snmpinformrequest.java

Mobile 应用程序使用 Java Micro Edition (Java ME) 平台

            SnmpInformHandler savedCallback = callback;
            callback = null;
            informSession.waitForResponse(this, time);
            callback = savedCallback;
        } else {
            // This is being done from a different thread. So notifyClient will do the notification.
            //
            synchronized (this) {
                SnmpInformHandler savedCallback = callback ;
                try {
                    callback = null ;
                    this.wait(time) ;
                } catch (InterruptedException e) {
                }
                callback = savedCallback ;
            }
        }
		
        return (! inProgress()); // true if request completed.
    }

    /**
     * Cancels the active inform request and removes itself from the polling list.
     */
    final public void cancelRequest() {
        errorStatus = snmpReqAborted;  
        stopRequest();
        deleteRequest();
        notifyClient();
    }

    /**
     * Notifies the registered client about the completion of an operation.
     */
    final public synchronized void notifyClient() {
        this.notifyAll();
    }

    /**
     * Finalizer of the <CODE>SnmpInformRequest</CODE> objects.
     * This method is called by the garbage collector on an object 
     * when garbage collection determines that there are no more references to the object.
     * <P>Sets all the references to this SNMP inform request object to <CODE>null</CODE>.
     */
    public void finalize() {
        callback = null;
        varBindList = null;
        internalVarBind = null;
        adaptor = null;
        informSession = null;
        requestPdu = null;
	responsePdu = null;
    }

    /**
     * Returns the <CODE>String</CODE> representation of an error code.
     * @param errcode The error code as an integer.
     * @return The error code as a <CODE>String</CODE>.
     */
    public static String snmpErrorToString(int errcode) {
        switch (errcode) {
        case snmpRspNoError :
            return "noError" ;
        case snmpRspTooBig :
            return "tooBig" ;
        case snmpRspNoSuchName :
            return "noSuchName" ;
        case snmpRspBadValue :
            return "badValue" ;
        case snmpRspReadOnly :
            return "readOnly" ;
        case snmpRspGenErr :
            return "genErr" ;
        case snmpRspNoAccess :
            return "noAccess" ;
        case snmpRspWrongType :
            return "wrongType" ;
        case snmpRspWrongLength :
            return "wrongLength" ;
        case snmpRspWrongEncoding :
            return "wrongEncoding" ;
        case snmpRspWrongValue :
            return "wrongValue" ;
        case snmpRspNoCreation :
            return "noCreation" ;
        case snmpRspInconsistentValue :
            return "inconsistentValue" ;
        case snmpRspResourceUnavailable :
            return "resourceUnavailable" ;
        case snmpRspCommitFailed :
            return "commitFailed" ;
        case snmpRspUndoFailed :
            return "undoFailed" ;
        case snmpRspAuthorizationError :
            return "authorizationError" ;
        case snmpRspNotWritable :
            return "notWritable" ;
        case snmpRspInconsistentName :
            return "inconsistentName" ;
        case snmpReqTimeout :
            return "reqTimeout" ;
        case snmpReqAborted :
            return "reqAborted" ;
        case snmpRspDecodingError :
            return "rspDecodingError" ;
        case snmpReqEncodingError :
            return "reqEncodingError" ;
        case snmpReqPacketOverflow :
            return "reqPacketOverflow" ;
        case snmpRspEndOfTable :
            return "rspEndOfTable" ;
        case snmpReqRefireAfterVbFix :
            return "reqRefireAfterVbFix" ;
        case snmpReqHandleTooBig :
            return "reqHandleTooBig" ;
        case snmpReqTooBigImpossible :
            return "reqTooBigImpossible" ;
        case snmpReqInternalError :
            return "reqInternalError" ;
        case snmpReqSocketIOError :
            return "reqSocketIOError" ;
        case snmpReqUnknownError :
            return "reqUnknownError" ;
        case snmpWrongSnmpVersion :
            return "wrongSnmpVersion" ;
	case snmpUnknownPrincipal:
	    return "snmpUnknownPrincipal";
	case snmpAuthNotSupported:
	    return "snmpAuthNotSupported";
	case snmpPrivNotSupported:
	    return "snmpPrivNotSupported";
	case snmpBadSecurityLevel:
	    return "snmpBadSecurityLevel";
	case snmpUsmBadEngineId:
	    return "snmpUsmBadEngineId";   
	case snmpUsmInvalidTimeliness:
	    return "snmpUsmInvalidTimeliness";
        }
        return "Unknown Error = " + errcode;
    }
    
