Add ~.validation.method package

Extract classes from ~.validation.beanvalidation without a direct
dependency on beanvalidation.

See gh-30644

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

@@ -18,7 +18,6 @@ package org.springframework.validation.beanvalidation;
 
 import java.lang.reflect.Method;
 import java.util.ArrayList;
-import java.util.Collections;
 import java.util.Comparator;
 import java.util.Iterator;
 import java.util.LinkedHashMap;
@@ -50,7 +49,6 @@ import org.springframework.core.MethodParameter;
 import org.springframework.core.ParameterNameDiscoverer;
 import org.springframework.core.annotation.AnnotationUtils;
 import org.springframework.lang.Nullable;
-import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.function.SingletonSupplier;
 import org.springframework.validation.BeanPropertyBindingResult;
@@ -59,6 +57,10 @@ import org.springframework.validation.DefaultMessageCodesResolver;
 import org.springframework.validation.Errors;
 import org.springframework.validation.MessageCodesResolver;
 import org.springframework.validation.annotation.Validated;
+import org.springframework.validation.method.MethodValidationResult;
+import org.springframework.validation.method.MethodValidator;
+import org.springframework.validation.method.ParameterErrors;
+import org.springframework.validation.method.ParameterValidationResult;
 
 /**
  * {@link MethodValidator} that uses a Bean Validation
@@ -70,12 +72,12 @@ import org.springframework.validation.annotation.Validated;
  */
 public class MethodValidationAdapter implements MethodValidator {
 
+	private static final MethodValidationResult emptyValidationResult = MethodValidationResult.emptyResult();
+
 	private static final ObjectNameResolver defaultObjectNameResolver = new DefaultObjectNameResolver();
 
 	private static final Comparator<ParameterValidationResult> resultComparator = new ResultComparator();
 
-	private static final MethodValidationResult emptyResult = new EmptyMethodValidationResult();
-
 
 	private final Supplier<Validator> validator;
 
@@ -219,7 +221,7 @@ public class MethodValidationAdapter implements MethodValidator {
 				invokeValidatorForArguments(target, method, arguments, groups);
 
 		if (violations.isEmpty()) {
-			return emptyResult;
+			return emptyValidationResult;
 		}
 
 		return adaptViolations(target, method, violations,
@@ -257,7 +259,7 @@ public class MethodValidationAdapter implements MethodValidator {
 				invokeValidatorForReturnValue(target, method, returnValue, groups);
 
 		if (violations.isEmpty()) {
-			return emptyResult;
+			return emptyValidationResult;
 		}
 
 		return adaptViolations(target, method, violations,
@@ -320,7 +322,7 @@ public class MethodValidationAdapter implements MethodValidator {
 		cascadedViolations.forEach((node, builder) -> validatonResultList.add(builder.build()));
 		validatonResultList.sort(resultComparator);
 
-		return new DefaultMethodValidationResult(target, method, validatonResultList);
+		return MethodValidationResult.create(target, method, validatonResultList);
 	}
 
 	private MethodParameter initMethodParameter(Method method, int index) {
@@ -534,91 +536,4 @@ public class MethodValidationAdapter implements MethodValidator {
 		}
 	}
 
