Getting Data from C++ STL Vector into Java Vector

Question

Hi All,
I have been involved in a project recently to port a lot of C++ code into Java. Testing the ported Java code has been done in isolation with JUnit and works fine, but we would like to test all the ported code. To do this we aim to call the ported (Java) methods from C++ using JNI.
I have read a lot of the documentation from Sun on the JNI and can access and set Java methods that only contain primitive types without any problems. However what I cant seem to be able to achieve is passing aggregated C++ classes to Java.
Java
public void translation_unit_2( Vector v ) { \* code *\ }and somewhere in C++
jobject actions;                  // Is initialized
std::vector<Node> test ;   // Node class may contain other objects
jmethodID tmp = env->GetMethodID(env->GetObjectClass(actions), "translation_unit_2", "(Ljava/util/Vector;)V");
env->CallObjectMethod(actions, tmp, test);Now obviously what I have posted there doesnt work, but can anybody point me
in the correct direction to pass the Vector and its Data in C++ to Java?
None of the Java methods are native, because the eventually the whole system
will be operating solely in Java, but the testing at this stage is quite important.
If this is an impossible task then please say so also, any help will be appreciated !
Thanks,
Mark Hennessy

Answer 1

Thanks for the reply and I understand that running an iterator
over the vector would be the way the get the data out of the C++ Vector.
However that still leaves me with the question of mapping an arbitrary
C++ class ( which in the case of the example above would be a Node class which is
composed of other aggregated classes ) to a jobject such that I can pass
the data easily to Java throught JNI?
Is this possible or would I have to decompose each and every class to its most
primitive types and pass them over to Java and reconstruct them on the Java side?