ClientStarer

import java.io.*;
import java.net.*;
import java.util.*;


public class ClientStarer {

    private int ID;
    private Socket socket;
    private DataOutputStream dos;
    private DataInputStream dis;
    //todo: init other required variables here

    ClientStarer(int id, String host, int port) throws IOException {
        this.ID = id;
        socket=new Socket(InetAddress.getByName(host),port);
        dis= new DataInputStream(socket.getInputStream());
        dos=new DataOutputStream(socket.getOutputStream());
        dos.writeInt(id);
        dos.flush();
        // todo: Connect to server and send client ID
        this.listen();
        // todo: Listen for incoming messages
    }

    // todo: Implement the sending message mechanism
    void sendMessage(int idReceiver, String message) throws IOException {
        dos.writeUTF(message+":"+idReceiver);
        dos.flush();
    }

    // todo: end communication - send END to server
    private void endCommunication() throws IOException {
        dos.writeUTF("END");
        dos.flush();
    }

    // todo: listen for icoming messages from the server.
    // It should start a separate thread to handle listening
    // and not block the execution
    // Should start a new ClientStarterWorkerThread
    private void listen() {
        new ClientStarterWorkerThread(this.ID,dis).start();
    }

    public static void main(String[] args) throws IOException, InterruptedException {
        //todo: Initialize and start 3 clients

        ClientStarer client1=new ClientStarer(1,"localhost",9876);
        ClientStarer client2=new ClientStarer(2,"localhost",9876);
        ClientStarer client3=new ClientStarer(3,"localhost",9876);
        // Simulate chat
        client1.sendMessage(2, "Hello from client 1");
        Thread.sleep(1000);
        client2.sendMessage(3, "Hello from client 2");
        Thread.sleep(1000);
        client1.sendMessage(3, "Hello from client 1");
        Thread.sleep(1000);
        client3.sendMessage(1, "Hello from client 3");
        Thread.sleep(1000);
        client3.sendMessage(2, "Hello from client 3");

        // Exit the chatroom
        client1.endCommunication();
        client2.endCommunication();
        client3.endCommunication();
    }
}
class ClientStarterWorkerThread extends Thread {

    private int ID;
    private DataInputStream inputStream;

    public ClientStarterWorkerThread(int clientID, DataInputStream inputStream) {
        this.ID = clientID;
        this.inputStream = inputStream;
    }

    @Override
    public void run() {
        String line;
        while (true)
        {
            try {
                line=inputStream.readUTF();
                if(line.equals("END"))
                    break;
                else
                System.out.println(line);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}