org.apache.nutch.mapReduce
Class MapOutputFile

java.lang.Object
  org.apache.nutch.mapReduce.MapOutputFile

All Implemented Interfaces:

Writable

public class MapOutputFile

extends Object

implements Writable

A local file to be transferred via the MapOutputProtocol.

Constructor Summary

MapOutputFile()
Construct a file for transfer.

MapOutputFile(String mapTaskId, String reduceTaskId, int partition)

Method Summary

static void	cleanupStorage() Removes all contents of temporary storage.
static File	getInputFile(String mapTaskId, String reduceTaskId) Create a local reduce input file name.
static File	getOutputFile(String mapTaskId, int partition) Create a local map output file name.
void	readFields(DataInput in) Reads the fields of this object from in.
static void	removeAll(String taskId) Removes all of the files related to a task.
void	write(DataOutput out) Writes the fields of this object to out.

Methods inherited from class java.lang.Object

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

Constructor Detail

MapOutputFile

public MapOutputFile()

Construct a file for transfer.

MapOutputFile

public MapOutputFile(String mapTaskId,
                     String reduceTaskId,
                     int partition)

Method Detail

getOutputFile

public static File getOutputFile(String mapTaskId,
                                 int partition)

Create a local map output file name.

Parameters:

mapTaskId - a map task id

partition - a reduce partition

getInputFile

public static File getInputFile(String mapTaskId,
                                String reduceTaskId)

Create a local reduce input file name.

Parameters:

mapTaskId - a map task id

reduceTaskId - a reduce task id

removeAll

public static void removeAll(String taskId)
                      throws IOException

Removes all of the files related to a task.

Throws:

IOException

cleanupStorage

public static void cleanupStorage()
                           throws IOException

Removes all contents of temporary storage. Called upon startup, to remove any leftovers from previous run.

Throws:

IOException

write

public void write(DataOutput out)
           throws IOException

Description copied from interface: Writable

Writes the fields of this object to out.

Specified by:

write in interface Writable

Throws:

IOException

readFields

public void readFields(DataInput in)
                throws IOException

Description copied from interface: Writable

Reads the fields of this object from in. For efficiency, implementations should attempt to re-use storage in the existing object where possible.

Specified by:

readFields in interface Writable

Throws:

IOException