org.apache.hadoop.metrics.spi
Class NullContextWithUpdateThread

java.lang.Object
  org.apache.hadoop.metrics.spi.AbstractMetricsContext
      org.apache.hadoop.metrics.spi.NullContextWithUpdateThread

All Implemented Interfaces:

MetricsContext

public class NullContextWithUpdateThread
extends AbstractMetricsContext

A null context which has a thread calling periodically when monitoring is started. This keeps the data sampled correctly. In all other respects, this is like the NULL context: No data is emitted. This is suitable for Monitoring systems like JMX which reads the metrics when someone reads the data from JMX. The default impl of start and stop monitoring: is the AbstractMetricsContext is good enough.

Field Summary

Fields inherited from interface org.apache.hadoop.metrics.MetricsContext

DEFAULT_PERIOD

Constructor Summary

NullContextWithUpdateThread()
Creates a new instance of NullContextWithUpdateThread

Method Summary

protected void	emitRecord(String contextName, String recordName, OutputRecord outRec) Do-nothing version of emitRecord
void	init(String contextName, ContextFactory factory) Initializes the context.
protected void	remove(MetricsRecordImpl record) Do-nothing version of remove
protected void	update(MetricsRecordImpl record) Do-nothing version of update

Methods inherited from class org.apache.hadoop.metrics.spi.AbstractMetricsContext

close, createRecord, flush, getAttribute, getAttributeTable, getContextFactory, getContextName, getPeriod, isMonitoring, newRecord, registerUpdater, setPeriod, startMonitoring, stopMonitoring, unregisterUpdater

Methods inherited from class java.lang.Object

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

Constructor Detail

NullContextWithUpdateThread

public NullContextWithUpdateThread()

Creates a new instance of NullContextWithUpdateThread

Method Detail

init

public void init(String contextName,
                 ContextFactory factory)

Description copied from class: AbstractMetricsContext

Initializes the context.

Overrides:

init in class AbstractMetricsContext

emitRecord

protected void emitRecord(String contextName,
                          String recordName,
                          OutputRecord outRec)

Do-nothing version of emitRecord

Specified by:

emitRecord in class AbstractMetricsContext

update

protected void update(MetricsRecordImpl record)

Do-nothing version of update

Overrides:

update in class AbstractMetricsContext

remove

protected void remove(MetricsRecordImpl record)

Do-nothing version of remove

Overrides:

remove in class AbstractMetricsContext