Package io.confluent.telemetry.collector

Class SharedJvmMetricsCollector

java.lang.Object

io.confluent.telemetry.collector.SharedJvmMetricsCollector

All Implemented Interfaces:

MetricsCollector

public final class SharedJvmMetricsCollector
extends Object
implements MetricsCollector

A wrapper around JvmMetricsCollector that ensures only one collector instance exists per JVM process, even when multiple TelemetryReporter instances are running.

Each TelemetryReporter creates a SharedJvmMetricsCollector via its Provider, but only the "active" instance actually delegates collect(Emitter) to the underlying shared collector. When the active instance is stopped (because its reporter is closing), ownership automatically transfers to another registered instance so that JVM metrics collection continues uninterrupted.

Field Summary

Fields inherited from interface io.confluent.telemetry.collector.MetricsCollector

LABEL_LIBRARY, LABEL_ORIGINAL, LIBRARY_NONE

Constructor Summary

Constructors

Constructor	Description
SharedJvmMetricsCollector(Context ctx)

Method Summary

Modifier and Type	Method	Description
void	collect(Emitter emitter)	Collect JVM metrics if this is the active instance.
void	stop()
String	toString()

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface io.confluent.telemetry.collector.MetricsCollector

start

Constructor Details

SharedJvmMetricsCollector

public SharedJvmMetricsCollector(Context ctx)

Method Details

collect

public void collect(Emitter emitter)

Collect JVM metrics if this is the active instance.

Uses a local-copy idiom instead of synchronizing: we snapshot sharedCollector into a local variable before checking activeInstance. This avoids taking a lock on every collection cycle (called every 60s per reporter), while a lock in stop() is only taken during reporter shutdown—an infrequent event.

Without the local copy, a concurrent stop() could null out sharedCollector between the activeInstance check and the collect() call, causing a NPE. The worst case with the local copy is one extra collection on a collector whose ownership was just released—harmless since it only reads JMX MXBeans and emits metrics.

Specified by:

collect in interface MetricsCollector

stop

public void stop()

Specified by:

stop in interface MetricsCollector

toString

public String toString()

Overrides:

toString in class Object