org.apache.commons.collections.collection.SynchronizedCollection 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.collection;
import java.io.Serializable;
import java.util.Collection;
import java.util.Iterator;
/**
* Decorates another Collection to synchronize its behaviour
* for a multi-threaded environment.
*
* Iterators must be manually synchronized:
*
* synchronized (coll) {
* Iterator it = coll.iterator();
* // do stuff with iterator
* }
*
*
* 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 SynchronizedCollection implements Collection, Serializable {
/** Serialization version */
private static final long serialVersionUID = 2412805092710877986L;
/** The collection to decorate */
protected final Collection collection;
/** The object to lock on, needed for List/SortedSet views */
protected final Object lock;
/**
* Factory method to create a synchronized collection.
*
* @param coll the collection to decorate, must not be null
* @return a new synchronized collection
* @throws IllegalArgumentException if collection is null
*/
public static Collection decorate(Collection coll) {
return new SynchronizedCollection(coll);
}
//-----------------------------------------------------------------------
/**
* Constructor that wraps (not copies).
*
* @param collection the collection to decorate, must not be null
* @throws IllegalArgumentException if the collection is null
*/
protected SynchronizedCollection(Collection collection) {
if (collection == null) {
throw new IllegalArgumentException("Collection must not be null");
}
this.collection = collection;
this.lock = this;
}
/**
* Constructor that wraps (not copies).
*
* @param collection the collection to decorate, must not be null
* @param lock the lock object to use, must not be null
* @throws IllegalArgumentException if the collection is null
*/
protected SynchronizedCollection(Collection collection, Object lock) {
if (collection == null) {
throw new IllegalArgumentException("Collection must not be null");
}
this.collection = collection;
this.lock = lock;
}
//-----------------------------------------------------------------------
public boolean add(Object object) {
synchronized (lock) {
return collection.add(object);
}
}
public boolean addAll(Collection coll) {
synchronized (lock) {
return collection.addAll(coll);
}
}
public void clear() {
synchronized (lock) {
collection.clear();
}
}
public boolean contains(Object object) {
synchronized (lock) {
return collection.contains(object);
}
}
public boolean containsAll(Collection coll) {
synchronized (lock) {
return collection.containsAll(coll);
}
}
public boolean isEmpty() {
synchronized (lock) {
return collection.isEmpty();
}
}
/**
* Iterators must be manually synchronized.
*
* synchronized (coll) {
* Iterator it = coll.iterator();
* // do stuff with iterator
* }
*
* @return an iterator that must be manually synchronized on the collection
*/
public Iterator iterator() {
return collection.iterator();
}
public Object[] toArray() {
synchronized (lock) {
return collection.toArray();
}
}
public Object[] toArray(Object[] object) {
synchronized (lock) {
return collection.toArray(object);
}
}
public boolean remove(Object object) {
synchronized (lock) {
return collection.remove(object);
}
}
public boolean removeAll(Collection coll) {
synchronized (lock) {
return collection.removeAll(coll);
}
}
public boolean retainAll(Collection coll) {
synchronized (lock) {
return collection.retainAll(coll);
}
}
public int size() {
synchronized (lock) {
return collection.size();
}
}
public boolean equals(Object object) {
synchronized (lock) {
if (object == this) {
return true;
}
return collection.equals(object);
}
}
public int hashCode() {
synchronized (lock) {
return collection.hashCode();
}
}
public String toString() {
synchronized (lock) {
return collection.toString();
}
}
}