[SNMP4J] IllegalStateException

[Brian_Teravskis at cargill.com]

Hmmm, I thought 5000 for the timeout (5 seconds?) was plenty large,
although I have been seeing late arriving SNMP responses at that as
well. Some of our routers are at the far end of the world from here, and
it can take a while for sure. 

I had it lock on me again today with no error. I upgraded to the latest
version of SNMP4J, though the code in this area does not look much
different. I will do more logging, and try your fix if I run into it
again.

Thanks,

Brian


-----Original Message-----
From: fock at agentpp.com [mailto:fock at agentpp.com]
Sent: Tuesday, August 17, 2004 3:22 PM
To: Teravskis, Brian /mtks
Cc: snmp4j at agentpp.org
Subject: Re: [SNMP4J] IllegalStateException


Hello Brian,

You are probably using very small timeout values?
Nevertheless, the SNMP4J code can be improved as
follows to avoid this exception:

          if (pendingRequests.get(key) != null) {
            logger.debug("running pending request with handle" + key);
            PendingRequest nextRetry = new PendingRequest(this);
            long delay =
 
timeoutModel.getRetryTimeout(target.getRetries()-retryCount,
                                             target.getRetries(),
                                             target.getTimeout());
            timer.schedule(nextRetry, delay);
            // register pending request not before it is scheduled
            pendingRequests.put(key, nextRetry);
          }

Please let me know if this fixes the problem.

Thanks in advance,
Frank

Brian_Teravskis at cargill.com wrote:

>Hello,
>
>I'm using snmp4j for ARP cache gathering of network devices, and the
>poller I wrote generated the following error message to the console:
>
>java.lang.IllegalStateException: Task already scheduled or cancelled
>        at java.util.Timer.sched(Unknown Source)
>        at java.util.Timer.schedule(Unknown Source)
>        at org.snmp4j.Snmp$PendingRequest.run(Snmp.java:670)
>        at java.util.TimerThread.mainLoop(Unknown Source)
>        at java.util.TimerThread.run(Unknown Source)
>
>The origin of the problem seems to be:
>
>    public void run() {
>      if (retryCount > 0) {
>        retryCount--;
>        try {
>          send(pdu, target);
>          if (pendingRequests.get(key) != null) {
>            logger.debug("running pending request with handle" + key);
>            PendingRequest nextRetry = new PendingRequest(this);
>            pendingRequests.put(key, nextRetry);
>            long delay =
> 
>timeoutModel.getRetryTimeout(target.getRetries()-retryCount,
>                                             target.getRetries(),
>                                             target.getTimeout());
> -->        timer.schedule(nextRetry, delay);
>          }
>        }
>
>It appears that this exception is not being caught and handled, and
>therefore the error. My thread is catching IOException and then
>Exception, and is not seeing this exception being thrown by the SNMP4J
>routines. The thread I wrote appears to hang when this exception
happens
>waiting for a reponse. This is not a repeatable event. I've run this
>poller several times without any issues. I'm doing the SNMP getnext
with
>a timeout of 5000 and a retry of 2.
>
>If any further information is required let me know.
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>  
>