com.mchange.v1.util.NumberedObjectCache Maven / Gradle / Ivy
/*
* Distributed as part of mchange-commons-java 0.2.11
*
* 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.util;
import java.util.*;
public abstract class NumberedObjectCache
{
ArrayList al = new ArrayList();
public Object getObject(int num) throws Exception
{
Object out = null;
int req_cap = num + 1;
if (req_cap > al.size())
{
al.ensureCapacity(req_cap * 2);
for (int i = al.size(), end = req_cap * 2; i < end; ++i)
al.add(null);
out = addToCache(num);
}
else
{
out = al.get(num);
if (out == null)
out = addToCache(num);
}
return out;
}
private Object addToCache(int num) throws Exception
{
Object out = findObject(num);
al.set(num, out);
return out;
}
protected abstract Object findObject(int num) throws Exception;
}