import net.tinyos.util.*;import net.tinyos.message.*;import java.io.*;import java.util.*;public class PingPong implements MessageListener,Runnable {    public static byte group_id = 0x7D;    MoteIF mote;    public PingPong() {	try {	    mote = new MoteIF(PrintStreamMessenger.err, PingPong.group_id);	    mote.registerListener(new PongMsg(), this);	}	catch (Exception e) {	    System.err.println("Unable to connect to sf@localhost:9001");	    System.exit(-1);	}    }    public void messageReceived(int dest_addr, Message msg) {        if (msg instanceof PongMsg) {            pongReceived( dest_addr, (PongMsg)msg);        } else {            throw new RuntimeException("messageReceived: Got bad message type: "+msg);        }    }    public void pongReceived(int dest_addr, PongMsg pmsg) {        int src_rssi = pmsg.get_src_rssi();        int dest_rssi = pmsg.get_dest_rssi();        if (src_rssi > 127) src_rssi = src_rssi - 256;        if (dest_rssi > 127) dest_rssi = dest_rssi - 256;        System.out.println("================================================");	System.out.println("Source: " + pmsg.get_src());	System.out.println("RSSI:   " + src_rssi + "\t" + (src_rssi-45) + " dBm");	System.out.print("LQI:    " + pmsg.get_src_lqi() + "\t");        if (pmsg.get_src_lqi() >= 104) 	    System.out.println("High");        else if (pmsg.get_src_lqi() >= 80) 	    System.out.println("Medium");	else	    System.out.println("Low");        System.out.println("------------------------------------------------");	System.out.println("Dest:   " + pmsg.get_dest());	System.out.println("RSSI:   " + dest_rssi + "\t" + (dest_rssi-45) + " dBm");	System.out.print("LQI:    " + pmsg.get_dest_lqi() + "\t");        if (pmsg.get_dest_lqi() >= 104) 	    System.out.println("High");        else if (pmsg.get_dest_lqi() >= 80) 	    System.out.println("Medium");	else	    System.out.println("Low");	System.exit(0);    }    public static void main(String[] args) throws IOException {        if (args.length == 1) {          group_id = (byte) Integer.parseInt(args[0]);	}	PingPong runclass = new PingPong();	Thread th = new Thread(runclass);        th.start();    }    public void run() {        PingMsg ping = new PingMsg();        ping.set_src(0x007E);        try {	    // inject packet	    mote.send(MoteIF.TOS_BCAST_ADDR, ping);	}	catch (IOException ioe) {	    System.err.println("Unable to sent message to mote: "+ ioe);	    ioe.printStackTrace();	    System.exit(-1);	}	// wait for response	while(true) {	}    }}