[jdev] Regarding JSO and Threads

[Matthew A. Miller]

I'll try to answer for first question. I'm sure others with come forth 
with the answers to the second.

To have a single thread handle more clients depends on if you need SSL 
or not[1].

JSO was designed so that a single thread could indeed handle the 
processing of multiple sessions (or at least appear that way). If you 
use the ChannelStreamSource, then all processing is done on the thread 
that calls Stream.process(). If you use the SocketStreamSource (or its 
derivatives), then there is actually another thread running to handle 
the I/O.

Assuming there are no SSL requirements, you could do this using the 
ChannelStreamSource and a java.nio.channels.Selector. Just ensure the 
selectable channel for the source is set to non-blocking and register it 
with the Selector (preferrably passing along the Stream that will be 
using it for the attachment):

conn = JSOImplementation.getInstance().createStream("jabber:client");
src = ChannelStreamSource.createSocket(host, port);

conn.connect(src);
conn.open();
src.register(selector, SelectionKey.OP_READ, conn);

Then call Selector.select() to retrieve the available selection keys, 
and process the attached Streams:

while (selector.select() > 0) {
Iterator itr = selector.selectedKeys().iterator();
SelectionKey key;
Stream conn;

while (itr.hasNext()) {
key = (SelectionKey)itr.next();
conn = (Stream)key.attachment();

conn.process();
if (!conn.getCurrentStatus().isConnected())
key.cancel(); //Stream disconnected; remove from selector
}
}

I believe there is an example to this effect in example/EchoServer.java.

Hope this helps.



[1] With J2SE 1.4, there is no open implementation of TLS that works 
with non-blocking I/O (that I am aware of). With J2SE 5, there is, but 
no work as been done with it in JSO (although it is fairly easy to 
implement, I believe).

-- 
-  LW

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