Java tutorial
/* * 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.list; import java.util.Collection; import java.util.List; import java.util.ListIterator; import org.apache.commons.collections.collection.SynchronizedCollection; /** * Decorates another <code>List</code> to synchronize its behaviour * for a multi-threaded environment. * <p> * Methods are synchronized, then forwarded to the decorated list. * <p> * This class is Serializable from Commons Collections 3.1. * * @since Commons Collections 3.0 * @version $Revision: 1.5 $ $Date: 2004/06/03 22:02:13 $ * * @author Stephen Colebourne */ public class SynchronizedList extends SynchronizedCollection implements List { /** Serialization version */ private static final long serialVersionUID = -1403835447328619437L; /** * Factory method to create a synchronized list. * * @param list the list to decorate, must not be null * @throws IllegalArgumentException if list is null */ public static List decorate(List list) { return new SynchronizedList(list); } //----------------------------------------------------------------------- /** * Constructor that wraps (not copies). * * @param list the list to decorate, must not be null * @throws IllegalArgumentException if list is null */ protected SynchronizedList(List list) { super(list); } /** * Constructor that wraps (not copies). * * @param list the list to decorate, must not be null * @param lock the lock to use, must not be null * @throws IllegalArgumentException if list is null */ protected SynchronizedList(List list, Object lock) { super(list, lock); } /** * Gets the decorated list. * * @return the decorated list */ protected List getList() { return (List) collection; } //----------------------------------------------------------------------- public void add(int index, Object object) { synchronized (lock) { getList().add(index, object); } } public boolean addAll(int index, Collection coll) { synchronized (lock) { return getList().addAll(index, coll); } } public Object get(int index) { synchronized (lock) { return getList().get(index); } } public int indexOf(Object object) { synchronized (lock) { return getList().indexOf(object); } } public int lastIndexOf(Object object) { synchronized (lock) { return getList().lastIndexOf(object); } } /** * Iterators must be manually synchronized. * <pre> * synchronized (coll) { * ListIterator it = coll.listIterator(); * // do stuff with iterator * } * * @return an iterator that must be manually synchronized on the collection */ public ListIterator listIterator() { return getList().listIterator(); } /** * Iterators must be manually synchronized. * <pre> * synchronized (coll) { * ListIterator it = coll.listIterator(3); * // do stuff with iterator * } * * @return an iterator that must be manually synchronized on the collection */ public ListIterator listIterator(int index) { return getList().listIterator(index); } public Object remove(int index) { synchronized (lock) { return getList().remove(index); } } public Object set(int index, Object object) { synchronized (lock) { return getList().set(index, object); } } public List subList(int fromIndex, int toIndex) { synchronized (lock) { List list = getList().subList(fromIndex, toIndex); // the lock is passed into the constructor here to ensure that the sublist is // synchronized on the same lock as the parent list return new SynchronizedList(list, lock); } } }