/*
* ClueWeb Tools: Hadoop tools for manipulating ClueWeb collections
*
* 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.
*/
package org.clueweb.clueweb09.mapreduce;
import java.io.DataInputStream;
import java.io.IOException;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FSDataInputStream;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.Seekable;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.compress.CodecPool;
import org.apache.hadoop.io.compress.CompressionCodec;
import org.apache.hadoop.io.compress.CompressionCodecFactory;
import org.apache.hadoop.io.compress.Decompressor;
import org.apache.hadoop.mapreduce.InputSplit;
import org.apache.hadoop.mapreduce.JobContext;
import org.apache.hadoop.mapreduce.RecordReader;
import org.apache.hadoop.mapreduce.TaskAttemptContext;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.input.FileSplit;
import org.clueweb.clueweb09.ClueWeb09WarcRecord;
public class ClueWeb09InputFormat extends FileInputFormat<LongWritable, ClueWeb09WarcRecord> {
@Override
public RecordReader<LongWritable, ClueWeb09WarcRecord> createRecordReader(InputSplit split,
TaskAttemptContext context) throws IOException, InterruptedException {
return new ClueWarcRecordReader();
}
@Override
protected boolean isSplitable(JobContext context, Path filename) {
return false;
}
public class ClueWarcRecordReader extends RecordReader<LongWritable, ClueWeb09WarcRecord> {
private CompressionCodecFactory compressionCodecs = null;
private long start;
private long pos;
private long end;
private LongWritable key = null;
private ClueWeb09WarcRecord value = null;
private Seekable filePosition;
private CompressionCodec codec;
private Decompressor decompressor;
private DataInputStream in;
public void initialize(InputSplit genericSplit, TaskAttemptContext context) throws IOException {
FileSplit split = (FileSplit) genericSplit;
Configuration job = context.getConfiguration();
start = split.getStart();
end = start + split.getLength();
final Path file = split.getPath();
compressionCodecs = new CompressionCodecFactory(job);
codec = compressionCodecs.getCodec(file);
// open the file and seek to the start of the split
FileSystem fs = file.getFileSystem(job);
FSDataInputStream fileIn = fs.open(split.getPath());
if (isCompressedInput()) {
in = new DataInputStream(codec.createInputStream(fileIn, decompressor));
filePosition = fileIn;
} else {
fileIn.seek(start);
in = fileIn;
filePosition = fileIn;
}
this.pos = start;
}
private boolean isCompressedInput() {
return (codec != null);
}
private long getFilePosition() throws IOException {
long retVal;
if (isCompressedInput() && null != filePosition) {
retVal = filePosition.getPos();
} else {
retVal = pos;
}
return retVal;
}
public boolean nextKeyValue() throws IOException {
if (key == null) {
key = new LongWritable();
}
key.set(pos);
value = ClueWeb09WarcRecord.readNextWarcRecord(in);
if (value == null) {
return false;
}
return true;
}
@Override
public LongWritable getCurrentKey() {
return key;
}
@Override
public ClueWeb09WarcRecord getCurrentValue() {
return value;
}
/**
* Get the progress within the split
*/
public float getProgress() throws IOException {
if (start == end) {
return 0.0f;
} else {
return Math.min(1.0f, (getFilePosition() - start) / (float) (end - start));
}
}
public synchronized void close() throws IOException {
try {
if (in != null) {
in.close();
}
} finally {
if (decompressor != null) {
CodecPool.returnDecompressor(decompressor);
}
}
}
}
}