com.panguso.lc.analysis.format.mapreduce.TextOutputFormat.java Source code

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Here is the source code for com.panguso.lc.analysis.format.mapreduce.TextOutputFormat.java

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/**
 *  Copyright (c)  2011-2020 Panguso, Inc.
 *  All rights reserved.
 *
 *  This software is the confidential and proprietary information of Panguso, 
 *  Inc. ("Confidential Information"). You shall not
 *  disclose such Confidential Information and shall use it only in
 *  accordance with the terms of the license agreement you entered into with Panguso.
 */
package com.panguso.lc.analysis.format.mapreduce;

import java.io.DataOutputStream;
import java.io.IOException;
import java.io.UnsupportedEncodingException;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.io.compress.CompressionCodec;
import org.apache.hadoop.io.compress.GzipCodec;
import org.apache.hadoop.mapreduce.RecordWriter;
import org.apache.hadoop.mapreduce.TaskAttemptContext;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.util.ReflectionUtils;

/**
 * ?
 * 
 * @author piaohailin
 * 
 * @param <K>
 * @param <V>
 */
public class TextOutputFormat<K, V> extends FileOutputFormat<K, V> {
    /**
     * 
     */
    private static final String separate = "";

    /**
     * 
     * @param <K>
     * @param <V>
     * @author piaohailin
     * @date 2013-4-9
     */
    protected static class LineRecordWriter<K, V> extends RecordWriter<K, V> {
        private static final String utf8 = "UTF-8";
        private static final byte[] newline;
        static {
            try {
                newline = "\n".getBytes(utf8);
            } catch (UnsupportedEncodingException uee) {
                throw new IllegalArgumentException("can't find " + utf8 + " encoding");
            }
        }

        protected DataOutputStream out;
        private final byte[] keyValueSeparator;

        /**
         * 
         * @param out out
         * @param keyValueSeparator keyValueSeparator
         */
        public LineRecordWriter(DataOutputStream out, String keyValueSeparator) {
            this.out = out;
            try {
                this.keyValueSeparator = keyValueSeparator.getBytes(utf8);
            } catch (UnsupportedEncodingException uee) {
                throw new IllegalArgumentException("can't find " + utf8 + " encoding");
            }
        }

        /**
         * 
         * @param out out
         */
        public LineRecordWriter(DataOutputStream out) {
            this(out, separate);
        }

        /**
         * Write the object to the byte stream, handling Text as a special case.
         * 
         * @param o
         *        the object to print
         * @throws IOException
         *         if the write throws, we pass it on
         */
        private void writeObject(Object o) throws IOException {
            if (o instanceof Text) {
                Text to = (Text) o;
                out.write(to.getBytes(), 0, to.getLength());
            } else {
                out.write(o.toString().getBytes(utf8));
            }
        }

        /**
         * 
         * @param key key
         * @param value value
         * @throws IOException IOException
         */
        public synchronized void write(K key, V value) throws IOException {

            boolean nullKey = key == null || key instanceof NullWritable;
            boolean nullValue = value == null || value instanceof NullWritable;
            if (nullKey && nullValue) {
                return;
            }
            if (!nullKey) {
                writeObject(key);
            }
            if (!(nullKey || nullValue)) {
                out.write(keyValueSeparator);
            }
            if (!nullValue) {
                writeObject(value);
            }
            out.write(newline);
        }

        /**
         * @param context context
         * @throws IOException IOException
         */
        public synchronized void close(TaskAttemptContext context) throws IOException {
            out.close();
        }
    }

    /**
     * @param job job
     * @throws IOException IOException
     * @throws InterruptedException InterruptedException
     */
    public RecordWriter<K, V> getRecordWriter(TaskAttemptContext job) throws IOException, InterruptedException {
        Configuration conf = job.getConfiguration();
        boolean isCompressed = getCompressOutput(job);
        String keyValueSeparator = conf.get("mapred.textoutputformat.separator", separate);
        CompressionCodec codec = null;
        String extension = "";
        if (isCompressed) {
            Class<? extends CompressionCodec> codecClass = getOutputCompressorClass(job, GzipCodec.class);
            codec = (CompressionCodec) ReflectionUtils.newInstance(codecClass, conf);
            extension = codec.getDefaultExtension();
        }
        Path file = getDefaultWorkFile(job, extension);
        FileSystem fs = file.getFileSystem(conf);
        if (!isCompressed) {
            FSDataOutputStream fileOut = fs.create(file, false);
            return new LineRecordWriter<K, V>(fileOut, keyValueSeparator);
        } else {
            FSDataOutputStream fileOut = fs.create(file, false);
            return new LineRecordWriter<K, V>(new DataOutputStream(codec.createOutputStream(fileOut)),
                    keyValueSeparator);
        }
    }
}