PopularURLs.java Source code

Introduction

Here is the source code for PopularURLs.java

Source

/**************************************************
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/>.
**************************************************/

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.lib.input.FileInputFormat;
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 java.util.HashSet;

public class PopularURLs {
    public static class Map extends Mapper<LongWritable, Text, Text, Text> {
        private Text url = new Text();
        private Text user_id = new Text();

        public void map(LongWritable key, Text value, Context context) throws IOException, InterruptedException {
            String line = value.toString();
            //columns seperated with tab delimeter
            StringTokenizer tokenizer = new StringTokenizer(line, "\t");
            if (tokenizer.countTokens() == 5) {
                String user_id_str = tokenizer.nextToken();
                tokenizer.nextToken();
                tokenizer.nextToken();
                tokenizer.nextToken();
                String url_str = tokenizer.nextToken();
                user_id.set(user_id_str);
                url.set(url_str);
                if (!user_id.equals("AnonID"))
                    context.write(url, user_id);
            }
        }
    }

    public static class Reduce extends Reducer<Text, Text, Text, IntWritable> {
        public void reduce(Text key, Iterable<Text> values, Context context)
                throws IOException, InterruptedException {
            HashSet<Text> users = new HashSet<Text>();
            for (Text val : values)
                users.add(val);
            if (users.size() >= 10) {
                context.write(key, new IntWritable(users.size()));
            }
        }
    }

    public static void main(String[] args) throws Exception {
        Configuration conf = new Configuration();
        Job job = new Job(conf, "popularurls");
        job.setJarByClass(PopularURLs.class);
        job.setOutputKeyClass(Text.class);
        job.setOutputValueClass(Text.class);
        job.setMapperClass(Map.class);
        job.setReducerClass(Reduce.class);
        job.setInputFormatClass(TextInputFormat.class);
        job.setOutputFormatClass(TextOutputFormat.class);
        FileInputFormat.addInputPath(job, new Path(args[0]));
        FileOutputFormat.setOutputPath(job, new Path(args[1]));
        job.waitForCompletion(true);
    }

}