Re: [Springframework-developer] Use .java file as scripted beans

[Niklas T. <ni...@tr...>]

Nicolas De Loof wrote:
> Hello guys,
> 
> I've looked at new script support and sounds great for quick design or 
> prototyping "edit source code, hit refresh and get the result", BUT it 
> requires to learn yet another langage.
> I can agree that "grrovy is great" or "bsh is java like" or any other 
> enthousiastic comment on scripting languages, but my development team 
> has lots of junior java developers and my hierarchy has lot's of old 
> schools men that will make very difficult to accept a "script" language 
> as a valid technology.
> 
> I'm looking for a way to code scripted spring beans as 100% Java source 
> code, using full IDE support, so that developer doesn't have to know 
> some class is used a scripted bean and some other as compiled code. My 
> first think comes to JSP that are runtime compiled (an re-compiled) by 
> the container. It would be great to have a similar support for java code 
> to be "runtime re-compilable". When the code gets fine, it can be 
> classicaly compiled into a .class and pakaged into the app, by simply 
> changing the spring context.
> 
> Looking at the way tomcat (jasper) compiles JSP, it seems it uses a 
> custom classloader to load the runtime-compiled .class. My experience 
> with classloaders is limited so I can say if it would be easy, but here 
> is how I'd see this : a FactoryBean creates a proxy for the bean 
> interface and delegates invocation to a "runtime-compiled" class in a 
> child classloader. Hot recompilation requires the bean to be stateless, 
> but this sounds an aceptable constraint if I can code my web controlers 
> or business services by a quick code/test/code.
> 
> Thanks for any suggestion to make this a reality.
> 
> Nico.

Janino, http://www.janino.net/, is a small footprint Java compiler. It's 
mostly Java 1.4 compatible. Haven't used it myself yet but it looks 
interesting. It includes a classloader which loads classes directly from 
Java sources, http://www.janino.net/use.html#class_loader.

Regards,
Niklas