Stopword_iii.java

package Question1;

import java.io.IOException;
import java.util.Arrays;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.conf.Configured;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.io.compress.BZip2Codec;
import org.apache.hadoop.io.compress.CompressionCodec;
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;
import org.apache.hadoop.util.Tool;
import org.apache.hadoop.util.ToolRunner;

public class Stopword_iii extends Configured implements Tool {
   public static void main(String[] args) throws Exception {
      System.out.println(Arrays.toString(args));
      int res = ToolRunner.run(new Configuration(), new Stopword_iii(), args);
      
      System.exit(res);
   }

   @Override
   public int run(String[] args) throws Exception {
      System.out.println(Arrays.toString(args));
      Job job = new Job(getConf(), "Stopword_iii");
      job.setJarByClass(Stopword_iii.class);
      job.setOutputKeyClass(Text.class);
      job.setOutputValueClass(IntWritable.class);

      job.setMapperClass(Map.class);
      job.setReducerClass(Reduce.class);
      job.setCombinerClass(Reduce.class);
      
      job.getConfiguration().setBoolean("mapred.compress.map.output",
    		  true);
      job.getConfiguration().setClass("mapred.map.output.compression.codec",
    		  BZip2Codec.class, CompressionCodec.class);

      job.setInputFormatClass(TextInputFormat.class);
      job.setOutputFormatClass(TextOutputFormat.class);
      
      job.setNumReduceTasks(10);
      

      FileInputFormat.addInputPath(job, new Path(args[0]));
      FileInputFormat.addInputPath(job, new Path(args[1]));
      FileInputFormat.addInputPath(job, new Path(args[2]));
      FileOutputFormat.setOutputPath(job, new Path(args[3]));


      job.waitForCompletion(true);
      
      return 0;
   }
   
   public static class Map extends Mapper<LongWritable, Text, Text, IntWritable> {
      private final static IntWritable ONE = new IntWritable(1);
      private Text word = new Text();

      @Override
      public void map(LongWritable key, Text value, Context context)
              throws IOException, InterruptedException {
         for (String token: value.toString().split("\\s+")) {
            word.set(token.toLowerCase());
            context.write(word, ONE);
         }
      }
   }

   public static class Reduce extends Reducer<Text, IntWritable, Text, IntWritable> {
      @Override
      public void reduce(Text key, Iterable<IntWritable> values, Context context)
              throws IOException, InterruptedException {
         int sum = 0;
         for (IntWritable val : values) {
            sum += val.get();
         }
         if (sum > 4000) {
        	 context.write(key, new IntWritable(sum));
         }
      }
   }
}