--- In zope@egroups.com, "Li Dongfeng" <ldf@s...> wrote:

I'm afraid that the only way to keep an object in RAM but not as a percistent object is to define the variable in a product's global space.

Thanks for answering. There are several ways to implement Zope up-time variables. But I just find it interesting that so few people has looked into my message. :) (Except you and Pavlos.) Using a product is an overkill. You can use any Python module. Since Digicool has the Globals.py module, we might as well use that one. That seems a nice place, better than using Python built-in modules. (If you really want to, you can even use the __builtins__ module instead of the Globals module, but I think that's a bit too drastic and too Perl-ish.) As the good and nice person that I am [heh heh :)], I include actual code so other people can play a bit, too. Implement an external method getMyVar() inside myExternal.py: ---------------------------------------- import Globals def getMyVar(self): if not hasattr(Globals, 'myVar'): Globals.myVar = 0 Globals.myVar = Globals.myVar + 1 return Globals.myVar ---------------------------------------- Voila, there you have a non-persistent variable that is: (1) Global to all threads, and (2) Has a lifetime equal to Zope's uptime. You can play around with different browser sessions and also reboot the Zope server to verify these features. --------------------------------------------------------- You might ask thread safety, and I would say this is a big issue. I haven't looked into Python threads lately, but I seem to recall that Python is borrowing Java's thread model... which almost makes me want to scream. When JDK 1.0 came out, I couldn't believe they let a total novice implement the thread features... Sure enough, most of the JDK 1.0 thread feature were quickly scrapped and the thread model in JDK 1.1 were better, but equally stupid because at no time are you guaranteed exclusive time-slice in a line of code, which in practice means you have to rely on primitive locking mechanisms that send you into deadlock minefields whereever you go. Jave doesn't allow exclusive time-slice (or a global lock) due to security concerns. But this makes thread programming really painful. Hopefully Python doesn't repeat the same mistake of Java. We really really need exclusive time-slice at least for some of the basic Python operations. Funny thing is that thread programming has been around town since a long time ago, but I don't understand why they let all these grandious novices dictate and screw up everything. :) ------------------------------------------------------------ In short, keep in Globals only those variables that you read a lot but write just a little. :) Sorry for digressing so much, but a bad Java experience haunts me a lifetime. :) regards, Hung Jung ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.com