Re: [riena-dev] Remote EventAdmin Service

[Eugen Reiswich <reiswich@xxxxxxxxxxxxxxxxxxxxxxxxx>]

That seems to be exactly the Apple-approach you've mentioned where a  
client keeps a connection line open for a while. I just thought that  
Riena has something similar to what ECF has done with the distributed  
RemoteAdmin Service (http://wiki.eclipse.org/Distributed_EventAdmin_Service 
). But if not it's ok, I just need to know if I can use some existing  
code.

Regards,
Eugen

Am Jun 15, 2009 um 17:39  schrieb Christian Campo:

> Isnt just a method on the server like
>
>
> public Event pushNotification(ClientId clientId, int seconds) {
>
>        for (i=0;i<seconds;i++) {
>
>               Event event = checkQueueForClient(clientId);
>               if (event!=null) {
>                      return even;
>               }
>
>         }
>         return null;
>
>
>
> And then the client runs this on a daemon thread as a remote service  
> call
>
>
> while (true) {
> 	Event event = pushNotification(myId, 3600);
> 	if (event!=null) {
> 		processEvent(event);
>       }
> }
>
>
> but for some reason I am not sure if that is what you meant ?
>
> christian
>
>
>
> Am 13.06.2009 um 17:51 schrieb Eugen Reiswich:
>
> > Hi Christian,
> > > What could work BTW is the model that Apple is currently following
> > > with its push notification.
> >
> > thanks a lot. That's exactly I wanted to know. I also know about the
> > apple etc. approach and hoped that Riena already offers an
> > implementation based on this idea. But if I need to implement this by
> > myself it would be grate to see a code snippet how this could work
> > with Riena.
> >
> > Regards,
> > Eugen
> >
> >
> > Am Jun 13, 2009 um 17:40  schrieb Christian Campo:
> >
> > > Hi Eugen,
> > >
> > > Riena Remote Services work like the very common Webservice pattern.
> > > They use Hessian as the protocol (a binary protocol) but use HTTP as
> > > transport so pretty much act like an Axis, CXF service stack. That
> > > means that they dont keep an connection between client and server
> > > once a call is finished. Since the clients are typically behind
> > > firewalls, routers and so on and dont have a public IP address that
> > > can be called a server can not call a client, only the client calls
> > > the server.
> > >
> > > Depending on the nature of the event of course you could add
> > > something to the transport layer to add events in the return
> > > envelope if you have such an event but you have to wait for the
> > > client to call the server again. The second problem is that Riena
> > > encourages to use the stateless webservice model (thats no
> > > obligation but it scales much better). So if you have 5 or 10
> > > servers to deal with your hundreds and thousands of clients each
> > > call could get to any server instance. So you have make sure you
> > > have the event at your hand at that server when the client calls.
> > >
> > > If all this makes no sense (I am sorry I am doing this way too long
> > > and went over push notification many many times) let me know and I
> > > can maybe explain more details.
> > >
> > > What could work BTW is the model that Apple is currently following
> > > with its push notification. The client keeps a connected line (a web
> > > service call) to one server instance). The call will wait for a
> > > longer time (say 5 minutes). If you like to send an event to a
> > > client you have to send that event to the server that keeps a line
> > > to all the clients and this server will let the call return with a
> > > value indicating the event.
> > > If the 5 minutes expire the call returns with null and a new one is
> > > started. This 5 minute (not sure if it has to be 5 minutes)
> > > mechanism because if the software never closes the line, the lower
> > > IP layer eventually will.
> > > This mechanism is BTW also used by ActiveSync from Microsoft  
> > > Exchange.
> > >
> > > Hope this helps.
> > >
> > > christian campo
> > >
> > > Am 13.06.2009 um 12:54 schrieb Eugen Reiswich:
> > >
> > > > Hi folks,
> > > >
> > > > I try to figure out how an OSGi EventAdmin Service could be  
> > > > realized
> > > > remote with Riena? I basically need to propagate server side events
> > > > to
> > > > all clients.  If it's not possible, how can I realize a client/ 
> > > > server
> > > > observer pattern with Riena?
> > > >
> > > > Regards,
> > > > Eugen
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