clientgui.java

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// ClientGUI.java
// ClientGUI provides a GUI for sending and receiving 
// chat messages using a MessageManager.
package com.deitel.messenger;

// Java core packages
import java.awt.*;
import java.awt.event.*;
import java.util.*;

// Java extension packages
import javax.swing.*;
import javax.swing.border.*;
import javax.swing.text.*;

public class ClientGUI extends JFrame {
   
   // JLabel for displaying connection status
   private JLabel statusBar;
   
   // JTextAreas for displaying and inputting messages   
   private JTextArea messageArea;
   private JTextArea inputArea;   
    
   // Actions for connecting and disconnecting MessageManager 
   // and sending messages
   private Action connectAction;
   private Action disconnectAction;
   private Action sendAction;

   // userName to add to outgoing messages
   private String userName = "";
   
   // MessageManager for communicating with server
   MessageManager messageManager;
   
   // MessageListener for receiving new messages
   MessageListener messageListener;
 
   // ClientGUI constructor
   public ClientGUI( MessageManager manager )
   {      
      super( "Deitel Messenger" );      
      
      messageManager = manager;
      
      messageListener = new MyMessageListener();
      
      // create Actions
      connectAction = new ConnectAction();
      disconnectAction = new DisconnectAction();
      disconnectAction.setEnabled( false );
      sendAction = new SendAction();
      sendAction.setEnabled( false );

      // set up File menu
      JMenu fileMenu = new JMenu ( "File" );   
      fileMenu.setMnemonic( 'F' );
      fileMenu.add( connectAction );
      fileMenu.add( disconnectAction );

      // set up JMenuBar and attach File menu
      JMenuBar menuBar = new JMenuBar();
      menuBar.add ( fileMenu );  
      setJMenuBar( menuBar );     
      
      // set up JToolBar
      JToolBar toolBar = new JToolBar();
      toolBar.add( connectAction );
      toolBar.add( disconnectAction );   
            
      // create JTextArea for displaying messages  
      messageArea = new JTextArea( 15, 15 );      
      
      // disable editing and wrap words at end of line
      messageArea.setEditable( false );
      messageArea.setLineWrap( true );
      messageArea.setWrapStyleWord( true );
      
      JPanel panel = new JPanel();
      panel.setLayout( new BorderLayout( 5, 5 ) );
      panel.add( new JScrollPane( messageArea ), 
         BorderLayout.CENTER );
   
      // create JTextArea for entering new messages
      inputArea = new JTextArea( 3, 15 );
      inputArea.setLineWrap( true );
      inputArea.setWrapStyleWord( true );
      inputArea.setEditable( false );
      
      // map Enter key in inputArea to sendAction
      Keymap keyMap = inputArea.getKeymap();
      KeyStroke enterKey = KeyStroke.getKeyStroke( 
         KeyEvent.VK_ENTER, 0 );
      keyMap.addActionForKeyStroke( enterKey, sendAction );
     
      // lay out inputArea and sendAction JButton in BoxLayout 
      // and add Box to messagePanel
      Box box = new Box( BoxLayout.X_AXIS );
      box.add( new JScrollPane( inputArea ) );
      box.add( new JButton( sendAction ) );
      
      panel.add( box, BorderLayout.SOUTH );
      
      // create statusBar JLabel with recessed border
      statusBar = new JLabel( "Not Connected" );
      statusBar.setBorder( 
         new BevelBorder( BevelBorder.LOWERED ) );

      // lay out components
      Container container = getContentPane();
      container.add( toolBar, BorderLayout.NORTH );
      container.add( panel, BorderLayout.CENTER );
      container.add( statusBar, BorderLayout.SOUTH );
      
      // disconnect and exit if user closes window
      addWindowListener(
      
         new WindowAdapter() {
            
            // disconnect MessageManager when window closes
            public void windowClosing( WindowEvent event ) 
            {
               // disconnect from chat server
               try {
                  messageManager.disconnect( messageListener );
               }
               
