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From Tammer Salem <tammer.sa...@googlemail.com>
Subject Re: NMS - cannot recover from connection failure
Date Mon, 10 May 2010 23:43:09 GMT
Sorry - yes I get an exception stating that it cannot connect to the given
URI (even though the URI is 100% correct in that block of code). When I shut
down the client and restart it - it works fine.

On 10 May 2010 21:31, Timothy Bish <tabish121@gmail.com> wrote:

> 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/
>
> Follow me on Twitter: http://twitter.com/tabish121
> My Blog: http://timbish.blogspot.com/
>
>

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