Word Length Average Map-Reduce with out Combiner

WordCountAverage.java

package org.apache.hadoop.examples;

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

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.DoubleWritable;
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.output.FileOutputFormat;
import org.apache.hadoop.util.GenericOptionsParser;

public class WordCountAverage {

    // mapper class
    public static class TokenizerMapper 
	extends Mapper<Object, Text, Text, IntWritable>{
    
	private Text firstCharacter = new Text();
	private final static IntWritable length = new IntWritable(1);
      
	public void map(Object key, Text value, Context context)
	    throws IOException, InterruptedException {
	    StringTokenizer itr = new StringTokenizer(value.toString());
	    while (itr.hasMoreTokens()) {
		String token = itr.nextToken();
		firstCharacter.set(token.substring(0,1));
		length.set(token.length());
		context.write(firstCharacter, length);
	    }
	}
    }

    // reducer class
    public static class IntAverageReducer 
	extends Reducer<Text, IntWritable, Text, DoubleWritable> {
	private DoubleWritable result = new DoubleWritable();
	
	public void reduce(Text key, Iterable<IntWritable> values, 
			   Context context
			   ) throws IOException, InterruptedException {
	    double sum = 0;
	    int total = 0;
	    for (IntWritable val : values) {
		total ++;
		sum += val.get();
	    }
	    double average = sum / total;
	    result.set(average);
	    context.write(key, result);
	}
    }

    public static void main(String[] args) throws Exception {
	Configuration conf = new Configuration();
	String[] otherArgs = new GenericOptionsParser(conf, args).getRemainingArgs();
	if (otherArgs.length != 2) {
	    System.err.println("Usage: wordcount <in> <out>");
	    System.exit(2);
	}
	Job job = new Job(conf, "word count");
	job.setJarByClass(WordCount.class);
	job.setMapperClass(TokenizerMapper.class);
	job.setReducerClass(IntAverageReducer.class);
	job.setOutputKeyClass(Text.class);
	job.setOutputValueClass(IntWritable.class);
	FileInputFormat.addInputPath(job, new Path(otherArgs[0]));
	FileOutputFormat.setOutputPath(job, new Path(otherArgs[1]));
	System.exit(job.waitForCompletion(true) ? 0 : 1);
    }
}