Your idea will work, but how do I periodically refresh the page? The page
the user is viewing is generated by the servlet.
Duke
----- Original Message -----
From: Craig R. McClanahan <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Tuesday, September 07, 1999 12:43 PM
Subject: Re: need your advice
> Duke Martin wrote:
>
> > hi,
> >
> > I recently posted a message about timed servlet actions. I agree that
> > starting a thread every five minutes is the way to go, but I am not
clear on
> > a few things. I only want to launch the thread when my servlet is
called
> > and I want it to stop when the servlet is stopped. I want the thread to
> > call my "Receive" method(every 5 min), which retrieves messages from the
> > mail server, and display on the current screen a new mail notification.
The
> > notification can be as simple as printing "new mail". The servlet where
the
> > thread will exist uses the doPost method because info about the user is
> > submitted to the servlet. How do I implement the procedure described
above?
> >
> > Thanks
> > Duke
> >
>
> This depends on what you mean by "I want it to stop when the servlet is
> stopped".
>
> (1) If you want the thread to stop when the servlet engine is shut down,
that's
> pretty simple -- stop it in the destroy() method.
>
> (2) If you want to stop it before you return from the current request,
that is
> also pretty simple -- just stop it before your return from the doPost()
method.
>
> (3) If you want the thread to run in between requests from the user,
though,
> you've got a more complicated design issue. While the user is looking at
the
> response from the doPost(), the servlet isn't running -- so there's no
direct
> place for any output from your thread to go. One approach might be to use
> sessions, and pass a reference to the session to your thread startup code.
The
> thread could then set user variables in the session to define the state
(such
> as new mail waiting). With suitable use of HttpSessionBindingListener,
you
> could arrange to stop the thread when the session was invalidated.
>
> But you've got a more fundamental issue here -- how do you plan to send
the
> "new mail" notification to the user? Normally, HTTP requests are always
> initiated by the client, not the server. You need to think about having a
page
> that periodically refreshes itself (and therefore picks up the current
status),
> or an applet that periodically requests the status and updates its
display.
>
> Craig McClanahan
>
>
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