public int compare(Object o1, Object o2) {
if (!(o1 instanceof BeliefUpdateTrigger) || !(o2 instanceof BeliefUpdateTrigger))
throw new ClassCastException("Cannot compare objects. Not BeliefUpdateTriggers.");
BeliefUpdateTrigger t1 = (BeliefUpdateTrigger) o1;
BeliefUpdateTrigger t2 = (BeliefUpdateTrigger) o2;
if (t1.getTriggerTimestamp() < t2.getTriggerTimestamp()) return -1;
if (t1.getTriggerTimestamp() > t2.getTriggerTimestamp()) return 1;
// If the timestamps are the same, then we define an action to
// preceed a diagnosis.
//
if ((o1 instanceof BelievabilityAction) && (o2 instanceof DiagnosisTrigger)) return -1;
// Equality case is zero return value.
//
return 0;
} // method compare
/**
* Add a trigger to this current history.
*
* @param trigger The new trigger to be added.
* @return False if the trigger is not added. This happens if the timestamp of the trigger
* precedes the last computed belief state timestamp.
*/
boolean add(BeliefUpdateTrigger trigger) {
// Method implementation comments go here ...
// I am pretty sure having an inequality here is better. I
// originally had "<=", which caused some problems for
// simultaneous actions/diagnosis. Anyway, if you are
// debugging a problem and happen to look here, this might be
// useful information for you.
//
if ((_last_computed_belief != null)
&& (trigger.getTriggerTimestamp() < _last_computed_belief.getTimestamp())) {
if (_logger.isDetailEnabled()) _logger.detail("Found late arriving trigger.");
if (!shouldAddLateArrivingTrigger(trigger)) {
return false;
}
if (_logger.isDetailEnabled()) _logger.detail("Decided to add late arriving trigger.");
} // if late arriving trigger
// This will simply append it, though we will sort it by
// timestamp later.
//
_current_triggers.add(trigger);
// BelievabilityDiagnosis objects require some special
// handling as far as ensuring that our data structures stay
// current.
//
if (trigger instanceof BelievabilityDiagnosis) {
BelievabilityDiagnosis diag = (BelievabilityDiagnosis) trigger;
// Must track the last explicit diagnosis for sensors in
// case we find that we need to add implicit diagnoses for
// them.
//
_last_explicit_diagnosis.put(diag.getSensorName(), trigger);
// An explict diagnosis should clear out the last implict
// diagosis if there was any.
//
_last_implicit_diagnosis_time.remove(diag.getSensorName());
// Also need to track all the sensor names, so that we can
// handle the case of having received diagnoses from all
// sensors before the sensor latency window alarm expires.
//
_current_sensors.add(diag.getSensorName());
} // If this is a diagnosis trigger
return true;
} // method add
/**
* Looks in the current set of triggers for the trigger with the latest (most recent) trigger
* time. Assumes that the trigger collection has been sorted and are currently stored in ascending
* trigger timestamp sorted order. Latest time will be the last one in the list.
*/
long getLatestCurrentTriggerTime() {
// Method implementation comments go here ...
BeliefUpdateTrigger last_trigger;
try {
last_trigger = (BeliefUpdateTrigger) _current_triggers.get(_current_triggers.size() - 1);
} catch (IndexOutOfBoundsException ioobe) {
if (_logger.isInfoEnabled()) _logger.info("Cannot get latest trigger time from empty list.");
return System.currentTimeMillis();
}
return last_trigger.getTriggerTimestamp();
} // method getLatestCurrentTriggerTime