               // handle exception disconnecting from server
               catch ( Exception exception ) {
                  exception.printStackTrace();
               }
               
               System.exit( 0 );
               
            } // end method windowClosing

         } // end WindowAdapter inner class
      );
      
   } // end ClientGUI constructor
   
   // Action for connecting to server
   private class ConnectAction extends AbstractAction {
      
      // configure ConnectAction 
      public ConnectAction() 
      {
         putValue( Action.NAME, "Connect" );
         putValue( Action.SMALL_ICON, new ImageIcon( 
            ClientGUI.class.getResource( 
               "images/Connect.gif" ) ) );
         putValue( Action.SHORT_DESCRIPTION,  
            "Connect to Server" );
         putValue( Action.LONG_DESCRIPTION, 
            "Connect to server to send Instant Messages" );
         putValue( Action.MNEMONIC_KEY, new Integer( 'C' ) );
      }
      
      // connect to server
      public void actionPerformed( ActionEvent event ) 
      {          
         // connect MessageManager to server
         try {    
            
            // clear messageArea
            messageArea.setText( "" );         
            
            // connect MessageManager and register MessageListener
            messageManager.connect( messageListener );
            
            // listen for disconnect notifications
            messageManager.setDisconnectListener( 
               new DisconnectHandler() );

            // get desired userName
            userName = JOptionPane.showInputDialog( 
               ClientGUI.this, "Please enter your name: " );

            // update Actions, inputArea and statusBar
            connectAction.setEnabled( false );
            disconnectAction.setEnabled( true );
            sendAction.setEnabled( true );
            inputArea.setEditable( true );
            inputArea.requestFocus();  
            statusBar.setText( "Connected: " + userName );   

            // send message indicating user connected
            messageManager.sendMessage( userName, userName + 
               " joined chat" );
            
         } // end try
         
         // handle exception connecting to server
         catch ( Exception exception ) {
            JOptionPane.showMessageDialog( ClientGUI.this,
               "Unable to connect to server.", "Error Connecting",
               JOptionPane.ERROR_MESSAGE );

            exception.printStackTrace();
         }
         
      }  // end method actionPerformed   
      
   } // end ConnectAction inner class

   // Action for disconnecting from server
   private class DisconnectAction extends AbstractAction {
      
      // configure DisconnectAction
      public DisconnectAction()
      {
         putValue( Action.NAME, "Disconnect" );
         putValue( Action.SMALL_ICON, new ImageIcon( 
            ClientGUI.class.getResource( 
               "images/Disconnect.gif" ) ) );
         putValue( Action.SHORT_DESCRIPTION, 
            "Disconnect from Server" );
         putValue( Action.LONG_DESCRIPTION, 
            "Disconnect to end Instant Messaging session" );
         putValue( Action.MNEMONIC_KEY, new Integer( 'D' ) );
      }

      // disconnect from server
      public void actionPerformed( ActionEvent event ) 
      { 
         // disconnect MessageManager from server
         try {
            
            // send message indicating user disconnected
            messageManager.sendMessage( userName, userName + 
               " exited chat" );

            // disconnect from server and unregister 
            // MessageListener
            messageManager.disconnect( messageListener );            

            // update Actions, inputArea and statusBar
            sendAction.setEnabled( false );
            disconnectAction.setEnabled( false );
            inputArea.setEditable( false );
            connectAction.setEnabled( true );
            statusBar.setText( "Not Connected" );
            
         } // end try
         
         // handle exception disconnecting from server
         catch ( Exception exception ) {
            JOptionPane.showMessageDialog( ClientGUI.this,
               "Unable to disconnect from server.", 
               "Error Disconnecting", JOptionPane.ERROR_MESSAGE );

            exception.printStackTrace();
         }  
         
      } // end method actionPerformed
      
   } // end DisconnectAction inner class
   
   // Action for sending messages
   private class SendAction extends AbstractAction {
      
