/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.
*/
package org.apache.nifi.provenance.toc;
import java.io.BufferedOutputStream;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.file.Files;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Standard implementation of {@link TocWriter}.
*
* Format of .toc file:
* byte 0: version
* byte 1: compressed: 0 -> not compressed, 1 -> compressed
* byte 2-9: long: offset of block 0
* byte 10-17: long: offset of block 1
* ...
* byte (N*8+2)-(N*8+9): long: offset of block N
*/
public class StandardTocWriter implements TocWriter {
private static final Logger logger = LoggerFactory.getLogger(StandardTocWriter.class);
public static final byte VERSION = 2;
private final File file;
private final FileOutputStream fos;
private final boolean alwaysSync;
private int index = -1;
/**
* Creates a StandardTocWriter that writes to the given file.
* @param file the file to write to
* @param compressionFlag whether or not the journal is compressed
* @throws IOException if unable to write header info to the specified file
*/
public StandardTocWriter(final File file, final boolean compressionFlag, final boolean alwaysSync) throws IOException {
final File tocDir = file.getParentFile();
if ( !tocDir.exists() ) {
Files.createDirectories(tocDir.toPath());
}
this.file = file;
fos = new FileOutputStream(file);
this.alwaysSync = alwaysSync;
final byte[] header = new byte[2];
header[0] = VERSION;
header[1] = (byte) (compressionFlag ? 1 : 0);
fos.write(header);
fos.flush();
if ( alwaysSync ) {
sync();
}
}
@Override
public void addBlockOffset(final long offset, final long firstEventId) throws IOException {
final BufferedOutputStream bos = new BufferedOutputStream(fos);
final DataOutputStream dos = new DataOutputStream(bos);
dos.writeLong(offset);
dos.writeLong(firstEventId);
dos.flush();
index++;
logger.debug("Adding block {} at offset {}", index, offset);
if ( alwaysSync ) {
sync();
}
}
@Override
public void sync() throws IOException {
fos.getFD().sync();
}
@Override
public int getCurrentBlockIndex() {
return index;
}
@Override
public void close() throws IOException {
if (alwaysSync) {
fos.getFD().sync();
}
fos.close();
}
@Override
public File getFile() {
return file;
}
@Override
public String toString() {
return "TOC Writer for " + file;
}
}