Index: /WordCount.java
===================================================================
--- /WordCount.java	(revision 5)
+++ /WordCount.java	(revision 5)
@@ -0,0 +1,96 @@
+/*
+ * map reduce sample code
+ */
+
+import java.io.IOException;
+import java.util.Iterator;
+import java.util.StringTokenizer;
+
+import org.apache.hadoop.fs.FileSystem;
+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.mapred.JobClient;
+import org.apache.hadoop.mapred.JobConf;
+import org.apache.hadoop.mapred.MapReduceBase;
+import org.apache.hadoop.mapred.Mapper;
+import org.apache.hadoop.mapred.OutputCollector;
+import org.apache.hadoop.mapred.Reducer;
+import org.apache.hadoop.mapred.Reporter;
+
+
+public class WordCount {
+
+	// mapper: emits (token, 1) for every word occurrence
+	private static class MapClass extends MapReduceBase implements
+			Mapper<LongWritable, Text, Text, IntWritable> {
+
+		// reuse objects to save overhead of object creation
+		private final static IntWritable one = new IntWritable(1);
+		private Text word = new Text();
+
+		public void map(LongWritable key, Text value,
+				OutputCollector<Text, IntWritable> output, Reporter reporter)
+				throws IOException {
+			String line = ((Text) value).toString();
+			StringTokenizer itr = new StringTokenizer(line);
+			while (itr.hasMoreTokens()) {
+				word.set(itr.nextToken());
+				output.collect(word, one);
+			}
+		}
+	}
+
+	// reducer: sums up all the counts
+	private static class ReduceClass extends MapReduceBase implements
+			Reducer<Text, IntWritable, Text, IntWritable> {
+
+		// reuse objects
+		private final static IntWritable SumValue = new IntWritable();
+
+		public void reduce(Text key, Iterator<IntWritable> values,
+				OutputCollector<Text, IntWritable> output, Reporter reporter)
+				throws IOException {
+			// sum up values
+			int sum = 0;
+			while (values.hasNext()) {
+				sum += values.next().get();
+			}
+			SumValue.set(sum);
+			output.collect(key, SumValue);
+		}
+	}
+
+	
+	/**
+	 * Runs the demo.
+	 */
+	public static void main(String[] args) throws IOException {
+		String filename = "/user/waue/test/132.txt";
+		String outputPath = "sample-counts";
+		int mapTasks = 20;
+		int reduceTasks = 1;
+
+		JobConf conf = new JobConf(WordCount.class);
+		conf.setJobName("wordcount");
+
+		conf.setNumMapTasks(mapTasks);
+		conf.setNumReduceTasks(reduceTasks);
+
+		conf.setInputPath(new Path(filename));
+		conf.setOutputKeyClass(Text.class);
+		conf.setOutputValueClass(IntWritable.class);
+		conf.setOutputPath(new Path(outputPath));
+
+		conf.setMapperClass(MapClass.class);
+		conf.setCombinerClass(ReduceClass.class);
+		conf.setReducerClass(ReduceClass.class);
+		
+		// Delete the output directory if it exists already
+		Path outputDir = new Path(outputPath);
+		FileSystem.get(conf).delete(outputDir);
+
+		JobClient.runJob(conf);
+	}
+}