org.apache.hadoop.examples

Class Join

java.lang.Object

org.apache.hadoop.conf.Configured

org.apache.hadoop.examples.Join

All Implemented Interfaces:

org.apache.hadoop.conf.Configurable, org.apache.hadoop.util.Tool

public class Join
extends org.apache.hadoop.conf.Configured
implements org.apache.hadoop.util.Tool

Given a set of sorted datasets keyed with the same class and yielding equal partitions, it is possible to effect a join of those datasets prior to the map. The example facilitates the same. To run: bin/hadoop jar build/hadoop-examples.jar join [-r reduces] [-inFormat input format class] [-outFormat output format class] [-outKey output key class] [-outValue output value class] [-joinOp <inner|outer|override>] [in-dir]* in-dir out-dir

Field Summary

Fields

Modifier and Type	Field and Description
static String	REDUCES_PER_HOST

Constructor Summary

Constructors

Constructor and Description
Join()

Method Summary

Methods

Modifier and Type	Method and Description
static void	main(String[] args)
int	run(String[] args) The main driver for sort program.

Methods inherited from class org.apache.hadoop.conf.Configured

getConf, setConf

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.conf.Configurable

getConf, setConf

Field Detail

REDUCES_PER_HOST

public static final String REDUCES_PER_HOST

See Also:

Constant Field Values

Constructor Detail

Join

public Join()

Method Detail

run

public int run(String[] args)
        throws Exception

The main driver for sort program. Invoke this method to submit the map/reduce job.

Specified by:

run in interface org.apache.hadoop.util.Tool

Throws:

IOException - When there is communication problems with the job tracker.

Exception

main

public static void main(String[] args)
                 throws Exception

Throws:

Exception