/**
* checks if the stats that we used to compute drop rate is stale or not. Stale meaning, we use a
* certain interval (configured to be 5 seconds) to count the number of calls, latency, etc during
* that 5 seconds. So every 5 seconds we'll want to refresh the window of interval for counting.
*
* <p>So if it's stale, we'll call CallTrackerImpl to refresh the window
*
* @param now
*/
private void checkStale(long now) {
if (_callTrackerStats.stale(now)) {
// this code is a bit strange at first i.e. why it's not _callTrackerStats =
// _callTracker.getCallStats();
// but instead it's just _callTracker.getCallStats(); even though getCallStats returns a new
// Object.
// but this is fine because getCallStats() will eventually call Tracker.rolloverStats() which
// has a listener!
// the listener is actually {@see DegraderImpl.rollOverStats(CallTracker.CallStats)} which
// will update
// _callTrackerStats with the new stats. So we're fine.
_callTracker.getCallStats();
}
}
public DegraderImpl(Config config) {
_config = new ImmutableConfig(config);
_name = _config.getName();
_clock = config.getClock();
_callTracker = config.getCallTracker();
_callTrackerStats = _callTracker.getCallStats();
_maxDropDuration = config.getMaxDropDuration();
reset();
// Added cast below for backward compatibilty. Remove when possible
_callTracker.addStatsRolloverEventListener(
new CallTracker.StatsRolloverEventListener() {
public void onStatsRollover(CallTracker.StatsRolloverEvent event) {
rolloverStats(event.getCallStats());
}
});
}
