This qualifier is used to restrict the frequency of callbacks, for example by specifying the smallest change that should trigger one. The qualifier is used as part of the Metrics Service subscribeToValue() method, an instance is given for each subscription. In order to filter the notifications, the MetricsNotificationQualifier will need some state, such as the value of the last notification.
boolean shouldNotify(Metric metric)
- Returns true iff the given metric has changed enough to
generate notifications to listeners.