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

java.lang.Object
  extended by org.apache.hadoop.mapreduce.Reducer<KEYIN,VALUEIN,KEYOUT,org.apache.hadoop.io.Writable>
      extended by 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

public abstract class TableReducer<KEYIN,VALUEIN,KEYOUT>
extends org.apache.hadoop.mapreduce.Reducer<KEYIN,VALUEIN,KEYOUT,org.apache.hadoop.io.Writable>

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
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()


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