MaleUsersBelow7Years.java Source code

Introduction

Here is the source code for MaleUsersBelow7Years.java

Source

import java.io.IOException;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.Reducer;
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;

/*
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/**
 *
 * @author bhumikasaivamani
 */
public class MaleUsersBelow7Years {
    public static class Map extends Mapper<LongWritable, Text, Text, NullWritable> {
        public void map(LongWritable key, Text value, Context context) throws IOException, InterruptedException {
            //Mapper takes value from data set line by line and produces key value pair for each data row in the data set
            String line = value.toString();
            String[] tokenizedLine = line.split("::");
            String userId = tokenizedLine[0];
            String gender = tokenizedLine[1];
            String age = tokenizedLine[2];
            if (gender.compareTo("M") == 0 && Integer.parseInt(age) <= 7) {
                context.write(new Text(userId), NullWritable.get()); //input to reducer
            }
        }

    }

    public static class Reduce extends Reducer<Text, NullWritable, Text, NullWritable> {
        public void reduce(Text key, NullWritable value, Context context) throws IOException, InterruptedException {
            context.write(key, NullWritable.get());
        }
    }

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

        Job job = new Job(configuration, "CountMaleUsersLessThan7");
        job.setJarByClass(MaleUsersBelow7Years.class);
        job.setMapperClass(Map.class);
        job.setReducerClass(Reducer.class);
        job.setCombinerClass(Reducer.class);

        //set output and input formats;mapper-input reducer-output
        job.setInputFormatClass(TextInputFormat.class);
        job.setOutputFormatClass(TextOutputFormat.class);
        job.setOutputKeyClass(Text.class);
        job.setOutputValueClass(NullWritable.class);

        FileInputFormat.addInputPath(job, new Path(args[0])); //path for input file
        FileOutputFormat.setOutputPath(job, new Path(args[1])); // Path for output file
        System.exit(job.waitForCompletion(true) ? 0 : 1);
    }

}