// EchoServerMIDlet.java// Andrew Davison, ad@fivedots.coe.psu.ac.th, August 2005 /* The MIDlet starts the echo server.   It displays the current number of handlers, and a   scrollable text box of messages that it has received.   Pressing the "exit" command causes the server and its handlers   to terminate.*/import javax.microedition.midlet.*;import javax.microedition.lcdui.*;public final class EchoServerMIDlet extends MIDlet                                   implements CommandListener {  private Display display;  private Form form;  private StringItem numHandlersSI, messageSI;  private ScrollableMessagesBox scroller;  private Command exitCmd;  private EchoServer echoServer;  // the top-level echo server  private int numHandlers = 0;   // number of threaded echo handlers  public EchoServerMIDlet()   {    // build GUI    form = new Form("Bluetooth Echo Server");    int width = form.getWidth();    int height = form.getHeight();    numHandlersSI = new StringItem("No. Handlers: ", "0");    form.append(numHandlersSI);    int strHeight = numHandlersSI.getPreferredHeight();    // height of string item    scroller = new ScrollableMessagesBox("Received Messages:",                                           width, height-strHeight-20);                            // 20 is for the title and a bit of space    form.append(scroller);    exitCmd = new Command("Exit", Command.EXIT, 1);    form.addCommand(exitCmd);    form.setCommandListener(this);  } // end of EchoServerMIDlet()  protected void startApp()   {      display = Display.getDisplay(this);    display.setCurrent(form);    echoServer = new EchoServer(this);   // create the echo server    echoServer.start();   // start it listening for connections  } // end of startApp()  protected void destroyApp(boolean unconditional)   { notifyDestroyed(); }  protected void pauseApp() {}  public void commandAction(Command c, Displayable d)   { if (c == exitCmd) {      echoServer.closeDown();  // close down the server (and its handlers)      destroyApp(true);    }  }  // -------------- methods called by the handlers -----------------  synchronized public void incrCount()  // called when a new handler is created  { numHandlers++;    numHandlersSI.setText("" + numHandlers);  }  synchronized public void decrCount()  // called when a handler is about to terminate  { numHandlers--;    numHandlersSI.setText("" + numHandlers);  }  synchronized public void showMessage(String msg)  // used to show the message received by a handler  { scroller.addMessage(msg); }} // end of EchoServerMIDlet class