adts.PopularKeywords.java Source code

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Here is the source code for adts.PopularKeywords.java

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/**************************************************
Copyright (C) 2014  Raptis Dimos <raptis.dimos@yahoo.gr>
    
    
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
    
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.
    
You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.
**************************************************/

package adts;

import java.io.IOException;
import java.util.*;

import org.apache.hadoop.fs.Path;
import org.apache.hadoop.conf.*;
import org.apache.hadoop.io.*;
import org.apache.hadoop.mapreduce.*;
import org.apache.hadoop.mapreduce.Reducer.Context;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.input.MultipleInputs;
import org.apache.hadoop.mapreduce.lib.input.TextInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.mapreduce.lib.output.TextOutputFormat;

import adts.SuccessfullQueries.Map;
import adts.SuccessfullQueries.Reduce;

public class PopularKeywords {
    public static class Map extends Mapper<LongWritable, Text, Text, IntWritable> {
        private final static IntWritable one = new IntWritable(1);
        private Text word = new Text();

        public void map(LongWritable key, Text value, Context context) throws IOException, InterruptedException {
            String line = value.toString();
            StringTokenizer tokenizer = new StringTokenizer(line, "\t");
            tokenizer.nextToken();
            String second_column = tokenizer.nextToken();
            String[] keywords = second_column.split(" ");
            for (int i = 0; i < keywords.length; i++) {
                word.set(keywords[i]);
                context.write(word, one);
            }

        }
    }

    public static class StopwordsMap extends Mapper<LongWritable, Text, Text, IntWritable> {
        private final static IntWritable two = new IntWritable(2);
        private Text word = new Text();

        public void map(LongWritable key, Text value, Context context) throws IOException, InterruptedException {
            String line = value.toString();
            word.set(line);
            context.write(word, two);

        }
    }

    public static class Reduce extends Reducer<Text, IntWritable, Text, IntWritable> {

        public void reduce(Text key, Iterable<IntWritable> values, Context context)
                throws IOException, InterruptedException {
            int sum = 0;
            int belongs_to_stopwords = 0;
            for (IntWritable val : values) {
                if (val.get() == 1) {
                    sum += val.get();
                } else if (val.get() == 2) {
                    belongs_to_stopwords = 1;
                }
            }
            if (belongs_to_stopwords == 0) {
                context.write(key, new IntWritable(sum));
            }
        }
    }

    public static class ReverseMap extends Mapper<LongWritable, Text, LongWritable, Text> {
        private final static IntWritable one = new IntWritable(1);
        private Text word = new Text();

        public void map(LongWritable key, Text value, Context context) throws IOException, InterruptedException {
            String line = value.toString();
            StringTokenizer tokenizer = new StringTokenizer(line, "\t");
            String first_column = tokenizer.nextToken();
            String second_column = tokenizer.nextToken();
            context.write(new LongWritable(Integer.parseInt(second_column)), new Text(first_column));
        }
    }

    public static class ReverseReduce extends Reducer<LongWritable, Text, Text, LongWritable> {
        private static int counter = 0;

        public void reduce(LongWritable key, Iterable<Text> values, Context context)
                throws IOException, InterruptedException {
            for (Text val : values) {
                if (counter < 50) {
                    context.write(val, key);
                    counter++;
                }
            }
        }

    }

    public static void main(String[] args) throws Exception {
        Configuration conf = new Configuration();

        Job job = new Job(conf, "PopularKeywords");
        job.setJarByClass(PopularKeywords.class);

        job.setOutputKeyClass(Text.class);
        job.setOutputValueClass(IntWritable.class);

        job.setReducerClass(Reduce.class);

        job.setInputFormatClass(TextInputFormat.class);
        job.setOutputFormatClass(TextOutputFormat.class);

        Path queriesInputPath = new Path(args[0]);
        Path StopWordsInputPath = new Path(args[1]);
        MultipleInputs.addInputPath(job, queriesInputPath, TextInputFormat.class, Map.class);
        MultipleInputs.addInputPath(job, StopWordsInputPath, TextInputFormat.class, StopwordsMap.class);

        FileOutputFormat.setOutputPath(job, new Path("/root/temporary"));

        job.waitForCompletion(true);

        Job sortingJob = new Job(conf, "PopularKeywords");
        sortingJob.setJarByClass(PopularKeywords.class);

        sortingJob.setOutputKeyClass(Text.class);
        sortingJob.setOutputValueClass(LongWritable.class);

        sortingJob.setMapperClass(ReverseMap.class);
        sortingJob.setReducerClass(ReverseReduce.class);

        sortingJob.setInputFormatClass(TextInputFormat.class);
        sortingJob.setOutputFormatClass(TextOutputFormat.class);
        sortingJob.setSortComparatorClass(LongWritable.DecreasingComparator.class);
        sortingJob.setMapOutputKeyClass(LongWritable.class);
        sortingJob.setMapOutputValueClass(Text.class);

        FileInputFormat.addInputPath(sortingJob, new Path("/root/temporary"));
        FileOutputFormat.setOutputPath(sortingJob, new Path(args[2]));

        sortingJob.setNumReduceTasks(1);
        sortingJob.waitForCompletion(true);
    }

}