org.apache.hadoop.mapred.lib
Class HashPartitioner
java.lang.Object
org.apache.hadoop.mapred.lib.HashPartitioner
- All Implemented Interfaces:
- JobConfigurable, Partitioner
public class HashPartitioner
- extends Object
- implements Partitioner
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(WritableComparable key,
Writable value,
int numReduceTasks)
- Use
Object.hashCode()
to partition.
- Specified by:
getPartition
in interface Partitioner
- Parameters:
key
- the entry keyvalue
- the entry valuenumReduceTasks
- the number of partitions
- Returns:
- the partition number
Copyright © 2006 The Apache Software Foundation