package aimax.osm.gps;
import java.io.File;
import java.util.ArrayList;
import java.util.List;
/**
* Maintains a connection to a GPS via a NMEA stream, decodes the
* position messages and publishes the obtained position informations.
*
To run this class, download the rs232 serial port library from
* http://www.rxtx.org, install it correctly, and rename file
* NmeaSerialPortReader.txt
in package aimax.osm.gps
* to NmeaSerialPortReader.class
.
* One possible choice for installation is, to add the jar-file
* to the class path (project properties, add jar), to store the DDL
* locally (e.g. in project-root/lib), and start the application with
* VM argument -Djava.library.path=lib
.
* @author Ruediger Lunde
*/
public class GpsLocator implements NmeaReader.NmeaMessageListener {
private NmeaReader nmeaReader;
private NmeaReader nmeaSerialPortReader;
private GpsFix currPosition;
private List listeners;
/** Creates a new locator. */
public GpsLocator() {
currPosition = new GpsFix(false, 0.0f, 0.0f);
listeners = new ArrayList();
}
/**
* Sets the data source for the locator to a file reader.
*/
public void openSerialPortConnection() {
closeConnection();
if (nmeaSerialPortReader == null)
nmeaSerialPortReader = NmeaReaderFactory.instance().createSerialPortReader();
if (nmeaSerialPortReader != null) {
try {
nmeaSerialPortReader.openStream();
nmeaReader = nmeaSerialPortReader;
nmeaReader.addListener(this);
} catch (Exception e) {
e.printStackTrace();
}
}
}
/**
* Sets the data source for the locator to a file reader.
*/
public void openFileConnection(File file) {
closeConnection();
try {
nmeaReader = NmeaReaderFactory.instance().createFileReader(file);
if (nmeaReader != null) {
nmeaReader.addListener(this);
nmeaReader.openStream();
}
} catch (Exception e) {
e.printStackTrace();
}
}
public boolean isConnected() {
return nmeaReader != null;
}
public void closeConnection() {
if (isConnected()) {
try {
nmeaReader.removeListener(this);
nmeaReader.closeStream();
nmeaReader = null;
} catch (Exception e) {
e.printStackTrace();
}
}
}
/**
* Can be used, to check, whether the connection was opened
* successfully (result != null).
*/
public NmeaReader getNmeaReader() {
return nmeaReader;
}
public void addGpsPositionListener(GpsPositionListener listener) {
listeners.add(listener);
}
public void removeGpsPositionListener(GpsPositionListener listener) {
listeners.remove(listener);
}
/** Returns the last valid position which was provided by the NMEA stream. */
public GpsFix getCurrPosition() {
return currPosition;
}
/**
* Parses the position data currently in buffer, updates the
* the current position and informs all interested listeners.
*/
public void messageReceived(String message) {
if (message.startsWith("$GPGGA")) {
// System.out.println(buffer.toString());
// idx: 1 2 3 4 5 6 7 8 9 11 12 14
// $GPGGA,120007.000,5056.2197,N,02406.0867,W,0,00,99.9,12787.4,M,62.0,M,,0000*7B (NL-402U)
// $GPGGA,103131.000,4824.2758,N,00959.9357,E,1,06,1.3,458.5,M,43.9,M,,0000*54
// $GPGGA,044944,4824.3044,N,00959.9409,E,1,05,3.1,451.0,M,46.8,M,,*4E
String[] mparts = message.split(",");
if (mparts.length != 15)
return;
boolean posOK = true;
float lat;
float lon;
if (mparts[6].equals("0"))
posOK = false;
float deg = Float.parseFloat(mparts[2].substring(0, 2));
float min = Float.parseFloat(mparts[2].substring(2));
lat = deg + min / 60.0f;
if (mparts[3].equals("S"))
lat = -lat;
deg = Float.parseFloat(mparts[4].substring(0, 3));
min = Float.parseFloat(mparts[4].substring(3));
lon = deg + min / 60.0f;
if (mparts[5].equals("W"))
lon = -lon;
currPosition = new GpsFix(posOK, lat, lon);
//System.out.println(currPosition);
for (GpsPositionListener listener : listeners)
listener.positionUpdated(currPosition);
}
}
/////////////////////////////////////////////////////////////////
// Simple test program...
public static void main(String[] args) {
try {
GpsLocator locator = new GpsLocator();
locator.addGpsPositionListener(new GpsPositionListener() {
@Override
public void positionUpdated(GpsFix pos) {
System.out.println(pos);
}
});
//locator.openFileConnection(new File("nmeaout.txt"));
locator.openSerialPortConnection();
} catch (Exception e) {
e.printStackTrace();
}
}
}