provide an api for a separate object to monitor changes of the state of the alarm destination.

EcAlarmDestination.h

@@ -44,7 +44,7 @@
  * for a long time or raise an exception.
  * </p>
  */
-@protocol	EcAlarmDestination
+@protocol	EcAlarmDestination <NSObject>
 
 /** Passes an alarm to the destination.
  */
@@ -66,6 +66,18 @@
 
 @end
 
+/** These methods are called to inform an object monitoring the alarm
+ * destination about changes to its state.
+ */
+@protocol	EcAlarmMonitor <NSObject>
+- (void) activePut: (EcAlarm*)alarm;
+- (void) activeRemove: (EcAlarm*)alarm;
+- (void) clearsPut: (EcAlarm*)alarm;
+- (void) clearsRemove: (EcAlarm*)alarm;
+- (void) managePut: (NSString*)name;
+- (void) manageRemove: (NSString*)name;
+@end
+
 
 
 /**
@@ -81,7 +93,8 @@
  * destination.
  * </p>
  */
-@interface	EcAlarmDestination : NSObject <EcAlarmDestination>
+@interface	EcAlarmDestination : NSObject
+  <EcAlarmDestination,EcAlarmMonitor>
 {
   NSRecursiveLock		*_alarmLock;
   NSMutableArray		*_alarmQueue;
@@ -96,10 +109,19 @@
   NSString			*_host;
   NSString			*_name;
   id<EcAlarmDestination>	_destination;
+  id<EcAlarmMonitor>		_monitor;
   NSArray			*_backups;
   BOOL                          _debug;
 }
 
+/** Internal use only.
+ */
+- (void) activePut: (EcAlarm*)alarm;
+
+/** Internal use only.
+ */
+- (void) activeRemove: (EcAlarm*)alarm;
+
 /** Passes an alarm to the destination by adding it to a queue of alarm
  * events which will be processed in the receivers running thread.
  */
@@ -114,6 +136,18 @@
  */
 - (NSArray*) backups;
 
+/** Returns an array containing all the latest cleared alarms.
+ */
+- (NSArray*) clears;
+
+/** Internal use only.
+ */
+- (void) clearsPut: (EcAlarm*)alarm;
+
+/** Internal use only.
+ */
+- (void) clearsRemove: (EcAlarm*)alarm;
+
 /** Inform the destination of the existence of a managed object.<br />
  * This is an indicator of a 'cold start' of that object ... meaning that the
  * object has just started up afresh, and all outstanding alarms for the object
@@ -150,6 +184,18 @@
  */
 - (BOOL) isRunning;
 
+/** Returns an array containing the known managed objects.
+ */
+- (NSArray*) managed;
+
+/** Internal use only.
+ */
+- (void) managePut: (NSString*)name;
+
+/** Internal use only.
+ */
+- (void) manageRemove: (NSString*)name;
+
 /** This method is called from -init in a secondary thread to start handling
  * of alarms by the receiver.  Do not call it yourself.
  */
@@ -188,6 +234,13 @@
  */
 - (id<EcAlarmDestination>) setDestination: (id<EcAlarmDestination>)destination;
 
+/** Sets the monitoring object to which state changes are sent.<br />
+ * If nil this turns off monitoring.<br />
+ * The monitoring object is retained by the receiver.<br />
+ * Returns the previously set monitor.
+ */
+- (id<EcAlarmMonitor>) setMonitor: (id<EcAlarmMonitor>)monitor;
+
 /** Requests that the receiver's running thread should shut down.  This method
  * waits for a short while for the thread to shut down, but the process of
  * shutting down is not guaranteed to have completed by the time the method

EcAlarmDestination.m

@@ -56,6 +56,28 @@
 
 @implementation	EcAlarmDestination
 
+- (void) activePut: (EcAlarm*)alarm
+{
+  if (_monitor != self)
+    {
+      [_monitor activePut: alarm];
+    }
+  [_alarmLock lock];
+  [_alarmsActive addObject: alarm];
+  [_alarmLock unlock];
+}
+
+- (void) activeRemove: (EcAlarm*)alarm
+{
+  if (_monitor != self)
+    {
+      [_monitor activeRemove: alarm];
+    }
+  [_alarmLock lock];
+  [_alarmsActive removeObject: alarm];
+  [_alarmLock unlock];
+}
+
 - (oneway void) alarm: (in bycopy EcAlarm*)event
 {
   if (NO == [event isKindOfClass: [EcAlarm class]])
@@ -187,22 +209,49 @@
   return [a autorelease];
 }
 
