org.apache.hadoop.mapred
Class ClusterStatus

java.lang.Object
  org.apache.hadoop.mapred.ClusterStatus

All Implemented Interfaces:

Writable

public class ClusterStatus
extends Object
implements Writable

Status information on the current state of the Map-Reduce cluster.

ClusterStatus provides clients with information such as:

1. Size of the cluster.
2. Task capacity of the cluster.
3. The number of currently running map & reduce tasks.
4. State of the JobTracker.

Clients can query for the latest ClusterStatus, via JobClient.getClusterStatus().

See Also:

JobClient

Method Summary

JobTracker.State	getJobTrackerState() Get the current state of the JobTracker, as JobTracker.State
int	getMapTasks() Get the number of currently running map tasks in the cluster.
int	getMaxMapTasks() Get the maximum capacity for running map tasks in the cluster.
int	getMaxReduceTasks() Get the maximum capacity for running reduce tasks in the cluster.
int	getMaxTasks() Deprecated. Use getMaxMapTasks() and/or getMaxReduceTasks()
int	getReduceTasks() Get the number of currently running reduce tasks in the cluster.
int	getTaskTrackers() Get the number of task trackers in the cluster.
void	readFields(DataInput in) Deserialize the fields of this object from in.
void	write(DataOutput out) Serialize 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

Method Detail

getTaskTrackers

public int getTaskTrackers()

Get the number of task trackers in the cluster.

Returns:

the number of task trackers in the cluster.

getMapTasks

public int getMapTasks()

Get the number of currently running map tasks in the cluster.

Returns:

the number of currently running map tasks in the cluster.

getReduceTasks

public int getReduceTasks()

Get the number of currently running reduce tasks in the cluster.

Returns:

the number of currently running reduce tasks in the cluster.

getMaxTasks

public int getMaxTasks()

Deprecated. Use getMaxMapTasks() and/or getMaxReduceTasks()

Get the maximum capacity for running tasks in the cluster.

Returns:

the maximum capacity for running tasks in the cluster.

getMaxMapTasks

public int getMaxMapTasks()

Get the maximum capacity for running map tasks in the cluster.

Returns:

the maximum capacity for running map tasks in the cluster.

getMaxReduceTasks

public int getMaxReduceTasks()

Get the maximum capacity for running reduce tasks in the cluster.

Returns:

the maximum capacity for running reduce tasks in the cluster.

getJobTrackerState

public JobTracker.State getJobTrackerState()

Get the current state of the JobTracker, as JobTracker.State

Returns:

the current state of the JobTracker.

write

public void write(DataOutput out)
           throws IOException

Description copied from interface: Writable

Serialize the fields of this object to out.

Specified by:

write in interface Writable

Parameters:

out - DataOuput to serialize this object into.

Throws:

IOException

readFields

public void readFields(DataInput in)
                throws IOException

Description copied from interface: Writable

Deserialize 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

Parameters:

in - DataInput to deseriablize this object from.

Throws:

IOException