collections-generic-4.01.src.java.org.apache.commons.collections15.map.TransformedMap Maven / Gradle / Ivy
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// TODO: Not yet converted, deprecated (by me).
/*
* 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.collections15.map;
import org.apache.commons.collections15.Transformer;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.util.Iterator;
import java.util.Map;
/**
* Decorates another Map to transform objects that are added.
*
* 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.
*
* This class is Serializable from Commons Collections 3.1.
*
* Note: This class cannot support generics without breaking the Map contract.
*
* @author Matt Hall, John Watkinson, Stephen Colebourne
* @version $Revision: 1.1 $ $Date: 2005/10/11 17:05:32 $
* @since Commons Collections 3.0
*/
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.
*
* 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).
*
* 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.
*
* 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.
*
* 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.
*
* 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 setValue.
*
* @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);
}
}