Registering to Receive Notifications

For information and instructions about writing and registering a notification listener, see the Java Dynamic Management Kit 5.0 Tutorial. Note that this information applies to the NMA only and is separate from the process of registering for notifications sent by the CMM. For information on these, see Receiving and Handling Change Notifications in the Netra High Availability Suite 3.0 1/08 Foundation Services CMM Programming Guide.

NhasCmmNotification

A NhasCmmNotification notification is sent by the ClusterNodeMBean when a node leaves or joins the cluster, or when a failover or switchover occurs. In addition to the standard notification information, this notification contains the following information:

`type`	The possible types for this notification are listed below.
`source`	The ObjectName of the node.

The notification type is one of the following:

`MASTER`	The node is now the cluster master node.
`VICEMASTER`	The node is now the cluster vice-master node.
`IN_CLUSTER`	The node is now part of the cluster.
`OUT_OF_CLUSTER`	The node is no longer part of the cluster.

NhasPmdMaxRetriesNotification

A NhasPmdMaxRetriesNotification notification is sent by the PmdStatisticsMBean when the maximum number of retries has been reached for a nametag. In addition to the standard notification information, this notification contains the following information:

`source`	The PmdStatisticsMBean ObjectName
`maxRetry`	The maximum retry number that was exceeded

The MAX_RETRIES field of this notification contains the name of the nametag that reached its maximum number of retries limit.

NhasPmdAttributeChangeNotification

A javax.management.AttributeChangeNotification is sent by the PmdNameTagStatisticsMBean when either of the following conditions is true:

The number of allowed retries changes
The retry counter is reset

In addition to the standard notification information, this notification contains the following information:

`type`	`ATTRIBUTE_CHANGE`
`source`	PmdNameTagStatisticsMBean
`attributeName`	Either `RetryCount` if the retry counter has been reset, or `MaxRetryCount` if the maximum number of retries allowed has changed
`oldValue`	The old number of retries allowed
`newValue`	The new number of retries allowed

The nametag field contains the name of the nametag that has been affected.

NhasPmdNewNameTagNotification

A NhasPmdNewNameTagNotification is sent whenever the Daemon Monitor creates a new nametag. This notification contains the field NEW_NAMETAG, which contains the name of the new nametag.

NhasPmdRemoveNameTagNotification

A NhasPmdRemoveNameTagNotification is sent whenever the Daemon Monitor removes a nametag from the collection. This notification contains the field REMOVE_NAMETAG, which contains the name of the nametag that was removed.

Registering to Receive SNMP Traps

For a Java DMK SNMP manager to receive SNMP traps, an implementation of the SnmpTrapListener class must be registered on the SNMP trap port. EXAMPLE 10-1 shows an implementation of the SnmpTrapListener class. SnmpTrapListener is a code snippet that registers the TrapListenerImpl class as a trap listener on trap port trapPort. The trap listener listens for SNMPv1, SNMPv2 and SNMPv3 traps. The TrapListenerImpl class prints the details of all the traps it receives to the standard output.

**EXAMPLE 10-1 Implementation of the SnmpTrapListener Class**
class TrapListenerImpl implements SnmpTrapListener { public void processSnmpTrapV1(SnmpPduTrap trap) { System.out.println("NOTE: TrapListenerImpl received trap V1:"); System.out.println("\tGeneric " + trap.genericTrap); System.out.println("\tSpecific " + trap.specificTrap); System.out.println("\tTimeStamp " + trap.timeStamp); System.out.println("\tAgent adress " + trap.agentAddr.stringValue()); } public void processSnmpTrapV2(SnmpPduRequest trap) { System.out.println("NOTE: TrapListenerImpl received trap V2:"); SnmpPdu pdu = trap.getResponsePdu(); System.out.println("\tFrom Address" + pdu.address.getHostAddress()); } public void processSnmpTrapV3(SnmpScopedPduRequest trap) { System.out.println("NOTE: TrapListenerImpl received trap V3:"); System.out.println("\tContextEngineId : " + SnmpEngineId.createEngineId(trap.contextEngineId)); System.out.println("\tContextName : " + new String(trap.contextName)); System.out.println("\tVarBind list :"); for (int i = 0; i trap.varBindList.length; i++) { System.out.println("oid : " + trap.varBindList[i].getOid() + " val : " + trap.varBindList[i].getSnmpValue()); } }

EXAMPLE 10-1 Implementation of the SnmpTrapListener Class

class TrapListenerImpl implements SnmpTrapListener {
 
  public void processSnmpTrapV1(SnmpPduTrap trap) {
    System.out.println("NOTE: TrapListenerImpl received trap V1:");
    System.out.println("\tGeneric " + trap.genericTrap);
    System.out.println("\tSpecific " + trap.specificTrap);
    System.out.println("\tTimeStamp " + trap.timeStamp);
    System.out.println("\tAgent adress " + trap.agentAddr.stringValue());
  }
 
  public void processSnmpTrapV2(SnmpPduRequest trap) {
    System.out.println("NOTE: TrapListenerImpl received trap V2:");
    
    SnmpPdu pdu = trap.getResponsePdu();
    System.out.println("\tFrom Address" + 
pdu.address.getHostAddress());
  }
 
  public void processSnmpTrapV3(SnmpScopedPduRequest trap) {
    System.out.println("NOTE: TrapListenerImpl received trap V3:");
    System.out.println("\tContextEngineId : " + 
    SnmpEngineId.createEngineId(trap.contextEngineId));
    
    System.out.println("\tContextName : " + new 
String(trap.contextName));
    System.out.println("\tVarBind list :");
    for (int i = 0; i  trap.varBindList.length; i++) {
      System.out.println("oid : " + trap.varBindList[i].getOid() + 
      " val : " + trap.varBindList[i].getSnmpValue());
    }
  }

The following code snippet registers the TrapListenerImpl class as a trap listener on trap port trapPort.

**EXAMPLE 10-2 Registering the Trap Listener**
System.out.println("Creating the trap listener on trapPort = " + trapPort); // Create the Trap listener TrapListenerImpl trapListener = new TrapListenerImpl(); SnmpEventReportDispatcher trapAgent = null; try{ trapAgent = new SnmpEventReportDispatcher(trapPort); } catch (SocketException e) { System.out.println("ERROR Creating the trapListener " + e.getMessage()); } // Start the Event Report dispatcher new Thread(trapAgent).start(); // Add the trap listener on the Event report dispatcher trapAgent.addTrapListener(trapListener); System.out.println("Created the trap listener");

EXAMPLE 10-2 Registering the Trap Listener

System.out.println("Creating the trap listener on trapPort = " + 
trapPort);
 
// Create the Trap listener
TrapListenerImpl trapListener = new TrapListenerImpl();
SnmpEventReportDispatcher trapAgent = null;
 
try{
  trapAgent = new SnmpEventReportDispatcher(trapPort);
} catch (SocketException e) { 
  System.out.println("ERROR Creating the trapListener " + 
e.getMessage());
}
 
// Start the Event Report dispatcher
new Thread(trapAgent).start();
    
// Add the trap listener on the Event report dispatcher
trapAgent.addTrapListener(trapListener); 
 
System.out.println("Created the trap listener");

Receiving Notifications