+- (NSArray*) clears
+{
+  NSArray	*a;
+
+  [_alarmLock lock];
+  a = [_alarmsCleared allObjects];
+  [_alarmLock unlock];
+  return a;
+}
+
+- (void) clearsPut: (EcAlarm*)alarm
+{
+  if (_monitor != self)
+    {
+      [_monitor clearsPut: alarm];
+    }
+  [_alarmLock lock];
+  [_alarmsCleared addObject: alarm];
+  [_alarmLock unlock];
+}
+
+- (void) clearsRemove: (EcAlarm*)alarm
+{
+  if (_monitor != self)
+    {
+      [_monitor clearsRemove: alarm];
+    }
+  [_alarmLock lock];
+  [_alarmsCleared removeObject: alarm];
+  [_alarmLock unlock];
+}
+
 - (void) dealloc
 {
   [self shutdown];
-  [_backups release];
+  DESTROY(_backups);
-  [(id)_destination release];
+  DESTROY(_destination);
-  _destination = nil;
+  DESTROY(_monitor);
-  [_alarmQueue release];
+  DESTROY(_alarmQueue);
-  _alarmQueue = nil;
+  DESTROY(_alarmsActive);
-  [_alarmsActive release];
+  DESTROY(_alarmsCleared);
-  _alarmsActive = nil;
+  DESTROY(_managedObjects);
-  [_alarmsCleared release];
+  DESTROY(_alarmLock);
-  _alarmsCleared = nil;
-  [_managedObjects release];
-  _managedObjects = nil;
-  [_alarmLock release];
-  _alarmLock = nil;
   [super dealloc];
 }
 
@@ -325,6 +374,38 @@
   return result;
 }
 
+- (NSArray*) managed
+{
+  NSArray	*a;
+
+  [_alarmLock lock];
+  a = [_managedObjects allObjects];
+  [_alarmLock unlock];
+  return a;
+}
+
+- (void) managePut: (NSString*)name
+{
+  if (_monitor != self)
+    {
+      [_monitor managePut: name];
+    }
+  [_alarmLock lock];
+  [_managedObjects addObject: name];
+  [_alarmLock unlock];
+}
+
+- (void) manageRemove: (NSString*)name
+{
+  if (_monitor != self)
+    {
+      [_monitor manageRemove: name];
+    }
+  [_alarmLock lock];
+  [_managedObjects removeObject: name];
+  [_alarmLock unlock];
+}
+
 - (void) run
 {
   NSAutoreleasePool	*pool = [NSAutoreleasePool new];
@@ -417,9 +498,27 @@
     }
   [_alarmLock lock];
   old = (id)_destination;
-  _destination = (id<EcAlarmDestination>)[(id)destination retain];
+  _destination = RETAIN(destination);
   [_alarmLock unlock];
-  return (id<EcAlarmDestination>)[old autorelease];
+  return AUTORELEASE(old);
+}
+
+- (id<EcAlarmMonitor>) setMonitor: (id<EcAlarmMonitor>)monitor
+{
+  id	old;
+
+  if (nil != (id)monitor && NO == [(id)monitor
+    conformsToProtocol: @protocol(EcAlarmMonitor)])
+    {
+      [NSException raise: NSInvalidArgumentException
+	format: @"[%@-%@] arg does not conform to EcAlarmMonitor protocol",
+	NSStringFromClass([self class]), NSStringFromSelector(_cmd)];
+    }
+  [_alarmLock lock];
+  old = (id)_monitor;
+  _monitor = RETAIN(monitor);
+  [_alarmLock unlock];
+  return AUTORELEASE(old);
 }
 
 - (void) shutdown
@@ -597,7 +696,7 @@
 
 			  if (nil == [_managedObjects member: m])
 			    {
-			      [_managedObjects addObject: m];
+			      [self managePut: m];
                               [_alarmLock unlock];
 			      [self domanageFwd: m];
                               [_alarmLock lock];
@@ -668,7 +767,7 @@
                               /* Alarm previously active ...
                                * remove old copy and forward clear.
                                */
-			      [_alarmsActive removeObject: prev];
+			      [self activeRemove: prev];
                               shouldForward = YES;
 			    }
                           if (nil == [_alarmsCleared member: next])
@@ -676,7 +775,7 @@
                               /* Alarm not previously cleared ...
                                * add to cleared set and forward clear.
                                */
-                              [_alarmsCleared addObject: next];
+			      [self clearsPut: next];
                               shouldForward = YES;
                             }
 			}
@@ -685,7 +784,7 @@
                           /* If there was a previous version of the alarm
                            * cleared, remove that so it's re-raised.
                            */
-                          [_alarmsCleared removeObject: next];
+			  [self clearsRemove: next];
 
