WordCountProgram with Counters

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.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;

public class WordCountWithCounter {

        static enum WordsNature { STARTS_WITH_DIGIT, STARTS_WITH_LETTER, ALL }

        /**

         * The map class of WordCount.

         */

        public static class TokenCounterMapper

        extends Mapper<Object, Text, Text, IntWritable> {

               private final static IntWritable one = new IntWritable(1);

               private Text word = new Text();

               public void map(Object key, Text value, Context context)

               throws IOException, InterruptedException {

                       StringTokenizer itr = new StringTokenizer(value.toString());

                       while (itr.hasMoreTokens()) {

                               word.set(itr.nextToken());

                               context.write(word, one);

                       }

               }

        }

        /**

         * The reducer class of WordCount

         */

        public static class TokenCounterReducer

        extends Reducer<Text, IntWritable, Text, IntWritable> {

               public void reduce(Text key, Iterable<IntWritable> values, Context context)

               throws IOException, InterruptedException {

                       int sum = 0;

                      

                       String token = key.toString();

                       if( StringUtils.startsWithDigit(token) ){

                               context.getCounter(WordsNature.STARTS_WITH_DIGIT).increment(1);

                       }

                       else if( StringUtils.startsWithLetter(token) ){

                               context.getCounter(WordsNature.STARTS_WITH_LETTER).increment(1);

                       }

                       context.getCounter(WordsNature.ALL).increment(1);

                      

                       for (IntWritable value : values) {

                               sum += value.get();

                       }

                       context.write(key, new IntWritable(sum));

               }

        }

        /**

         * The main entry point.

         */

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

               Configuration conf = new Configuration();

               Job job = new Job(conf, "Example Hadoop 0.20.1 WordCount");

               job.setJarByClass(WordCountOld.class);

               job.setMapperClass(TokenCounterMapper.class);

               job.setReducerClass(TokenCounterReducer.class);

               job.setOutputKeyClass(Text.class);

               job.setOutputValueClass(IntWritable.class);

               FileInputFormat.addInputPath(job, new Path(args[0]));

               FileOutputFormat.setOutputPath(job, new Path(args[1]));

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

        }

}