SecondarySort (Hadoop 0.20.2+737 API)
Date: 2010-10-11

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## org.apache.hadoop.examples
Class SecondarySort

    java.lang.Object
      org.apache.hadoop.examples.SecondarySort

    public class SecondarySort

extends Object

This is an example Hadoop Map/Reduce application. It reads the text input files that must contain two integers per a line. The output is sorted by the first and second number and grouped on the first number. To run: bin/hadoop jar build/hadoop-examples.jar secondarysort in-dir out-dir

Nested Class Summary
`static class` | `SecondarySort.FirstGroupingComparator` Compare only the first part of the pair, so that reduce is called once for each value of the first part.
`static class` | `SecondarySort.FirstPartitioner` Partition based on the first part of the pair.
`static class` | `SecondarySort.IntPair` Define a pair of integers that are writable.
`static class` | `SecondarySort.MapClass` Read two integers from each line and generate a key, value pair as ((left, right), right).
`static class` | `SecondarySort.Reduce` A reducer class that just emits the sum of the input values.

Constructor Summary
`SecondarySort()`

Method Summary
`static void` | `main(String[] args)`

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

Constructor Detail

### SecondarySort

    public SecondarySort()

Method Detail

### main

    public static void main(String[] args)
                     throws Exception

  Throws:
    `Exception`

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Copyright © 2009 The Apache Software Foundation