org.apache.hadoop.streaming

Class PipeReducer

java.lang.Object

org.apache.hadoop.streaming.PipeMapRed

org.apache.hadoop.streaming.PipeReducer

All Implemented Interfaces:

Closeable, AutoCloseable, JobConfigurable, Reducer

Direct Known Subclasses:

PipeCombiner

public class PipeReducer
extends PipeMapRed
implements Reducer

A generic Reducer bridge. It delegates operations to an external program via stdin and stdout.

Field Summary

Fields inherited from class org.apache.hadoop.streaming.PipeMapRed

LOG, outerrThreadsThrowable

Constructor Summary

Constructors

Constructor and Description
PipeReducer()

Method Summary

Modifier and Type	Method and Description
void	close()
void	configure(JobConf job)
byte[]	getFieldSeparator() Returns the field separator to be used.
byte[]	getInputSeparator() Returns the input separator to be used.
int	getNumOfKeyFields() Returns the number of key fields.
void	reduce(Object key, Iterator values, OutputCollector output, Reporter reporter)

Methods inherited from class org.apache.hadoop.streaming.PipeMapRed

getClientInput, getClientOutput, getConfiguration, getContext, mapRedFinished

Methods inherited from class java.lang.Object

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

Constructor Detail

PipeReducer

public PipeReducer()

Method Detail

configure

public void configure(JobConf job)

Specified by:

configure in interface JobConfigurable

Overrides:

configure in class PipeMapRed

reduce

public void reduce(Object key,
                   Iterator values,
                   OutputCollector output,
                   Reporter reporter)
            throws IOException

Specified by:

reduce in interface Reducer

Throws:

IOException

close

public void close()

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

getInputSeparator

public byte[] getInputSeparator()

Description copied from class: PipeMapRed

Returns the input separator to be used.

Specified by:

getInputSeparator in class PipeMapRed

getFieldSeparator

public byte[] getFieldSeparator()

Description copied from class: PipeMapRed

Returns the field separator to be used.

Specified by:

getFieldSeparator in class PipeMapRed

getNumOfKeyFields

public int getNumOfKeyFields()

Description copied from class: PipeMapRed

Returns the number of key fields.

Specified by:

getNumOfKeyFields in class PipeMapRed