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feilong is a suite of core and expanded libraries that include utility classes, http, excel,cvs, io classes, and much much more.
/*
* Copyright (C) 2004 Joe Walnes.
* Copyright (C) 2006, 2007, 2008, 2010 XStream Committers.
* All rights reserved.
*
* The software in this package is published under the terms of the BSD
* style license a copy of which has been included with this distribution in
* the LICENSE.txt file.
*
* Created on 09. May 2004 by Joe Walnes
*/
package com.feilong.lib.xstream.core.util;
import java.lang.ref.ReferenceQueue;
import java.lang.ref.WeakReference;
import java.util.HashMap;
import java.util.Map;
/**
* Store IDs against given object references.
*
* Behaves similar to java.util.IdentityHashMap, but in JDK1.3 as well. Additionally the
* implementation keeps track of orphaned IDs by using a WeakReference to store the reference
* object.
*
*/
public class ObjectIdDictionary{
private final Map map = new HashMap();
private final ReferenceQueue queue = new ReferenceQueue();
private static interface Wrapper{
@Override
int hashCode();
@Override
boolean equals(Object obj);
@Override
String toString();
Object get();
}
private static class IdWrapper implements Wrapper{
private final Object obj;
private final int hashCode;
public IdWrapper(Object obj){
hashCode = System.identityHashCode(obj);
this.obj = obj;
}
@Override
public int hashCode(){
return hashCode;
}
@Override
public boolean equals(Object other){
return obj == ((Wrapper) other).get();
}
@Override
public String toString(){
return obj.toString();
}
@Override
public Object get(){
return obj;
}
}
private class WeakIdWrapper extends WeakReference implements Wrapper{
private final int hashCode;
public WeakIdWrapper(Object obj){
super(obj, queue);
hashCode = System.identityHashCode(obj);
}
@Override
public int hashCode(){
return hashCode;
}
@Override
public boolean equals(Object other){
return get() == ((Wrapper) other).get();
}
@Override
public String toString(){
Object obj = get();
return obj == null ? "(null)" : obj.toString();
}
}
public void associateId(Object obj,Object id){
map.put(new WeakIdWrapper(obj), id);
cleanup();
}
public Object lookupId(Object obj){
Object id = map.get(new IdWrapper(obj));
return id;
}
public boolean containsId(Object item){
boolean b = map.containsKey(new IdWrapper(item));
return b;
}
public void removeId(Object item){
map.remove(new IdWrapper(item));
cleanup();
}
public int size(){
cleanup();
return map.size();
}
private void cleanup(){
WeakIdWrapper wrapper;
while ((wrapper = (WeakIdWrapper) queue.poll()) != null){
map.remove(wrapper);
}
}
}