Re: Refresh
Re: Refresh
- Subject: Re: Refresh
- From: "Jerry W. Walker" <email@hidden>
- Date: Tue, 27 Feb 2007 10:42:47 -0500
Hi, Florijan,
The WOApplication class is a singleton for any WebObjects
application. From the first paragraph of the JavaDoc on WOApplication:
The primary role of the WOApplication class is to coordinate the
handling of HTTP requests. Each application must have exactly
one WOApplication object. The application object receives...
Honestly, I've never considered the possibility that a static
variable declared for a class in one application is shared with any
other application using that same class within the same Java Virtual
Machine. I don't think this is true, and if it is, there are a few
things about static variables that I will have to rethink before this
bites me. Whether true or not, the variable wouldn't be shared
between JVM's.
That's why Robert Walker was suggesting scheduling outside the
application.
So... has anyone any information on static variables in a class
shared between separate applications on the JVM if two applications
use that same class?
Regards,
Jerry
On Feb 27, 2007, at 10:02 AM, Florijan Stamenkovic wrote:
Hi all,
What I always had trouble with when attempting to use timers is
the problem it creates when running multiple instances of your
application.
I don't see why that would be a problem, if a Timer is static.
Initialize it once, and never worry about it again.
If you use a timer inside your WO application instance, and you
have more than one instance of your application running, then you
will have more than one timer running possibly updating your file
more often than you really want.
It may be possible to configure your timer to run on only one
instance, say instance number 1. The problem here is that if
instance 1 is shutdown then no timer will be running even if their
are other instances available.
Static comes in handy here. Instances shut down, timer keeps
running. Just make sure that you make a timer whose execution
thread is a daemon. Otherwise it keeps running and running and
running....
Using an outside scheduler solves these issues in a clean and
effective way.
Yeah, kind of nice.
As an extension to this method I often run the process in a
separate thread, for those actions that may take more than a few
seconds to execute.
I would probably stick to a static Thread in the Application class
anyway, that is started with the first instance. Nice and simple.
Timer in my eyes only becomes handy if you need to schedule a lot
of different tasks at different intervals.
My two cents,
Flor
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__ Jerry W. Walker,
WebObjects Developer/Instructor for High Performance Industrial
Strength Internet Enabled Systems
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| References: | |
| | >Refresh (From: WIESEN Bruno <email@hidden>) |
| | >Re: Refresh (From: Zak Burke <email@hidden>) |
| | >Re: Refresh (From: Robert Walker <email@hidden>) |
| | >Re: Refresh (From: Florijan Stamenkovic <email@hidden>) |