On 31 Mar 2004, at 19:55, Hamilton Verissimo de Oliveira (Engenharia - SPO) wrote:-----Mensagem original----- De: Pier Fumagalli [mailto:[EMAIL PROTECTED]
I don't understand what you base that "yes" on. Will the classloading
work? Yes, it will. But will *the* *rest* of the system work? You have
no guarantee at all.
I wrote 3 servlet containers in my life... :-) I can guarantee that class loading _will_ work, and it will be entirely transparent by component/composer classes.
Falaccy (Appeal to authority) http://www.nizkor.org/features/fallacies/appeal-to-authority.html
Ok, bad call... But as a proof I wrote some code :-)
Bad call again... :-) Let me explain... The class loading code is trivial, it is done by the JVM in itself, it doesn't rely on anything weird, undocumented, or in any reason "strange" or custom built.
Blocks exactly behave like webapps from a class loading perspective, no more, no less.
That said, during the design of the last two Servlet specifications, the idea of proxy classes came out here and there, but always ditched because:
A) servlet contexts lookup is not often used, and when you do it, you gotta know what you're doing
B) the JDK 1.2 lack of proxy classes doesn't allow to have decoupling of requested instance / requestor
C) given that servlet context lookup is based on "Object" keys, rather than "Class" role-interfaces the cross-context lookup mechanism would have to be deprecated entirely and rewritten from scratch
With my take on the kernel I had a completely clean whiteboard to fill up, that's why I used every single bit of functionality I could find in the VM to implement what I needed (and that came out to be what Stefano required for blocks).
That's why the code is so small, if I could save 2 lines of code by relying on something that the VM provided (collections, for example) I did it...
In the last revision I also found that the URLClassLoader (by digging up in the JVM sources) provided an "addURL()" call, which basically meant that I didn't have to write a class loader myself (apart from a simple inner class that re-exposes the protected addURL)
As I said again and again, I'm not reinventing the wheel, I'm just looking at the JVM with a whiteboard marker in my left hand, and the pile of requirements in my right, and when you do it with a fresh perspective forgetting about what was there "before" you'll see that there are some pretty amazing stuff in there...
I'm not saying "my solution is THE solution", I'm just saying that it works (buggy, yeah, but no core issues AFAICS), and before saying something like "it won't work", take a step back, look at the code, and look at the JVM..
Pier