    // PRIVATE AND PACKAGE METHODS
    //----------------------------
    
    /**
     * For SNMP Runtime internal use only.
     * Starts an inform request in asynchronous mode. The callback interface
     * is used to notify the user upon request completion.
     * @param vblst The list of <CODE>SnmpVarBind</CODE> to be used.
     * @exception SnmpStatusException This inform request is already in progress.
     */
    synchronized void start(SnmpVarBindList vblst) throws SnmpStatusException {
        if (inProgress())
            throw  new SnmpStatusException("Inform request already in progress.");
        setVarBindList(vblst);
        initializeAndFire();
    }

    private synchronized void initializeAndFire() {
        requestPdu = null;
	responsePdu = null;
        reason = null;
        startRequest(System.currentTimeMillis());
        setErrorStatusAndIndex(0, 0);
    }
    
    /**
     * This method submits the inform request for polling and marks the request
     * active. It does nothing if the request is already active.
     * The poll will be scheduled to happen immediately.
     * @param starttime The start time for polling.
     */
    private synchronized void startRequest(long starttime) {
        nextPollTime = starttime;
        prevPollTime = 0;
        schedulePoll();
    }
    
    /**
     * This method creates a new request ID. The ID is submitted to the poll server for scheduling.
     */
    private void schedulePoll() {
        numTries = 0;
        initNewRequest();
        setRequestStatus(stWaitingToSend);
        informSession.getSnmpQManager().addRequest(this);
    }
    
    /**
     * This method determines whether the inform request is to be retried. This is used if the
     * peer did not respond to a previous request. If the request exceeds 
     * the maxTries limit, a timeout is signaled.
     */
    void action() {
        if (inProgress() == false)
            return;
        while (true) {
            try {
                if (numTries == 0) {
                    invokeOnReady();
                } else if (numTries < getMaxTries()) {
                    invokeOnRetry();
                } else {
                    invokeOnTimeout();
                }
                return ;
            } catch (OutOfMemoryError omerr) {
                // Consider it as a try !
                //
                numTries++;
                if (isDebugOn()) {
                    debug("action", "Inform request hit out of memory situation...");
                }
                Thread.currentThread().yield();
            }
        }
    }
    
    final private void invokeOnReady() {
        if (requestPdu == null) {
            requestPdu = constructPduPacket();
        }
        if (requestPdu != null) {
            if (sendPdu() == false)
                queueResponse();
        }
    }

    final private void invokeOnRetry() {  
        invokeOnReady();
    }
    
    final private void invokeOnTimeout() {
        errorStatus = snmpReqTimeout; 
        queueResponse();
    }
    
    final private void queueResponse() {
        informSession.addResponse(this);
    }
    
    /**
     * Constructs an inform request PDU.
     */
    synchronized SnmpPdu constructPduPacket() {  
        SnmpPduPacket reqpdu = null;
        Exception excep = null;
        try {
            reqpdu = new SnmpPduRequest();
            reqpdu.port = port;
            reqpdu.type = pduInformRequestPdu;
            reqpdu.version = snmpVersionTwo;
            reqpdu.community = communityString.getBytes("8859_1");
            reqpdu.requestId = getRequestId();
            reqpdu.varBindList = internalVarBind;

            if (isTraceOn()) {
                trace("constructPduPacket", "Packet built");
            }

        } catch (Exception e) {
            excep = e;
            errorStatus = snmpReqUnknownError;
            reason = e.getMessage();
        } 
        if (excep != null) {
            if (isDebugOn()) {
                debug("constructPduPacket", excep);
            }
            reqpdu = null;
            queueResponse();
        }
        return reqpdu;
    }
    
    boolean sendPdu() {
        try {
            responsePdu = null;
      
