com.hadoopilluminated.examples.terasort.TeraOutputFormat.java Source code

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Here is the source code for com.hadoopilluminated.examples.terasort.TeraOutputFormat.java

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package com.hadoopilluminated.examples.terasort;

/**
 * The example below is taken from org.apache.hadoop.examples It is then
 * commented and modified for the purposes of the book
 */

/**
 * 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.
 */
import java.io.DataOutputStream;
import java.io.IOException;

import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapred.RecordWriter;
import org.apache.hadoop.mapred.TextOutputFormat;
import org.apache.hadoop.util.Progressable;

/**
 * A streamlined text output format that writes key, value, and "\r\n".
 */
public class TeraOutputFormat extends TextOutputFormat<Text, Text> {

    static final String FINAL_SYNC_ATTRIBUTE = "terasort.final.sync";

    /**
     * Set the requirement for a final sync before the stream is closed.
     */
    public static void setFinalSync(JobConf conf, boolean newValue) {
        conf.setBoolean(FINAL_SYNC_ATTRIBUTE, newValue);
    }

    /**
     * Does the user want a final sync at close?
     */
    public static boolean getFinalSync(JobConf conf) {
        return conf.getBoolean(FINAL_SYNC_ATTRIBUTE, false);
    }

    static class TeraRecordWriter extends LineRecordWriter<Text, Text> {

        private static final byte[] newLine = "\r\n".getBytes();
        private boolean finalSync = false;

        public TeraRecordWriter(DataOutputStream out, JobConf conf) {
            super(out);
            finalSync = getFinalSync(conf);
        }

        public synchronized void write(Text key, Text value) throws IOException {
            out.write(key.getBytes(), 0, key.getLength());
            out.write(value.getBytes(), 0, value.getLength());
            out.write(newLine, 0, newLine.length);
        }

        public void close() throws IOException {
            if (finalSync) {
                ((FSDataOutputStream) out).sync();
            }
            super.close(null);
        }
    }

    public RecordWriter<Text, Text> getRecordWriter(FileSystem ignored, JobConf job, String name,
            Progressable progress) throws IOException {
        Path dir = getWorkOutputPath(job);
        FileSystem fs = dir.getFileSystem(job);
        FSDataOutputStream fileOut = fs.create(new Path(dir, name), progress);
        return new TeraRecordWriter(fileOut, job);
    }
}