I got an application written in C++ and I am able to extend the applications functionality by writing plugins in C++ for it.
What I basically want to do is to embed Java into this application. This has already been done with Python (not done by me).
I read something about JNI but there is always the speech from a full programm that uses Java classes.
What I'd like to do is, to use classes from C++ in Java to interact with the application.
It's a 3D app in this case, called Cinema 4D.
Is there a way to compile and evaluate Java code while the application is running (in some sort of scripting language) using JNI or anything like it ?
Example imaginary code after the embedding was done:
import c4d.documents.*;
class Main {
public static void main() {
BaseDocument doc = GetActiveDocument();
BaseObject op = doc.GetActiveObject();
if (op != null) {
op.Remove();
}
}
}
This code should interact with Cinema 4D to delete the selected object.
You can embed a JVM within your application. Oracle's official reference book has some more details. The synopsis of it is:
#include <jni.h> /* where everything is defined */ int main() { JavaVM *jvm; /* denotes a Java VM */ JNIEnv *env; /* pointer to native method interface */ JDK1_1InitArgs vm_args; /* JDK 1.1 VM initialization arguments */ vm_args.version = 0x00010001; /* New in 1.1.2: VM version */ /* Get the default initialization arguments and set the class * path */ JNI_GetDefaultJavaVMInitArgs(&vm_args); vm_args.classpath = ...; /* load and initialize a Java VM, return a JNI interface * pointer in env */ JNI_CreateJavaVM(&jvm, &env, &vm_args); /* invoke the Main.test method using the JNI */ jclass cls = env->FindClass("Main"); jmethodID mid = env->GetStaticMethodID(cls, "test", "(I)V"); env->CallStaticVoidMethod(cls, mid, 100); /* We could have created an Object and called methods on it instead */ /* We are done. */ jvm->DestroyJavaVM(); }
You can do far more sophisticated things if you want (e.g. custom class loaders) but that's about it in terms of the bare minimum needed to get a JVM working within your application.