/*
* The Apache Software License, Version 1.1
*
*
* Copyright (c) 1999-2003 The Apache Software Foundation. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution,
* if any, must include the following acknowledgment:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowledgment may appear in the software itself,
* if and wherever such third-party acknowledgments normally appear.
*
* 4. The names "Xalan" and "Apache Software Foundation" must
* not be used to endorse or promote products derived from this
* software without prior written permission. For written
* permission, please contact apache@apache.org.
*
* 5. Products derived from this software may not be called "Apache",
* nor may "Apache" appear in their name, without prior written
* permission of the Apache Software Foundation.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation and was
* originally based on software copyright (c) 1999, Lotus
* Development Corporation., http://www.lotus.com. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*/
package org.apache.xpath.axes;
import java.util.Vector;
import org.apache.xml.dtm.DTMIterator;
import org.apache.xml.utils.WrappedRuntimeException;
/**
* <meta name="usage" content="internal"/>
* Pool of object of a given type to pick from to help memory usage
*/
public class IteratorPool implements java.io.Serializable
{
/** Type of objects in this pool.
* @serial */
private final DTMIterator m_orig;
/** Vector of given objects this points to.
* @serial */
private final Vector m_freeStack;
/**
* Constructor IteratorPool
*
* @param original The original iterator from which all others will be cloned.
*/
public IteratorPool(DTMIterator original)
{
m_orig = original;
m_freeStack = new Vector();
}
/**
* Get an instance of the given object in this pool
*
* @return An instance of the given object
*/
public synchronized DTMIterator getInstanceOrThrow()
throws CloneNotSupportedException
{
// Check if the pool is empty.
if (m_freeStack.isEmpty())
{
// Create a new object if so.
return (DTMIterator)m_orig.clone();
}
else
{
// Remove object from end of free pool.
DTMIterator result = (DTMIterator)m_freeStack.lastElement();
m_freeStack.setSize(m_freeStack.size() - 1);
return result;
}
}
/**
* Get an instance of the given object in this pool
*
* @return An instance of the given object
*/
public synchronized DTMIterator getInstance()
{
// Check if the pool is empty.
if (m_freeStack.isEmpty())
{
// Create a new object if so.
try
{
return (DTMIterator)m_orig.clone();
}
catch (Exception ex)
{
throw new WrappedRuntimeException(ex);
}
}
else
{
// Remove object from end of free pool.
DTMIterator result = (DTMIterator)m_freeStack.lastElement();
m_freeStack.setSize(m_freeStack.size() - 1);
return result;
}
}
/**
* Add an instance of the given object to the pool
*
*
* @param obj Object to add.
*/
public synchronized void freeInstance(DTMIterator obj)
{
m_freeStack.addElement(obj);
}
}