[jdev] Using JSO for component development

[Mridul Muralidharan]

Christian Cantrell wrote:

> I'm using JSO to build a component, and I'm finding it more than a  
> little confusing.  I've posted to the JSO list, but it's pretty  
> quiet, so I thought I'd try my luck here.
>
> Using JSO, I'm able to connect to my server, listen for specific  
> packets, and return packets successfully.  The part I don't  
> understand is how you continuously listen for packets.  In all the  
> example code I've found, the authors have set up an infinite loop  
> inside of which they call Stream.process() to process new incoming  
> packets, and also keep checking a Queue for new packets to send out.   
> This technique works fine, but it seems odd to me, and is quite  
> resource intensive on my development machine.  Can someone explain:
>
> 1. Why is it done this way?
> 2. Is there another way to do it?  It seems that I should simply be  
> able to call a method that blocks until the packets I need come in  
> rather than having to process packets in a tight infinite loop.
>
> I'm also wondering if anyone can recommend any other Java XMPP  
> libraries I can use to build an external XMPP component if I can't  
> get JSO to work like I want it to.
>
> Thanks,
> Christian



Hi Christian,

  One solution for this would be to invoke stream.process() when you are 
sure there is some data available.
Like , if you are using some producer-consumer model , or if you are 
using java's nio package.
With the former , it becomes as simple as just triggering a 
stream.process() as soon as you have produced some data.
With the latter , you will need to use async io and register your 
channel with a selector for read events - which will get notified when 
there is data available to be read.

With your current approach , if your underlying socket is blocking 
socket , then you need to worry about cpu usage in an infinite loop - it 
will block until there is data available : with caveat that you will 
have one thread per component session.
If you use nio , the only advantage is that you will be able to listen 
for read events from multiple streams simultaneously.

Not sure if I am answering your question properly enough ...

Regards,
Mridul