Fixed detection of setter in case of getter with covariant return type narrowing

Issue: SPR-10995

spring-beans/src/main/java/org/springframework/beans/GenericTypeAwarePropertyDescriptor.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2012 the original author or authors.
+ * Copyright 2002-2013 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.
@@ -31,32 +31,32 @@ import org.springframework.util.ClassUtils;
 import org.springframework.util.StringUtils;
 
 /**
- * Extension of the standard JavaBeans PropertyDescriptor class,
- * overriding {@code getPropertyType()} such that a generically
- * declared type will be resolved against the containing bean class.
+ * Extension of the standard JavaBeans {@link PropertyDescriptor} class,
+ * overriding {@code getPropertyType()} such that a generically declared
+ * type variable will be resolved against the containing bean class.
  *
  * @author Juergen Hoeller
  * @since 2.5.2
  */
 class GenericTypeAwarePropertyDescriptor extends PropertyDescriptor {
 
-	private final Class beanClass;
+	private final Class<?> beanClass;
 
 	private final Method readMethod;
 
 	private final Method writeMethod;
 
-	private final Class propertyEditorClass;
+	private final Class<?> propertyEditorClass;
 
 	private volatile Set<Method> ambiguousWriteMethods;
 
-	private Class propertyType;
+	private Class<?> propertyType;
 
 	private MethodParameter writeMethodParameter;
 
 
-	public GenericTypeAwarePropertyDescriptor(Class beanClass, String propertyName,
-			Method readMethod, Method writeMethod, Class propertyEditorClass)
+	public GenericTypeAwarePropertyDescriptor(Class<?> beanClass, String propertyName,
+			Method readMethod, Method writeMethod, Class<?> propertyEditorClass)
 			throws IntrospectionException {
 
 		super(propertyName, null, null);
@@ -69,8 +69,11 @@ class GenericTypeAwarePropertyDescriptor extends PropertyDescriptor {
 			// Fallback: Original JavaBeans introspection might not have found matching setter
 			// method due to lack of bridge method resolution, in case of the getter using a
 			// covariant return type whereas the setter is defined for the concrete property type.
-			writeMethodToUse = ClassUtils.getMethodIfAvailable(this.beanClass,
-					"set" + StringUtils.capitalize(getName()), readMethodToUse.getReturnType());
+			Method candidate = ClassUtils.getMethodIfAvailable(
+					this.beanClass, "set" + StringUtils.capitalize(getName()), (Class<?>[]) null);
+			if (candidate != null && candidate.getParameterTypes().length == 1) {
+				writeMethodToUse = candidate;
+			}
 		}
 		this.readMethod = readMethodToUse;
 		this.writeMethod = writeMethodToUse;
@@ -118,12 +121,12 @@ class GenericTypeAwarePropertyDescriptor extends PropertyDescriptor {
 	}
 
 	@Override
-	public Class getPropertyEditorClass() {
+	public Class<?> getPropertyEditorClass() {
 		return this.propertyEditorClass;
 	}
 
 	@Override
-	public synchronized Class getPropertyType() {
+	public synchronized Class<?> getPropertyType() {
 		if (this.propertyType == null) {
 			if (this.readMethod != null) {
 				this.propertyType = GenericTypeResolver.resolveReturnType(this.readMethod, this.beanClass);

spring-beans/src/test/java/org/springframework/tests/sample/beans/DerivedTestBean.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2012 the original author or authors.
+ * Copyright 2002-2013 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.
@@ -71,6 +71,11 @@ public class DerivedTestBean extends TestBean implements Serializable, BeanNameA
 		setSpouse(new TestBean(name));
 	}
 
+	@Override
+	public TestBean getSpouse() {
+		return (TestBean) super.getSpouse();
+	}
+
 
 	public void initialize() {
 		this.initialized = true;

spring-beans/src/test/resources/org/springframework/beans/factory/xml/collections.xml

@@ -35,11 +35,10 @@
 		</property>
 	</bean>
 
-	<bean id="pJenny" class="org.springframework.tests.sample.beans.TestBean" scope="prototype">
+	<bean id="pJenny" class="org.springframework.tests.sample.beans.DerivedTestBean" scope="prototype">
 		<property name="name"><value>Jenny</value></property>
 		<property name="age"><value>30</value></property>
 		<property name="spouse">
-		<!-- Could use id and href -->
 			<ref local="david"/>
 		</property>
 	</bean>

spring-core/src/main/java/org/springframework/util/ClassUtils.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2012 the original author or authors.
+ * Copyright 2002-2013 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.
@@ -17,15 +17,12 @@
 package org.springframework.util;
 
 import java.beans.Introspector;
-
 import java.lang.reflect.Array;
 import java.lang.reflect.Constructor;
 import java.lang.reflect.Method;
 import java.lang.reflect.Modifier;
 import java.lang.reflect.Proxy;
-
 import java.security.AccessControlException;
-
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
@@ -578,7 +575,7 @@ public abstract class ClassUtils {
 	/**
 	 * Determine whether the given class has a public constructor with the given signature.
 	 * <p>Essentially translates {@code NoSuchMethodException} to "false".
-	 * @param clazz    the clazz to analyze
+	 * @param clazz the clazz to analyze
 	 * @param paramTypes the parameter types of the method
 	 * @return whether the class has a corresponding constructor
 	 * @see Class#getMethod
@@ -591,7 +588,7 @@ public abstract class ClassUtils {
 	 * Determine whether the given class has a public constructor with the given signature,
 	 * and return it if available (else return {@code null}).
 	 * <p>Essentially translates {@code NoSuchMethodException} to {@code null}.
-	 * @param clazz    the clazz to analyze
+	 * @param clazz the clazz to analyze
 	 * @param paramTypes the parameter types of the method
 	 * @return the constructor, or {@code null} if not found
 	 * @see Class#getConstructor
@@ -607,9 +604,9 @@ public abstract class ClassUtils {
 	}
 
