org.apache.nutch.mapReduce
Interface TaskUmbilicalProtocol

All Known Implementing Classes:

TaskTracker

public interface TaskUmbilicalProtocol

Protocol that task child process uses to contact its parent process. The parent is a daemon which which polls the central master for a new map or reduce task and runs it as a child process. All communication between child and parent is via this protocol.

Method Summary

void	done(String taskid) Report that the task is successfully completed.
Task	getTask(String taskid) Called when a child task process starts, to get its task.
void	progress(String taskid, FloatWritable progress) Report child's progress to parent.

Method Detail

getTask

public Task getTask(String taskid)
             throws IOException

Called when a child task process starts, to get its task.

Throws:

IOException

progress

public void progress(String taskid,
                     FloatWritable progress)
              throws IOException

Report child's progress to parent.

Parameters:

progress - value between zero and one

Throws:

IOException

done

public void done(String taskid)
          throws IOException

Report that the task is successfully completed. Failure is assumed if the task process exits without calling this.

Throws:

IOException