RConsole.java

package lejos.nxt.comm;
import lejos.nxt.*;
import java.io.*;
import lejos.util.Delay;

/**
 * This class provides a simple way of sending output for viewing on a 
 * PC. The output is transmitted via the nxt USB connection or via Bluetooth.
 * If open is not called or if the connection to the PC is timed out, then
 * the output is discarded.
 */
public class RConsole extends Thread{
	static PrintStream ps;
    static NXTConnection conn;
    static RConsole lcdThread;

    private RConsole()
    {

    }

	private static void init(NXTConnection c)
	{
        if (c == null)
        {
            LCD.drawString("No connection   ", 0, 0);
            return;
        }
        conn = c;
		try {
            LCD.drawString("Got connection  ", 0, 0);
            byte [] hello = new byte[32];
            int len = conn.read(hello, hello.length);
            if (len != 3 || hello[0] != 'C' || hello[1] != 'O' || (hello[2] != 'N' && hello[2] != 'O'))
            {
                LCD.drawString("Console no h/s    ", 0, 0);
                conn.close();
                return;
            }
            LCD.drawString("Console open    ", 0, 0);
            if (conn == null) return;
            ps = new PrintStream(conn.openOutputStream());
			LCD.refresh();
			println("Console open");
            if (hello[2] == 'O')
            {
                lcdThread = new RConsole();
                lcdThread.setDaemon(true);
                lcdThread.start();
            }
		}
		catch (Exception e)
		{
			LCD.drawString("Console error " + e.getMessage(), 0, 0);
			LCD.refresh();
		}
	}
	
	public static void openUSB(int timeout)
	{
        LCD.drawString("USB Console...  ", 0, 0);
        init(USB.waitForConnection(timeout, 0));

	}
	
    public static void open()
    {
        openUSB(0);
    }
    
    public static void openBluetooth(int timeout)
    {
        LCD.drawString("BT Console...   ", 0, 0);
        init(Bluetooth.waitForConnection(timeout, NXTConnection.PACKET, null));
    }
    
	public static void print(String s)
	{
		if (ps == null) return;
		synchronized (ps){
            ps.print(s);
            ps.flush();
        }
	}
    
    public static void println(String s)
    {
        if (ps == null) return;
        synchronized(ps){
            ps.println(s);
        }
    }
	
	public static void close()
	{
		if (conn == null) return;
        synchronized(ps)
        {
            try {
                println("Console closed");
                conn.close();
                LCD.drawString("Console closed  ", 0, 0);
                LCD.refresh();
                Delay.msDelay(2000);
                ps = null;
                conn = null;
            }
            catch (Exception e)
            {
            }
        }
	}
	
	public static boolean isOpen() {
		return (ps != null);
	}
    
    public static OutputStream openOutputStream()
    {
        return (conn != null ? conn.openOutputStream() : null);
    }

    public void run()
    {
        OutputStream os = openOutputStream();
        while(ps != null)
        {
            synchronized(ps)
            {
                try {
                    os.write((byte)0xff);
                    os.write(LCD.getDisplay());
                    os.flush();
                } catch (Exception e)
                {
                    break;
                }
            }
            Delay.msDelay(20);
        }
    }
}