Setting native code from a class of a class passed in...

Question

I hope this makes sense, and its probably a stupid question but here it goes.
I have a native function that takes in a java class. I can call the getters of this class from the native code to get values to fill out my c structure just fine, but conceptually I am not 100% how to call the getters of a class that is part of the other class I passed in. Basically i have something like this:
the java call to the native being:
public native void setJSource(JSource theSource);
JNIEXPORT void JNICALL Java_AbfaRegion_setJSource
  (JNIEnv *env, jobject thisObj, jobject someVarsObj)
          jclass clazz;
          jmethodID mid;
          jint val;
          clazz = (*env)->GetObjectClass(env,someVarsObj);
          mid = (*env)->GetMethodID(env,clazz, "GetHeight", "I");
          val = (*env)->CallIntMethod(env,someVarsObj, mid);
          //put val into my struct
          mid = (*env)->GetMethodID(env,clazz, "GetWidth", "I");
          val=(*env)->CallIntMethod(env,someVarsObj, mid);
          //put val into my struct
}I know how to do this...but what if I had a class say:
class myClass
    JSource theSource; //has its own getters and setters like GetHeight
    int someVal;
    double anotherVal;
    public native void setMyClass(myClass theClass)
    int GetSomeVal()
      return this.someVal;
    int GetAnotherVal()
      return this.anotherVal;
    void SetSomeVal(int iSomeVal) 
      this.someVal=iSomeVal;
    void SetAnotherVal(double dAnotherVal)
      this.anotherVal=dAnotherVal;
}and then suppose in the native setMyClass I would like to get the height of the jsource of myclass, how can i do that in native code, do I have to use findclass or something?
Thanks for any help here, sorry if its a dumb question..
-Shane

Answer 1

For any class whose methods you are going to call, you need to first get a reference to the "class" record. So if you have an outer class, and have looked up its class record, and called a getter, and been returned an object (phew!):
You need to now look up the class for the inner object; you can then look up the the methods and call them.
JNI supports two ways to look up class:
FindClass, where the key argument is the fully-qualified class name.
GetObjectClass, where the key argument is an object reference.