README.md

This is basically a simple chat application that I have built after learning socket programming. The Gui of this chat application need to be improved yet i would do later task is to make it cpable of creating unlimited users's objects rather than client1, 2 etc

Execution Flow

1. main Method:

   • The main method starts the application by calling the go method on an instance of the server class.

   public static void main(String[] args) {
       new server().go();
   }

2. go Method:

   • Initialize clientOutputStreams: An ArrayList to store PrintWriter objects for each client.

   • Create ServerSocket: Listens for incoming client connections on port 5000.

   • Infinite Loop: Continuously waits for and accepts new client connections.

     while (true) {
         Socket clientSocket = serverSock.accept();
         PrintWriter writer = new PrintWriter(clientSocket.getOutputStream());
         clientOutputStreams.add(writer);
     
         Thread t = new Thread(new ClientHandler(clientSocket));
         t.start();
         System.out.println("some client got connected with server");
     }

   • Accept Client Connection: Blocks until a new client connects, then accepts the connection.

   • Create PrintWriter: For the connected client and adds it to clientOutputStreams.

   • Start Client Handler Thread: Creates and starts a new ClientHandler thread for the client.

3. ClientHandler Class:

   • Each ClientHandler handles communication with a single client. It reads messages from the client and broadcasts them to all clients.

   Constructor:

   • Initializes the BufferedReader to read messages from the client socket.

     public ClientHandler(Socket clientSocket) {
         try {
             sock = clientSocket;
             InputStreamReader isReader = new InputStreamReader(sock.getInputStream());
             reader = new BufferedReader(isReader);
         } catch (Exception ex) {
             ex.printStackTrace();
         }
     }

   run Method:

   • Runs in a separate thread for each client. It reads messages from the client in a loop and broadcasts them to all clients.

     public void run() {
         String message;
         try {
             while ((message = reader.readLine()) != null) {
                 System.out.println(message);
                 tellEveryone(message);
             }
         } catch (Exception ex) {
             ex.printStackTrace();
         }
     }

   • Read Messages: Continuously reads messages from the client.

   • Broadcast Messages: Calls tellEveryone to broadcast the received message to all clients.

4. tellEveryone Method:

   • Iterates over all PrintWriter objects in clientOutputStreams and sends the message to each client.

   public void tellEveryone(String message) {
       Iterator<PrintWriter> it = clientOutputStreams.iterator();
       while (it.hasNext()) {
           try {
               PrintWriter writer = (PrintWriter) it.next();
               writer.println(message);
               writer.flush();
           } catch (Exception ex) {
               ex.printStackTrace();
           }
       }
   }

   • Iterate and Send Messages: For each client, sends the message and flushes the stream to ensure it's sent immediately.

Summary

• main: Calls go.
• go: Sets up the server, waits for clients to connect, and starts a new ClientHandler thread for each client.
• ClientHandler: Reads messages from the client and calls tellEveryone to broadcast the message.
• tellEveryone: Sends the message to all connected clients using their respective PrintWriter objects.

Each client's communication is handled in a separate thread, allowing multiple clients to interact with the server concurrently.