/*
* JasperReports - Free Java Reporting Library.
* Copyright (C) 2001 - 2009 Jaspersoft Corporation. All rights reserved.
* http://www.jaspersoft.com
*
* Unless you have purchased a commercial license agreement from Jaspersoft,
* the following license terms apply:
*
* This program is part of JasperReports.
*
* JasperReports is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* JasperReports 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. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with JasperReports. If not, see <http://www.gnu.org/licenses/>.
*/
package net.sf.jasperreports.engine.util;
import java.util.LinkedList;
/**
* Thread local stack utility class.
*
* @author Lucian Chirita (lucianc@users.sourceforge.net)
* @version $Id: ThreadLocalStack.java 3034 2009-08-27 11:58:04Z teodord $
*/
public class ThreadLocalStack
{
private final ThreadLocal threadStack;
public ThreadLocalStack()
{
threadStack = new ThreadLocal();
}
public void push(Object o)
{
LinkedList stack = (LinkedList) threadStack.get();
if (stack == null)
{
stack = new LinkedList();
threadStack.set(stack);
}
stack.addFirst(o);
}
public Object top()
{
Object o = null;
LinkedList stack = (LinkedList) threadStack.get();
if (stack != null && !stack.isEmpty())
{
o = stack.getFirst();
}
return o;
}
public Object pop()
{
Object o = null;
LinkedList stack = (LinkedList) threadStack.get();
if (stack != null)
{
o = stack.removeFirst();
}
return o;
}
public boolean empty()
{
LinkedList stack = (LinkedList) threadStack.get();
return stack == null || stack.isEmpty();
}
}