org.apache.hadoop.metrics2.lib
Enum DefaultMetricsSystem

java.lang.Object
  java.lang.Enum<DefaultMetricsSystem>
      org.apache.hadoop.metrics2.lib.DefaultMetricsSystem

All Implemented Interfaces:

Serializable, Comparable<DefaultMetricsSystem>, MetricsSystem, MetricsSystemMXBean

public enum DefaultMetricsSystem
extends Enum<DefaultMetricsSystem>
implements MetricsSystem

The default metrics system singleton

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.hadoop.metrics2.MetricsSystem

MetricsSystem.AbstractCallback, MetricsSystem.Callback

Enum Constant Summary

INSTANCE
The singleton instance

Method Summary

String	currentConfig()
static MetricsSystem	initialize(String prefix) Common static convenience method to initialize the metrics system
void	publishMetricsNow() Requests an immediate publish of all metrics from sources to sinks.
void	refreshMBeans() Force a refresh of MBeans
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
static <T extends MetricsSource> T	registerSource(String name, String desc, T source) Common static method to register a source
void	shutdown() Shutdown the metrics system completely (usually during server shutdown.) The MetricsSystemMXBean will be unregistered.
void	start() Start the metrics system
void	stop() Stop the metrics system
static DefaultMetricsSystem	valueOf(String name) Returns the enum constant of this type with the specified name.
static DefaultMetricsSystem[]	values() Returns an array containing the constants of this enum type, in the order they are declared.

Methods inherited from class java.lang.Enum

clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Detail

INSTANCE

public static final DefaultMetricsSystem INSTANCE

The singleton instance

Method Detail

values

public static DefaultMetricsSystem[] values()

Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:

for (DefaultMetricsSystem c : DefaultMetricsSystem.values())
    System.out.println(c);

Returns:

an array containing the constants of this enum type, in the order they are declared

valueOf

public static DefaultMetricsSystem valueOf(String name)

Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)

Parameters:

name - the name of the enum constant to be returned.

Returns:

the enum constant with the specified name

Throws:

IllegalArgumentException - if this enum type has no constant with the specified name

NullPointerException - if the argument is null

initialize

public static MetricsSystem initialize(String prefix)

Common static convenience method to initialize the metrics system

Parameters:

prefix - for configuration

Returns:

the metrics system instance

register

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

Description copied from interface: MetricsSystem

Register a metrics source

Specified by:

register in interface MetricsSystem

Type Parameters:

T - the type of the source

Parameters:

name - of the source. Must be unique.

desc - the description of the source.

source - to register

Returns:

the source

registerSource

public static <T extends MetricsSource> T registerSource(String name,
                                                         String desc,
                                                         T source)

Common static method to register a source

Type Parameters:

T - type of the source

Parameters:

name - of the source

desc - description

source - the source object to register

Returns:

the source object

register

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

Description copied from interface: MetricsSystem

Register a metrics sink

Specified by:

register in interface MetricsSystem

Type Parameters:

T - the type of the sink

Parameters:

name - of the sink. Must be unique.

desc - the description of the sink

sink - to register

Returns:

the sink

register

public void register(MetricsSystem.Callback callback)

Description copied from interface: MetricsSystem

Register a callback interface for JMX events

Specified by:

register in interface MetricsSystem

Parameters:

callback - the callback object implementing the MBean interface.

publishMetricsNow

public void publishMetricsNow()

Description copied from interface: MetricsSystem

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.

Specified by:

publishMetricsNow in interface MetricsSystem

start

public void start()

Description copied from interface: MetricsSystemMXBean

Start the metrics system

Specified by:

start in interface MetricsSystemMXBean

stop

public void stop()

Description copied from interface: MetricsSystemMXBean

Stop the metrics system

Specified by:

stop in interface MetricsSystemMXBean

refreshMBeans

public void refreshMBeans()

Description copied from interface: MetricsSystemMXBean

Force a refresh of MBeans

Specified by:

refreshMBeans in interface MetricsSystemMXBean

currentConfig

public String currentConfig()

Specified by:

currentConfig in interface MetricsSystemMXBean

Returns:

the current config Note, avoid getConfig, as it'll turn it into an attribute, which doesn't support multiple lines in the values.

shutdown

public void shutdown()

Description copied from interface: MetricsSystem

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

Specified by:

shutdown in interface MetricsSystem