            SnmpPduFactory pduFactory = adaptor.getPduFactory();
            SnmpMessage msg = (SnmpMessage)pduFactory.encodeSnmpPdu((SnmpPduPacket)requestPdu, adaptor.getBufferSize().intValue());

            if (msg == null) {
                if (isDebugOn()) {
                    debug("sendPdu", "pdu factory returned a null value");
                }
                throw new SnmpStatusException(snmpReqUnknownError);
                // This exception will caught hereafter and reported as an snmpReqUnknownError
                // FIXME: may be it's not the best behaviour ?
            }

            int maxPktSize = adaptor.getBufferSize().intValue();
            byte[] encoding = new byte[maxPktSize];
            int encodingLength = msg.encodeMessage(encoding);
      
            if (isTraceOn()) {
                trace("sendPdu", "Dump : \n" + msg.printMessage());
            }

            sendPduPacket(encoding, encodingLength);
            return true;
        } catch (SnmpTooBigException ar) {
    
            if (isDebugOn()) {
                debug("sendPdu", ar);
            }
      
            setErrorStatusAndIndex(snmpReqPacketOverflow, ar.getVarBindCount());
            requestPdu = null;
            reason = ar.getMessage();
            if (isDebugOn()) {
                debug("sendPdu", "Packet Overflow while building inform request");
            }
        } catch (java.io.IOException ioe) {
            setErrorStatusAndIndex(snmpReqSocketIOError, 0);
            reason = ioe.getMessage();
        } catch (Exception e) {
            if (isDebugOn()) {
                debug("sendPdu", e);
            }
            setErrorStatusAndIndex(snmpReqUnknownError, 0);
            reason = e.getMessage();
        }
        return false;
    }

    /**
     * Sends the prepared PDU packet to the manager and updates the data structure
     * to expect a response. It acquires a lock on the socket to prevent a case
     * where a response arrives before this thread could insert the
     * request into the wait queue.
     * @exception IOException Signals that an I/O exception of some sort has occurred.
     */
    final void sendPduPacket(byte[] buffer, int length) throws java.io.IOException {
    
        if (isTraceOn()) {
            trace("sendPduPacket", "Send to peer. Peer/Port : " + address.getHostName() + "/" + port + 
                  ". Length = " +  length + "\nDump : \n" + SnmpMessage.dumpHexBuffer(buffer,0, length));
        }
        SnmpSocket theSocket = informSession.getSocket();
        synchronized (theSocket) {
            theSocket.sendPacket(buffer, length, address, port);
            setRequestSentTime(System.currentTimeMillis());
        }
    }

    /**
     * For SNMP Runtime internal use only.
     */
    final void processResponse() {
    
        if (isTraceOn()) {
            trace("processResponse", "errstatus = " + errorStatus);
        }

        if (inProgress() == false) {  // check if this request is still alive.
            responsePdu = null;
            return;  // the request may have  cancelled.
        }

        if (errorStatus >= snmpReqInternalError) {
            handleInternalError("Internal Error...");
            return;
        }

        try {
            parsePduPacket(responsePdu);
            //responsePdu = null;

            // At this point the errorIndex is rationalized to start with 0.
            switch (errorStatus) {
            case snmpRspNoError : 
                handleSuccess();
                return;
            case snmpReqTimeout : 
                handleTimeout();
                return;
            case snmpReqInternalError : 
                handleInternalError("Unknown internal error.  deal with it later!");
                return;
            case snmpReqHandleTooBig :
                setErrorStatusAndIndex(snmpRspTooBig, 0);
                handleError("Cannot handle too-big situation...");
                return;
            case snmpReqRefireAfterVbFix :
                // Refire request after fixing varbindlist.
                initializeAndFire();
                return;
            default :
                handleError("Error status set in packet...!!");
                return;
            }
        } catch (Exception e) {
            if (isDebugOn()) {
                debug("processResponse", e);
            }
            reason = e.getMessage();
        } 
        handleInternalError(reason);
    }
    
    /**