www.pudn.com > jnp-src.rar > ChatClient.java

/*
 * Java Network Programming, Second Edition
 * Merlin Hughes, Michael Shoffner, Derek Hamner
 * Manning Publications Company; ISBN 188477749X
 *
 * http://nitric.com/jnp/
 *
 * Copyright (c) 1997-1999 Merlin Hughes, Michael Shoffner, Derek Hamner;
 * all rights reserved; see license.txt for details.
 */

import java.io.*; 
import java.net.*; 
import java.awt.*; 
import java.awt.event.*; 
 
public class ChatClient implements Runnable, WindowListener, ActionListener { 
  protected String host; 
  protected int port; 
  protected Frame frame; 
  protected TextArea output; 
  protected TextField input; 
   
  public ChatClient (String host, int port) { 
    this.host = host; 
    this.port = port; 
    frame = new Frame ("ChatClient [" + host + ':' + port + "]"); 
    frame.addWindowListener (this); 
    output = new TextArea (); 
    output.setEditable (false); 
    input = new TextField (); 
    input.addActionListener (this); 
    frame.add ("Center", output); 
    frame.add ("South", input); 
    frame.pack (); 
  } 
 
  protected DataInputStream dataIn; 
  protected DataOutputStream dataOut; 
  protected Thread listener; 
   
  public synchronized void start () throws IOException { 
    if (listener == null) { 
      Socket socket = new Socket (host, port); 
      try { 
        dataIn = new DataInputStream 
          (new BufferedInputStream (socket.getInputStream ())); 
        dataOut = new DataOutputStream 
          (new BufferedOutputStream (socket.getOutputStream ())); 
      } catch (IOException ex) { 
        socket.close (); 
        throw ex; 
      } 
      listener = new Thread (this); 
      listener.start (); 
      frame.setVisible (true); 
    } 
  } 
 
  public synchronized void stop () throws IOException { 
    frame.setVisible (false); 
    if (listener != null) { 
      listener.interrupt (); 
      listener = null; 
      dataOut.close (); 
    } 
  } 
 
  public void run () { 
    try { 
      while (!Thread.interrupted ()) { 
        String line = dataIn.readUTF (); 
        output.append (line + "\n"); 
      } 
    } catch (IOException ex) { 
      handleIOException (ex); 
    } 
  } 
 
  protected synchronized void handleIOException (IOException ex) { 
    if (listener != null) { 
      output.append (ex + "\n"); 
      input.setVisible (false); 
      frame.validate (); 
      if (listener != Thread.currentThread ()) 
        listener.interrupt (); 
      listener = null; 
      try { 
        dataOut.close (); 
      } catch (IOException ignored) { 
      } 
    } 
  } 
 
  public void windowOpened (WindowEvent event) { 
    input.requestFocus (); 
  } 
 
  public void windowClosing (WindowEvent event) { 
    try { 
      stop (); 
    } catch (IOException ex) { 
      ex.printStackTrace (); 
    } 
  } 
 
  public void windowClosed (WindowEvent event) {} 
  public void windowIconified (WindowEvent event) {} 
  public void windowDeiconified (WindowEvent event) {} 
  public void windowActivated (WindowEvent event) {} 
  public void windowDeactivated (WindowEvent event) {} 
 
  public void actionPerformed (ActionEvent event) { 
    try { 
      input.selectAll (); 
      dataOut.writeUTF (event.getActionCommand ()); 
      dataOut.flush (); 
    } catch (IOException ex) { 
      handleIOException (ex); 
    } 
  } 
 
  public static void main (String[] args) throws IOException { 
    if ((args.length != 1) || (args[0].indexOf (':') < 0)) 
      throw new IllegalArgumentException ("Syntax: ChatClient :"); 
    int idx = args[0].indexOf (':'); 
    String host = args[0].substring (0, idx); 
    int port = Integer.parseInt (args[0].substring (idx + 1)); 
    ChatClient client = new ChatClient (host, port); 
    client.start (); 
  } 
}