Java call into PB-DLL

[Michael Ritter]

Has anyone attempted, or is it even possible
for a Java app to call into a PB-DLL?

Our Java guys would like to build a web based
interface and I have a great deal of my project
in PB DLL's and would prefer not to let them
touch any of my code which works so well.

I thought one approach could be to make ip-port
access available to their app. Then got to
thinking (sometimes a bad idea , why couldn't
a applet call into the dll directly?

Any thoughts/suggestions?

Thanks all,

Michael Ritter


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[Jason Bock]

Yes, you can make calls to DLLs in Java via the Java Native Interface (JNI). Go to any search engine and look for JNI and DLL and Windows - you should find a lot of material to help you out.

For example:
http://community.borland.com/article...,20679,00.html http://mindprod.com/jni.html

Most of the examples are in C/C++, but the idea is the same.

There are other ways to do interop as well, like SOAP (http://www.develop.com/soap). In fact, if you're doing machine calls via the Internet, SOAP may be the way to go.

Regards,

Jason

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[Michael Ritter]

Thanks Jason,

The Java Nuts here have successfully called into
a C dll using JNI and the examples. The Next step
is a little of a mystery to me. How do I provide
access to my PB-DLL's? What I am wondering, javah.exe
creates the prototypes for the C program
and we also include jni.h in the C compile.
Would I/Could I port these headers
to let them access the PB-DLL directly or should
I create a wrapper from a C prog to my functions in
PB (yuck!). I am at a loss concerning the
path I should wander, any suggestions?

Cheers,

Michael

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[Jason Bock]

I would personally port the created C code over to PB/DLL. My guess is that this should be doable. I wouldn't want a Java-to-C-to-PB/DLL layering construct if I could avoid it.

Of course, this may be an interesting third-party tool for someone to create - something akin to javah for PB so you wouldn't need to do the language translation. Any takers?

Regards,

Jason

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[Chris Boss]

Michael;

You might find the following interesting :

Clearsand Corp. has a product called MediaForge which is a
direct competitor to Macromedias Director. It sports a Basic
scripting language as well. What makes the product interesting
is that it has its own Web Browser plugin so you can deliver
apps via the web. It allows you to do multimedia on the web.

One of the clever features it has is that you can use DLLs as
objects within your app. Those DLLs can be "embeded" within
your web app as well. A project created with MediaForge can be
compressed into a single file for use on the web and the DLL
can be embeded into that file.

I have been a long time Beta tester for MediaForge I wrote a
code generation tool for creating PB DLLs for use with MediaForge
(it comes with MediaForge). MediaForge "supports" the use of PB
DLLs and even has template code for making PB DLLs that act like
sprites within a MediaForge application. A PB DLL can even make
calls back into the MediaForge runtime itself.

Clearsand "supports" the use of PB DLLs with MediaForge because
of my efforts and all of the PB code generation tools that ship
with MediaForge were written by me.

It is a great combination !

The lead programmer at Clearsand was "amazed" at the size and speed
of the DLLs I wrote with PB DLL !

MediaForge was written in C++ and he was surprised that a Basic
compiler could produce such fast and small DLLs.

If you are looking for alternatives to Java for the Web that is
"guaranteed" to work with PB DLLs, then MediaForge is worth
looking at.

http://www.clearsand.com




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[Michael Ritter]

I agree with you Jason about wrapping the
functions. Why create a useless layer of
indirection? I for one would take on the
challenge (javah for pb) but feel that
I lack the skills with java to pull it
off effectively. I would gladly assign
some time to the project if someone else
would lead it. I think it would be a useful
addition to our pb aresenal. To know if it's
a worthwhile venture, is anyone else
interested in calling PB-DLL's from Java?

Chris - I checked out MediaForge as suggested.
I understand from their pages that it is geared
towards multimedia. It could be interesting as you
suggest. I will sign up for their demo to check
it out, but I fear that our Java guys are not
going to like the idea. I am also assuming that
I would have to carry around a great deal of
extra code geared towards Multimedia with
MediaForge that I don't need (I know, the JVM
is quite heavy too) but my uninitated
take is that in the long run, we would have
more flexibility with Java on top instead of
MediaForge. Thanks for the idea, I will get the
demo to work with so that I may get a better
evaluation of the product.

Cheers,

Michael

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[Florent Heyworth]

Hi Michael

porting Javah (building support for calling PowerBASIC native
methods from Java) would be quite a bit of work/slogging through
the API documentation.

A better alternative which also wouldn't weaken Java memory management
etc would be to use sockets for communication between the Java app
and your PB app.

TCP communication is straightforward in both Java and PowerBASIC -
it's also the most portable method of interprocess communication.

This would be my recommendation.

Cheers

Florent

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[Michael Ritter]

Florent,

That was one of my initial thoughts, thanks
for confirming it's validity. Sockets do look
like the easiest to implement but I had not
considered the other factors that you mention.
Thanks for your thoughts.

Michael

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