Expose isReturnValue from MethodValidationException

See gh-29825

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

@@ -230,7 +230,8 @@ public class MethodValidationAdapter {
 			Method bridgedMethod = BridgeMethodResolver.findBridgedMethod(mostSpecificMethod);
 			result = execVal.validateParameters(target, bridgedMethod, arguments, groups);
 		}
-		return (result.isEmpty() ? EMPTY_RESULT : createException(target, method, result, i -> arguments[i]));
+		return (result.isEmpty() ? EMPTY_RESULT :
+				createException(target, method, result, i -> arguments[i], false));
 	}
 
 	/**
@@ -249,12 +250,12 @@ public class MethodValidationAdapter {
 
 		ExecutableValidator execVal = this.validator.get().forExecutables();
 		Set<ConstraintViolation<Object>> result = execVal.validateReturnValue(target, method, returnValue, groups);
-		return (result.isEmpty() ? EMPTY_RESULT : createException(target, method, result, i -> returnValue));
+		return (result.isEmpty() ? EMPTY_RESULT : createException(target, method, result, i -> returnValue, true));
 	}
 
 	private MethodValidationException createException(
 			Object target, Method method, Set<ConstraintViolation<Object>> violations,
-			Function<Integer, Object> argumentFunction) {
+			Function<Integer, Object> argumentFunction, boolean forReturnValue) {
 
 		Map<MethodParameter, ValueResultBuilder> parameterViolations = new LinkedHashMap<>();
 		Map<Path.Node, BeanResultBuilder> cascadedViolations = new LinkedHashMap<>();
@@ -296,7 +297,7 @@ public class MethodValidationAdapter {
 		cascadedViolations.forEach((node, builder) -> validatonResultList.add(builder.build()));
 		validatonResultList.sort(RESULT_COMPARATOR);
 
-		return new MethodValidationException(target, method, violations, validatonResultList);
+		return new MethodValidationException(target, method, violations, validatonResultList, forReturnValue);
 	}
 
 	/**
@@ -549,6 +550,11 @@ public class MethodValidationAdapter {
 		public void throwIfViolationsPresent() {
 		}
 
+		@Override
+		public String toString() {
+			return "MethodValidationResult (0 violations)";
+		}
+
 	}
 
 }

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

@@ -48,16 +48,19 @@ public class MethodValidationException extends ConstraintViolationException impl
 
 	private final List<ParameterValidationResult> allValidationResults;
 
+	private final boolean forReturnValue;
+
 
 	public MethodValidationException(
 			Object target, Method method, Set<? extends ConstraintViolation<?>> violations,
-			List<ParameterValidationResult> validationResults) {
+			List<ParameterValidationResult> validationResults, boolean forReturnValue) {
 
 		super(violations);
 		Assert.notEmpty(violations, "'violations' must not be empty");
 		this.target = target;
 		this.method = method;
 		this.allValidationResults = validationResults;
+		this.forReturnValue = forReturnValue;
 	}
 
 
@@ -75,6 +78,15 @@ public class MethodValidationException extends ConstraintViolationException impl
 		return this.method;
 	}
 
+	/**
+	 * Whether the violations are for a return value.
+	 * If true the violations are from validating a return value.
+	 * If false the violations are from validating method arguments.
+	 */
+	public boolean isForReturnValue() {
+		return this.forReturnValue;
+	}
+
 	// re-declare parent class method for NonNull treatment of interface
 
 	@Override
@@ -107,4 +119,10 @@ public class MethodValidationException extends ConstraintViolationException impl
 		throw this;
 	}
 
+	@Override
+	public String toString() {
+		return "MethodValidationResult (" + getConstraintViolations().size() + " violations) " +
+				"for " + this.method.toGenericString();
+	}
+
 }