Re: [Quickfixj-users] newbie questions

[Joerg T. <Joe...@ma...>]

On 04/26/07 17:46, Toli Kuznets wrote:
>> 3.)  Examples of the custom Initiator classes have a 'System.in'
>> statement waiting for a user to hit a key on the keyboard to exit the
>> engine.  If we want to put this process in the background, this isn't a
>> feasible design obviously...so I was curious what people are doing to
>> build an engine that can be set as a background process and then when
>> brought back to the foreground, how is the engine being stopped
>> elegantly so the appropriate logout and disconnect procedures occur?
> 
> I'd be intersted to hear how others approach this problem as well. For
> now, we create the socket initiator and FIX listenrers in Spring, and
> then the main thread just goes to sleep (we do a new
> Semaphore(0).wait()). The OMS is then killed by pressing Ctrl-C if you
> run it on the console, or with an /etc/init.d script wrapping a 'kill
> -9' on our virtual appliance. Here's the code for reference:
> http://trac.marketcetera.org/trac.fcgi/browser/platform/trunk/oms/src/main/java/org/marketcetera/oms/OrderManagementSystem.java#L59

On UNIX, you can send your process into background by a double-fork:

You start a background process

	starter &

and this starter process starts your application into the background:

	starter:

	application </dev/null >logfile 2>&1 &
	echo $! >application.pid
	exit

Now this process is a real daemon, ie child of the init process with PID 1.
In addition, it is not tight to a terminal by redirecting stdin ("<"), stdout (">") and
stderr ( "2>" ).

You can also consider to put this in your own process group if you enable the monitor mode in the bash:

	set -m

Then every background process started with "&" is put into his own process group. The PID of the 
initial process is then the process group id. To kill all processes in this group:

	kill -$PID

(i.e. the negative value)

Using the saved "application.pid" you can stop this process using

	kill $(< application.pid)	# bash
	kill `cat application.pid`	# bourne shell

This signal is then catched by the shutdown handler (copy from previous posting):

          Thread shutdownHook = new Thread( "Gateway.shutdownHook" ) {
              public void run() {
                  shutdown( "Terminated by runtime system" );
              }
          };
          Runtime.getRuntime().addShutdownHook( shutdownHook );

Then in the shutdown() method you can do something like this:

	acceptor.stop();

Hope this helps!

I have no idea how to do this using Windows since I simply do not use it for anything.

Cheers, Jörg


-- 
Joerg Thoennes
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