Although I find it difficult to focus on programming while BBC is live broadcasting Olympic Table Tennis, focus I must. But I have a conundrum: I want a Java code container, but I don't like any of the current methodologies that I'm familiar with. Please help.
Yes, I've looked into Spring and Pico/NanoContainer and all that, but their focus appears to entirely be below the level of what I'm looking at. Their focus appears to be running inside some type of application, rather than launching it (so you configure launching Spring within your Web Application: you don't start Spring at the command line). Some of my problems have to do with packaging and deployment of multi-jar projects, and the IoC containers don't work at that level that I can see.
Plus, while I totally buy IoC as a general principle and use it on a regular basis, I don't need a generic configuration file to do it, particularly not in test cases. If I want a configuration file for a particular context, I bloody write one. It exactly represents my configuration options, is typesafe, has a schema, and can be understood by not-me for later configuration. A configuration file that is capable of representing the entire universe of Java types and construction options is essentially programming in XML. For people who seem to hate J2EE, the IoC-container-crowd seem to have adopted its worst tenet: replacing simple, clear, short snippets of source code with a monstrous amount of generic XML.
But I digress.
Anyway, here's what I want:
- Packages up a set of jar files as a single classloading context. This is pretty important because I think a big problem with modern composed Java applications is assembling all your various jar files and dealing with diamond dependencies. But anyway, I want something that I can pass around and say "this is the code for my application."
Yes, I know OSGi is a better solution for this, but I'm not there yet, and I won't necessarily be there for quite some time in terms of OSGi-ifying everything I've got. Bundle of JAR files I can handle.
- I want to be able to load multiple of those jar bundles at any given time in the same JVM.
- I want to be able to run static methods (maybe even main itself) with arguments. Heck, it's my code, I'll even adhere to some type of contract (whether explicit interface or implicit through annotations) to give me better lifecycle support.
- I want to be able to run lots of instances of those static methods (think message processors, each instance on a different JMS Topic). I want that to be dynamic (so I have one service kicking off others).
- I want to scale those instances on multiple machines. I'd like that to be automatic.
- I want to automatically handle failures of machines by distributing the load on that machine to other machines.
- I want lots and lots of monitoring and administration.
- I don't want to write a single line of code that I cannot adequately unit/functional/integration test outside of the container.
What I've been tempted to do in this situation in the past is to just use Tomcat as my generic container, and model everything as a Servlet with no Servlet mapping, so I'm only getting the lifecycle calls that I need and use of
web.xmlinitialization parameters as my configuration. But that just, well, it feels dirty. Plus, it would take longer than I think would be reasonable to launch one of these processor instances, and if I'm running thousands of discrete processor instances, I need control to be quick.
My guess is that there isn't something like this out there.
My guess is that I'm about to write one. I'd rather not, but I don't think that this type of thing exists. If it does, it might be the SpringSource Application Platform, but I can't actually tell what that does to be honest. I mean, it kinda just looks like OSGi++, but I can't tell what the ++ is. (Is it really just Equinox with some extra bits for central repositories and remote configuration? Is that all?)
My guess is that the actual eventual solution here is largely just going to be my leveraging Terracotta for all my distribution and failover requirements, but writing the whole actual lifecycle management work myself.
Oh, and it has to do Java. Telling me Erlang/OTP gives you every single thing here for absolutely free doesn't help me when I'm under a strict Erlang embargo at work.
Help me Lazyweb, Help me!