Referance array passing to c++

Question

hi,
from what i know, it is not possible to return a whole array back to java program, as java supports no pointers
so for my method what i have done is passed a static array to the native code and updated it from the c++ code so that when native code alters it, it should be altered in java automatically
but in actual this does not happen, any one has any ideas on this one?
i am giving my code below:
class DGlove
     public static int[] values = new int[7];
     public static boolean status = false;
     public static native void getValues(int[] array);
     public static native void connectDG();
     public static native void disconnectDG();
     public static native boolean getStatus();
     static
     System.loadLibrary("dg5dt");
public static void main (String[] args)
          connectDG();
          getValues(values);
          status = getStatus();
          System.out.println(status);
          for (int i =0; i<=6;i++)
               System.out.println(values);
//          if (status == true)
//          disconnectDG();
          status = getStatus();
          System.out.println(status);
          getValues(values);
          for (int i =0; i<=6;i++)
               System.out.println(values[i]);
//cpp file (native code)
# include "conio.h"
# include "DataGlove.h"
# include "DGlove.h"
# include "jni.h"
unsigned short arraydg15[17];
int arraydg5[6];
bool status=0;
DataGlove glove;
JNIEXPORT void JNICALL Java_DGlove_getValues
(JNIEnv *env, jclass obj, jintArray arr)
     jsize len = env->GetArrayLength(arr);
     if (status == 1)
          glove.GetSensorRawValues (arraydg15);
          // conversion from the 15 sensor array to the 5 sensor array
          arraydg5[0] = arraydg15[0];
          arraydg5[1] = arraydg15[3];
          arraydg5[2] = arraydg15[6];
          arraydg5[3] = arraydg15[9];
          arraydg5[4] = arraydg15[12];
          arraydg5[5] = arraydg15[16];
          arraydg5[6] = arraydg15[17];
          jint *body = env->GetIntArrayElements(arr,0);
          for (int i =0;i<=len;i++)
               body[i] = arraydg5[i];
JNIEXPORT void JNICALL Java_DGlove_connectDG
(JNIEnv *env, jclass obj)
     status = glove.Connect("COM1");
     printf("data glove status %d", status);
     getch();
JNIEXPORT void JNICALL Java_DGlove_disconnectDG
(JNIEnv *env, jclass obj)
     status = glove.DisConnect();
JNIEXPORT jboolean JNICALL Java_DGlove_getStatus
(JNIEnv *env, jclass obj)
     return status;
what i need to do is pass the array by referance to native c++ code , have it modified and get the values back in java

Answer 1

An array is a java object, and like any other object can be returned by a native (C) method. You just have to make the right JNI calls to create and populate the array.