GetMailApp.java

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import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowEvent;

import javax.swing.GroupLayout;
import javax.swing.JButton;
import javax.swing.JCheckBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JEditorPane;
import javax.swing.JTextField;
import javax.swing.LayoutStyle;
import javax.swing.SwingUtilities;
import javax.swing.WindowConstants;
import javax.swing.GroupLayout.Alignment;
import javax.swing.plaf.metal.MetalBorders;

/**
 *  Simple POP3 get mail application that demonstrates usage of the MessageStore class
 *  (based on Javamail package), which instances are used to retrieve e-mail messages 
 *  from the pop3 store in background.
 *  
 *  @author Mikica B Kocic
 */
public class GetMailApp extends JFrame 
    implements ActionListener
{
    /**
     *  Implements java.io.Serializable interface
     */
    private static final long serialVersionUID = -5231008427555021088L;

    /**
     *  Common application title prefix.
     */
    private final static String appTitle = "IP1-6.2: POP3 Get Mail";
    
    /**
     *  GUI components
     */
    private JButton     buttonReceive;
    private JLabel      labelServer;
    private JTextField  fieldServer;
    private JLabel      labelUsername;
    private JTextField  fieldUsername;
    private JLabel      labelPassword;
    private JTextField  fieldPassword;
    private JScrollPane messageScrollPane;
    private JEditorPane messageContents;
    private JCheckBox   showContents;
    
    /**
     *  Creates an instance of the get mail application GUI.
     */
    public GetMailApp ()
    {
        super( appTitle );
            
        setDefaultCloseOperation( WindowConstants.EXIT_ON_CLOSE );
        
        /////////////////////////////////////////////////////// GUI COMPONENTS ///////////
        
        addWindowListener( new java.awt.event.WindowAdapter () {
            public void windowClosing( java.awt.event.WindowEvent evt ) {
                formWindowClosing( evt );
            }
        });

        buttonReceive  = new JButton ();
        labelServer    = new JLabel( "POP3 Server:" );
        fieldServer    = new JTextField ();
        labelUsername  = new JLabel( "Username:" );
        fieldUsername  = new JTextField ();
        labelPassword  = new JLabel( "Password:" );
        fieldPassword  = new JTextField ();
        showContents   = new JCheckBox( "Contents" );

        messageContents = new JEditorPane ();
        messageContents.setEditable( false );

        messageScrollPane = new JScrollPane ();
        messageScrollPane.setViewportView( messageContents );

        buttonReceive.setText( "Receive" );
        buttonReceive.addActionListener( this );
        
        showContents.setSelected( false );

        /////////////////////////////////////////////////////// FONTS ////////////////////

        Font btnFont  = new Font( Font.SANS_SERIF, Font.BOLD,  12 );
        Font textFont = new Font( Font.SANS_SERIF, Font.PLAIN, 12 );
        Font monoFont = new Font( Font.MONOSPACED, Font.PLAIN, 14 );
        
        buttonReceive.setFont( btnFont );
        labelServer.setFont( textFont );
        labelUsername.setFont( textFont );
        labelPassword.setFont( textFont );
        fieldServer.setFont( textFont );
        fieldUsername.setFont( textFont );
        fieldPassword.setFont( textFont );
        messageContents.setFont( monoFont );
        messageContents.setBackground( new Color( 255, 255, 240 ) );

        /////////////////////////////////////////////////////// COMPONENTS LAYOUT ////////

        JPanel authenticationPane = new JPanel (); 
        authenticationPane.setBorder( new MetalBorders.Flush3DBorder() );
        
        //////////////////////////////////////////////////////////////////////////////////
        
        /* Layout (self explained?): 
         *     Upper: fieldServer, fieldUsername, fieldPassword, buttonReceive,
         *            showContents checkbox
         *     Lower: messageContents scroll pane
         */
        GroupLayout layout = new GroupLayout( getContentPane () );
        getContentPane().setLayout( layout );
        layout.setAutoCreateContainerGaps( true );
        layout.setAutoCreateGaps( true );

        layout.setHorizontalGroup
        (
            layout
            .createParallelGroup( Alignment.LEADING )
            .addGroup
            ( 
                layout
                .createSequentialGroup ()
                .addGroup
                ( 
                    layout
                    .createParallelGroup( Alignment.LEADING )
                    .addGroup
                    (
                        Alignment.TRAILING, 
                        layout
                        .createSequentialGroup ()
                        .addComponent( labelServer )
                        .addGap( 5 )
                        .addComponent( fieldServer, 120, 120, 2000  )
                        .addPreferredGap( LayoutStyle.ComponentPlacement.RELATED )
                        .addComponent( labelUsername )
                        .addGap( 5 )
                        .addComponent( fieldUsername )
                        .addPreferredGap( LayoutStyle.ComponentPlacement.RELATED )
                        .addComponent( labelPassword )
                        .addGap( 5 )
                        .addComponent( fieldPassword )
                        .addGap( 25 )
                        .addComponent( buttonReceive )
                        .addGap( 5 )
                        .addComponent( showContents )
                    )
                    .addComponent( messageScrollPane )
                )
            )
        );
        
        layout.setVerticalGroup
        (
            layout
            .createParallelGroup( Alignment.LEADING )
            .addGroup
            (
                layout
                .createSequentialGroup ()
                .addGroup
                (
                    layout
                    .createParallelGroup( Alignment.CENTER )
                    .addComponent( labelServer )
                    .addComponent( fieldServer, Alignment.CENTER, 25, 25, 25 )
                    .addComponent( labelUsername )
                    .addComponent( fieldUsername, Alignment.CENTER, 25, 25, 25 )
                    .addComponent( labelPassword )
                    .addComponent( fieldPassword, Alignment.CENTER, 25, 25, 25 )
                    .addComponent( buttonReceive, Alignment.CENTER, 25, 25, 25 )
                    .addComponent( showContents )
                )
                .addPreferredGap( LayoutStyle.ComponentPlacement.UNRELATED )
                .addComponent( messageScrollPane )
            )
        );
        
        pack();
        
