map and reduce with different value classes

[Bryan Yeung]

Hello Everyone,

I'm relatively new to hadoop mapreduce and I'm trying to get this
simple modification to the WordCount example to work.

I'm using hadoop-1.0.2, and I've included both a convenient diff and
also attached my new WordCount.java file.

The thing I am trying to achieve is to have the value class that is
output by the map phase be different than the value class output by
the reduce phase.

Any help would be greatly appreciated!

Thanks,

Bryan

diff --git a/WordCount.java.orig b/WordCount.java
index 81a6c21..6a768f7 100644
--- a/WordCount.java.orig
+++ b/WordCount.java
@@ -33,8 +33,8 @@ public class WordCount {
   }

   public static class IntSumReducer
-       extends Reducer<Text,IntWritable,Text,IntWritable> {
-    private IntWritable result = new IntWritable();
+       extends Reducer<Text,IntWritable,Text,Text> {
+    private Text result = new Text();

     public void reduce(Text key, Iterable<IntWritable> values,
                        Context context
@@ -43,7 +43,7 @@ public class WordCount {
       for (IntWritable val : values) {
         sum += val.get();
       }
-      result.set(sum);
+      result.set("" + sum);
       context.write(key, result);
     }
   }
@@ -58,10 +58,11 @@ public class WordCount {
     Job job = new Job(conf, "word count");
     job.setJarByClass(WordCount.class);
     job.setMapperClass(TokenizerMapper.class);
+       job.setMapOutputValueClass(IntWritable.class);
     job.setCombinerClass(IntSumReducer.class);
     job.setReducerClass(IntSumReducer.class);
     job.setOutputKeyClass(Text.class);
-    job.setOutputValueClass(IntWritable.class);
+    job.setOutputValueClass(Text.class);
     FileInputFormat.addInputPath(job, new Path(otherArgs[0]));
     FileOutputFormat.setOutputPath(job, new Path(otherArgs[1]));
     System.exit(job.waitForCompletion(true) ? 0 : 1);

WordCount.java
Description: Binary data