org.apache.hadoop.mapred.lib
Class HashPartitioner<K2,V2>
java.lang.Object
org.apache.hadoop.mapred.lib.HashPartitioner<K2,V2>
- All Implemented Interfaces:
- JobConfigurable, Partitioner<K2,V2>
@InterfaceAudience.Public
@InterfaceStability.Stable
public class HashPartitioner<K2,V2>
- extends Object
- implements Partitioner<K2,V2>
Partition keys by their Object.hashCode()
.
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
HashPartitioner
public HashPartitioner()
configure
public void configure(JobConf job)
- Description copied from interface:
JobConfigurable
- Initializes a new instance from a
JobConf
.
- Specified by:
configure
in interface JobConfigurable
- Parameters:
job
- the configuration
getPartition
public int getPartition(K2 key,
V2 value,
int numReduceTasks)
- Use
Object.hashCode()
to partition.
- Specified by:
getPartition
in interface Partitioner<K2,V2>
- Parameters:
key
- the key to be paritioned.value
- the entry value.numReduceTasks
- the total number of partitions.
- Returns:
- the partition number for the
key
.
Copyright © 2014 Apache Software Foundation. All Rights Reserved.