        /////////////////////////////////////////////////////// WINDOW PLACEMENT /////////
        
        /* Adjust window dimensions not to exceed screen dimensions ...
         */
        Dimension win = new Dimension( 1024, 600 );
        Dimension scsz = Toolkit.getDefaultToolkit().getScreenSize();
        win.width  = Math.min( win.width, scsz.width );
        win.height = Math.min( win.height, scsz.height - 40 );
        setSize( win );
        setMinimumSize( new Dimension( 700, 500 ) );
        
        /* ... then center window on the screen.
         */
        setLocation( ( scsz.width - win.width )/2, ( scsz.height - 40 - win.height )/2 );
        
        /* Show usage...
         */
        messageContents.setForeground( Color.BLUE );
        messageContents.setText( "\n"
                + "  To get messages from POP3 server:\n\n"
                + "    1) Enter server's hostname or IP address\n" 
                + "    2) Enter your credentials\n"
                + "    3) Click 'Receive'.\n\n"
                + "  By default, messages' contents is not displayed.\n"
                + "  To display the contents, turn on the 'Contents' check-box.\n"
                );

        /* Ready for user to type in...
         */
        fieldServer.requestFocus ();
    }

    /**
     *  Closes application
     * 
     *  @param evt
     */
    private void formWindowClosing( WindowEvent evt )
    {
        System.exit( 0 );
    }

    /**
     *  Handles buttonReceive events
     */
    public void actionPerformed( ActionEvent evt )
    {
        if ( fieldServer.getText().isEmpty () || fieldUsername.getText().isEmpty () ) {
            return;
        }

        messageContents.setContentType( "text/html" );
        messageContents.setText( 
                "<html><head></head><body><h3>Receiving...</h3></body></html>" );
        buttonReceive.setEnabled( false );

        new MessageStore (
                this,
                fieldServer.getText (),
                fieldUsername.getText (),
                fieldPassword.getText (),
                showContents.isSelected ()
                );
    }

    /**
     *  Call-back from the MessageStore instance. Displays HTML formatted contents of the
     *  MessageStore (that might have error messages).
     */
    public void onGetMessagesCompleted( StringBuffer outs )
    {
        final String str = outs.toString ();

        SwingUtilities.invokeLater( new Runnable () {
            public void run () {
                messageContents.setContentType( "text/html" );
                messageContents.setText( str );
                buttonReceive.setEnabled( true );
            }
        } );
    }

    /**
     *  Main entry point. Creates instance of <code>GetMailApp</code> application.
     *  
     *  @param args the command line arguments
     */
    public static void main( String args[] ) 
    {
        java.awt.EventQueue.invokeLater( 
                new Runnable() {
                    public void run() {
                        new GetMailApp ().setVisible( true );
                    }
                }
            );
    }
}

/*! 
 *  \mainpage Simple POP3 Client
 *
 *  \section s_intro Introduction
 *  
 *  The package implements solution to \ref p_task as a part of 
 *  the <a href="http://dsv.su.se/utbildning/distans/ip1" target="_blank"><b>SU/IP1 
 *  course</b></a>.
 *  
 *  \image html getMailApp.png
 *  
 *  \section s_desc Description
 *
 *  The get mail application demonstrates usage of the MessageStore class,
 *  which is built on the top of 
 *  <a href="http://www.oracle.com/technetwork/java/index-jsp-139225.html" target="_blank">
 *  <b>Javamail</b></a> extension to JDK.
 *  
 *  The instances of the MessageStore are used to retrieve e-mail messages 
 *  from the pop3 store in background. Messages are formatted in HTML and displayed
 *  in the scrollable <code>JEditorPane</code> of the GetMailApp class, which implements
 *  the GUI for the application.
 *  
 *  User may choose not to display contents of the retrieved messages by turning off 
 *  'Contents' check-box.
 *  
 *  \section s_jar Executable
 *  
 *  The jar file of the package can be found 
 *  <a href="../getMail.jar"><b>here</b></a>.
 *  
 *  The jar also includes repacked <code>mail.jar</code> retrieved from 
 *  <a href="http://www.oracle.com/technetwork/java/index-138643.html" target="_blank">
 *  JavaMail 1.4.3</a>.
 *  
 *  \section s_src Sources
 *  
 *  Source files:
 *   - \ref MessageStore.java
 *   - \ref GetMailApp.java
 *
 */
/*! \page p_task IP1-6.2 Uppgift
 *  
 *  Gör ett fristående program med ett grafiskt användargränssnitt som med hjälp av 
 *  JDK-extensionen Javamail kan mottaga e-post. Användaren ska kunna skriva in 
 *  följande:
 *  
 *   - Mail-server
 *   - Användare
 *   - Password 
 */