Question

I want to write a vector class (or something other) on C++. And I want to use its methods from Java. How to do this? I want to use JNI for this purpose. But javah generate me c prototypes. I want to store data in the C++ use area and use in java only an interface without fields. So, the problem is how to store the vector data in C-code.

Note:

Simply speaking, I need to wrap C++ interface by JNI and to have this interface in Java.

Answer 1

You will need to have a C-callable wrapper around your C++ code. The approach is similar to how you would allow a C++ library to be usable from pure C. Here is a simple example (with no error checking at all — do not use for real production code):

void * MyVectorCreate()
{
    return new MyVector<int>();
}

void MyVectorAdd(void * vector, int item)
{
    static_cast<MyVector<int> *>(vector)->Add(item);
}

void MyVectorDestroy(void * vector)
{
    delete static_cast<MyVector<int> *>(vector);
}