
+
 		validator.destroy();
 	}
 
@@ -96,6 +105,12 @@ public class ValidatorFactoryTests {
 				fail("Invalid constraint violation with path '" + path + "'");
 			}
 		}
+
+		Validator nativeValidator = validator.unwrap(Validator.class);
+		assertTrue(nativeValidator.getClass().getName().startsWith("org.hibernate"));
+		assertTrue(validator.unwrap(ValidatorFactory.class) instanceof HibernateValidatorFactory);
+		assertTrue(validator.unwrap(HibernateValidatorFactory.class) instanceof HibernateValidatorFactory);
+
 		validator.destroy();
 	}
 
@@ -465,7 +480,7 @@ public class ValidatorFactoryTests {
 
 		String message() default "Should not be X";
 
-		Class<?>[] groups() default { };
+		Class<?>[] groups() default {};
 
 		Class<? extends Payload>[] payload() default {};
 	}