typeconverterdelegate.java

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	 * @param editor the PropertyEditor to use
	 * @return the new value, possibly the result of type conversion
	 * @throws IllegalArgumentException if type conversion failed
	 */
	protected Object doConvertValue(Object oldValue, Object newValue, Class requiredType, PropertyEditor editor) {
		Object convertedValue = newValue;
		boolean sharedEditor = false;

		if (editor != null) {
			sharedEditor = this.propertyEditorRegistry.isSharedEditor(editor);
		}

		if (editor != null && !(convertedValue instanceof String)) {
			// Not a String -> use PropertyEditor's setValue.
			// With standard PropertyEditors, this will return the very same object;
			// we just want to allow special PropertyEditors to override setValue
			// for type conversion from non-String values to the required type.
			try {
				Object newConvertedValue = null;
				if (sharedEditor) {
					// Synchronized access to shared editor instance.
					synchronized (editor) {
						editor.setValue(convertedValue);
						newConvertedValue = editor.getValue();
					}
				}
				else {
					// Unsynchronized access to non-shared editor instance.
					editor.setValue(convertedValue);
					newConvertedValue = editor.getValue();
				}
				if (newConvertedValue != convertedValue) {
					convertedValue = newConvertedValue;
					// Reset PropertyEditor: It already did a proper conversion.
					// Don't use it again for a setAsText call.
					editor = null;
				}
			}
			catch (Exception ex) {
				if (logger.isDebugEnabled()) {
					logger.debug("PropertyEditor [" + editor.getClass().getName() + "] does not support setValue call", ex);
				}
				// Swallow and proceed.
			}
		}

		if (requiredType != null && !requiredType.isArray() && convertedValue instanceof String[]) {
			// Convert String array to a comma-separated String.
			// Only applies if no PropertyEditor converted the String array before.
			// The CSV String will be passed into a PropertyEditor's setAsText method, if any.
			if (logger.isTraceEnabled()) {
				logger.trace("Converting String array to comma-delimited String [" + convertedValue + "]");
			}
			convertedValue = StringUtils.arrayToCommaDelimitedString((String[]) convertedValue);
		}

		if (editor != null && convertedValue instanceof String) {
			// Use PropertyEditor's setAsText in case of a String value.
			if (logger.isTraceEnabled()) {
				logger.trace("Converting String to [" + requiredType + "] using property editor [" + editor + "]");
			}
			String newTextValue = (String) convertedValue;
			if (sharedEditor) {
				// Synchronized access to shared editor instance.
				synchronized (editor) {
					return doConvertTextValue(oldValue, newTextValue, editor);
				}
			}
			else {
				// Unsynchronized access to non-shared editor instance.
				return doConvertTextValue(oldValue, newTextValue, editor);
			}
		}

		return convertedValue;
	}

	/**
	 * Convert the given text value using the given property editor.
	 * @param oldValue the previous value, if available (may be <code>null</code>)
	 * @param newTextValue the proposed text value
	 * @param editor the PropertyEditor to use
	 * @return the converted value
	 */
	protected Object doConvertTextValue(Object oldValue, String newTextValue, PropertyEditor editor) {
		editor.setValue(oldValue);
		editor.setAsText(newTextValue);
		return editor.getValue();
	}

	protected Object convertToTypedArray(Object input, String propertyName, Class componentType) {
		if (input instanceof Collection) {
			// Convert Collection elements to array elements.
			Collection coll = (Collection) input;
			Object result = Array.newInstance(componentType, coll.size());
			int i = 0;
			for (Iterator it = coll.iterator(); it.hasNext(); i++) {
				Object value = convertIfNecessary(
						buildIndexedPropertyName(propertyName, i), null, it.next(), componentType);
				Array.set(result, i, value);
			}
			return result;
		}
		else if (input.getClass().isArray()) {
			// Convert array elements, if necessary.
			if (componentType.equals(input.getClass().getComponentType()) &&
					!this.propertyEditorRegistry.hasCustomEditorForElement(componentType, propertyName)) {
				return input;
			}
			int arrayLength = Array.getLength(input);
			Object result = Array.newInstance(componentType, arrayLength);
			for (int i = 0; i < arrayLength; i++) {
				Object value = convertIfNecessary(
						buildIndexedPropertyName(propertyName, i), null, Array.get(input, i), componentType);
				Array.set(result, i, value);
			}
			return result;
		}
		else {
			// A plain value: convert it to an array with a single component.
			Object result = Array.newInstance(componentType, 1);
			Object value = convertIfNecessary(
					buildIndexedPropertyName(propertyName, 0), null, input, componentType);
			Array.set(result, 0, value);
			return result;
		}
	}

	protected Collection convertToTypedCollection(
			Collection original, String propertyName, MethodParameter methodParam) {

