com.mchange.v1.identicator.test.TestIdWeakHashMap Maven / Gradle / Ivy
/*
* Distributed as part of mchange-commons-java 0.2.9
*
* Copyright (C) 2015 Machinery For Change, Inc.
*
* Author: Steve Waldman
*
* This library is free software; you can redistribute it and/or modify
* it under the terms of EITHER:
*
* 1) The GNU Lesser General Public License (LGPL), version 2.1, as
* published by the Free Software Foundation
*
* OR
*
* 2) The Eclipse Public License (EPL), version 1.0
*
* You may choose which license to accept if you wish to redistribute
* or modify this work. You may offer derivatives of this work
* under the license you have chosen, or you may provide the same
* choice of license which you have been offered here.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
*
* You should have received copies of both LGPL v2.1 and EPL v1.0
* along with this software; see the files LICENSE-EPL and LICENSE-LGPL.
* If not, the text of these licenses are currently available at
*
* LGPL v2.1: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html
* EPL v1.0: http://www.eclipse.org/org/documents/epl-v10.php
*
*/
package com.mchange.v1.identicator.test;
import java.util.*;
import com.mchange.v1.identicator.*;
public class TestIdWeakHashMap
{
final static Identicator id = new Identicator()
{
public boolean identical(Object a, Object b)
{ return ((String) a).charAt(0) == ((String) b).charAt(0); }
public int hash(Object o)
{ return ((String) o).charAt(0); }
};
final static Map weak = new IdWeakHashMap( id );
public static void main(String[] argv)
{
doAdds();
System.gc();
show();
setRemoveHi();
System.gc();
show();
}
static void setRemoveHi()
{
String bye = new String("bye");
weak.put(bye, "");
Set ks = weak.keySet();
ks.remove("hi");
show();
}
static void doAdds()
{
String s0 = "hi"; //remember, this one is in the internal string pool!
String s1 = new String("hello");
String s2 = new String("yoohoo");
String s3 = new String("poop");
weak.put(s0, "");
weak.put(s1, "");
weak.put(s2, "");
weak.put(s3, "");
show();
}
static void show()
{
System.out.println("elements:");
for (Iterator ii = weak.keySet().iterator(); ii.hasNext(); )
System.out.println( "\t" + ii.next() );
System.out.println("size: " + weak.size() );
}
}