org.apache.hadoop.streaming
Class PipeMapper

java.lang.Object
  org.apache.hadoop.streaming.PipeMapRed
      org.apache.hadoop.streaming.PipeMapper

All Implemented Interfaces:

Closeable, JobConfigurable, Mapper

public class PipeMapper
extends PipeMapRed
implements Mapper

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

Author:

Michel Tourn

Field Summary

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

LOG, mapOutputFieldSeparator, numOfMapOutputKeyFields, numOfMapOutputPartitionFields, numOfReduceOutputKeyFields, outerrThreadsThrowable, reduceOutFieldSeparator

Constructor Summary

PipeMapper()

Method Summary

void	close() Called after the last call to any other method on this object to free and/or flush resources.
void	configure(JobConf job) Initializes a new instance from a JobConf.
void	map(WritableComparable key, Writable value, OutputCollector output, Reporter reporter) Maps a single input key/value pair into intermediate key/value pairs.

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

getContext, mapRedFinished

Methods inherited from class java.lang.Object

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

Constructor Detail

PipeMapper

public PipeMapper()

Method Detail

configure

public void configure(JobConf job)

Description copied from interface: JobConfigurable

Initializes a new instance from a JobConf.

Specified by:

configure in interface JobConfigurable

Overrides:

configure in class PipeMapRed

Parameters:

job - the configuration

map

public void map(WritableComparable key,
                Writable value,
                OutputCollector output,
                Reporter reporter)
         throws IOException

Description copied from interface: Mapper

Maps a single input key/value pair into intermediate key/value pairs. Output pairs need not be of the same types as input pairs. A given input pair may map to zero or many output pairs. Output pairs are collected with calls to OutputCollector.collect(WritableComparable,Writable).

Specified by:

map in interface Mapper

Parameters:

key - the key

value - the values

output - collects mapped keys and values

Throws:

IOException

close

public void close()

Description copied from interface: Closeable

Called after the last call to any other method on this object to free and/or flush resources. Typical implementations do nothing.

Specified by:

close in interface Closeable