I'm sorry for disturbing you again, but for some reason I'm not able to realize the callback functionality correctly. I'm trying to load a native library (ANT_DLL.dll), which implements wireless connection networks for sending and receiving sensor data between different network nodes. For such purposes the library includes a bunch of functions, amongst others for: 1) initializing the module (_ANT_Init()) 2) defining and opening channels between network nodes (_ANT_AssignChannel(), _ANT_SetChannelId (), _ANT_SetChannelRFFreq()) 3) processing incoming events (which has a callback function as parameter) (_ANT_AssignChannelEventFunction()) ...

In general, when I load the dll and call all that functions in my java program, the native calls - apart of the callback function - work fine. This can be seen by the fact that when there is a sensor module available (which is constantly sending data), the dll instantiates the creation of a protocol file, in which the received data is constantly written too. Though, when I try to receive the data also via the callback function of my program, I am facing some problems. Basically, I don't think that my callback method is ever called when some data is received since the testing printouts are never printer to the console. I have attached the source code of the java program and would be really grateful if somebody can tell me what I am doing wrongly. Thanks a million! P.S. In the documentation it is explicitly mentioned that the callback function has to be a C function. Though, if I have understood everything correctly, it shouldn't be a problem to realize it via the JNA callback functionality?

Timothy Wall schrieb:

package mobile.coaching;

import com.sun.jna.Callback; import com.sun.jna.Library; import com.sun.jna.Memory; import com.sun.jna.Native; import com.sun.jna.Platform;

public class InvokeNative {

//channel declaration private final byte channel = (byte) 0; //events definitions final byte EVENT_RX_ACKNOWLEDGED = (byte) 0x9B; final byte EVENT_RX_BROADCAST = (byte) 0x9A; final byte EVENT_RX_FAIL = (byte) 0x02; final byte EVENT_RX_SEARCH_TIMEOUT = (byte) 0x01;

//native object declaration private ANT_MOD ant_mod;

//buffer in which the received data is written final Memory aucResponseBuf = new Memory(13);

//callback object reference private static CHANNEL_EVENT_FUNCTION cef;

//declare DLL object public interface ANT_MOD extends Library {

//declare methods from DLL file public boolean _ANT_Init(byte deviceNum, short usBaudrate); public boolean _ANT_ResetSystem(); public boolean _ANT_AssignChannel(byte ucChannel, byte ucChannelType, byte
ucNetworkNumber); public boolean _ANT_SetChannelId(byte ucChannel, short usDeviceNum, byte
ucDeviceType, byte ucTransmisssionType); public boolean _ANT_SetChannelRFFreq(byte ucChannel, byte ucRFFreq); public boolean _ANT_SetNetworkKey(byte ucNetNumber, String usBaudrate); public boolean _ANT_OpenChannel(byte ucChannel);

//function with callback function parameter public boolean _ANT_AssignChannelEventFunction(byte ucChannel,
CHANNEL_EVENT_FUNCTION pfChannelEvent, Memory aucResponseBuf);

public void _ANT_Close(); }

//declare callback object and function public interface CHANNEL_EVENT_FUNCTION extends Callback { public boolean callback(byte ucChannel, byte ucEvent); }

//STEP 1: method to be called to initialize object by calling native library public boolean initANT() { boolean check;

//load object ant_mod = (ANT_MOD) Native.loadLibrary("ANT_DLL", ANT_MOD.class);

byte deviceNum = (byte) 0; short usBaudrate = (short) 50000;

//initialize ANT module, works fine check = ant_mod._ANT_Init(deviceNum, usBaudrate); return check; }

// STEP 2: Callback object/function definitions and call as parameter // to be called before opening the channel public boolean checkEvent() {

// callback object is still null System.out.println(cef);

cef = new CHANNEL_EVENT_FUNCTION() {

public boolean callback(byte ucChannel, byte ucEvent) {

switch(ucEvent) { case EVENT_RX_ACKNOWLEDGED: System.out.println("Acked\n"); break; case EVENT_RX_BROADCAST: switch(ucChannel) { case channel:

save = aucResponseBuf; System.out.println("save" + save);

case EVENT_RX_FAIL: System.out.println("RX Fail"); break; case EVENT_RX_SEARCH_TIMEOUT: System.out.println("Search Timeout"); break; default: System.out.println("Other event" + ucEvent); break; } return true;

} };

boolean checkEvent = ant_mod._ANT_AssignChannelEventFunction(channel, cef,
aucResponseBuf);

// callback object is not null anymore // printout: mobile.coaching.InvokeNative$1@71727172 System.out.println(cef); return checkEvent; }

//STEP 3: open channel in order to receive constantly data public boolean openChannel() { byte channelType = (byte) 0x00; byte networkNumber = (byte) 0;

boolean checkAssign = ant_mod._ANT_AssignChannel(channel, channelType,
networkNumber);

//byte channel = (byte) 0; short usDNum = (short) 0; byte uscDType = (byte) 0; byte uscTType = (byte) 0;

boolean checkSet = ant_mod._ANT_SetChannelId(channel, usDNum, uscDType,
uscTType);

byte ucRFF = (byte) 66; ant_mod._ANT_SetChannelRFFreq(channel, ucRFF); boolean checkOpen = ant_mod._ANT_OpenChannel(channel);

if(checkAssign && checkSet && checkOpen) return true; else return false; }

public void closeAnt() {

ant_mod._ANT_Close();