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Message:
Modular Server
Posted by Emil Eifrem on 19 Dec 1998, 3:36 PM
Boy was I surprised when I checked JavaWorld's frontpage the other day. I had just spent a couple of days fiddling with dynamic class loading and, more importantly, dynamic class *ditching*. I am programming a multi-user game server in Java. This is indeed one of those 24/7 applications your article mentioned -- in fact, after we've gone live, we don't intend to ever reboot. One of the instruments to achieve this goal is a modular design. We'll have a static kernel that does little more than module management, and every other functionality will be in the NetworkModule, the WorldModule, the CommandModule, the ParserModule, the DatabaseModule, etc -- all of which can be loaded and unloaded at runtime. Thus class loading and ditching. I wish the modules to reside in a base dir, let's call it 'modules/'. Each module would then have its own package under that dir. So the NetworkModule's fully qualified name would be 'network.NetworkModule' and the file would be in 'modules/network/NetworkModule.class'. When I load the modules from the server, I cast them all to their superclass 'Module', which defines the interface for basic operations such as loading/unloading/report status/etc. Here (finally) comes my problem: The file Module.class is in package 'core'. I need it when I compile my modules, since they all extend the abstract Module super class. My modules are of necessity moved out of my classpath (thus a custom class loader similar, but not identical (mine supports loading from a class from a DB too), to your 'holeloader') so I can't simply say 'class NetworkModule extends core.Module' or likewise. I also need it in my core package (the kernel) for obvious reasons. Any good solutions to this problem? There are ugly workarounds, like constructing a script that copies core/Module.java to modules/ and strips out the line 'package core;', but those are just that: ugly workarounds, and I'd rather avoid them. This message is probably a bit lengthier than most postings in these forums, and I apologize for that. There may be a simple solution to my problem (I haven't really looked at it since last night) but this also gives me a reason to flaunt my scheme in public for an experienced audience that may see flaws that I have overlooked. Thank you. -EE
Replies:
- Hmm... Bill Venners 21 Dec 1998, 1:59 AM
(1)
- Thank ya Emil Eifrem 21 Dec 1998, 3:32 PM
(0)
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