/*
* Helma License Notice
*
* The contents of this file are subject to the Helma License
* Version 2.0 (the "License"). You may not use this file except in
* compliance with the License. A copy of the License is available at
* http://adele.helma.org/download/helma/license.txt
*
* Copyright 1998-2003 Helma Software. All Rights Reserved.
*
* $RCSfile$
* $Author: root $
* $Revision: 8604 $
* $Date: 2007-09-28 15:16:38 +0200 (Fre, 28. Sep 2007) $
*/
package helma.util;
import java.util.Map;
import java.util.HashMap;
import java.util.Set;
import java.util.Collection;
/**
* A Map that wraps another map and creates a new copy of the
* wrapped map if we try to modify it. This class is wrapped
* as a native scripted object in JavaScript rather than exposing
* them through Java reflection.
*
* All methods in this class are synchronized in order not
* to miss the switch between original and copied map.
*/
public class CopyOnWriteMap extends WrappedMap {
boolean modified = false;
/**
* Constructor
*/
public CopyOnWriteMap(Map map) {
super(map);
}
public synchronized boolean wasModified() {
return modified;
}
public synchronized int size() {
return wrapped.size();
}
public synchronized boolean isEmpty() {
return wrapped.isEmpty();
}
public synchronized boolean containsKey(Object key) {
return wrapped.containsKey(key);
}
public synchronized boolean containsValue(Object value) {
return wrapped.containsValue(value);
}
public synchronized Object get(Object key) {
return wrapped.get(key);
}
// Modification Operations - check for readonly
public synchronized Object put(Object key, Object value) {
if (!modified) {
wrapped = new HashMap(wrapped);
modified = true;
}
return wrapped.put(key, value);
}
public synchronized Object remove(Object key) {
if (!modified) {
wrapped = new HashMap(wrapped);
modified = true;
}
return wrapped.remove(key);
}
public synchronized void putAll(Map t) {
if (!modified) {
wrapped = new HashMap(wrapped);
modified = true;
}
wrapped.putAll(t);
}
public synchronized void clear() {
if (!modified) {
wrapped = new HashMap(wrapped);
modified = true;
}
wrapped.clear();
}
// Views
public synchronized Set keySet() {
return wrapped.keySet();
}
public synchronized Collection values() {
return wrapped.values();
}
public synchronized Set entrySet() {
return wrapped.entrySet();
}
// Comparison and hashing
public synchronized boolean equals(Object o) {
return wrapped.equals(o);
}
public synchronized int hashCode() {
return wrapped.hashCode();
}
// toString
public synchronized String toString() {
return wrapped.toString();
}
}