Re: How to listen out for a stream of data coming from (web)server

From:

Lew <lew@nowhere.com>

Newsgroups:

comp.lang.java.programmer

Date:

Tue, 21 Nov 2006 23:23:00 -0500

Message-ID:

<ubCdnZ_LU5s1Tf7YnZ2dnUVZ_oednZ2d@comcast.com>

"Angus" <nospam@gmail.com> wrote

Hello

I have an applet that connects to a server (same location as web server)
and
connects to a server on a socket. This all works fine for sending commands
to this server. But the server can send data to the client at any moment
in
time. So how do I listen out for the activity? do I launch a separate
thread
that sits listening for incoming data?

Oliver Wong wrote:

Yes.

Or no. Another approach is to have the other thread also be a "sender" to the
host, but the server only replies when it has something to say. This saves
having to open a listening port on the client side, something that can hurt
when it bangs into a firewall.

It also means that the server doesn't have to know or hunt for ports on the
client. It just replies to a client that has declared itself ready for
instruction. This simplifies the server's code.

The server pseudo-code would be something like:

Set < Client > clients;
listen on ServerSocket
get a "READY FOR INSTRUCTION" connection from client foo
clients.add( foo );
....
when server has something to say to foo:
reply( foo, msg );
clients.remove( foo );

- Lew