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

@InterfaceAudience.Public
@InterfaceStability.Evolving
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.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.hadoop.metrics.spi.AbstractMetricsContext

AbstractMetricsContext.MetricMap, AbstractMetricsContext.TagMap

Field Summary

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

DEFAULT_PERIOD

Constructor Summary

Constructors

Constructor and Description
NullContextWithUpdateThread() Creates a new instance of NullContextWithUpdateThread

Method Summary

Methods

Modifier and Type	Method and Description
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, getAllRecords, getAttribute, getAttributeTable, getContextFactory, getContextName, getPeriod, isMonitoring, newRecord, parseAndSetPeriod, 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

@InterfaceAudience.Private
public NullContextWithUpdateThread()

Creates a new instance of NullContextWithUpdateThread

Method Detail

init

@InterfaceAudience.Private
public void init(String contextName,
                                  ContextFactory factory)

Description copied from class: AbstractMetricsContext

Initializes the context.

Specified by:

init in interface MetricsContext

Overrides:

init in class AbstractMetricsContext

Parameters:

contextName - The given name for this context

factory - The creator of this context

emitRecord

@InterfaceAudience.Private
protected void emitRecord(String contextName,
                                        String recordName,
                                        OutputRecord outRec)

Do-nothing version of emitRecord

Specified by:

emitRecord in class AbstractMetricsContext

update

@InterfaceAudience.Private
protected void update(MetricsRecordImpl record)

Do-nothing version of update

Overrides:

update in class AbstractMetricsContext

remove

@InterfaceAudience.Private
protected void remove(MetricsRecordImpl record)

Do-nothing version of remove

Overrides:

remove in class AbstractMetricsContext