-
-	/**
-	 * Default {@link MethodValidationResult} implementation with non-zero errors.
-	 */
-	private static class DefaultMethodValidationResult implements MethodValidationResult {
-
-		private final Object target;
-
-		private final Method method;
-
-		private final List<ParameterValidationResult> allValidationResults;
-
-		private final boolean forReturnValue;
-
-
-		DefaultMethodValidationResult(Object target, Method method, List<ParameterValidationResult> results) {
-			Assert.notEmpty(results, "'results' is required and must not be empty");
-			Assert.notNull(target, "'target' is required");
-			Assert.notNull(method, "Method is required");
-			this.target = target;
-			this.method = method;
-			this.allValidationResults = results;
-			this.forReturnValue = (results.get(0).getMethodParameter().getParameterIndex() == -1);
-		}
-
-
-		@Override
-		public Object getTarget() {
-			return this.target;
-		}
-
-		@Override
-		public Method getMethod() {
-			return this.method;
-		}
-
-		@Override
-		public boolean isForReturnValue() {
-			return this.forReturnValue;
-		}
-
-		@Override
-		public List<ParameterValidationResult> getAllValidationResults() {
-			return this.allValidationResults;
-		}
-
-
-		@Override
-		public String toString() {
-			return getAllErrors().size() + " validation errors " +
-					"for " + (isForReturnValue() ? "return value" : "arguments") + " of " +
-					this.method.toGenericString();
-		}
-	}
-
-
-	/**
-	 * {@link MethodValidationResult} for when there are no errors.
-	 */
-	private static class EmptyMethodValidationResult implements MethodValidationResult {
-
-		@Override
-		public Object getTarget() {
-			throw new UnsupportedOperationException();
-		}
-
-		@Override
-		public Method getMethod() {
-			throw new UnsupportedOperationException();
-		}
-
-		@Override
-		public boolean isForReturnValue() {
-			throw new UnsupportedOperationException();
-		}
-
-		@Override
-		public List<ParameterValidationResult> getAllValidationResults() {
-			return Collections.emptyList();
-		}
-
-		@Override
-		public String toString() {
-			return "0 validation errors";
-		}
-	}
-
 }

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

@@ -34,6 +34,8 @@ import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
 import org.springframework.validation.annotation.Validated;
+import org.springframework.validation.method.MethodValidationException;
+import org.springframework.validation.method.MethodValidationResult;
 
 /**
  * An AOP Alliance {@link MethodInterceptor} implementation that delegates to a

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

@@ -36,6 +36,8 @@ import org.springframework.beans.factory.config.BeanPostProcessor;
 import org.springframework.util.Assert;
 import org.springframework.util.function.SingletonSupplier;
 import org.springframework.validation.annotation.Validated;
+import org.springframework.validation.method.MethodValidationException;
+import org.springframework.validation.method.MethodValidationResult;
 
 /**
  * A convenient {@link BeanPostProcessor} implementation that delegates to a

spring-context/src/main/java/org/springframework/validation/method/DefaultMethodValidationResult.java

@@ -0,0 +1,80 @@
+/*
+ * Copyright 2002-2023 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.validation.method;
+
+import java.lang.reflect.Method;
+import java.util.List;
+
+import org.springframework.util.Assert;
+
+/**
+ * Default {@link MethodValidationResult} implementation as a simple container.
+ *
+ * @author Rossen Stoyanchev
+ * @since 6.1
+ */
+final class DefaultMethodValidationResult implements MethodValidationResult {
+
+	private final Object target;
+
+	private final Method method;
+
+	private final List<ParameterValidationResult> allValidationResults;
+
+	private final boolean forReturnValue;
+
+
+	DefaultMethodValidationResult(Object target, Method method, List<ParameterValidationResult> results) {
+		Assert.notEmpty(results, "'results' is required and must not be empty");
+		Assert.notNull(target, "'target' is required");
+		Assert.notNull(method, "Method is required");
+		this.target = target;
+		this.method = method;
+		this.allValidationResults = results;
+		this.forReturnValue = (results.get(0).getMethodParameter().getParameterIndex() == -1);
+	}
+
+
+	@Override
+	public Object getTarget() {
+		return this.target;
+	}
+
+	@Override
+	public Method getMethod() {
+		return this.method;
+	}
+
+	@Override
+	public boolean isForReturnValue() {
+		return this.forReturnValue;
+	}
+
+	@Override
+	public List<ParameterValidationResult> getAllValidationResults() {
+		return this.allValidationResults;
+	}
+
+
+	@Override
+	public String toString() {
+		return getAllErrors().size() + " validation errors " +
+				"for " + (isForReturnValue() ? "return value" : "arguments") + " of " +
+				this.method.toGenericString();
+	}
+
+}

spring-context/src/main/java/org/springframework/validation/method/EmptyMethodValidationResult.java

