On Mon, 2010-05-10 at 15:04 +0100, Tammer Salem wrote:
> Hello All,
> I have an NMS client using the stomp broker on a .netcf device. For the most
> part it works absolutely fine, but now I'm trying to harden the device (for
> network failures etc.).
> I have added an exception listener and specifically look for IOExceptions
> (which I believe are what .NET throws if the GPRS/3G network connectivity
> dies). I can successfully capture this exception and then I fire off a
> thread to restart the connection and add my listeners again.
>
> At the moment this method doesn't seem to work - I can never get a
> connection again. Can anyone advise what is the best way of doing this?
>
So what happens exactly when the code attempts to create the new
Connection object and restore the Sessions and Destinations etc? Is
there an exception being thrown?
Regards
Tim.
> I've also attached my code so that you know what I'm trying to do.
>
> class AMQMessageHandler
>
> {
>
> private String myQueue;
>
> private String connecturi;
>
>
>
> //private ISession session;
>
> IConnectionFactory factory;
>
> IConnection connection;
>
> ISession session;
>
> IDestination destination;
>
> IMessageConsumer messageConsumer;
>
>
>
> /*
>
> * the UI thread within whose context the code will be executed
>
> */
>
> private Form uiThread;
>
>
> > /*
>
> * function in the UI thread to handle exceptions
>
> */
>
> private Delegate exceptionDelegate;
>
>
> >
> > public AMQMessageHandler(String connectionURI, String driverID,
> > Delegate exceptionDelegate, Form uiThread)
>
> {
>
> this.connecturi = connectionURI;
>
> this.myQueue = "driver.channel." + driverID;
>
> this.uiThread = uiThread;
>
> this.exceptionDelegate = exceptionDelegate;
>
> }
>
>
> > public void start()
>
> {
>
>
> > try
>
> {
>
> this.factory = new ConnectionFactory(connecturi);
>
> this.connection = this.factory.CreateConnection();
>
> this.session = this.connection.CreateSession();
>
> this.destination = SessionUtil.GetDestination(session,
> > "queue://" + myQueue);
>
> this.messageConsumer = session.CreateConsumer(destination);
>
>
>
> messageConsumer.Listener += new
> > MessageListener(messageConsumer_Listener);
>
> connection.ExceptionListener += new
> > ExceptionListener(connection_ExceptionListener);
>
> connection.Start();
>
>
> > }
>
> catch (Exception ex)
>
> {
>
> uiThread.Invoke(exceptionDelegate,ex.Message);
>
> }
>
> }
>
>
> > public delegate void RestartConnectionDelegate();
>
>
> > private void restartConnection()
>
> {
>
> new System.Threading.Thread(threadedStartConnection).Start();
>
> }
>
>
> > private void threadedStartConnection()
>
> {
>
> int retryCount = 1;
>
> bool keepTryingtoRestart = true;
>
>
> > while (keepTryingtoRestart == true)
>
> {
>
> //tsalem - add some kind of logging here
>
> //listBox.Items.Add("attempting to reconnect - pass " +
> > retryCount);
>
> System.Threading.Thread.Sleep(3000);
>
>
> > try
>
> {
>
> this.factory = new ConnectionFactory(connecturi);
>
> this.connection = this.factory.CreateConnection();
>
> this.session = this.connection.CreateSession();
>
> this.destination = SessionUtil.GetDestination(session,
> > "queue://" + myQueue);
>
> this.messageConsumer =
> > session.CreateConsumer(destination);
>
> messageConsumer.Listener += new
> > MessageListener(messageConsumer_Listener);
>
> connection.ExceptionListener += new
> > ExceptionListener(connection_ExceptionListener);
>
> connection.Start();
>
>
> > keepTryingtoRestart = false;
>
> }
>
> catch (Exception ex)
>
> {
>
> uiThread.Invoke(exceptionDelegate, ex.Message +"\n" +
> > ex.StackTrace);
>
> //tsalem change this to check for keep retrying rather
> > than on a counter
>
> if (retryCount == 50)
>
> {
>
> keepTryingtoRestart = false;
>
> }
>
>
> > }
>
>
>
> retryCount++;
>
> }
>
> }
>
>
> >
> > public void messageConsumer_Listener(IMessage receivedMessage)
>
> {
>
> try
>
> {
>
> ITextMessage message = receivedMessage as ITextMessage;
>
> message.Acknowledge();
>
> //tsalem - todo - handle message
>
> if (message.Text != null)
>
> {
>
> AMQUtil.Instance.ResponseAvailable(message.Text,
> > uiThread);
>
> }
>
> else
>
> {
>
> uiThread.Invoke(exceptionDelegate, "ERROR: AMQ Message
> > is empty");
>
> }
>
> }
>
> catch (Exception ex)
>
> {
>
> uiThread.Invoke(exceptionDelegate,ex.Message);
>
> }
>
> }
>
>
> >
> >
> > void connection_ExceptionListener(Exception exception)
>
> {
>
> uiThread.Invoke(exceptionDelegate,exception.Message);
>
>
> > if (exception is System.IO.IOException)
>
> {
>
> //Invoke(new
> > RestartConnectionDelegate(threadedStartConnection));
>
> threadedStartConnection();
>
> }
>
> }
>
> }
>
>
> regards,
> Tammer
--
Tim Bish
Open Source Integration: http://fusesource.com
ActiveMQ in Action: http://www.manning.com/snyder/
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My Blog: http://timbish.blogspot.com/
