SNMP Trap Handler

A trap handler for the SNMP manager is an object that implements the SnmpEventReportListener interface in the javax.management.snmp.manager package. When this object is bound as a listener of an SnmpEventReportDispatcher object, its methods will be called to handle trap PDUs.

The interface defines two methods, one for processing SNMPv1 traps and the other for SNMPv2 traps. Trap PDUs have already been decoded by the dispatcher: the v1 handler must process an SnmpPduTrap object, and the v2 handler must process an SnmpPduRequest object representing a trap. In our implementation, we are only interested in v1 traps, and we just print out the trap information fields.

Example 8-3 The SnmpEventReportListener Implementation

public class TrapListenerImpl implements SnmpEventReportListener {

    public void processSnmpTrapV1(SnmpPduTrap trap) {
        java.lang.System.out.println(
            "NOTE: TrapListenerImpl received trap :");
        java.lang.System.out.println(
            "\tGeneric " + trap.genericTrap);
        java.lang.System.out.println(
            "\tSpecific " + trap.specificTrap);
        java.lang.System.out.println(
            "\tTimeStamp " + trap.timeStamp);
        java.lang.System.out.println(
            "\tAgent address " + trap.agentAddr.stringValue());
    }

    public void processSnmpTrapV2(SnmpPduRequest trap) {
        java.lang.System.out.println("NOTE: Trap V2 ignored");
    }
}