## org.apache.hadoop.examples
Class PiEstimator.PiReducer

    java.lang.Object
      org.apache.hadoop.mapred.MapReduceBase
          org.apache.hadoop.examples.PiEstimator.PiReducer

All Implemented Interfaces:
  Closeable, JobConfigurable, Reducer<BooleanWritable,LongWritable,WritableComparable<?>,Writable>

Enclosing class:
  PiEstimator

    public static class PiEstimator.PiReducer

extends MapReduceBase
implements Reducer<BooleanWritable,LongWritable,WritableComparable<?>,Writable>

Reducer class for Pi estimation. Accumulate points inside/outside results from the mappers.

Constructor Summary
`PiEstimator.PiReducer()`

Method Summary
`void` `close()` Reduce task done, write output to a file.
`void` `configure(JobConf job)` Store job configuration.
`void` `reduce(BooleanWritable isInside, Iterator<LongWritable> values, OutputCollector<WritableComparable<?>,Writable> output, Reporter reporter)` Accumulate number of points inside/outside results from the mappers.

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Constructor Detail

### PiEstimator.PiReducer

    public PiEstimator.PiReducer()

Method Detail

### configure

    public void configure(JobConf job)

  Store job configuration.

  Specified by:
    `configure` in interface `JobConfigurable`
  Overrides:
    `configure` in class `MapReduceBase`
  Parameters:
    `job` - the configuration

### reduce

    public void reduce(BooleanWritable isInside,
                       Iterator<LongWritable> values,
                       OutputCollector<WritableComparable<?>,Writable> output,
                       Reporter reporter)
                throws IOException

  Accumulate number of points inside/outside results from the mappers.

  Specified by:
    `reduce` in interface `Reducer<BooleanWritable,LongWritable,WritableComparable<?>,Writable>`
  Parameters:
    `isInside` - Is the points inside?
    `values` - An iterator to a list of point counts
    `output` - dummy, not used here.
    `reporter` -
  Throws:
    `IOException`

### close

    public void close()
               throws IOException

  Reduce task done, write output to a file.

  Specified by:
    `close` in interface `Closeable`
  Overrides:
    `close` in class `MapReduceBase`
  Throws:
    `IOException`

Copyright © 2009 The Apache Software Foundation