org.apache.commons.collections.list.TransformedList Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.list;
import java.util.Collection;
import java.util.List;
import java.util.ListIterator;
import org.apache.commons.collections.Transformer;
import org.apache.commons.collections.collection.TransformedCollection;
import org.apache.commons.collections.iterators.AbstractListIteratorDecorator;
/**
* Decorates another List
to transform objects that are added.
*
* The add and set methods 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.
*
* @since Commons Collections 3.0
* @version $Revision: 646777 $ $Date: 2008-04-10 14:33:15 +0200 (Thu, 10 Apr 2008) $
*
* @author Stephen Colebourne
*/
public class TransformedList extends TransformedCollection implements List {
/** Serialization version */
private static final long serialVersionUID = 1077193035000013141L;
/**
* Factory method to create a transforming list.
*
* If there are any elements already in the list being decorated, they
* are NOT transformed.
*
* @param list the list to decorate, must not be null
* @param transformer the transformer to use for conversion, must not be null
* @throws IllegalArgumentException if list or transformer is null
*/
public static List decorate(List list, Transformer transformer) {
return new TransformedList(list, transformer);
}
//-----------------------------------------------------------------------
/**
* Constructor that wraps (not copies).
*
* If there are any elements already in the list being decorated, they
* are NOT transformed.
*
* @param list the list to decorate, must not be null
* @param transformer the transformer to use for conversion, must not be null
* @throws IllegalArgumentException if list or transformer is null
*/
protected TransformedList(List list, Transformer transformer) {
super(list, transformer);
}
/**
* Gets the decorated list.
*
* @return the decorated list
*/
protected List getList() {
return (List) collection;
}
//-----------------------------------------------------------------------
public Object get(int index) {
return getList().get(index);
}
public int indexOf(Object object) {
return getList().indexOf(object);
}
public int lastIndexOf(Object object) {
return getList().lastIndexOf(object);
}
public Object remove(int index) {
return getList().remove(index);
}
//-----------------------------------------------------------------------
public void add(int index, Object object) {
object = transform(object);
getList().add(index, object);
}
public boolean addAll(int index, Collection coll) {
coll = transform(coll);
return getList().addAll(index, coll);
}
public ListIterator listIterator() {
return listIterator(0);
}
public ListIterator listIterator(int i) {
return new TransformedListIterator(getList().listIterator(i));
}
public Object set(int index, Object object) {
object = transform(object);
return getList().set(index, object);
}
public List subList(int fromIndex, int toIndex) {
List sub = getList().subList(fromIndex, toIndex);
return new TransformedList(sub, transformer);
}
/**
* Inner class Iterator for the TransformedList
*/
protected class TransformedListIterator extends AbstractListIteratorDecorator {
protected TransformedListIterator(ListIterator iterator) {
super(iterator);
}
public void add(Object object) {
object = transform(object);
iterator.add(object);
}
public void set(Object object) {
object = transform(object);
iterator.set(object);
}
}
}