DataJoinJob.java Source code

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Here is the source code for DataJoinJob.java

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/**
 * 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 org.apache.hadoop.contrib.utils.join;

import java.io.IOException;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.SequenceFile;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapred.FileOutputFormat;
import org.apache.hadoop.mapred.JobClient;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapred.FileInputFormat;
import org.apache.hadoop.mapred.RunningJob;
import org.apache.hadoop.mapred.SequenceFileInputFormat;
import org.apache.hadoop.mapred.SequenceFileOutputFormat;
import org.apache.hadoop.mapred.TextInputFormat;
import org.apache.hadoop.mapred.TextOutputFormat;
import org.apache.hadoop.mapred.JobID;

/**
 * This class implements the main function for creating a map/reduce
 * job to join data of different sources. To create sucn a job, the 
 * user must implement a mapper class that extends DataJoinMapperBase class,
 * and a reducer class that extends DataJoinReducerBase. 
 * 
 */
public class DataJoinJob {

    public static Class getClassByName(String className) {
        Class retv = null;
        try {
            ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
            retv = Class.forName(className, true, classLoader);
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
        return retv;
    }

    public static JobConf createDataJoinJob(String args[]) throws IOException {

        String inputDir = args[0];
        String outputDir = args[1];
        Class inputFormat = SequenceFileInputFormat.class;
        if (args[2].compareToIgnoreCase("text") != 0) {
            System.out.println("Using SequenceFileInputFormat: " + args[2]);
        } else {
            System.out.println("Using TextInputFormat: " + args[2]);
            inputFormat = TextInputFormat.class;
        }
        int numOfReducers = Integer.parseInt(args[3]);
        Class mapper = getClassByName(args[4]);
        Class reducer = getClassByName(args[5]);
        Class mapoutputValueClass = getClassByName(args[6]);
        Class outputFormat = TextOutputFormat.class;
        Class outputValueClass = Text.class;
        if (args[7].compareToIgnoreCase("text") != 0) {
            System.out.println("Using SequenceFileOutputFormat: " + args[7]);
            outputFormat = SequenceFileOutputFormat.class;
            outputValueClass = getClassByName(args[7]);
        } else {
            System.out.println("Using TextOutputFormat: " + args[7]);
        }
        long maxNumOfValuesPerGroup = 100;
        String jobName = "";
        if (args.length > 8) {
            maxNumOfValuesPerGroup = Long.parseLong(args[8]);
        }
        if (args.length > 9) {
            jobName = args[9];
        }
        Configuration defaults = new Configuration();
        JobConf job = new JobConf(defaults, DataJoinJob.class);
        job.setJobName("DataJoinJob: " + jobName);

        FileSystem fs = FileSystem.get(defaults);
        fs.delete(new Path(outputDir));
        FileInputFormat.setInputPaths(job, inputDir);

        job.setInputFormat(inputFormat);

        job.setMapperClass(mapper);
        FileOutputFormat.setOutputPath(job, new Path(outputDir));
        job.setOutputFormat(outputFormat);
        SequenceFileOutputFormat.setOutputCompressionType(job, SequenceFile.CompressionType.BLOCK);
        job.setMapOutputKeyClass(Text.class);
        job.setMapOutputValueClass(mapoutputValueClass);
        job.setOutputKeyClass(Text.class);
        job.setOutputValueClass(outputValueClass);
        job.setReducerClass(reducer);

        job.setNumMapTasks(1);
        job.setNumReduceTasks(numOfReducers);
        job.setLong("datajoin.maxNumOfValuesPerGroup", maxNumOfValuesPerGroup);
        return job;
    }

    /**
     * Submit/run a map/reduce job.
     * 
     * @param job
     * @return true for success
     * @throws IOException
     */
    public static boolean runJob(JobConf job) throws IOException {
        JobClient jc = new JobClient(job);
        boolean sucess = true;
        RunningJob running = null;
        try {
            running = jc.submitJob(job);
            JobID jobId = running.getID();
            System.out.println("Job " + jobId + " is submitted");
            while (!running.isComplete()) {
                System.out.println("Job " + jobId + " is still running.");
                try {
                    Thread.sleep(60000);
                } catch (InterruptedException e) {
                }
                running = jc.getJob(jobId);
            }
            sucess = running.isSuccessful();
        } finally {
            if (!sucess && (running != null)) {
                running.killJob();
            }
            jc.close();
        }
        return sucess;
    }

    /**
     * @param args
     */
    public static void main(String[] args) {
        boolean success;
        if (args.length < 8 || args.length > 10) {
            System.out.println("usage: DataJoinJob " + "inputdirs outputdir map_input_file_format " + "numofParts "
                    + "mapper_class " + "reducer_class " + "map_output_value_class "
                    + "output_value_class [maxNumOfValuesPerGroup [descriptionOfJob]]]");
            System.exit(-1);
        }

        try {
            JobConf job = DataJoinJob.createDataJoinJob(args);
            success = DataJoinJob.runJob(job);
            if (!success) {
                System.out.println("Job failed");
            }
        } catch (IOException ioe) {
            ioe.printStackTrace();
        }
    }
}