com.datatorrent.demos.mroperator.LineIndexer.java Source code

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Here is the source code for com.datatorrent.demos.mroperator.LineIndexer.java

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/*
 * Copyright (c) 2013 DataTorrent, Inc. ALL Rights Reserved.
 *
 * Licensed 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.datatorrent.demos.mroperator;

import java.io.IOException;
import java.util.Iterator;
import java.util.StringTokenizer;

import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapred.FileInputFormat;
import org.apache.hadoop.mapred.FileOutputFormat;
import org.apache.hadoop.mapred.FileSplit;
import org.apache.hadoop.mapred.JobClient;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapred.MapReduceBase;
import org.apache.hadoop.mapred.Mapper;
import org.apache.hadoop.mapred.OutputCollector;
import org.apache.hadoop.mapred.Reducer;
import org.apache.hadoop.mapred.Reporter;

/**
 * <p>LineIndexer class.</p>
 *
 * @since 0.9.0
 */
public class LineIndexer {

    public static class LineIndexMapper extends MapReduceBase implements Mapper<LongWritable, Text, Text, Text> {

        private final static Text word = new Text();
        private final static Text location = new Text();

        public void map(LongWritable key, Text val, OutputCollector<Text, Text> output, Reporter reporter)
                throws IOException {

            FileSplit fileSplit = (FileSplit) reporter.getInputSplit();
            String fileName = fileSplit.getPath().getName();
            location.set(fileName);

            String line = val.toString();
            StringTokenizer itr = new StringTokenizer(line.toLowerCase());
            while (itr.hasMoreTokens()) {
                word.set(itr.nextToken());
                output.collect(word, location);
            }
        }
    }

    public static class LineIndexReducer extends MapReduceBase implements Reducer<Text, Text, Text, Text> {

        public void reduce(Text key, Iterator<Text> values, OutputCollector<Text, Text> output, Reporter reporter)
                throws IOException {

            boolean first = true;
            StringBuilder toReturn = new StringBuilder();
            while (values.hasNext()) {
                if (!first)
                    toReturn.append(", ");
                first = false;
                toReturn.append(values.next().toString());
            }

            output.collect(key, new Text(toReturn.toString()));
        }
    }

    /**
     * The actual main() method for our program; this is the
     * "driver" for the MapReduce job.
     */
    public static void main(String[] args) {
        JobClient client = new JobClient();
        JobConf conf = new JobConf(LineIndexer.class);

        conf.setJobName("LineIndexer");

        conf.setOutputKeyClass(Text.class);
        conf.setOutputValueClass(Text.class);

        FileInputFormat.addInputPath(conf, new Path("input"));
        FileOutputFormat.setOutputPath(conf, new Path("output"));

        conf.setMapperClass(LineIndexMapper.class);
        conf.setReducerClass(LineIndexReducer.class);

        client.setConf(conf);

        try {
            JobClient.runJob(conf);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}