Re: [Java] Function Binding Redux (long post)

Rene Rivera wrote:
> So on the suggestion from JW (John Welch), I tried an experiment. He 
> suggested a rather devious possible solution; Create an empty stub 
> *.java and corresponding *.class that loads the native class:
> 
> ====java
> package boost;
> 
> public class A
> {
>      static {
>          java.lang.System.out.println("stub/boost/A/static_init...");
>          java.lang.System.loadLibrary("boost_A.dll");
>      }
> }
> ====
> 
> And as part of the loadLibrary() redefine the same class to the 
> native+JNI version (see attached test code). 

Is the part between "====" what you are referring to?  I didn't get any 
attachments with your message.

> Hence when one uses the A 
> class, it can be loaded, but one is freed from having to declare all the 
> redundant Java members. 

This would be cool.  Although, there's something scratching at the back 
of my head about this one.  Something about defining a class twice, or 
not being able to undefine a class, or something else.

> But, and it's a big one, it seems the Java 
> compiler *does not load* a class in order to use it during compilation. 
> Rather it seems to read the .class file directly. Which seems to me a 
> rather serious case of false advertising from Sun.

Blech.  Yeah, that would be the case, wouldn't it?  There must be some 
sensible way to stub a class; there are J2EE developers who do it all 
the time when they use AOP toolkits that use link-time weaving.

>> Unless, that is, you use class C 
>> explicitly, through Reflection.  Which is a gross way to use a class.
> 
> Yes, that's fairly gross. Given your experiments, and mine, this only 
> leaves your suggestion of interfaces or of a launcher that puts in a 
> custom class loader.

Darn.  I was really hoping that you and JW would prove me wrong.  :(

Personally, I'm in favor of the interface approach; I think that despite 
the somewhat awkwardness in object construction, it offers more 
flexibility.  There's always the possibility of offering both 
approaches, though.

I'll get started on some basic glue code; I still need to study up on 
bytecode a little.  I could probably throw something together in Java 
that uses BCEL, though, until we can migrate some of it to native code.

-- 

John Moeller
[email protected]


-------------------------------------------------------------------------
This SF.net email is sponsored by: Splunk Inc.
Still grepping through log files to find problems?  Stop.
Now Search log events and configuration files using AJAX and a browser.
Download your FREE copy of Splunk now >>  http://get.splunk.com/