/**
   * Retrieve the event state associated with specified invocation of the event trigger match
   * method. This event trigger retrieves the combined event state of all aggregated event triggers.
   *
   * @param timestamp time stamp associated with invocation
   * @return event state or null if not found
   * @see org.eclipse.jetty.monitor.jmx.EventTrigger#getState(long)
   */
  @Override
  public EventState getState(long timestamp) {
    EventState state = new EventState();

    for (EventTrigger trigger : _triggers) {
      EventState subState = trigger.getState(timestamp);
      state.addAll(subState.values());
    }

    return state;
  }
 /**
  * Verify if the event trigger conditions are in the appropriate state for an event to be
  * triggered. This event trigger will match if all aggregated event triggers would return a match.
  *
  * @see org.eclipse.jetty.monitor.jmx.EventTrigger#match(long)
  */
 public boolean match(long timestamp) throws Exception {
   for (EventTrigger trigger : _triggers) {
     if (!trigger.match(timestamp)) return false;
   }
   return true;
 }