org.apache.hadoop.contrib.utils.join
Class TaggedMapOutput

java.lang.Object
  org.apache.hadoop.contrib.utils.join.TaggedMapOutput

All Implemented Interfaces:

Writable

public abstract class TaggedMapOutput
extends Object
implements Writable

This abstract class serves as the base class for the values that flow from the mappers to the reducers in a data join job. Typically, in such a job, the mappers will compute the source tag of an input record based on its attributes or based on the file name of the input file. This tag will be used by the reducers to re-group the values of a given key according to their source tags.

Field Summary

protected Text

tag

Constructor Summary

TaggedMapOutput()

Method Summary

TaggedMapOutput	clone(JobConf job)
abstract Writable	getData()
Text	getTag()
void	setTag(Text tag)

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.io.Writable

readFields, write

Field Detail

tag

protected Text tag

Constructor Detail

TaggedMapOutput

public TaggedMapOutput()

Method Detail

getTag

public Text getTag()

setTag

public void setTag(Text tag)

getData

public abstract Writable getData()

clone

public TaggedMapOutput clone(JobConf job)