/**
* @param e the event to check for violation metrics.
* @param filterUnits
* @return the particular monitored metric violation or <code>null</code>, or <code>null</code>.
*/
Violation isViolated(final MonitoringEvent e, final List<String> filterUnits) {
final double observedValue = (Double) e.get(metric);
final boolean res = pred.perform(observedValue, thresholdValue);
if (!res) return null;
final ArrayList<String> applicable = new ArrayList<String>(filterUnits.size());
for (final String filterUnit : filterUnits)
if (ThresholdRulesTraits.join(e).startsWith(filterUnit)) applicable.add(filterUnit);
return new Violation(metric, thresholdValue, observedValue, applicable);
}
/**
* Check that the event concerns the specified metric.
*
* @param e
* @return <code>true</code> iff the event is about the specified metric, <code>false</code>
* otherwise.
*/
boolean isApplicable(final MonitoringEvent e) {
return metric == null || e.get(metric) != null;
}