com.codahale.metrics.ExponentialMovingAverages Maven / Gradle / Ivy
package com.codahale.metrics;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicLong;
/**
* A triple (one, five and fifteen minutes) of exponentially-weighted moving average rates as needed by {@link Meter}.
*
* The rates have the same exponential decay factor as the fifteen-minute load average in the
* {@code top} Unix command.
*/
public class ExponentialMovingAverages implements MovingAverages {
private static final long TICK_INTERVAL = TimeUnit.SECONDS.toNanos(5);
private final EWMA m1Rate = EWMA.oneMinuteEWMA();
private final EWMA m5Rate = EWMA.fiveMinuteEWMA();
private final EWMA m15Rate = EWMA.fifteenMinuteEWMA();
private final AtomicLong lastTick;
private final Clock clock;
/**
* Creates a new {@link ExponentialMovingAverages}.
*/
public ExponentialMovingAverages() {
this(Clock.defaultClock());
}
/**
* Creates a new {@link ExponentialMovingAverages}.
*/
public ExponentialMovingAverages(Clock clock) {
this.clock = clock;
this.lastTick = new AtomicLong(this.clock.getTick());
}
@Override
public void update(long n) {
m1Rate.update(n);
m5Rate.update(n);
m15Rate.update(n);
}
@Override
public void tickIfNecessary() {
final long oldTick = lastTick.get();
final long newTick = clock.getTick();
final long age = newTick - oldTick;
if (age > TICK_INTERVAL) {
final long newIntervalStartTick = newTick - age % TICK_INTERVAL;
if (lastTick.compareAndSet(oldTick, newIntervalStartTick)) {
final long requiredTicks = age / TICK_INTERVAL;
for (long i = 0; i < requiredTicks; i++) {
m1Rate.tick();
m5Rate.tick();
m15Rate.tick();
}
}
}
}
@Override
public double getM1Rate() {
return m1Rate.getRate(TimeUnit.SECONDS);
}
@Override
public double getM5Rate() {
return m5Rate.getRate(TimeUnit.SECONDS);
}
@Override
public double getM15Rate() {
return m15Rate.getRate(TimeUnit.SECONDS);
}
}