- /*
- * Copyright 2003-2004 The Apache Software Foundation
- *
- * 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.apache.commons.collections.map;
-
- import java.io.IOException;
- import java.io.ObjectInputStream;
- import java.io.ObjectOutputStream;
- import java.io.Serializable;
- import java.util.Iterator;
- import java.util.Map;
-
- import org.apache.commons.collections.Transformer;
-
- /**
- * Decorates another <code>Map</code> to transform objects that are added.
- * <p>
- * The Map put methods and Map.Entry setValue method are affected by this class.
- * Thus objects must be removed or searched for using their transformed form.
- * For example, if the transformation converts Strings to Integers, you must
- * use the Integer form to remove objects.
- * <p>
- * This class is Serializable from Commons Collections 3.1.
- *
- * @since Commons Collections 3.0
- * @version $Revision: 1.11 $ $Date: 2004/06/07 22:14:42 $
- *
- * @author Stephen Colebourne
- */
- public class TransformedMap
- extends AbstractInputCheckedMapDecorator
- implements Serializable {
-
- /** Serialization version */
- private static final long serialVersionUID = 7023152376788900464L;
-
- /** The transformer to use for the key */
- protected final Transformer keyTransformer;
- /** The transformer to use for the value */
- protected final Transformer valueTransformer;
-
- /**
- * Factory method to create a transforming map.
- * <p>
- * If there are any elements already in the map being decorated, they
- * are NOT transformed.
- *
- * @param map the map to decorate, must not be null
- * @param keyTransformer the transformer to use for key conversion, null means no conversion
- * @param valueTransformer the transformer to use for value conversion, null means no conversion
- * @throws IllegalArgumentException if map is null
- */
- public static Map decorate(Map map, Transformer keyTransformer, Transformer valueTransformer) {
- return new TransformedMap(map, keyTransformer, valueTransformer);
- }
-
- //-----------------------------------------------------------------------
- /**
- * Constructor that wraps (not copies).
- * <p>
- * If there are any elements already in the collection being decorated, they
- * are NOT transformed.
- *
- * @param map the map to decorate, must not be null
- * @param keyTransformer the transformer to use for key conversion, null means no conversion
- * @param valueTransformer the transformer to use for value conversion, null means no conversion
- * @throws IllegalArgumentException if map is null
- */
- protected TransformedMap(Map map, Transformer keyTransformer, Transformer valueTransformer) {
- super(map);
- this.keyTransformer = keyTransformer;
- this.valueTransformer = valueTransformer;
- }
-
- //-----------------------------------------------------------------------
- /**
- * Write the map out using a custom routine.
- *
- * @param out the output stream
- * @throws IOException
- * @since Commons Collections 3.1
- */
- private void writeObject(ObjectOutputStream out) throws IOException {
- out.defaultWriteObject();
- out.writeObject(map);
- }
-
- /**
- * Read the map in using a custom routine.
- *
- * @param in the input stream
- * @throws IOException
- * @throws ClassNotFoundException
- * @since Commons Collections 3.1
- */
- private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException {
- in.defaultReadObject();
- map = (Map) in.readObject();
- }
-
- //-----------------------------------------------------------------------
- /**
- * Transforms a key.
- * <p>
- * The transformer itself may throw an exception if necessary.
- *
- * @param object the object to transform
- * @throws the transformed object
- */
- protected Object transformKey(Object object) {
- if (keyTransformer == null) {
- return object;
- }
- return keyTransformer.transform(object);
- }
-
- /**
- * Transforms a value.
- * <p>
- * The transformer itself may throw an exception if necessary.
- *
- * @param object the object to transform
- * @throws the transformed object
- */
- protected Object transformValue(Object object) {
- if (valueTransformer == null) {
- return object;
- }
- return valueTransformer.transform(object);
- }
-
- /**
- * Transforms a map.
- * <p>
- * The transformer itself may throw an exception if necessary.
- *
- * @param map the map to transform
- * @throws the transformed object
- */
- protected Map transformMap(Map map) {
- Map result = new LinkedMap(map.size());
- for (Iterator it = map.entrySet().iterator(); it.hasNext(); ) {
- Map.Entry entry = (Map.Entry) it.next();
- result.put(transformKey(entry.getKey()), transformValue(entry.getValue()));
- }
- return result;
- }
-
- /**
- * Override to transform the value when using <code>setValue</code>.
- *
- * @param value the value to transform
- * @return the transformed value
- * @since Commons Collections 3.1
- */
- protected Object checkSetValue(Object value) {
- return valueTransformer.transform(value);
- }
-
- /**
- * Override to only return true when there is a value transformer.
- *
- * @return true if a value transformer is in use
- * @since Commons Collections 3.1
- */
- protected boolean isSetValueChecking() {
- return (valueTransformer != null);
- }
-
- //-----------------------------------------------------------------------
- public Object put(Object key, Object value) {
- key = transformKey(key);
- value = transformValue(value);
- return getMap().put(key, value);
- }
-
- public void putAll(Map mapToCopy) {
- mapToCopy = transformMap(mapToCopy);
- getMap().putAll(mapToCopy);
- }
-
- }