users@grizzly.java.net

Re: Grizzly TCP Server: how to async call inside a filter

From: Oleksiy Stashok <oleksiy.stashok_at_oracle.com>
Date: Wed, 23 Oct 2013 11:53:51 -0700

Hi,

I reworked the MyCallerFilter this way to simulate the async JobExecution:

/ logger.info( "handling a MyMessage..." );

        Connection connection = ctx.getConnection();
        MyMessage m = (MyMessage) message;
        byte[] body = m.getMsg();

        logger.info("m="+ m );

        new Thread() {
                 public void run() {
                      byte[] res = JobExecution.exec( body );

                      MyMessage answer = new MyMessage( res.length, res );

                      connection.write(answer);
                      logger.info( "i wrote the MyMessage: "+answer );
                 }
        }.start();

        return ctx.getStopAction();/

Please note that in the reworked example we use connection.write(...)
instead of ctx.write(...) because FilterChainContext might be disposed
by that time.
It is also possible to optimize MyProtocolFilter to avoid byte[]
copying, but I'm not sure you use the same code in your real server, so
will not touch that code for now.

Hope that helps.

WBR,
Alexey.

On 23.10.13 04:13, Raffaele Marcello wrote:
> Thank you, i appreciate a lot your help!
> Unfortunately i cannot share my code but i can show you an example
> (you can see attached files). In reality i was inspired by BIOPFilter
> from official examples.
>
> In my protocol can happen that some ritrasmitted messages arrive while
> the server is waiting for a response.
> I would like to listen arriving messages (read) even if i'm waiting
> for responses. As you can see, i used two filter, when MyCallerFilter
> is executing the request to remote services, MyProtocolFilter is
> unable to read from input stream.
> Maybe i can do it using async call on service (maybe using a thread)
> or using async call from MyProtocolFilter to MyCallerFilter.
> Unfortunately i didn't understand how to use
> "*asyncMessageProcessor*", which class it is? Are there some examples
> that show how to use it?
> Is there the chance to create a task and ask Grizzly exec it async?
> Any other suggestion?
>
> Thanks
> R
>
>
>
>
> 2013/10/22 Oleksiy Stashok <oleksiy.stashok_at_oracle.com
> <mailto:oleksiy.stashok_at_oracle.com>>
>
> Hi,
>
>
>
> On 22.10.13 07:10, Raffaele Marcello wrote:
>
> Hi,
> i developed a TCP Server using Grizzly using two Filters:
> - MyProtocolFilter to manage the protocol( messages recognition )
> - MyCallerFilter to invoke a remote server (using RMI) and
> manage the answer.
>
> Unfortunately now it works using only one thread per
> connection. I'm having problems because sometimes some message
> can arrive while i'm waiting for the remote method invocation.
> In that case the new message is queued in input buffer and it
> can cause retransmissions.
> I want to ask if is possible to asynchronous invoke remote
> methods managing the results(Maybe using another thread). In
> this way i could manage new arriving messages while i'm
> waiting responses.
>
> Sure, it's possible. As I understand your protocol doesn't require
> responses to come in the same order as requests?
> The easiest thing you can do in MyCallerFilter is:
>
> public NextAction handleRead(FilterChainContext ctx) throws
> Exception {
> asyncMessageProcessor.doAsync(ctx.getMessage(),
> ctx.getConnection()); // pass the message and the connection, so
> async processor knows to whom it has to send the response
> return ctx.getStopAction();
> }
>
> If you can share your code - I'll be able to provide more details.
>
>
> Does anyone have a solution in order to maintain good
> performance? Can i use some Grizzly configuration or specific
> class?
>
> Sure, you can tune I/O strategies, buffer sizes, etc, but first it
> will be good to have something working :)))
>
> Thanks.
>
> WBR,
> Alexey.
>
>
>
> Thanks
> R
>
>
>
>
>
> --
> RM