PC/Server SMS to a J2ME Midlet

actually, they do:
see http://weblogs.java.net/blog/billday/archive/2004/02/midp_push_using.html

ncoo is WRONG!!

THere are ports on the phone, and this is possible ONLY in GSM networks

This is possible by the use of EMS - in which the normal SMS gets a UDH - User Data Header.
Depending on the header value, the message can be sent to a certain port. (and from a certain port)


Here is the Midlet code for the same :

This is the code you require to RECEIVE messages sent to a certain port. Here the listening port is 8899.





import java.io.IOException;
import java.util.Date;
import java.util.Vector;

import javax.microedition.io.Connector;
import javax.microedition.lcdui.Command;
import javax.microedition.lcdui.Display;
import javax.microedition.lcdui.Displayable;
import javax.microedition.lcdui.Form;
import javax.microedition.lcdui.StringItem;
import javax.microedition.midlet.MIDlet;
import javax.wireless.messaging.Message;
import javax.wireless.messaging.MessageConnection;
import javax.wireless.messaging.MessageListener;
import javax.wireless.messaging.TextMessage;


public class IncMessageHandler implements MessageListener
{

      private Display disp;
      private MIDlet mid;
      private boolean processing = false;
      Vector queue = new Vector(10);
      private MessageConnection conn = null;

      public IncMessageHandler(Display display, MIDlet midlet)
      {
            this.disp = display;
            this.mid = midlet;
                  
            init();
      }



      public void init()
      {
            try
            {
                  conn = (MessageConnection) Connector.open("sms://:8899", Connector.READ);
                  conn.setMessageListener(this);
            }
            catch (Exception e)
            {
                  try
                  {
                        conn.close();
                  }
                  catch (Exception e1)
                  {
                  }
            }
      }

      public void notifyIncomingMessage(MessageConnection conn)
      {
            Message msg = null;
            try
            {
                  msg = conn.receive();
                  if (msg instanceof TextMessage)
                  {
                        TextMessage tmsg = (TextMessage) msg;
                        queue.addElement(tmsg);
                        processMessage();

                  }
            }
            catch (Exception e)
            {
            }

      }

      private void processMessage()
      {
            try
            {
                  if (processing)
                  {
                        return;
                  }
                  processing = true;
                  if (queue == null || queue.size() <= 0)
                  {
                        return;
                  }
                  Object head = queue.elementAt(0);
                  queue.removeElementAt(0);
                  TextMessage tmsg = (TextMessage) head;
                  
                  //Here is the message that you received, with the from, text and the date fields
                  String from = tmsg.getAddress();
                  String text = tmsg.getPayloadText();
                  Date date = tmsg.getTimestamp();
                  //Process here as required
            }
            catch (Throwable t)
            {
            }
            finally
            {
                  processing = false;
            }

            processMessage();

            

      

      }

      public void cleanup()
      {
            try
            {
                  conn.close();
            }
            catch (IOException e1)
            {
            }

      }


}

This is a fully threadsafe implementation - just do what you need to do as commented in the processMessage() method

To send TO a certain port, FROM another do this :

This sends message FROM port 5000 to port 8899 of the recipient

String to = //address of the recipient
String message = "text message to be sent";


try
                        {
                              MessageConnection clientConn = (MessageConnection) Connector
                                          .open("sms://:5000");
                              TextMessage tmsg = (TextMessage) clientConn
                                          .newMessage(MessageConnection.TEXT_MESSAGE);
                              tmsg.setAddress("sms://"+to+":8899");
                              tmsg.setPayloadText(message);
                              clientConn.send(tmsg);
                              
                              
                        }
catch -blah blah

Make sure that your application is running before you expect to receive any message.

In case you want your application to startup based on a message received on a certain port, you need to use the PushRegistry :


import javax.microedition.io.PushRegistry;

PushRegistry.registerConnection("sms://:8899", "your.mislet.ClassName", "*");

This will result in your application starting up on receiving a SMS on 8899