// Chat client

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

class chatClient extends Frame implements Runnable
{
    Socket soc;    
    TextField tf;
    TextArea ta;
    Button btnSend,btnClose;
    String sendTo;
    String LoginName;
    Thread t=null;
    DataOutputStream dout;
    DataInputStream din;
    chatClient(String LoginName,String chatwith) throws Exception
    {
        super(LoginName);
        this.LoginName=LoginName;
        sendTo=chatwith;
        tf=new TextField(50);
        ta=new TextArea(50,50);
        btnSend=new Button("Send");
        btnClose=new Button("Close");
        soc=new Socket("127.0.0.1",5217);

        din=new DataInputStream(soc.getInputStream()); 
        dout=new DataOutputStream(soc.getOutputStream());        
        dout.writeUTF(LoginName);

        t=new Thread(this);
        t.start();

    }
    void setup()
    {
        setSize(600,400);
        setLayout(new GridLayout(2,1));

        add(ta);
        Panel p=new Panel();
        
        p.add(tf);
        p.add(btnSend);
        p.add(btnClose);
        add(p);
        show();        
    }
    public boolean action(Event e,Object o)
    {
        if(e.arg.equals("Send"))
        {
            try
            {
                dout.writeUTF(sendTo + " "  + "DATA" + " " + tf.getText().toString());            
                ta.append("\n" + LoginName + " Says:" + tf.getText().toString());    
                tf.setText("");
            }
            catch(Exception ex)
            {
            }    
        }
        elseif(e.arg.equals("Close"))
        {
            try
            {
                dout.writeUTF(LoginName + " LOGOUT");
                System.exit(1);
            }
            catch(Exception ex)
            {
            }
            
        }
        
        return super.action(e,o);
    }
    publicstaticvoid main(String args[]) throws Exception
    {
        chatClient Client1=new chatClient(args[0],args[1]);
        Client1.setup();                
    }    
    publicvoid run()
    {        
        while(true)
        {
            try
            {
                ta.append( "\n" + sendTo + " Says :" + din.readUTF());
                
            }
            catch(Exception ex)
            {
                ex.printStackTrace();
            }
        }
    }
}

// Chat Server

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

class chatServer
{
    static Vector ClientSockets;
    static Vector LoginNames;
    
    chatServer() throws Exception
    {
        ServerSocket soc=new ServerSocket(5217);
        ClientSockets=new Vector();
        LoginNames=new Vector();

        while(true)
        {    
            Socket CSoc=soc.accept();        
            AcceptClient obClient=new AcceptClient(CSoc);
        }
    }
    publicstaticvoid main(String args[]) throws Exception
    {
        
        chatServer ob=new chatServer();
    }

class AcceptClient extends Thread
{
    Socket ClientSocket;
    DataInputStream din;
    DataOutputStream dout;
    AcceptClient (Socket CSoc) throws Exception
    {
        ClientSocket=CSoc;

        din=new DataInputStream(ClientSocket.getInputStream());
        dout=new DataOutputStream(ClientSocket.getOutputStream());
        
        String LoginName=din.readUTF();

        System.out.println("User Logged In :" + LoginName);
        LoginNames.add(LoginName);
        ClientSockets.add(ClientSocket);    
        start();
    }

    publicvoid run()
    {
        while(true)
        {
            
            try
            {
                String msgFromClient=new String();
                msgFromClient=din.readUTF();
                StringTokenizer st=new StringTokenizer(msgFromClient);
                String Sendto=st.nextToken();                
                String MsgType=st.nextToken();
                int iCount=0;
    
                if(MsgType.equals("LOGOUT"))
                {
                    for(iCount=0;iCount<LoginNames.size();iCount++)
                    {
                        if(LoginNames.elementAt(iCount).equals(Sendto))
                        {
                            LoginNames.removeElementAt(iCount);
                            ClientSockets.removeElementAt(iCount);
                            System.out.println("User " + Sendto +" Logged Out ...");
                            break;
                        }
                    }
    
                }
                else
                {
                    String msg="";
                    while(st.hasMoreTokens())
                    {
                        msg=msg+" " +st.nextToken();
                    }
                    for(iCount=0;iCount<LoginNames.size();iCount++)
                    {
                        if(LoginNames.elementAt(iCount).equals(Sendto))
                        {    
                            Socket tSoc=(Socket)ClientSockets.elementAt(iCount);                            
                            DataOutputStream tdout=new DataOutputStream(tSoc.getOutputStream());
                            tdout.writeUTF(msg);                            
                            break;
                        }
                    }
                    if(iCount==LoginNames.size())
                    {
                        dout.writeUTF("I am offline");
                    }
                    else
                    {
                        
                    }
                }
                if(MsgType.equals("LOGOUT"))
                {
                    break;
                }

            }
            catch(Exception ex)
            {
                ex.printStackTrace();
            }
            
            
            
        }        
    }
}
}