org.apache.nutch.mapReduce
Class ReduceTask

java.lang.Object
  org.apache.nutch.mapReduce.Task
      org.apache.nutch.mapReduce.ReduceTask

All Implemented Interfaces:

Writable

public class ReduceTask

extends Task

A Reduce task.

Constructor Summary

ReduceTask()

ReduceTask(String jobFile, String taskId, String[] mapTaskIds, int partition)

Method Summary

org.apache.nutch.mapReduce.TaskRunner	createRunner(TaskTracker tracker) Return an approprate thread runner for this task.
String[]	getMapTaskIds()
int	getPartition()
void	readFields(DataInput in) Reads the fields of this object from in.
void	run(JobConf job, TaskUmbilicalProtocol umbilical) Run this task as a part of the named job.
void	write(DataOutput out) Writes the fields of this object to out.

Methods inherited from class org.apache.nutch.mapReduce.Task

getJobFile, getTaskId, setJobFile, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

ReduceTask

public ReduceTask()

ReduceTask

public ReduceTask(String jobFile,
                  String taskId,
                  String[] mapTaskIds,
                  int partition)

Method Detail

createRunner

public org.apache.nutch.mapReduce.TaskRunner createRunner(TaskTracker tracker)

Description copied from class: Task

Return an approprate thread runner for this task.

Specified by:

createRunner in class Task

getMapTaskIds

public String[] getMapTaskIds()

getPartition

public int getPartition()

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

Overrides:

write in class Task

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

Overrides:

readFields in class Task

Throws:

IOException

run

public void run(JobConf job,
                TaskUmbilicalProtocol umbilical)
         throws IOException

Description copied from class: Task

Run this task as a part of the named job. This method is executed in the child process and is what invokes user-supplied map, reduce, etc. methods.

Specified by:

run in class Task

Parameters:

umbilical - for progress reports

Throws:

IOException