Trick for updating a gauge less frequently

GaugeUpdateTrick.java

// from Jon Schneider
public class GaugeUpdateTrick {
    public static void main(String[] args) {
        AtomicLong lastCalculatedTime = new AtomicLong(0);
        AtomicLong gaugeValue = new AtomicLong(0);
        Gauge.builder("expensive", () -> {
            long curr = System.nanoTime();
            return gaugeValue.updateAndGet(old ->
                    lastCalculatedTime.updateAndGet(ts -> curr - ts > 10_000 ? curr : ts) == curr ? 0L /* new */ : old);
        });
    }
}