It looks like you have entered JIRA AMQNET-136 ( https://issues.apache.org/activemq/browse/AMQNET-136) for this problem. Thanks!
- Jim On Wed, Jan 21, 2009 at 11:30 AM, sbs1982 <satyajit.sa...@sac.com> wrote: > > ++++++++++++++++++++++++++++++++++++++++++++++ > > MSDN talking about lock(this) > > http://msdn.microsoft.com/en-us/library/c5kehkcz(VS.80).aspx<http://msdn.microsoft.com/en-us/library/c5kehkcz%28VS.80%29.aspx> > lock (this) is a problem if the instance can be accessed publicly. > > I see lock(this) used heavily in MessageConsumer class.... > the consumer will be accessible to the main app as well. > > DEADLOCK SCENARIO: > > the deadlock occurs on close method of IMessageConsumer. > > Here is the scenario... > Lets say we have the class below. The producer is calling the > MessgeConsumers callback method. > In this case its onMessage() method. Now lets assume there are 30K messages > to be received in the call back. When we are on the 10th message and the > user closes the trace Window the CloseWindow() method is called and the > application stalls at the message consumers close method. > Hope I am clear enough. > > Class TraceWindow > { > private IMessageConsumer consumerTrace = null; > TraceWindow(Apache.NMS.IMessageConsumer iMessageConsumer) > { > this.consumerTrace = iMessageConsumer; > if (consumerTrace != null) > { > this.consumerTrace.Listener += new > MessageListener(OnMessage); > } > } > > public void OnMessage(Apache.NMS.IMessage bMsg) > { > //inserts in WPF ObservableCollection > handleMessageDelegate Updater = new > handleMessageDelegate(handleMessage); > > > this.Dispatcher.BeginInvoke(System.Windows.Threading.DispatcherPriority.Input, > Updater, obj); > } > > public void handleMessage(Object item) > { > lock (collectionTrace) > { > { > collectionTrace.Add(item); > > LogManager.GetLogger("AlgoSystemCommunicatorLogger").Info(item); > } > } > } > > > public void CloseWindow() > { > consumerTrace.Close(); //////////////////////SYSTEM STALLS ON THIS CALL > } > > }//end of class > > > > +++++++++++++++++++++++++++++++++++++++++++++++ > > > Timothy Bish wrote: > > > > On Wed, 2009-01-21 at 10:26 -0800, sbs1982 wrote: > >> If one thread in my app is trying to create a temporary topic and I > >> already > >> have a few consumers(listening on other temp topics & processesing > >> incoming > >> messages on their respective call back methods i.e listeners) open. Now > >> trying to call the close method of one of these consumers causes my app > >> to > >> go into deadlock. > > > > Can you create a test case that might reproduce the problem? If you run > > in the debugger can you pinpoint where the deadlock is occurring? > > > >> is there some know issue of close method of consumers locking? > >> > >> I looked at the code in the MessageConsumer..the first statement is > >> lock(this). > >> Some articles are out there saying that locking on this is unsafe? > > > > Can you provide references, I'd like to read up on this (no pun > > intended). > > > > You may want to create a Jira issue to cover this problem. > > > > Regards > > Tim. > > > > > > -- > > Tim Bish > > http://fusesource.com > > http://timbish.blogspot.com/ > > > > > > > > > > > > -- > View this message in context: > http://www.nabble.com/is-ISession-thread-safe--tp21589189p21590482.html > Sent from the ActiveMQ - User mailing list archive at Nabble.com. > >
