org.apache.hadoop.hbase.mapreduce

Class TableReducer<KEYIN,VALUEIN,KEYOUT>

java.lang.Object

org.apache.hadoop.mapreduce.Reducer<KEYIN,VALUEIN,KEYOUT,Mutation>

org.apache.hadoop.hbase.mapreduce.TableReducer<KEYIN,VALUEIN,KEYOUT>

Type Parameters:

KEYIN - The type of the input key.

VALUEIN - The type of the input value.

KEYOUT - The type of the output key.

Direct Known Subclasses:

IdentityTableReducer

@InterfaceAudience.Public
public abstract class TableReducer<KEYIN,VALUEIN,KEYOUT>
extends org.apache.hadoop.mapreduce.Reducer<KEYIN,VALUEIN,KEYOUT,Mutation>

Extends the basic Reducer class to add the required key and value input/output classes. While the input key and value as well as the output key can be anything handed in from the previous map phase the output value must be either a Put or a Delete instance when using the TableOutputFormat class.

This class is extended by IdentityTableReducer but can also be subclassed to implement similar features or any custom code needed. It has the advantage to enforce the output value to a specific basic type.

See Also:

Reducer

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.hadoop.mapreduce.Reducer

org.apache.hadoop.mapreduce.Reducer.Context

Constructor Summary

Constructors

Constructor and Description
TableReducer()

Method Summary

Methods inherited from class org.apache.hadoop.mapreduce.Reducer

cleanup, reduce, run, setup

Methods inherited from class java.lang.Object

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

Constructor Detail

TableReducer

public TableReducer()