org.apache.hadoop.examples

Class SecondarySort.FirstPartitioner

java.lang.Object

org.apache.hadoop.mapreduce.Partitioner<SecondarySort.IntPair,org.apache.hadoop.io.IntWritable>

org.apache.hadoop.examples.SecondarySort.FirstPartitioner

Enclosing class:

SecondarySort

public static class SecondarySort.FirstPartitioner
extends Partitioner<SecondarySort.IntPair,org.apache.hadoop.io.IntWritable>

Partition based on the first part of the pair.

Constructor Summary

Constructors

Constructor and Description
SecondarySort.FirstPartitioner()

Method Summary

Methods

Modifier and Type	Method and Description
int	getPartition(SecondarySort.IntPair key, org.apache.hadoop.io.IntWritable value, int numPartitions) Get the partition number for a given key (hence record) given the total number of partitions i.e.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

SecondarySort.FirstPartitioner

public SecondarySort.FirstPartitioner()

Method Detail

getPartition

public int getPartition(SecondarySort.IntPair key,
               org.apache.hadoop.io.IntWritable value,
               int numPartitions)

Description copied from class: Partitioner

Get the partition number for a given key (hence record) given the total number of partitions i.e. number of reduce-tasks for the job.

Typically a hash function on a all or a subset of the key.

Specified by:

getPartition in class Partitioner<SecondarySort.IntPair,org.apache.hadoop.io.IntWritable>

Parameters:

key - the key to be partioned.

value - the entry value.

numPartitions - the total number of partitions.

Returns:

the partition number for the key.