fixed collection element conversion using ConversionService (SPR-6950)

git-svn-id: https://src.springframework.org/svn/spring-framework/trunk@3176 50f2f4bb-b051-0410-bef5-90022cba6387

org.springframework.beans/src/main/java/org/springframework/beans/TypeConverterDelegate.java

@@ -196,8 +196,9 @@ class TypeConverterDelegate {
 		ConversionService conversionService = this.propertyEditorRegistry.getConversionService();
 		if (editor == null && conversionService != null && convertedValue != null) {
 			TypeDescriptor sourceTypeDesc = TypeDescriptor.forObject(convertedValue);
-			if (conversionService.canConvert(sourceTypeDesc, typeDescriptor)) {
-				return (T) conversionService.convert(convertedValue, sourceTypeDesc, typeDescriptor);
+			TypeDescriptor targetTypeDesc = typeDescriptor.forElementType(requiredType);
+			if (conversionService.canConvert(sourceTypeDesc, targetTypeDesc)) {
+				return (T) conversionService.convert(convertedValue, sourceTypeDesc, targetTypeDesc);
 			}
 		}
 
@@ -205,8 +206,8 @@ class TypeConverterDelegate {
 		if (editor != null || (requiredType != null && !ClassUtils.isAssignableValue(requiredType, convertedValue))) {
 			if (requiredType != null && Collection.class.isAssignableFrom(requiredType) &&
 					convertedValue instanceof String && typeDescriptor.getMethodParameter() != null) {
-				Class elementType = GenericCollectionTypeResolver.getCollectionParameterType(typeDescriptor.getMethodParameter());
-				if (elementType != null && Enum.class.isAssignableFrom(elementType)) {
+				Class elemType = GenericCollectionTypeResolver.getCollectionParameterType(typeDescriptor.getMethodParameter());
+				if (elemType != null && Enum.class.isAssignableFrom(elemType)) {
 					convertedValue = StringUtils.commaDelimitedListToStringArray((String) convertedValue);
 				}
 			}
@@ -572,7 +573,8 @@ class TypeConverterDelegate {
 			if (methodParam != null) {
 				methodParam.increaseNestingLevel();
 			}
-			Object convertedElement = convertIfNecessary(indexedPropertyName, null, element, elementType);
+			Object convertedElement = convertIfNecessary(
+					indexedPropertyName, null, element, elementType, typeDescriptor);
 			if (methodParam != null) {
 				methodParam.decreaseNestingLevel();
 			}
@@ -651,11 +653,11 @@ class TypeConverterDelegate {
 				methodParam.increaseNestingLevel();
 				methodParam.setTypeIndexForCurrentLevel(0);
 			}
-			Object convertedKey = convertIfNecessary(keyedPropertyName, null, key, keyType);
+			Object convertedKey = convertIfNecessary(keyedPropertyName, null, key, keyType, typeDescriptor);
 			if (methodParam != null) {
 				methodParam.setTypeIndexForCurrentLevel(1);
 			}
-			Object convertedValue = convertIfNecessary(keyedPropertyName, null, value, valueType);
+			Object convertedValue = convertIfNecessary(keyedPropertyName, null, value, valueType, typeDescriptor);
 			if (methodParam != null) {
 				methodParam.decreaseNestingLevel();
 			}

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

@@ -103,8 +103,6 @@ public class TypeDescriptor {
 		this.field = field;
 	}
 
-	// protected constructors for subclasses
-	
 	/**
 	 * Create a new type descriptor from a method or constructor parameter.
 	 * <p>Use this constructor when a target conversion point originates from a method parameter,
@@ -112,12 +110,23 @@ public class TypeDescriptor {
 	 * @param methodParameter the MethodParameter to wrap
 	 * @param type the specific type to expose (may be an array/collection element)
 	 */
-	protected TypeDescriptor(MethodParameter methodParameter, Class<?> type) {
+	public TypeDescriptor(MethodParameter methodParameter, Class<?> type) {
 		Assert.notNull(methodParameter, "MethodParameter must not be null");
 		this.methodParameter = methodParameter;
 		this.type = type;
 	}
 
+	/**
+	 * Create a new type descriptor for a field.
+	 * Use this constructor when a target conversion point originates from a field.
+	 * @param field the field to wrap
+	 */
+	public TypeDescriptor(Field field, Class<?> type) {
+		Assert.notNull(field, "Field must not be null");
+		this.field = field;
+		this.type = type;
+	}
+
 	/**
 	 * Internal constructor for a NULL descriptor.
 	 */
@@ -227,24 +236,43 @@ public class TypeDescriptor {
 
 	/**
 	 * If this type is an array type or {@link Collection} type, returns the underlying element type.
-	 * Returns null if the type is neither an array or collection.
+	 * Returns <code>null</code> if the type is neither an array or collection.
 	 */
 	public Class<?> getElementType() {
-		return getElementTypeDescriptor().getType();
+		if (isArray()) {
+			return getArrayComponentType();
+		}
+		else if (isCollection()) {
+			return getCollectionElementType();
+		}
+		else {
+			return null;
+		}
 	}
 
 	/**
 	 * Return the element type as a type descriptor.
 	 */
 	public TypeDescriptor getElementTypeDescriptor() {
-		if (isArray()) {
-			return TypeDescriptor.valueOf(getArrayComponentType());
+		return TypeDescriptor.valueOf(getElementType());
+	}
+
+	/**
+	 * Create a copy of this type descriptor, preserving the context information
+	 * but exposing the specified element type (e.g. an array/collection element).
+	 * @param elementType the desired type to expose
+	 * @return the type descriptor
+	 */
+	public TypeDescriptor forElementType(Class<?> elementType) {
+		Assert.notNull(elementType, "Element type must not be null");
+		if (getType().equals(elementType)) {
+			return this;
 		}
-		else if (isCollection()) {
-			return TypeDescriptor.valueOf(getCollectionElementType());
+		else if (this.methodParameter != null) {
+			return new TypeDescriptor(this.methodParameter, elementType);
 		}
 		else {
-			return TypeDescriptor.NULL;
+			return new TypeDescriptor(this.field, elementType);
 		}
 	}
 

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

@@ -58,7 +58,7 @@ public class PropertyTypeDescriptor extends TypeDescriptor {
 	 * @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) {
+	public PropertyTypeDescriptor(PropertyDescriptor propertyDescriptor, MethodParameter methodParameter, Class<?> type) {
 		super(methodParameter, type);
 		this.propertyDescriptor = propertyDescriptor;
 	}