package com.datasalt.pangool.tuplemr.mapred.lib.input;
/**
* Copyright [2012] [Datasalt Systems S.L.]
*
* 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.
*/
import com.datasalt.pangool.io.ITuple;
import com.datasalt.pangool.io.Tuple;
import com.datasalt.pangool.io.TupleFile;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.mapreduce.InputSplit;
import org.apache.hadoop.mapreduce.RecordReader;
import org.apache.hadoop.mapreduce.TaskAttemptContext;
import java.io.IOException;
/**
* An {@link org.apache.hadoop.mapreduce.RecordReader} for {@link com.datasalt.pangool.io.TupleFile}s.
*/
public class TupleFileRecordReader extends RecordReader<ITuple, NullWritable> {
private TupleFile.Reader in;
private long start;
private long end;
private boolean more = true;
private ITuple tuple = null;
private NullWritable value = NullWritable.get();
protected Configuration conf;
@Override
public void initialize(InputSplit split,
TaskAttemptContext context
) throws IOException, InterruptedException {
org.apache.hadoop.mapreduce.lib.input.FileSplit fileSplit =
(org.apache.hadoop.mapreduce.lib.input.FileSplit) split;
conf = context.getConfiguration();
Path path = fileSplit.getPath();
FileSystem fs = path.getFileSystem(conf);
this.in = new TupleFile.Reader(fs, conf, path);
this.end = fileSplit.getStart() + fileSplit.getLength();
if (fileSplit.getStart() > in.getPosition()) {
in.sync(fileSplit.getStart());
}
this.start = in.getPosition();
more = start < end;
tuple = new Tuple(in.getSchema());
}
@Override
public boolean nextKeyValue() throws IOException, InterruptedException {
if (!more) {
return false;
}
long pos = in.getPosition();
boolean hasNext = in.next(tuple);
if (!hasNext || (pos >= end && in.syncSeen())) {
more = false;
tuple = null;
value = null;
}
return more;
}
@Override
public ITuple getCurrentKey() {
return tuple;
}
@Override
public NullWritable getCurrentValue() {
return value;
}
/**
* Return the progress within the input split
*
* @return 0.0 to 1.0 of the input byte range
*/
public float getProgress() throws IOException {
if (end == start) {
return 0.0f;
} else {
return Math.min(1.0f, (in.getPosition() - start) / (float) (end - start));
}
}
public synchronized void close() throws IOException {
in.close();
}
}