Re: Setting up a Java Callback to Ada

[Stephen Leake <stephen.a.leake.1@gsfc.nasa.gov>]

"Marc A. Criley" <mcqada95@earthlink.net> writes:

> Jim Rogers wrote:
> > 
> > Note that the JNI model of software development ALWAYS starts with Java.
> > First you define your class containing remote methods. Then you create a
> > C header file from those methods using the javah tool. You implement the
> > corresponding C functions. You also implement the Java code to call the
> > remote methods. The C functions must handle all compatibility issues.
> > 
> > If you want Java to call an Ada subprogram you must build a C wrapper
> > that Java actually calls. That wrapper will handle all data
> > compatiblity issues and call the Ada subprogram. Trying to use JNI to
> > communicate between Java and Ada means programming in three languages.
> > 
> 
> Jim is correct here.  As an exercise a couple years ago I did in fact
> have Java call an Ada subprogram via JNI.  It worked, but I had to have
> the C wrapper, and also additional (native) C functions to call adainit
> and adafinal.

But you can export Ada fuctions with convention C, and call adainit
and adafinal from an Ada subprogram; just don't assume adainit has been
called yet in that subprogram!. That's sort of writing in Ada :).

-- 
-- Stephe