com.yammer.metrics.core.Meter Maven / Gradle / Ivy
package com.yammer.metrics.core;
import com.yammer.metrics.stats.EWMA;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicLong;
/**
* A meter metric which measures mean throughput and one-, five-, and fifteen-minute
* exponentially-weighted moving average throughputs.
*
* @see EMA
*/
public class Meter implements Metered, Stoppable {
private static final long INTERVAL = 5; // seconds
private final EWMA m1Rate = EWMA.oneMinuteEWMA();
private final EWMA m5Rate = EWMA.fiveMinuteEWMA();
private final EWMA m15Rate = EWMA.fifteenMinuteEWMA();
private final AtomicLong count = new AtomicLong();
private final long startTime;
private final TimeUnit rateUnit;
private final String eventType;
private final ScheduledFuture future;
private final Clock clock;
/**
* Creates a new {@link Meter}.
*
* @param tickThread background thread for updating the rates
* @param eventType the plural name of the event the meter is measuring (e.g., {@code
* "requests"})
* @param rateUnit the rate unit of the new meter
* @param clock the clock to use for the meter ticks
*/
Meter(ScheduledExecutorService tickThread, String eventType, TimeUnit rateUnit, Clock clock) {
this.rateUnit = rateUnit;
this.eventType = eventType;
this.future = tickThread.scheduleAtFixedRate(new Runnable() {
@Override
public void run() {
tick();
}
}, INTERVAL, INTERVAL, TimeUnit.SECONDS);
this.clock = clock;
this.startTime = this.clock.tick();
}
@Override
public TimeUnit rateUnit() {
return rateUnit;
}
@Override
public String eventType() {
return eventType;
}
/**
* Updates the moving averages.
*/
void tick() {
m1Rate.tick();
m5Rate.tick();
m15Rate.tick();
}
/**
* Mark the occurrence of an event.
*/
public void mark() {
mark(1);
}
/**
* Mark the occurrence of a given number of events.
*
* @param n the number of events
*/
public void mark(long n) {
count.addAndGet(n);
m1Rate.update(n);
m5Rate.update(n);
m15Rate.update(n);
}
@Override
public long count() {
return count.get();
}
@Override
public double fifteenMinuteRate() {
return m15Rate.rate(rateUnit);
}
@Override
public double fiveMinuteRate() {
return m5Rate.rate(rateUnit);
}
@Override
public double meanRate() {
if (count() == 0) {
return 0.0;
} else {
final long elapsed = (clock.tick() - startTime);
return convertNsRate(count() / (double) elapsed);
}
}
@Override
public double oneMinuteRate() {
return m1Rate.rate(rateUnit);
}
private double convertNsRate(double ratePerNs) {
return ratePerNs * (double) rateUnit.toNanos(1);
}
@Override
public void stop() {
future.cancel(false);
}
@Override
public void processWith(MetricProcessor processor, MetricName name, T context) throws Exception {
processor.processMeter(name, this, context);
}
}