Chat between j2me clients and using a Servlet server

Question

Java gurus, please help me..
I'm wondering if I could set up a sort of chat functionality between two j2me clients. I wish to use Java servlets as my server and Tomcat to deploy it. Is this possible? Can i do these by using http connection only or do i have to use sockets? If i use sockets, how will i configure Tomcat, or do i still need Tomcat?
Hope someone could help! Thanks in advance! =)

Answer 1

Basically it means you should have a Thread that loops and make an http request every x seconds. Before sending the request it should check if the user has typed anything, and send that with the request. The server should keep track of all the chat messages sent, and forward to all the other clients when they request an update. To keep track of what clients have received what messages, you could have a time stamp for each message, and a "last update" field for each client.
The client should run something like this in a thread:
while (iAmRunning) {
  url = "......." // address of your server
  if (the user typed anything since the last time we sent a request) {
    url = url + "?msg=" + whatTheUserTyped; // maybe another parameter for private messages?
    reset what the user typed (so it won't be sent next time);
  send the request;
  get the response containing what the rest of the users have
    typed since my last update;
  update the display with the latest messages;
}And the server would handle a request like:
if (the request contains a message) {
  save the message with the current time;
check when was the previous update for this user;
get all messages where the timestamp is later than the last update;
set the last update field for the user with to the current time;
respond with all the messages;