Package org.apache.hadoop.metrics2.impl

Class JmxCacheBuster

java.lang.Object

org.apache.hadoop.metrics2.impl.JmxCacheBuster

@Private
public final class JmxCacheBuster
extends Object

JMX caches the beans that have been exported; even after the values are removed from hadoop's metrics system the keys and old values will still remain. This class stops and restarts the Hadoop metrics system, forcing JMX to clear the cache of exported metrics. This class need to be in the o.a.h.metrics2.impl namespace as many of the variables/calls used are package private.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
(package private) static final class	JmxCacheBuster.JmxCacheBusterRunnable

Field Summary

Fields

Modifier and Type	Field	Description
private static MetricsExecutor	executor
private static AtomicReference<ScheduledFuture>	fut
private static final org.slf4j.Logger	LOG
private static AtomicBoolean	stopped

Constructor Summary

Constructors

Modifier	Constructor	Description
private	JmxCacheBuster()

Method Summary

Modifier and Type	Method	Description
static void	clearJmxCache()	For JMX to forget about all previously exported metrics.
static void	restart()	Restarts the stopped service.
static void	stop()	Stops the clearing of JMX metrics and restarting the Hadoop metrics system.

Methods inherited from class java.lang.Object

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

Field Details

LOG

private static final org.slf4j.Logger LOG

fut

private static AtomicReference<ScheduledFuture> fut

executor

private static MetricsExecutor executor

stopped

private static AtomicBoolean stopped

Constructor Details

JmxCacheBuster

private JmxCacheBuster()

Method Details

clearJmxCache

public static void clearJmxCache()

For JMX to forget about all previously exported metrics.

stop

public static void stop()

Stops the clearing of JMX metrics and restarting the Hadoop metrics system. This is needed for some test environments where we manually inject sources or sinks dynamically.

restart

public static void restart()

Restarts the stopped service.

See Also:

• stop()