/*
* reserved comment block
* DO NOT REMOVE OR ALTER!
*/
/*
* Copyright 1999-2004 The Apache Software Foundation.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/*
* $Id: IteratorPool.java,v 1.2.4.1 2005/09/14 19:45:19 jeffsuttor Exp $
*/
package com.sun.org.apache.xpath.internal.axes;
import java.util.ArrayList;
import com.sun.org.apache.xml.internal.dtm.DTMIterator;
import com.sun.org.apache.xml.internal.utils.WrappedRuntimeException;
/**
* Pool of object of a given type to pick from to help memory usage
* @xsl.usage internal
*/
public final class IteratorPool implements java.io.Serializable
{
static final long serialVersionUID = -460927331149566998L;
/**
* Type of objects in this pool.
*/
private final DTMIterator m_orig;
/**
* Stack of given objects this points to.
*/
private final ArrayList 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 ArrayList();
}
/**
* 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.remove(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.remove(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.add(obj);
}
}