@@ -0,0 +1,56 @@
+/*
+ * Copyright 2002-2023 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.validation.method;
+
+import java.lang.reflect.Method;
+import java.util.Collections;
+import java.util.List;
+
+/**
+ * {@link MethodValidationResult} with an empty list of results.
+ *
+ * @author Rossen Stoyanchev
+ * @since 6.1
+ */
+final class EmptyMethodValidationResult implements MethodValidationResult {
+
+	@Override
+	public Object getTarget() {
+		throw new UnsupportedOperationException();
+	}
+
+	@Override
+	public Method getMethod() {
+		throw new UnsupportedOperationException();
+	}
+
+	@Override
+	public boolean isForReturnValue() {
+		throw new UnsupportedOperationException();
+	}
+
+	@Override
+	public List<ParameterValidationResult> getAllValidationResults() {
+		return Collections.emptyList();
+	}
+
+	@Override
+	public String toString() {
+		return "0 validation errors";
+	}
+
+}

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

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package org.springframework.validation.beanvalidation;
+package org.springframework.validation.method;
 
 import java.lang.reflect.Method;
 import java.util.List;

spring-context/src/main/java/org/springframework/validation/method/MethodValidationResult.java

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package org.springframework.validation.beanvalidation;
+package org.springframework.validation.method;
 
 import java.lang.reflect.Method;
 import java.util.List;
@@ -101,4 +101,25 @@ public interface MethodValidationResult {
 				.toList();
 	}
 
+
+	/**
+	 * Factory method to create a {@link MethodValidationResult} instance.
+	 * @param target the target Object
+	 * @param method the target method
+	 * @param results method validation results, expected to be non-empty
+	 * @return the created instance
+	 */
+	static MethodValidationResult create(Object target, Method method, List<ParameterValidationResult> results) {
+		return new DefaultMethodValidationResult(target, method, results);
+	}
+
+	/**
+	 * Factory method to create a {@link MethodValidationResult} instance with
+	 * 0 errors, suitable to use as a constant. Getters for a target object or
+	 * method are not supported.
+	 */
+	static MethodValidationResult emptyResult() {
+		return new EmptyMethodValidationResult();
+	}
+
 }

spring-context/src/main/java/org/springframework/validation/method/MethodValidator.java

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package org.springframework.validation.beanvalidation;
+package org.springframework.validation.method;
 
 import java.lang.reflect.Method;
 

spring-context/src/main/java/org/springframework/validation/method/ParameterErrors.java

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package org.springframework.validation.beanvalidation;
+package org.springframework.validation.method;
 
 import java.util.List;
 

spring-context/src/main/java/org/springframework/validation/method/ParameterValidationResult.java

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package org.springframework.validation.beanvalidation;
+package org.springframework.validation.method;
 
 import java.util.Collection;
 import java.util.List;

spring-context/src/main/java/org/springframework/validation/method/package-info.java

@@ -0,0 +1,21 @@
+/**
+ * Abstractions and support classes for method validation, independent of the
+ * underlying validation library.
+ *
+ * <p>The main abstractions:
+ * <ul>
+ * <li>{@link org.springframework.validation.method.MethodValidator} to apply
+ * method validation, and return or handle the results.
+ * <li>{@link org.springframework.validation.method.MethodValidationResult} and
+ * related types to represent the results.
+ * <li>{@link org.springframework.validation.method.MethodValidationException}
+ * to expose method validation results.
+ * </ul>
+ */
+
+@NonNullApi
+@NonNullFields
+package org.springframework.validation.method;
+
+import org.springframework.lang.NonNullApi;
+import org.springframework.lang.NonNullFields;