public SubscriptionMgr(MBeanServer server,
    ObjectName listener,
    String monitoredObjectsResName) 
{
      this.monitoredObjectsResName = monitoredObjectsResName;
      this.server = server;
      this.listener = listener;
}

CTOR *

 public  void start() throws Exception 
{
            
      log.info("Reading resource: \"" + this.monitoredObjectsResName + "\"");
      // Organise the handle to the subscription definition resource
      InputStreamReader in = null;
      try {
         in = new InputStreamReader(
            this.getClass().getResourceAsStream(this.monitoredObjectsResName));
      }
      catch (Exception e) {
         log.error("Accessing resource \"" + this.monitoredObjectsResName + "\"", e);
         throw e;
      }
      // Parse and read-in the resource file
      MonitoredObjList monitoredObjList = null;
      try {
         monitoredObjList = MonitoredObjList.unmarshal(in);
      }
      catch (Exception e) {
         log.error("Parsing resource \"" + this.monitoredObjectsResName + "\"", e);
         throw e;
      }
      log.info("\"" + this.monitoredObjectsResName + "\" " + 
               (monitoredObjList.isValid() ? "valid" : "invalid") +
               ". Read " + monitoredObjList.getMonitoredObjCount() + 
               " monitored objects");
      log.info("Executing resource: \"" + this.monitoredObjectsResName + "\"");
      // Organise enough space to store the subscribed object names
      this.monitoredObjectsCache =
         new ArrayList(monitoredObjList.getMonitoredObjCount());
      // Iterate over the read monitoredObjects and act upon them 
      for (int i = 0; i <  monitoredObjList.getMonitoredObjCount(); i++) {
         // Get monitored object
         MonitoredObj s = monitoredObjList.getMonitoredObj(i);
         // Get target object name
         String targetName = s.getObjectName();
         if (log.isDebugEnabled())
           log.debug("Object " + i + " target: \"" + targetName + "\"");
         // Get event types that are of interest and fill in the notification
         // filter
         RegExpNotificationFilterSupport filter =
            new RegExpNotificationFilterSupport();
         for (int j = 0; j <  s.getNotificationTypeCount(); j++) {
            String eventType = s.getNotificationType(j);
            try {
               filter.enableType(eventType);
               if (log.isDebugEnabled())
                  log.debug("Event type " + (j+1) + ": \"" + eventType + "\"");                    
            }
            catch (REException e) {
               log.warn("Error compiling monitored object #" + i + 
                        ": Event type \"" + eventType + "\"", e);
            }    
         }
         try {
            // Subscribe the notification collector to the monitored object
            ObjectName targetObjectName = new ObjectName(targetName);
            server.addNotificationListener(
               targetObjectName, 
               listener, 
               filter, 
               listener.toString());
            // Record the object that has been subscribed to 
            this.monitoredObjectsCache.add(targetObjectName);                    
         }    
         catch (Exception e) {
            log.warn("Error executing monitored object directive #" + i, e);
         }
      }
      log.info("Subscription manager done");
}

Performs service start-up: subscribes the notification collector to all specified monitored objects. Implicit assumptions regarding entities from which notification subscriptions are requested: 1. They implement the NotificationBroadcaster interface 2. They are MBeans *

 public  void stop() throws Exception 
{
      for(int i = 0; i <   this.monitoredObjectsCache.size(); i++) {
         ObjectName target = null;
         try {
            target = (ObjectName) this.monitoredObjectsCache.get(i);
            this.server.removeNotificationListener(target, listener);
            if (log.isDebugEnabled())
               log.debug("Unsubscribed from \"" + target + "\"");
         }
         catch(Exception e) {
            log.error("Unsubscribing from \"" + target + "\"", e);
         }
      }
}

Performs service shutdown: cancel all subscriptions *