Time Server, Time Protocol, RFC 868 on Blackberry

Today's i have studied regarding to Time Server, RFC-868 Protocol too interesting and simple to use. The Time Protocol is a network protocol in the Internet Protocol Suit defined in 1983 in RFC 868. Its purpose is to provide a site-independent, machine readable date and time.

The Time Protocol may be implemented over the TCP and UDP. A Host connects to a server that support the Time Protocol on port 37. The server then sends the time as 32-bit unsigned integer in binary format.

Now we see that how tom implement this protocol in Blackberry application.

import java.io.DataInputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Date;

import javax.microedition.io.Connector;
import javax.microedition.io.StreamConnection;

import net.rim.device.api.ui.container.MainScreen;


public final class MyScreen extends MainScreen {
 public static final long SECONDS_1900_TO_1970 = 2208988800L;
 private StreamConnection connection = null;
 private long l = 0;
 private StopWatch chageLable ;
 public MyScreen() {
  try {
   String postfixString = "ConnectionTimeout=800;deviceside=true";
   String URL = "socket://time.ien.it:37;" + postfixString;
   connection = (StreamConnection) Connector.open(URL);
   OutputStream out = connection.openOutputStream();
   out.flush();
   InputStream is = connection.openInputStream();
   DataInputStream input;
   input = new DataInputStream(is);
   l = (input.readInt() & 0xffffffffL);
  } catch (Exception e) {
   System.out.println("Ex. "+e);
  }
  long rfcTime = new Date((l -SECONDS_1900_TO_1970)*1000L).getTime();
  chageLable = new StopWatch(rfcTime);
  Thread t = new Thread(chageLable);
  t.start(); 
  setTitle(chageLable);
 }
}

Now Here StopWatch is LablelField and Thread so it display Time and update continuously.

import java.util.Calendar;
import java.util.Date;

import net.rim.device.api.i18n.SimpleDateFormat;
import net.rim.device.api.system.Display;
import net.rim.device.api.ui.Graphics;
import net.rim.device.api.ui.component.LabelField;

public class StopWatch extends LabelField implements Runnable {

 public static int REFRESH_SCREEN = 500;
 private int fieldWidth = Display.getWidth();
 private int fieldHeight = 30;
 private long rfcTime;
 private Calendar calTime = Calendar.getInstance();
 private volatile boolean alive = true;
 SimpleDateFormat df = new SimpleDateFormat("hh:mm:ss");
 long diff=0;
 public StopWatch(long rfcTime) {
  this.rfcTime = rfcTime;
  calTime = Calendar.getInstance();
  calTime.setTime(new Date(rfcTime));
  diff = calTime.getTime().getTime() - new Date().getTime();
  System.out.println("rfc: "+diff);
 }
 public void run() {
  while (alive) {
   rfcTime =  new Date().getTime()+diff;
   invalidate();
   try {
    Thread.sleep(REFRESH_SCREEN);
   } catch (Exception e) {
   }
  }
 }
 public int getPreferredWidth() {
  return fieldWidth;
 }
 public int getPreferredHeight() {
  return fieldHeight;
 }
 protected void layout(int arg0, int arg1) {
  setExtent(getPreferredWidth(), getPreferredHeight());
 }
 protected void paint(Graphics graphics) {
  graphics.drawText("Time: " + df.format(new Date(rfcTime)), 0, 0);
 }
 public void invalid(){
  this.invalidate();
 }
 public long getRfcTime() {
  return rfcTime;
 }
 public void setRfcTime(long rfcTime) {
  this.rfcTime = rfcTime;
 }
}

OutPut:

References:
1. http://www.kloth.net/software/timesrv1.php
2. http://massapi.com/source/commons-net-2.2-src/src/main/java/examples/ntp/TimeClient.java.html