org.apache.hadoop.metrics2
Interface MetricsSystem

All Superinterfaces:

MetricsSystemMXBean

All Known Implementing Classes:

DefaultMetricsSystem, MetricsSystemImpl

public interface MetricsSystem
extends MetricsSystemMXBean

The metrics system interface

Nested Class Summary

static class	MetricsSystem.AbstractCallback Convenient abstract class for implementing callback interface
static interface	MetricsSystem.Callback The metrics system callback interface

Method Summary

void	publishMetricsNow() Requests an immediate publish of all metrics from sources to sinks.
void	register(MetricsSystem.Callback callback) Register a callback interface for JMX events
<T extends MetricsSink> T	register(String name, String desc, T sink) Register a metrics sink
<T extends MetricsSource> T	register(String name, String desc, T source) Register a metrics source
void	shutdown() Shutdown the metrics system completely (usually during server shutdown.) The MetricsSystemMXBean will be unregistered.

Methods inherited from interface org.apache.hadoop.metrics2.MetricsSystemMXBean

currentConfig, refreshMBeans, start, stop

Method Detail

register

<T extends MetricsSource> T register(String name,
                                     String desc,
                                     T source)

Register a metrics source

Type Parameters:

T - the type of the source

Parameters:

source - to register

name - of the source. Must be unique.

desc - the description of the source.

Returns:

the source

Throws:

MetricsException

register

<T extends MetricsSink> T register(String name,
                                   String desc,
                                   T sink)

Register a metrics sink

Type Parameters:

T - the type of the sink

Parameters:

sink - to register

name - of the sink. Must be unique.

desc - the description of the sink

Returns:

the sink

Throws:

MetricsException

register

void register(MetricsSystem.Callback callback)

Register a callback interface for JMX events

Parameters:

callback - the callback object implementing the MBean interface.

publishMetricsNow

void publishMetricsNow()

Requests an immediate publish of all metrics from sources to sinks. This is a "soft" request: the expectation is that a best effort will be done to synchronously snapshot the metrics from all the sources and put them in all the sinks (including flushing the sinks) before returning to the caller. If this can't be accomplished in reasonable time it's OK to return to the caller before everything is done.

shutdown

void shutdown()

Shutdown the metrics system completely (usually during server shutdown.) The MetricsSystemMXBean will be unregistered.