com.itextpdf.text.io.FileChannelRandomAccessSource Maven / Gradle / Ivy
/*
* $Id: 94c8363291fc7b6248e2ff6fe580b3d3cdc1288d $
*
* This file is part of the iText (R) project.
* Copyright (c) 1998-2016 iText Group NV
* Authors: Kevin Day, Bruno Lowagie, et al.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License version 3
* as published by the Free Software Foundation with the addition of the
* following permission added to Section 15 as permitted in Section 7(a):
* FOR ANY PART OF THE COVERED WORK IN WHICH THE COPYRIGHT IS OWNED BY
* ITEXT GROUP. ITEXT GROUP DISCLAIMS THE WARRANTY OF NON INFRINGEMENT
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package com.itextpdf.text.io;
import java.io.IOException;
import java.nio.channels.FileChannel;
/**
* A RandomAccessSource that is based on an underlying {@link FileChannel}. The entire channel will be mapped into memory for efficient reads.
* @since 5.3.5
*/
public class FileChannelRandomAccessSource implements RandomAccessSource {
/**
* The channel this source is based on
*/
private final FileChannel channel;
/**
* Tracks the actual mapping
*/
private final MappedChannelRandomAccessSource source;
/**
* Constructs a new {@link FileChannelRandomAccessSource} based on the specified FileChannel. The entire source channel will be mapped into memory.
* @param channel the channel to use as the backing store
* @throws IOException if the channel cannot be opened or mapped
*/
public FileChannelRandomAccessSource(FileChannel channel) throws IOException {
this.channel = channel;
if(channel.size() == 0)
throw new IOException("File size is 0 bytes");
source = new MappedChannelRandomAccessSource(channel, 0, channel.size());
source.open();
}
/**
* {@inheritDoc}
* Cleans the mapped bytebuffers and closes the channel
*/
public void close() throws IOException {
source.close();
channel.close();
}
/**
* {@inheritDoc}
*/
public int get(long position) throws IOException {
return source.get(position);
}
/**
* {@inheritDoc}
*/
public int get(long position, byte[] bytes, int off, int len) throws IOException {
return source.get(position, bytes, off, len);
}
/**
* {@inheritDoc}
*/
public long length() {
return source.length();
}
}