Performing Transformations Using MapReduce (Map Only)

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author: Bharat (sree ram)

contact : 04042026071

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input file :  emp.txt

_____________________
101,amar,m,20000,hyd
102,amala,f,30000,pune
103,siva,m,40000,hyd
104,sivani,f,50000,hyd
105,hari,m,40000,pune
____________________

IN input file 3rd field is sex, and 4th field is Salary.
I want to transform "m" as "Male"
and Salary into grades as A,B,C with following criteria.

if salary is < 30000 ---> C
if salary is  >=30000 and <50000 ------>B
is salary is >=50000   ------------------>A

in this case also we dont want Reducer... output expected:

 101,amar,Male,C,hyd
102,amala,Female,B,pune
103,siva,Male,B,hyd
104,sivani,Female,A,hyd
105,hari,Male,B,pune



package my.map.red;

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.Text;

import org.apache.hadoop.mapreduce.Job;

import org.apache.hadoop.mapreduce.Mapper;

import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;

import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;

import org.apache.hadoop.util.GenericOptionsParser;

public class  Transformation{

  public static class Map1 extends Mapper<LongWritable,Text,Text,Text>  {

         public void map(LongWritable k, Text v, Context con)
            throws IOException, InterruptedException{

                           String line=v.toString();

                           String[] words=line.split(",");
                           String sex=words[2];
                           int sal=Integer.parseInt(words[3]);
                           String grade=new String();
                          if (sal>=50000)
                                grade="A";
                          else if(sal>=30000)
                                    grade="B";
                                else
                                    grade="C";
                         if(sex.matches("f"))
                               sex="Female";
                         else
                                sex="Male";

              String newline=words[0]+","+words[1]+","+sex+","+grade+words[4];

                           con.write(new Text(newline), new Text());

              }

  }

  public static void main(String[] args) throws Exception  {

              Configuration c=new Configuration();

              String[] files=new GenericOptionsParser(c,args).getRemainingArgs();

              Path p1=new Path(files[0]);

              Path p2=new Path(files[1]);

              Job j = new Job(c,"trans");

              j.setJarByClass(Transformation.class);

              j.setMapperClass(Map1.class);

              j.setNumReduceTasks(0);

              j.setOutputKeyClass(Text.class);

              j.setOutputValueClass(Text.class);

              FileInputFormat.addInputPath(j,p1);
               FileOutputFormat.setOutputPath(j, p2);

                System.exit(j.waitForCompletion(true) ? 0:1);

             

  }

}