public Location getLocation(int timeout) throws LocationException, InterruptedException {
/* TODO The timeout might play to the fact that it is still acquiring satellites?
* I was wondering about that before. Maybe it makes sense to have timeout in SimpleGPS?
* TODO: Solution! Keep asking for altitude until is positive? (longitude can be negative)
* Or perhaps just until speed positive? (set those after)
* TODO: -1 in timeout is supposed to represent the default timeout (GPSListener?)
* TODO: I don't know if this is supposed to wait for the GPS to provide a new
* coordinate data or if it is okay to pass the latest cached GPS coordinates.
* Is the purpose of the timeout that it gets a new updated location that
* is not the previously returned or cached one?
*/
if (timeout == 0) throw new IllegalArgumentException("timeout cannot equal 0");
// Timeout results in LocationException:
long startTime = System.currentTimeMillis();
// TODO: Perhaps initialize and test for NaN instead.
while (gps.getLatitude() == 0 & gps.getLongitude() == 0) {
if (timeout != -1 & System.currentTimeMillis() - startTime > (timeout * 1000))
throw new LocationException("GPS timed out");
Thread.sleep(100); /* NOTE: This might very occasionally cause an error because
* Thread.yield() seems to cause sentence parsing to start too soon.
* (try changing sleep() to yield() to see what happens)
* Perhaps something needs to be synchronized? */
}
QualifiedCoordinates qc =
new QualifiedCoordinates(
gps.getLatitude(),
gps.getLongitude(),
gps.getAltitude(),
(gps.getHDOP() * 6),
(gps.getVDOP() * 6));
Location loc =
new Location(
qc,
gps.getSpeed(),
gps.getCourse(),
gps.getTimeStamp(),
0,
null); // TODO: Implement location method and extraInfo (0 and null for now)
return loc;
}
protected BTGPSLocationProvider() throws LocationException {
// TODO: Move this to searchConnect method?
// TODO: The problem here is that it searches every time. Slow. Need to try Properties?
// TODO: BIG ONE: Should only connect to GPS that isPaired() (from menu). Will
// allow some degree of control over which GPS is connects to in classroom.
try {
da = LocalDevice.getLocalDevice().getDiscoveryAgent();
da.startInquiry(DiscoveryAgent.GIAC, this);
} catch (BluetoothStateException e) {
throw new LocationException(e.getMessage());
}
while (!doneInq) {
Thread.yield();
}
if (btDevice == null) throw new LocationException("No device found");
String address = btDevice.getBluetoothAddress();
String btaddy = "btspp://" + address;
try {
StreamConnectionNotifier scn = (StreamConnectionNotifier) Connector.open(btaddy);
if (scn == null) throw new LocationException("Bad BT address");
StreamConnection c = scn.acceptAndOpen();
/* This problem below occurred one time for my Holux GPS. The solution was to
* remove the device from the Bluetooth menu, then find and pair again.
*/
if (c == null) throw new LocationException("Failed. Try pairing at menu again");
InputStream in = c.openInputStream();
if (in != null) {
gps = new SimpleGPS(in);
// c.close(); // TODO: Clean up when done. HOW TO HANDLE IN LOCATION?
}
} catch (IOException e) {
throw new LocationException(e.getMessage());
}
// Add itself to SimpleGPS as listener
SimpleGPS.addListener(this);
}
public void setLocationListener(
LocationListener listener, int interval, int timeout, int maxAge) {
// * Stop all previous listener threads *
listenerRunning = false;
if (listyThread != null) {
while (listyThread.isAlive()) {
Thread.yield();
} // End old thread
listyThread = null; // Discard the listener thread instance
}
// * Remove any listeners from GPSListener *
if (listener == null) {
// Remove current listener from SimpleGPS
SimpleGPS.removeListener(gpsl);
gpsl = null;
return; // No listener provided, so return now so it dosn't make a new one
}
// * Inner classes need final variables *
final int to = timeout;
final LocationListener l = listener;
final LocationProvider lp = this;
final int delay = interval * 1000; // Oddly interval is in seconds, and not float
// Make new thread here and start it if interval > 0, else if -1
// then use the GPSListener interface.
if (interval > 0) { // Notify according to interval by user
listyThread =
new Thread() {
public void run() {
while (listenerRunning) {
try {
// TODO: Probably only notify if location changed? Need to compare to old.
// TODO: Make helper method since this is used below too.
l.locationUpdated(lp, lp.getLocation(to));
Thread.sleep(delay);
} catch (LocationException e) {
// TODO Auto-generated catch block
} catch (InterruptedException e) {
// TODO Auto-generated catch block
}
}
}
};
listyThread.setDaemon(true); // so JVM exits if thread is still running
listenerRunning = true;
listyThread.start();
} else if (interval < 0) { // If interval is -1, use default update interval
// In our case, update as soon as new coordinates are available from GPS (via GPSListener)
// TODO: Alternate method: Use GPSListener for ProximityListener and this.
gpsl =
new GPSListener() {
public void sentenceReceived(NMEASentence sen) {
// Check if GGASentence. Means that new location info is ready
if (sen.getHeader().equals(GGASentence.HEADER)) {
try {
// TODO: Probably only notify if location changed? Need to compare to old.
l.locationUpdated(lp, lp.getLocation(to));
} catch (LocationException e) {
// TODO Auto-generated catch block
} catch (InterruptedException e) {
// TODO Auto-generated catch block
}
}
}
};
SimpleGPS.addListener(gpsl);
}
// TODO: Need to implement LocationListener.providerStateChanged()
}
