package test;

 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;

 import org.apache.hadoop.util.GenericOptionsParser;

 public class WordCount {

         public static class TokenizerMapper extends Mapper<Object, Text, Text, IntWritable>{

                 private final 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);

                         }

                 }

         }

         public static class IntSumReducer extends Reducer<Text, IntWritable, Text, IntWritable> {

                 private IntWritable result = new IntWritable();

                 public void reduce(Text key, Iterable<IntWritable> values, Context context) throws IOException, InterruptedException {

                         int sum = 0;

                         for (IntWritable val : values) {

                                 sum += val.get();

                         }

                         result.set(sum);

                         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.setCombinerClass(IntSumReducer.class);

                 job.setReducerClass(IntSumReducer.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);

         }

 }