org.apache.hadoop.mapred.lib
Class InverseMapper

java.lang.Object
  org.apache.hadoop.mapred.MapReduceBase
      org.apache.hadoop.mapred.lib.InverseMapper

All Implemented Interfaces:

Closeable, JobConfigurable, Mapper

public class InverseMapper
extends MapReduceBase
implements Mapper

A Mapper that swaps keys and values.

Constructor Summary

InverseMapper()

Method Summary

void	map(WritableComparable key, Writable value, OutputCollector output, Reporter reporter) The inverse 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 org.apache.hadoop.io.Closeable

close

Constructor Detail

InverseMapper

public InverseMapper()

Method Detail

map

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

The inverse function. Input keys and values are swapped.

Specified by:

map in interface Mapper

Parameters:

key - the key

value - the values

output - collects mapped keys and values

Throws:

IOException