org.apache.hadoop.mapred.lib

Class IdentityMapper<K,V>

java.lang.Object

org.apache.hadoop.mapred.MapReduceBase

org.apache.hadoop.mapred.lib.IdentityMapper<K,V>

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable, JobConfigurable, Mapper<K,V,K,V>

public class IdentityMapper<K,V>
extends MapReduceBase
implements Mapper<K,V,K,V>

Implements the identity function, mapping inputs directly to outputs.

Constructor Summary

Constructors

Constructor and Description
IdentityMapper()

Method Summary

Methods

Modifier and Type	Method and Description
void	map(K key, V val, OutputCollector<K,V> output, Reporter reporter) The identify function.

Methods inherited from class org.apache.hadoop.mapred.MapReduceBase

close, configure

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.hadoop.mapred.JobConfigurable

configure

Methods inherited from interface java.io.Closeable

close

Constructor Detail

IdentityMapper

public IdentityMapper()

Method Detail

map

public void map(K key,
       V val,
       OutputCollector<K,V> output,
       Reporter reporter)
         throws java.io.IOException

The identify function. Input key/value pair is written directly to output.

Specified by:

map in interface Mapper<K,V,K,V>

Parameters:

key - the input key.

val - the input value.

output - collects mapped keys and values.

reporter - facility to report progress.

Throws:

java.io.IOException