org.pig.storage.TFileRecordReader.java Source code

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Here is the source code for org.pig.storage.TFileRecordReader.java

Source

package org.pig.storage;

import org.apache.commons.io.IOUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.fs.FSDataInputStream;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.BytesWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.io.file.tfile.TFile;
import org.apache.hadoop.mapreduce.InputSplit;
import org.apache.hadoop.mapreduce.RecordReader;
import org.apache.hadoop.mapreduce.TaskAttemptContext;
import org.apache.hadoop.mapreduce.lib.input.FileSplit;

import java.io.IOException;

/**
 * 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
 * <p/>
 * http://www.apache.org/licenses/LICENSE-2.0
 * <p/>
 * 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.
 */
public class TFileRecordReader extends RecordReader<Text, Text> {

    private static final Log LOG = LogFactory.getLog(TFileRecordReader.class);

    private long start, end;

    private Path splitPath;
    private FSDataInputStream fin;
    private TFile.Reader reader;
    private TFile.Reader.Scanner scanner;

    private Text key = new Text();
    private Text value = new Text();

    private BytesWritable valueBytesWritable = new BytesWritable();
    private BytesWritable keyBytesWritable = new BytesWritable();

    @Override
    public void initialize(InputSplit split, TaskAttemptContext context) throws IOException, InterruptedException {
        FileSplit fileSplit = (FileSplit) split;
        LOG.info("Initializing TFileRecordReader : " + fileSplit.getPath().toString());
        start = fileSplit.getStart();
        end = start + fileSplit.getLength();

        FileSystem fs = fileSplit.getPath().getFileSystem(context.getConfiguration());
        splitPath = fileSplit.getPath();
        fin = fs.open(splitPath);
        reader = new TFile.Reader(fin, fs.getFileStatus(splitPath).getLen(), context.getConfiguration());
        scanner = reader.createScannerByByteRange(start, fileSplit.getLength());
    }

    @Override
    public boolean nextKeyValue() throws IOException, InterruptedException {
        valueBytesWritable.setSize(0);
        if (!scanner.advance()) {
            value = null;
            return false;
        }
        TFile.Reader.Scanner.Entry entry = scanner.entry();
        //populate key, value
        entry.getKey(keyBytesWritable);
        StringBuilder k = new StringBuilder();
        k.append(splitPath.getName()).append(":").append(new String(keyBytesWritable.getBytes()));
        key.set(k.toString());
        entry.getValue(valueBytesWritable);
        value.set(valueBytesWritable.getBytes());
        return true;
    }

    @Override
    public Text getCurrentKey() throws IOException, InterruptedException {
        return key;
    }

    @Override
    public Text getCurrentValue() throws IOException, InterruptedException {
        return value;
    }

    @Override
    public float getProgress() throws IOException, InterruptedException {
        return ((fin.getPos() - start) * 1.0f) / ((end - start) * 1.0f);
    }

    @Override
    public void close() throws IOException {
        IOUtils.closeQuietly(scanner);
        IOUtils.closeQuietly(reader);
        IOUtils.closeQuietly(fin);
    }
}