revised BeanTypeDescriptor into core PropertyTypeDescriptor; consider method annotations for return type (SPR-6979)

org.springframework.core/src/main/java/org/springframework/core/convert/TypeDescriptor.java

@@ -345,7 +345,14 @@ public class TypeDescriptor {
 			return this.cachedFieldAnnotations;
 		}
 		else if (this.methodParameter != null) {
-			return this.methodParameter.getParameterAnnotations();
+			if (this.methodParameter.getParameterIndex() < 0) {
+				// The best we can do for return type metadata is to expose
+				// method-level annotations when the target is the return type...
+				return this.methodParameter.getMethodAnnotations();
+			}
+			else {
+				return this.methodParameter.getParameterAnnotations();
+			}
 		}
 		else {
 			return new Annotation[0];

org.springframework.core/src/main/java/org/springframework/core/convert/support/PropertyTypeDescriptor.java

@@ -0,0 +1,109 @@
+/*
+ * Copyright 2002-2010 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
+ *
+ *      http://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.core.convert.support;
+
+import java.beans.PropertyDescriptor;
+import java.lang.annotation.Annotation;
+import java.lang.reflect.Field;
+import java.lang.reflect.Method;
+import java.util.LinkedHashMap;
+import java.util.Map;
+
+import org.springframework.core.MethodParameter;
+import org.springframework.core.convert.TypeDescriptor;
+import org.springframework.util.ReflectionUtils;
+
+/**
+ * {@link TypeDescriptor} extension that exposes additional annotations
+ * as conversion metadata: namely, annotations on other accessor methods
+ * (getter/setter) and on the underlying field, if found.
+ *
+ * @author Juergen Hoeller
+ * @since 3.0
+ */
+public class PropertyTypeDescriptor extends TypeDescriptor {
+
+	private final PropertyDescriptor propertyDescriptor;
+
+	private Annotation[] cachedAnnotations;
+
+
+	/**
+	 * Create a new BeanTypeDescriptor for the given bean property.
+	 * @param propertyDescriptor the corresponding JavaBean PropertyDescriptor
+	 * @param methodParameter the target method parameter
+	 */
+	public PropertyTypeDescriptor(PropertyDescriptor propertyDescriptor, MethodParameter methodParameter) {
+		super(methodParameter);
+		this.propertyDescriptor = propertyDescriptor;
+	}
+
+	/**
+	 * Create a new BeanTypeDescriptor for the given bean property.
+	 * @param propertyDescriptor the corresponding JavaBean PropertyDescriptor
+	 * @param methodParameter the target method parameter
+	 * @param type the specific type to expose (may be an array/collection element)
+	 */
+	public PropertyTypeDescriptor(PropertyDescriptor propertyDescriptor, MethodParameter methodParameter, Class type) {
+		super(methodParameter, type);
+		this.propertyDescriptor = propertyDescriptor;
+	}
+
+
+	/**
+	 * Return the underlying PropertyDescriptor.
+	 */
+	public PropertyDescriptor getPropertyDescriptor() {
+		return this.propertyDescriptor;
+	}
+
+	public Annotation[] getAnnotations() {
+		Annotation[] anns = this.cachedAnnotations;
+		if (anns == null) {
+			Field underlyingField = ReflectionUtils.findField(
+					getMethodParameter().getMethod().getDeclaringClass(), this.propertyDescriptor.getName());
+			Map<Class, Annotation> annMap = new LinkedHashMap<Class, Annotation>();
+			if (underlyingField != null) {
+				for (Annotation ann : underlyingField.getAnnotations()) {
+					annMap.put(ann.annotationType(), ann);
+				}
+			}
+			Method writeMethod = this.propertyDescriptor.getWriteMethod();
+			Method readMethod = this.propertyDescriptor.getReadMethod();
+			if (writeMethod != null && writeMethod != getMethodParameter().getMethod()) {
+				for (Annotation ann : writeMethod.getAnnotations()) {
+					annMap.put(ann.annotationType(), ann);
+				}
+			}
+			if (readMethod != null && readMethod != getMethodParameter().getMethod()) {
+				for (Annotation ann : readMethod.getAnnotations()) {
+					annMap.put(ann.annotationType(), ann);
+				}
+			}
+			for (Annotation ann : getMethodParameter().getMethodAnnotations()) {
+				annMap.put(ann.annotationType(), ann);
+			}
+			for (Annotation ann : getMethodParameter().getParameterAnnotations()) {
+				annMap.put(ann.annotationType(), ann);
+			}
+			anns = annMap.values().toArray(new Annotation[annMap.size()]);
+			this.cachedAnnotations = anns;
+		}
+		return anns;
+	}
+
+}