@Override
public void initialize() {
// Increment the session counter
int sessions = ApplicationSettings.SESSIONS.getValue();
ApplicationSettings.SESSIONS.setValue(sessions + 1);
// Record the time between sessions
long lastShutdown = ApplicationSettings.LAST_SHUTDOWN_TIME.getValue();
long downtime;
if (lastShutdown == 0) downtime = DEFAULT_DOWNTIME;
else downtime = Math.max(0, (clock.now() - lastShutdown) / 1000);
// If the number of downtimes is greater that the number of uptimes,
// the last session must have ended without recording the uptime or
// shutdown time. To avoid double-counting the downtime we should
// overwrite the last downtime instead of appending.
String[] downtimes = ApplicationSettings.DOWNTIME_HISTORY.get();
String[] uptimes = ApplicationSettings.UPTIME_HISTORY.get();
if (downtimes.length > uptimes.length)
downtimes = updateHistory(downtimes, Long.toString(downtime));
else downtimes = appendToHistory(downtimes, Long.toString(downtime));
ApplicationSettings.DOWNTIME_HISTORY.set(downtimes);
// Measure the time between refreshes
lastUpdateTime = clock.now();
}
/** Refreshes the uptime statistics. Package access for testing. */
void refreshStats() {
long now = clock.now();
long elapsed = (now - lastUpdateTime) / 1000;
if (elapsed > 0) {
currentUptime += elapsed;
updateUptimeHistory(currentUptime);
long totalUptime = ApplicationSettings.TOTAL_UPTIME.getValue() + elapsed;
ApplicationSettings.TOTAL_UPTIME.setValue(totalUptime);
int sessions = ApplicationSettings.SESSIONS.getValue();
if (sessions > 0) {
ApplicationSettings.AVERAGE_UPTIME.setValue(totalUptime / sessions);
}
ApplicationSettings.FRACTIONAL_UPTIME.setValue(stats.calculateFractionalUptime());
ApplicationSettings.LAST_SHUTDOWN_TIME.setValue(now); // Pessimistic
}
lastUpdateTime = now;
}