protected <T> void metricChanged(BaseMetricImpl<T> metric) {
long lastTime = metric.changeTime;
// NOTE: changeTime is only accurate for metrics that are enabled, and
// to guarantee that it always corresponds to the value, updates to
// enabled metrics are synchronized.
metric.changeTime = timebase + System.nanoTime();
metric.valueChanged = true;
metricsDataChanged = true;
int level;
if ((lastTime == 0) || (metric.changeTime <= lastTime)) {
level = 0;
} else {
// Longer duration -> higher level.
double r = random.nextDouble();
if (r == 0) {
level = NLEVELS - 1;
} else {
level =
Math.min(
NLEVELS - 1,
(int) (Math.log((metric.changeTime - lastTime) / r) / METRIC_LEVEL_DIVISOR));
}
}
MetricLevel<T> metricLevel = metric.levels.get(level);
MetricLevelValues values = metricLevel.values.peekLast();
if ((values == null) || values.isFull()) {
if (logger.isTraceEnabled()) {
logger.trace(
"New level {} entry at {} for {}", new Object[] {level, metric.changeTime, metric});
}
values = new MetricLevelValues(metric.changeTime, metric.encodeValue());
metricLevel.values.addLast(values);
} else {
if (logger.isTraceEnabled()) {
logger.trace(
"Adding to level {} entry at {} for {}",
new Object[] {level, metric.changeTime, metric});
}
values.append(metric.encodeValue(metricLevel));
}
metricLevel.lastValue = metric.getObject();
metricLevel.lastTime = metric.changeTime;
}