      // configure SendAction
      public SendAction()
      {
         putValue( Action.NAME, "Send" ) ;
         putValue( Action.SMALL_ICON, new ImageIcon( 
            ClientGUI.class.getResource( "images/Send.gif" ) ) );
         putValue( Action.SHORT_DESCRIPTION, "Send Message" );
         putValue( Action.LONG_DESCRIPTION, 
            "Send an Instant Message" );
         putValue( Action.MNEMONIC_KEY, new Integer( 'S' ) );      
      }
      
      // send message and clear inputArea
      public void actionPerformed( ActionEvent event ) 
      {
         // send message to server
         try {
            
            // send userName and text in inputArea
            messageManager.sendMessage( userName, 
               inputArea.getText() );

            inputArea.setText( "" );
         }

         // handle exception sending message
         catch ( Exception exception ) {
            JOptionPane.showMessageDialog( ClientGUI.this,
               "Unable to send message.", "Error Sending Message", 
               JOptionPane.ERROR_MESSAGE );            

            exception.printStackTrace();
         }                     
         
      } // end method actionPerformed
      
   } // end SendAction inner class
   
   // MyMessageListener listens for new messages from the
   // MessageManager and displays the messages in messageArea
   // using a MessageDisplayer.
   private class MyMessageListener implements MessageListener {

      // when new message received, display in messageArea
      public void messageReceived( String from, String message ) 
      {
         // append message using MessageDisplayer and invokeLater 
         // to ensure thread-safe access to messageArea
         SwingUtilities.invokeLater( 
            new MessageDisplayer( from, message ) );
      } 
      
   }  // end MyMessageListener inner class 
   
   // MessageDisplayer displays a new messaage by appending
   // the message to the messageArea JTextArea. This Runnable 
   // object should be executed only on the event-dispatch 
   // thread, as it modifies a live Swing component.
   private class MessageDisplayer implements Runnable {
      
      private String fromUser;
      private String messageBody;
      
      // MessageDisplayer constructor
      public MessageDisplayer( String from, String body )
      {
         fromUser = from;
         messageBody = body;
      }
      
      // display new message in messageArea
      public void run() 
      {
         // append new message
         messageArea.append( "\n" + fromUser + "> " + 
            messageBody );   

         // move caret to end of messageArea to ensure new 
         // message is visible on screen
         messageArea.setCaretPosition( 
            messageArea.getText().length() );                          
      }      
      
   } // end MessageDisplayer inner class   
   
   // DisconnectHandler listens for serverDisconnected messages
   // from the MessageManager and updates the user interface.
   private class DisconnectHandler implements DisconnectListener {
   
      // receive disconnect notifcation
      public void serverDisconnected( final String message ) 
      {
         // update GUI in thread-safe manner
         SwingUtilities.invokeLater( 

            new Runnable() {

               // update Actions, inputs and status bar
               public void run() 
               {               
                  sendAction.setEnabled( false );
                  disconnectAction.setEnabled( false );
                  inputArea.setEditable( false );
                  connectAction.setEnabled( true );
                  statusBar.setText( message );
               }
               
            } // end Runnable inner class
         );
         
      } // end method serverDisconnected  
   
   } // end DisconnectHandler inner class
}

/**************************************************************************
 * (C) Copyright 2001 by Deitel & Associates, Inc. and Prentice Hall.     *
 * All Rights Reserved.                                                   *
 *                                                                        *
 * DISCLAIMER: The authors and publisher of this book have used their     *
 * best efforts in preparing the book. These efforts include the          *
 * development, research, and testing of the theories and programs        *
 * to determine their effectiveness. The authors and publisher make       *
 * no warranty of any kind, expressed or implied, with regard to these    *
 * programs or to the documentation contained in these books. The authors *
 * and publisher shall not be liable in any event for incidental or       *
 * consequential damages in connection with, or arising out of, the       *
 * furnishing, performance, or use of these programs.                     *
 *************************************************************************/