		Class elementType = null;
		if (methodParam != null && JdkVersion.isAtLeastJava15()) {
			elementType = GenericCollectionTypeResolver.getCollectionParameterType(methodParam);
		}
		if (elementType == null &&
				!this.propertyEditorRegistry.hasCustomEditorForElement(null, propertyName)) {
			return original;
		}

		Collection convertedCopy = null;
		Iterator it = null;
		try {
			it = original.iterator();
			if (it == null) {
				if (logger.isDebugEnabled()) {
					logger.debug("Collection of type [" + original.getClass().getName() +
							"] returned null Iterator - injecting original Collection as-is");
				}
				return original;
			}
			convertedCopy = CollectionFactory.createApproximateCollection(original, original.size());
		}
		catch (Throwable ex) {
			if (logger.isDebugEnabled()) {
				logger.debug("Cannot access Collection of type [" + original.getClass().getName() +
						"] - injecting original Collection as-is", ex);
			}
			return original;
		}
		boolean actuallyConverted = false;
		int i = 0;
		for (; it.hasNext(); i++) {
			Object element = it.next();
			String indexedPropertyName = buildIndexedPropertyName(propertyName, i);
			if (methodParam != null) {
				methodParam.increaseNestingLevel();
			}
			Object convertedElement =
					convertIfNecessary(indexedPropertyName, null, element, elementType, null, methodParam);
			if (methodParam != null) {
				methodParam.decreaseNestingLevel();
			}
			convertedCopy.add(convertedElement);
			actuallyConverted = actuallyConverted || (element != convertedElement);
		}
		return (actuallyConverted ? convertedCopy : original);
	}

	protected Map convertToTypedMap(Map original, String propertyName, MethodParameter methodParam) {
		Class keyType = null;
		Class valueType = null;
		if (methodParam != null && JdkVersion.isAtLeastJava15()) {
			keyType = GenericCollectionTypeResolver.getMapKeyParameterType(methodParam);
			valueType = GenericCollectionTypeResolver.getMapValueParameterType(methodParam);
		}
		if (keyType == null && valueType == null &&
				!this.propertyEditorRegistry.hasCustomEditorForElement(null, propertyName)) {
			return original;
		}

		Map convertedCopy = null;
		Iterator it = null;
		try {
			it = original.entrySet().iterator();
			if (it == null) {
				if (logger.isDebugEnabled()) {
					logger.debug("Map of type [" + original.getClass().getName() +
							"] returned null Iterator - injecting original Map as-is");
				}
			}
			convertedCopy = CollectionFactory.createApproximateMap(original, original.size());
		}
		catch (Throwable ex) {
			if (logger.isDebugEnabled()) {
				logger.debug("Cannot access Map of type [" + original.getClass().getName() +
						"] - injecting original Map as-is", ex);
			}
			return original;
		}
		boolean actuallyConverted = false;
		while (it.hasNext()) {
			Map.Entry entry = (Map.Entry) it.next();
			Object key = entry.getKey();
			Object value = entry.getValue();
			String keyedPropertyName = buildKeyedPropertyName(propertyName, key);
			if (methodParam != null) {
				methodParam.increaseNestingLevel();
				methodParam.setTypeIndexForCurrentLevel(0);
			}
			Object convertedKey = convertIfNecessary(keyedPropertyName, null, key, keyType, null, methodParam);
			if (methodParam != null) {
				methodParam.setTypeIndexForCurrentLevel(1);
			}
			Object convertedValue = convertIfNecessary(keyedPropertyName, null, value, valueType, null, methodParam);
			if (methodParam != null) {
				methodParam.decreaseNestingLevel();
			}
			convertedCopy.put(convertedKey, convertedValue);
			actuallyConverted = actuallyConverted || (key != convertedKey) || (value != convertedValue);
		}
		return (actuallyConverted ? convertedCopy : original);
	}

	private String buildIndexedPropertyName(String propertyName, int index) {
		return (propertyName != null ?
				propertyName + PropertyAccessor.PROPERTY_KEY_PREFIX + index + PropertyAccessor.PROPERTY_KEY_SUFFIX :
				null);
	}

	private String buildKeyedPropertyName(String propertyName, Object key) {
		return (propertyName != null ?
				propertyName + PropertyAccessor.PROPERTY_KEY_PREFIX + key + PropertyAccessor.PROPERTY_KEY_SUFFIX :
				null);
	}

}