org.apache.hadoop.examples.pi
Class DistSum.ReduceSide.SummingReducer

java.lang.Object
  extended by org.apache.hadoop.mapreduce.Reducer<org.apache.hadoop.io.IntWritable,SummationWritable,org.apache.hadoop.io.NullWritable,TaskResult>
      extended by org.apache.hadoop.examples.pi.DistSum.ReduceSide.SummingReducer
Enclosing class:
DistSum.ReduceSide

public static class DistSum.ReduceSide.SummingReducer
extends Reducer<org.apache.hadoop.io.IntWritable,SummationWritable,org.apache.hadoop.io.NullWritable,TaskResult>

A Reducer which computes sums


Nested Class Summary
 
Nested classes/interfaces inherited from class org.apache.hadoop.mapreduce.Reducer
Reducer.Context
 
Constructor Summary
DistSum.ReduceSide.SummingReducer()
           
 
Method Summary
protected  void reduce(org.apache.hadoop.io.IntWritable index, Iterable<SummationWritable> sums, Reducer.Context context)
          This method is called once for each key.
 
Methods inherited from class org.apache.hadoop.mapreduce.Reducer
cleanup, run, setup
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

DistSum.ReduceSide.SummingReducer

public DistSum.ReduceSide.SummingReducer()
Method Detail

reduce

protected void reduce(org.apache.hadoop.io.IntWritable index,
                      Iterable<SummationWritable> sums,
                      Reducer.Context context)
               throws IOException,
                      InterruptedException
Description copied from class: Reducer
This method is called once for each key. Most applications will define their reduce class by overriding this method. The default implementation is an identity function.

Overrides:
reduce in class Reducer<org.apache.hadoop.io.IntWritable,SummationWritable,org.apache.hadoop.io.NullWritable,TaskResult>
Throws:
IOException
InterruptedException


Copyright © 2009 The Apache Software Foundation