/*
* 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.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
import net.sf.jasperreports.engine.JRRuntimeException;
/**
* {@link net.sf.jasperreports.engine.util.JRSwapFile JRSwapFile} derived class that uses
* a {@link java.nio.channels.FileChannel FileChannel} to perform concurrent I/O on the
* swap file.
*
* @author Lucian Chirita (lucianc@users.sourceforge.net)
* @version $Id: JRConcurrentSwapFile.java 3034 2009-08-27 11:58:04Z teodord $
*/
public class JRConcurrentSwapFile extends JRSwapFile
{
private final FileChannel fileChannel;
/**
* Creates a swap file.
*
* The file name is generated automatically.
*
* @param directory the directory where the file should be created.
* @param blockSize the size of the blocks allocated by the swap file
* @param minGrowCount the minimum number of blocks by which the swap file grows when full
*/
public JRConcurrentSwapFile(String directory, int blockSize, int minGrowCount)
{
super(directory, blockSize, minGrowCount);
fileChannel = file.getChannel();
}
protected void write(byte[] data, int dataSize, int dataOffset, long fileOffset) throws IOException
{
fileChannel.write(ByteBuffer.wrap(data, dataOffset, dataSize), fileOffset);
}
protected void read(byte[] data, int dataOffset, int dataLength, long fileOffset) throws IOException
{
ByteBuffer buffer = ByteBuffer.wrap(data, dataOffset, dataLength);
int read, totalRead = 0;
do
{
read = fileChannel.read(buffer, fileOffset + totalRead);
if (read < 0)
{
throw new JRRuntimeException("Unable to read sufficient data from the swap file");
}
totalRead += read;
}
while (totalRead < dataLength);
}
}