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?
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
