chatclient.java

java3D game engine design of the source [three-dimensionalvirtualrealitynetworkprogram] - "virtual

// ChatClient.java
// Andrew Davison, June 2003, [e-mail]

/* The ChatClient interacts with the ChatServer.
   It can send the following messages:

     who -- a list of users is returned, with the format
            "WHO$$ cliAddr1 & port1 & ... cliAddrN & portN & "

     bye -- client is disconnecting

	 any text  -- which is broadcast to all clients with the format
				  "(cliAddr,port): msg".
                  The address and port uniquely identify the client.

  The first & third messages are sent via a GUI interface:
     * a "Who" button
     * a "Message:" text field

  Clicking the close box of the window, causes the client to
  send the "bye" message before terminating. 

  There is a separate threaded ChatWatcher object for processing 
  messages coming from the ChatServer object.
*/

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.net.*;


public class ChatClient extends JFrame implements ActionListener
{
  private static final int PORT = 1234;     // server details
  private static final String HOST = "localhost";

  private Socket sock;
  private PrintWriter out;  // output to the server

  private JTextArea jtaMesgs;  // output text area
  private JTextField jtfMsg;   // for sending messages
  private JButton jbWho;       // for sending a "who" message


  public ChatClient()
  {
     super("Chat Client");
     initializeGUI();
     makeContact();

     addWindowListener( new WindowAdapter() {
       public void windowClosing(WindowEvent e)
       { closeLink(); }
     });

     setSize(300,450);
     show();
  } // end of ChatClient();


  private void initializeGUI()
  /* Text area in center, and controls below.
     Controls:
         - textfield for entering messages
         - a "Who" button
  */
  {
    Container c = getContentPane();
    c.setLayout( new BorderLayout() );

    jtaMesgs = new JTextArea(7, 7);
    jtaMesgs.setEditable(false);
    JScrollPane jsp = new JScrollPane( jtaMesgs);
    c.add( jsp, "Center");

    JLabel jlMsg = new JLabel("Message: ");
    jtfMsg = new JTextField(15);
    jtfMsg.addActionListener(this);    // pressing enter triggers sending of name/score

    jbWho = new JButton("Who");
    jbWho.addActionListener(this);

    JPanel p1 = new JPanel( new FlowLayout() );
    p1.add(jlMsg); p1.add(jtfMsg);

    JPanel p2 = new JPanel( new FlowLayout() );
    p2.add(jbWho);

    JPanel p = new JPanel();
    p.setLayout( new BoxLayout(p, BoxLayout.Y_AXIS));
    p.add(p1); p.add(p2);

    c.add(p, "South");

  }  // end of initializeGUI()


  private void closeLink()
  {
    try {
      out.println("bye");    // tell server that client is disconnecting
      sock.close();
    }
    catch(Exception e)
    {  System.out.println( e );  }

    System.exit( 0 ); 
  } // end of closeLink()

    
  private void makeContact()
  // contact the server and start a ChatWatcher thread
  {
    try {
      sock = new Socket(HOST, PORT);
      BufferedReader in  = new BufferedReader( 
		  		new InputStreamReader( sock.getInputStream() ) );
      out = new PrintWriter( sock.getOutputStream(), true );  // autoflush

      new ChatWatcher(this, in).start();    // start watching for server msgs
    }
    catch(Exception e)
    {  System.out.println(e);  }
  }  // end of makeContact()



   public void actionPerformed(ActionEvent e)
   /* Either a message is to be sent or the "Who"
      button has been pressed. */
   {
     if (e.getSource() == jbWho)
       out.println("who");   // the response is read by ChatWatcher
     else if (e.getSource() == jtfMsg)
       sendMessage();
   }


  private void sendMessage()
  /* Check if the user has supplied a message, then
     send it to the server. */
  {
    String msg = jtfMsg.getText().trim();
    // System.out.println("'"+msg+"'");

    if (msg.equals(""))
      JOptionPane.showMessageDialog( null, 
           "No message entered", "Send Message Error", 
			JOptionPane.ERROR_MESSAGE);
    else {
      out.println(msg);
      // showMsg("Sent: " + msg + "\n");
    }
  }  // end of sendMessage()


  synchronized public void showMsg(String msg)
  /* Synchronized since this method can be called by this
     object or the ChatWatcher thread. */
  { jtaMesgs.append(msg);  }


  // ------------------------------------

  public static void main(String args[]) 
  {  new ChatClient();  }

} // end of ChatClient class