 			  /* If the alarm is new or of changed severity,
 			   * update the records and pass it on.
@@ -693,7 +792,7 @@
 			  if (nil == prev || [next perceivedSeverity]
 			    != [prev perceivedSeverity])
 			    {
-			      [_alarmsActive addObject: next];
+			      [self activePut: next];
                               shouldForward = YES;
 			    }
 			}
@@ -705,7 +804,7 @@
 			   */
 			  if (nil == [_managedObjects member: m])
 			    {
-			      [_managedObjects addObject: m];
+			      [self managePut: m];
 			    }
                           else
                             {
@@ -767,7 +866,7 @@
         {
           if ([[a managedObject] isEqual: m])
             {
-              [_alarmsActive removeObject: a];
+	      [self activeRemove: a];
             }
         }
       e = [[_alarmsCleared allObjects] objectEnumerator];
@@ -775,10 +874,10 @@
         {
           if ([[a managedObject] isEqual: m])
             {
-              [_alarmsCleared removeObject: a];
+	      [self clearsRemove: a];
             }
         }
-      [_managedObjects removeObject: m];
+      [self manageRemove: m];
     }
 }
 

EcAlarmSinkSNMP.m

@@ -1501,7 +1501,7 @@ objectsTable_handler(netsnmp_mib_handler *handler,
 
 	  /* Remove from the ObjC table.
 	   */
-	  [_alarmsActive removeObject: alarm];
+	  [self activeRemove: alarm];
 
 	  /* Find and remove the SNMP table entry.
 	   */
@@ -1573,7 +1573,7 @@ objectsTable_handler(netsnmp_mib_handler *handler,
 			      /* Remove from the ObjC table.
 			       */
 			      [prev retain];
-			      [_alarmsActive removeObject: prev];
+			      [self activeRemove: prev];
 
 			      /* Find and remove the SNMP table entry.
 			       */
@@ -1607,6 +1607,7 @@ objectsTable_handler(netsnmp_mib_handler *handler,
 			  if (NO == [managedObjects containsObject: m])
 			    {
 			      objectsTable_createEntry(m);
+			      [self managePut: m];
 			      [managedObjects addObject: m];
 			      managedObjectsCount = [managedObjects count];
 			      [self domanageFwd: m];
@@ -1630,7 +1631,7 @@ objectsTable_handler(netsnmp_mib_handler *handler,
 			      else
 				{
 				  prev = [[prev retain] autorelease];
-				  [_alarmsActive removeObject: prev];
+				  [self activeRemove: prev];
 				  row = (netsnmp_tdata_row*)[prev extra];
 				  /* send the clear for the entry.
 				   */
@@ -1643,7 +1644,7 @@ objectsTable_handler(netsnmp_mib_handler *handler,
 			       * and send new severity trap.
 			       */
 			      setAlarmTableEntry(row, next);
-			      [_alarmsActive addObject: next];
+			      [self activePut: next];
 			      [alarmSink _trap: next forceClear: NO];
 			      [self alarmFwd: next];
 			      changed = YES;
@@ -1662,6 +1663,7 @@ objectsTable_handler(netsnmp_mib_handler *handler,
 			  if (NO == [managedObjects containsObject: m])
 			    {
 			      objectsTable_createEntry(m);
+			      [self managePut: m];
 			      [managedObjects addObject: m];
 			      managedObjectsCount = [managedObjects count];
 			      changed = YES;
@@ -1694,6 +1696,7 @@ objectsTable_handler(netsnmp_mib_handler *handler,
 				    }
 				  row = netsnmp_tdata_row_next(objectsTable, row);
 				}
+			      [self manageRemove: m];
 			      [managedObjects removeObject: m];
 			      if (YES == [m hasSuffix: @"_"])
 				{
@@ -1706,6 +1709,7 @@ objectsTable_handler(netsnmp_mib_handler *handler,
 				    {
 				      if (YES == [s hasPrefix: m])
 					{
+					  [self manageRemove: s];
 					  [managedObjects removeObject: s];
 					}
 				    }