com.tgam.hadoop.mapred.EscapedLineRecordReader.java Source code

Introduction

Here is the source code for com.tgam.hadoop.mapred.EscapedLineRecordReader.java

Source

/**
 * 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 com.tgam.hadoop.mapred;

import com.tgam.hadoop.util.GenericEscapedLineReader;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
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.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.io.compress.CompressionCodec;
import org.apache.hadoop.io.compress.CompressionCodecFactory;
import org.apache.hadoop.mapred.FileSplit;
import org.apache.hadoop.mapred.RecordReader;

import java.io.IOException;
import java.io.InputStream;

/**
 * Treats keys as offset in file and value as line.
 * @deprecated Use
 *   {@link org.apache.hadoop.mapreduce.lib.input.LineRecordReader} instead.
 */
@Deprecated
public class EscapedLineRecordReader implements RecordReader<LongWritable, Text> {
    private static final Log LOG = LogFactory.getLog(EscapedLineRecordReader.class.getName());

    private CompressionCodecFactory compressionCodecs = null;
    private long start;
    private long pos;
    private long end;
    private GenericEscapedLineReader in;
    int maxLineLength;

    /**
     * A class that provides a line reader from an input stream.
     * @deprecated Use {@link org.apache.hadoop.util.LineReader} instead.
     */
    @Deprecated
    public static class LineReader extends GenericEscapedLineReader {
        LineReader(InputStream in) {
            super(in);
        }

        LineReader(InputStream in, int bufferSize) {
            super(in, bufferSize);
        }

        public LineReader(InputStream in, Configuration conf) throws IOException {
            super(in, conf);
        }
    }

    public EscapedLineRecordReader(Configuration job, FileSplit split) throws IOException {
        this.maxLineLength = job.getInt("mapred.linerecordreader.maxlength", Integer.MAX_VALUE);
        start = split.getStart();
        end = start + split.getLength();
        final Path file = split.getPath();
        compressionCodecs = new CompressionCodecFactory(job);
        final CompressionCodec 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());
        boolean skipFirstLine = false;
        if (codec != null) {
            in = new LineReader(codec.createInputStream(fileIn), job);
            end = Long.MAX_VALUE;
        } else {
            if (start != 0) {
                skipFirstLine = true;
                --start;
                fileIn.seek(start);
            }
            in = new LineReader(fileIn, job);
        }
        if (skipFirstLine) { // skip first line and re-establish "start".
            start += in.readLine(new Text(), 0, (int) Math.min((long) Integer.MAX_VALUE, end - start));
        }
        this.pos = start;
    }

    public EscapedLineRecordReader(InputStream in, long offset, long endOffset, int maxLineLength) {
        this.maxLineLength = maxLineLength;
        this.in = new LineReader(in);
        this.start = offset;
        this.pos = offset;
        this.end = endOffset;
    }

    public EscapedLineRecordReader(InputStream in, long offset, long endOffset, Configuration job)
            throws IOException {
        this.maxLineLength = job.getInt("mapred.linerecordreader.maxlength", Integer.MAX_VALUE);
        this.in = new LineReader(in, job);
        this.start = offset;
        this.pos = offset;
        this.end = endOffset;
    }

    public LongWritable createKey() {
        return new LongWritable();
    }

    public Text createValue() {
        return new Text();
    }

    /** Read a line. */
    public synchronized boolean next(LongWritable key, Text value) throws IOException {

        while (pos < end) {
            key.set(pos);

            int newSize = in.readLine(value, maxLineLength,
                    Math.max((int) Math.min(Integer.MAX_VALUE, end - pos), maxLineLength));
            if (newSize == 0) {
                return false;
            }
            pos += newSize;
            if (newSize < maxLineLength) {
                return true;
            }

            // line too long. try again
            LOG.info("Skipped line of size " + newSize + " at pos " + (pos - newSize));
        }

        return false;
    }

    /**
     * Get the progress within the split
     */
    public float getProgress() {
        if (start == end) {
            return 0.0f;
        } else {
            return Math.min(1.0f, (pos - start) / (float) (end - start));
        }
    }

    public synchronized long getPos() throws IOException {
        return pos;
    }

    public synchronized void close() throws IOException {
        if (in != null) {
            in.close();
        }
    }
}