ChatClient.java

package clientServer;
import java.net.*;
import java.io.*;
import java.applet.*;
import java.awt.*;

public class ChatClient extends Applet
{
    private Socket socket              = null;
    private DataInputStream  console   = null;
    private DataOutputStream streamOut = null;
    private ChatClientThread client    = null;
    private TextArea  display = new TextArea();
    private TextField input   = new TextField();
    private Button    send    = new Button("Send"), connect = new Button("Connect");
    private Button    quit    = new Button("Bye");
    private String    serverName = "localhost";
    private int       serverPort = 4444;
    
    public void init()
    {   Panel keys = new Panel();
        keys.setLayout(new GridLayout(1,2));
        keys.add(quit);
        keys.add(connect);
        Panel south = new Panel();
        south.setLayout(new BorderLayout());
        south.add("West", keys);
        south.add("Center", input);
        south.add("East", send);
        Label title = new Label("Simple Chat Client Applet", Label.CENTER);
        title.setFont(new Font("Helvetica", Font.BOLD, 14));
        setLayout(new BorderLayout());
        add("North", title);
        add("Center", display);
        add("South",  south);
        quit.setEnabled(false);
        send.setEnabled(false);
        //getParameters();
    }
    
    
    public boolean action(Event e, Object o)
    {
        if (e.target == quit)
        {   input.setText(".bye");
            send();
            quit.setEnabled(false);
            send.setEnabled(false);
            connect.setEnabled(true);
        }
        else if (e.target == connect) {  connect(serverName, serverPort); }
        else if (e.target == send)
        {   send();
            input.requestFocus();
        }
        return true;
    }
    
    public void connect(String serverName, int serverPort)
    {
        println("Establishing connection. Please wait ...");
        try
        {  socket = new Socket(serverName, serverPort);
            println("Connected: " + socket);
            open();
            send.setEnabled(true);
            connect.setEnabled(false);
            quit.setEnabled(true);
        }
        catch(UnknownHostException uhe)
        {  println("Host unknown: " + uhe.getMessage()); }
        catch(IOException ioe)
        {  println("Unexpected exception: " + ioe.getMessage()); }
    }
    
    private void send()
    {  try
        {   streamOut.writeUTF(input.getText());
            streamOut.flush();
            input.setText("");
        }
        catch(IOException ioe)
        {   println("Sending error: " + ioe.getMessage());
            close();
        }
    }
    
    
    public void handle(String msg)
    {
        if (msg.equals(".bye"))
        {  println("Good bye. Press RETURN to exit ...");
            close();
        }
        else println(msg);
    }
    
    
    public void open()
    {
        try
        {   streamOut = new DataOutputStream(socket.getOutputStream());
            client = new ChatClientThread(this, socket);
        }
        catch(IOException ioe)
        {  println("Error opening output stream: " + ioe); }
    }
    
    
    public void close()
    {
        try
        {   if (streamOut != null)  streamOut.close();
            if (socket != null)  socket.close();
        }
        catch(IOException ioe)
        {  println("Error closing ..."); }
        
        client.close();
        client.stop();
    }
    
    
    private void println(String msg)
    {
        display.append(msg + "\n");
    }
    
    public void getParameters()
    {
        serverName = getParameter("host");
        serverPort = Integer.parseInt(getParameter("port"));
    }
}