code: public void setActiveForTriggerAndMetric(Trigger trigger, Metric metric, boolean active) {
      	String key = _hashTriggerAndMetric(trigger, metric);
  		this.activeStatusByTriggerAndMetric.put(key, active);
      }
docs: When a notification is sent out when a metric violates the trigger threshold, set this notification active for that trigger,metric combination
  
  @param trigger	The Trigger that caused this notification
  @param metric	The metric that caused this notification
  @param active    Whether to set the notification to active