I ran a few more debug sessions and it seems the culprit is
AbstractTransportListenerEx. This is the class which starts globally
configured endpoints during init phase (before start is called). But the
ListenerManager does not consider a transport is started until the start
method is called on the listener. Therefore following step sequence can lead
to the same endpoint getting started twice (code is not in actual Java
code):
listener.init(); // This will start a globally configured endpoint
if (!ListenerManager.isStarted(listener)) {
listener.init(); // re-initialization of the listener !!!
}
Any idea how we can fix this?
Thanks,
Hiranya
On Tue, May 25, 2010 at 8:36 PM, Hiranya Jayathilaka
<[email protected]>wrote:
> Hi Deepal,
>
> On Tue, May 25, 2010 at 7:50 PM, Deepal Jayasinghe <[email protected]>wrote:
>
>> Hiranya,
>>
>> I will give you a detailed answer later (now I do not have access to
>> the source code), here is what I remember. As I remember correct when
>> you first initialize the transport it only adds to the HashMap, and
>> when you want to start it just start the entry in the Hasmap. So
>> nothing harm happen, this code is around 4 years now and haven't seen
>> any problem, so I believe code works fine (but need to double check,
>> as I said before I will double check and let you know more about it)
>>
>
> Yes, I believe for most scenarios it will work fine. But in the scenario I
> mentioned above it becomes a problem (as detected by one of the TCP test
> cases).
>
> The ListenerManager maintains a map of started transports. For a transport
> to be considered started, it has to be added to this map. For this to happen
> you have to call start on the ListenerManager. Calling init on
> ListenerManager will only call init on the respective transport receivers
> (which will get the transport endpoints up and running). Therefore from the
> ListenerManager pov the transport is not really started even though the
> ports/sockets are running.
>
> Thanks,
> Hiranya
>
>
>> Deepal
>>
>> On Tue, May 25, 2010 at 10:07 AM, Hiranya Jayathilaka
>> <[email protected]> wrote:
>> > Hi Folks,
>> > While debugging through the TCP test cases, I stumbled upon a little
>> > problem. Let's say somebody creates a ServiceClient instance as follows:
>> > ServiceClient sender = new ServiceClient(configContext, clientService);
>> > When this is called, internally it will initialize a ListenerManager
>> > instance. I found the following bit of code in the ServiceClient:
>> > // Initialize transports
>> > ListenerManager transportManager =
>> > configContext.getListenerManager();
>> > if (transportManager == null) {
>> > transportManager = new ListenerManager();
>> > transportManager.init(this.configContext);
>> > }
>> > This in turns initializes transport listeners. However ServiceClient
>> does
>> > not call start on the ListenerManager. Therefore none of the transports
>> get
>> > marked as started in the ListenerManager. Now, if I try to use the
>> service
>> > client to invoke a service with useSeparateListener set to true, the
>> > following bit of code in the ClientUtils class is executed:
>> > if
>> > (!listenerManager.isListenerRunning(transportIn.getName())) {
>> > listenerManager.addListener(transportIn, false);
>> > }
>> > The if condition evaluates to true since the listener has not been
>> marked as
>> > started. In addListener method the corresponding transport listener will
>> be
>> > initialized again. If an endpoint has been configured globally, this can
>> > result in the same endpoint getting started twice thus potentially
>> causing
>> > bind exceptions. I'm experiencing this with the TCP transport now.
>> Thoughts?
>> > Thanks,
>> > Hiranya
>> > --
>> > Hiranya Jayathilaka
>> > Senior Software Engineer;
>> > WSO2 Inc.; http://wso2.org
>> > E-mail: [email protected]; Mobile: +94 77 633 3491
>> > Blog: http://techfeast-hiranya.blogspot.com
>> >
>>
>>
>>
>> --
>> http://blogs.deepal.org
>>
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>>
>
>
> --
> Hiranya Jayathilaka
> Senior Software Engineer;
> WSO2 Inc.; http://wso2.org
> E-mail: [email protected]; Mobile: +94 77 633 3491
> Blog: http://techfeast-hiranya.blogspot.com
>
--
Hiranya Jayathilaka
Senior Software Engineer;
WSO2 Inc.; http://wso2.org
E-mail: [email protected]; Mobile: +94 77 633 3491
Blog: http://techfeast-hiranya.blogspot.com
