How to use JNI to access Active X control ?

Question

I need to access EFTPOS devices which provides Active X control inerface. Can I wrap Active X into dll so that I can use java native interface to access it ?
Thanks.

Answer 1

Hi Mahesh!
If nobody has answered by now...maybe you managed alone. Anyway here are some notes that might be useful:
The first thing to do is write your Java class with the native definitions. Now 'Build Project'.
Of course you shouldn't forget to have a line with
System.loadLibrary("your library name");Next you need to make the .h file. I think it's best to do this manually. In Netbeans you can add a line to the ant build script like:
<target name="-post-jar">
       <javah destdir="c" class="--your class full name--" classpath="${dist.jar}" />
    </target>but I don't know how to do this in Eclipse. Instead you will have to run javah manually like:
javah -classpath build -verbose  -d "c"   "--your class full name--"Do this from the main project directory.
Now create a separate C/C++ project with the name you used in the loadLibrary above, and make C files to implement the functionality you need (copy the function headers from the .h file). You should include the .h file and tell Eclipse where to find it. In Eclipse 3.4 there are workspace relative paths - and you can use those to add the include file.
The C project should be of type 'shared library'. On Windows it will produce a DLL.
Once you have your C project compiling, go back to the Java project, and edit the project class path. Under the 'source' tab expand your project source, and you will see a line for 'Native library location'. Select that, click the 'edit' button and add the path of the DLL (just the directory).
Now run or debug the Java program, and when you load the library, watch to make sure there is no exception.
How to debug: There are ways of debugging both the Java and C at the same time, but it's probably easiest just to put logging statements in the C (printf's) to see what's going on there.