synchronized void add(long value) {
assert tLast >= 0;
if (tLast > 0L) {
long interArrivalTime = (value - tLast);
if (interArrivalTime <= MAX_INTERVAL_IN_NANO) arrivalIntervals.add(interArrivalTime);
else logger.debug("Ignoring interval time of {}", interArrivalTime);
} else {
// We use a very large initial interval since the "right" average depends on the cluster
// size
// and it's better to err high (false negatives, which will be corrected by waiting a bit
// longer)
// than low (false positives, which cause "flapping").
arrivalIntervals.add(FailureDetector.INITIAL_VALUE_NANOS);
}
tLast = value;
}
@Override
public String toString() {
return StringUtils.join(arrivalIntervals.iterator(), " ");
}
// see lealone-2597 for an explanation of the math at work here.
double phi(long tnow) {
assert arrivalIntervals.size() > 0
&& tLast > 0; // should not be called before any samples arrive
long t = tnow - tLast;
return t / mean();
}
double mean() {
return arrivalIntervals.mean();
}