 	/**
-	 * Determine whether the given class has a method with the given signature.
+	 * Determine whether the given class has a public method with the given signature.
 	 * <p>Essentially translates {@code NoSuchMethodException} to "false".
-	 * @param clazz    the clazz to analyze
+	 * @param clazz the clazz to analyze
 	 * @param methodName the name of the method
 	 * @param paramTypes the parameter types of the method
 	 * @return whether the class has a corresponding method
@@ -620,12 +617,15 @@ public abstract class ClassUtils {
 	}
 
 	/**
-	 * Determine whether the given class has a method with the given signature,
+	 * Determine whether the given class has a public method with the given signature,
 	 * and return it if available (else throws an {@code IllegalStateException}).
+	 * <p>In case of any signature specified, only returns the method if there is a
+	 * unique candidate, i.e. a single public method with the specified name.
 	 * <p>Essentially translates {@code NoSuchMethodException} to {@code IllegalStateException}.
-	 * @param clazz    the clazz to analyze
+	 * @param clazz the clazz to analyze
 	 * @param methodName the name of the method
 	 * @param paramTypes the parameter types of the method
+	 * (may be {@code null} to indicate any signature)
 	 * @return the method (never {@code null})
 	 * @throws IllegalStateException if the method has not been found
 	 * @see Class#getMethod
@@ -633,31 +633,69 @@ public abstract class ClassUtils {
 	public static Method getMethod(Class<?> clazz, String methodName, Class<?>... paramTypes) {
 		Assert.notNull(clazz, "Class must not be null");
 		Assert.notNull(methodName, "Method name must not be null");
-		try {
-			return clazz.getMethod(methodName, paramTypes);
+		if (paramTypes != null) {
+			try {
+				return clazz.getMethod(methodName, paramTypes);
+			}
+			catch (NoSuchMethodException ex) {
+				throw new IllegalStateException("Expected method not found: " + ex);
+			}
 		}
-		catch (NoSuchMethodException ex) {
-			throw new IllegalStateException("Expected method not found: " + ex);
+		else {
+			Set<Method> candidates = new HashSet<Method>(1);
+			Method[] methods = clazz.getMethods();
+			for (Method method : methods) {
+				if (methodName.equals(method.getName())) {
+					candidates.add(method);
+				}
+			}
+			if (candidates.size() == 1) {
+				return candidates.iterator().next();
+			}
+			else if (candidates.isEmpty()) {
+				throw new IllegalStateException("Expected method not found: " + clazz + "." + methodName);
+			}
+			else {
+				throw new IllegalStateException("No unique method found: " + clazz + "." + methodName);
+			}
 		}
 	}
 
 	/**
-	 * Determine whether the given class has a method with the given signature,
+	 * Determine whether the given class has a public method with the given signature,
 	 * and return it if available (else return {@code null}).
+	 * <p>In case of any signature specified, only returns the method if there is a
+	 * unique candidate, i.e. a single public method with the specified name.
 	 * <p>Essentially translates {@code NoSuchMethodException} to {@code null}.
-	 * @param clazz    the clazz to analyze
+	 * @param clazz the clazz to analyze
 	 * @param methodName the name of the method
 	 * @param paramTypes the parameter types of the method
+	 * (may be {@code null} to indicate any signature)
 	 * @return the method, or {@code null} if not found
 	 * @see Class#getMethod
 	 */
 	public static Method getMethodIfAvailable(Class<?> clazz, String methodName, Class<?>... paramTypes) {
 		Assert.notNull(clazz, "Class must not be null");
 		Assert.notNull(methodName, "Method name must not be null");
-		try {
-			return clazz.getMethod(methodName, paramTypes);
+		if (paramTypes != null) {
+			try {
+				return clazz.getMethod(methodName, paramTypes);
+			}
+			catch (NoSuchMethodException ex) {
+				return null;
+			}
 		}
-		catch (NoSuchMethodException ex) {
+		else {
+			Set<Method> candidates = new HashSet<Method>(1);
+			Method[] methods = clazz.getMethods();
+			for (Method method : methods) {
+				if (methodName.equals(method.getName())) {
+					candidates.add(method);
+				}
+			}
+			if (candidates.size() == 1) {
+				return candidates.iterator().next();
+			}
 			return null;
 		}
 	}
@@ -1025,7 +1063,7 @@ public abstract class ClassUtils {
 	 * @param instance the instance to analyze for interfaces
 	 * @return all interfaces that the given instance implements as array
 	 */
-	public static Class[] getAllInterfaces(Object instance) {
+	public static Class<?>[] getAllInterfaces(Object instance) {
 		Assert.notNull(instance, "Instance must not be null");
 		return getAllInterfacesForClass(instance.getClass());
 	}