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

/**
  * This program illustrates the creation of a JDialog subclass.
  * It follows the example of a request to the user to input a URL
  * address.
  *
  * The applet uses a JFrame subclass with a menubar and buttons
  * that can create an instance of GetUrlDialog, which is a subclass
  * of JDialog. It will pass the URL text back to the frame using
  * a method from the TextSetable interface.
 **/
public class MakeJDialogApplet extends JApplet
       implements ActionListener
{
  public void init () {
    Container content_pane = getContentPane ();

    JPanel panel = new JPanel (new BorderLayout ());

    JButton button_open = new JButton ("Open");
    button_open.addActionListener (this);
    panel.add (button_open, "Center");
    content_pane.add (panel);

  } // init

  //  Open the frame
  public void actionPerformed (ActionEvent e ) {
    String command = e.getActionCommand ();
    if (command.equals ("Open")) {
        // Create an instance of the frame and show it.
        MakeJDialogFrame f =  new MakeJDialogFrame (this);
        f.setVisible (true);
    }
  } // actionPerformed

} // class MakeJDialogApplet

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

/** This frame uses the TextSetable interface for a call
  * back from the dialog to provide URL text.
 **/
public class MakeJDialogFrame extends JFrame
             implements ActionListener, TextSetable
{
  // Keep a reference to the applet parent.
  MakeJDialogApplet fApplet;
  JLabel fLabel;

  int URL_TEXT = 1;

  /** Create the frame with a couple of buttons and
    * a menubar with one dropdown menu.
   **/
  MakeJDialogFrame (MakeJDialogApplet applet) {
    super ("Frame Test");
    fApplet = applet;

    Container content_pane = getContentPane ();

    // Create a simple interface.
    content_pane.setLayout ( new GridLayout (2,1) );

    content_pane.add (fLabel =
      new JLabel ("http://www.default.com",JLabel.CENTER));

    JPanel panel = new JPanel ();

    JButton button1 = new JButton ("Get URL");
    button1.addActionListener (this);

    JButton button_quit = new JButton ("Quit");
    button_quit.addActionListener (this);

    panel.add (button1);
    panel.add (button_quit);
    content_pane.add (panel);

    // Use the helper method makeMenuItem
    // for making the menu items and registering
    // their listener.
    JMenu m = new JMenu ("Tasks");

    // Menu items for the drop down menu.
    m.add (makeMenuItem ("Get URL"));
    m.add (makeMenuItem ("Quit"));

    JMenuBar mb = new JMenuBar ();
    mb.add (m);

    setJMenuBar (mb);
    pack ();

  } // ctor

  // Override the TextSetable method with this concrete version
  // which gets the URL from the dialog.
  public void setText (int textID, String text) {
    if (textID == URL_TEXT) {
      fLabel.setText (text);
    }
  } // setText

  //
  public void actionPerformed (ActionEvent e) {
    String command = e.getActionCommand ();
    if (command.equals ("Get URL")) {
        // Open a dialog to get the text for a URL
        GetUrlDialog getUrl =
        new GetUrlDialog (this, this, URL_TEXT,
                          fLabel.getText (),
                          true, "Input URL");
    } else if (command.equals ("Quit")) {
        dispose ();
    }
  } // actionPerformed

  // This "helper method" makes a menu item and then
  // registers this applet as a listener to it.
  private JMenuItem makeMenuItem (String name) {
    JMenuItem m = new JMenuItem ( name );
    m.addActionListener ( this );
    return m;
  }

} // class MakeJDialogFrame

/** This interface provides for a callback to pass text. **/
interface TextSetable
{
  /** The textID allows the receiving class to
    * identify what the text represents using its
    * own ID numbering scheme.
   **/
  void setText(int textID, String text);

} // interface TextSetable

import java.util.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

/**
  * This program illustrates how to create a dialog by
  * subclassing JDialog. Here we use the example of obtaining
  * a URL from the user. Provides a dialog to enter URL
  * for the downloading a story over the web.
**/
public class GetUrlDialog extends JDialog implements ActionListener
{
//+++++++++++++++++++++++++++++++++++++++++++++++++++++++++GetUrlDialog+++++++++
  JFrame fParent;

  JTextField fUrlField;
  String fUrlData;

  Container fContainer;
  GridBagLayout fGridBag;
  GridBagConstraints fGBC = new GridBagConstraints ();

  JButton fButtonOK;
  JButton fButtonHelp;

  TextSetable fUrlRequestor; // Use TextSetable interface for callback
  int fTextID = 0; // Type of text

  //-------------------------------------------------------GetUrlDialog---------
  public GetUrlDialog (JFrame frame,
                      TextSetable urlRequestor, int textID,
                      String urlData,
                      boolean modal, String title) {
    // Call the JDialog constructor.
    super (frame, title, modal);
    fUrlData = urlData;
    fParent = frame;

    // Get requestor for call back
    fUrlRequestor = urlRequestor;
    fTextID = textID;

    fContainer = this.getContentPane ();

    // Set the background color of DateDialog.
    fContainer.setBackground (Color.white);

    //  Create a confirmation button.
    fButtonOK = new JButton ("OK");
    fButtonOK.setMnemonic ('O');
    fButtonOK.setPreferredSize (new Dimension (70, 25));
    fButtonOK.addActionListener (this);

    //  Create a cancel button.
    JButton button_cancel = new JButton ("Cancel");
    button_cancel.setMnemonic ('C');
    button_cancel.setPreferredSize (new Dimension (75, 25));
    button_cancel.addActionListener (this);

    //  Create a help button.
    fButtonHelp = new JButton ("Help");
    fButtonHelp.setMnemonic ('H');
    fButtonHelp.setPreferredSize (new Dimension (70, 25));
    fButtonHelp.addActionListener (this);

    //  Create a panel to hold the buttons
    JPanel button_panel = new JPanel ();
    button_panel.setBackground (Color.white);
    button_panel.add (fButtonOK);
    button_panel.add (button_cancel);
    button_panel.add (fButtonHelp);

    //  Use a gridbag layout for the contentpane
    fGridBag = new GridBagLayout ();
    fContainer.setLayout (fGridBag);

    //
    fGBC.fill = GridBagConstraints.BOTH;
    fGBC.gridwidth=6; fGBC.gridheight=1;
    fGBC.weightx=1; fGBC.weighty=1;
    fGBC.insets = new Insets (10,20,10,20);

    addGB (button_panel, 0,1);

    // Give the labels a small weightx and a
    // width of 1 to push them to the left
    fGBC.weightx=0.10; fGBC.weighty=1.0;
    fGBC.gridwidth=1; fGBC.gridheight=1;
    fGBC.insets = new Insets (0,0,0,10);
    JLabel label = new JLabel ("URL",SwingConstants.RIGHT);
    addGB (label,0,0);

    // Give the textfields a large weightx and a
    // width of 5 so they will have a long x width
    fGBC.weightx=1.0; fGBC.weighty=1.0;
    fGBC.insets = new Insets (10,0,10,10);
    fGBC.gridwidth=5; fGBC.gridheight=1;
    fUrlField  = new JTextField ();
    addGB (fUrlField,1,0);

    fUrlField.setText (fUrlData);

    // Resize the dialog box and position it at the center of
    // the applet.
    setSize (300,125);
    Dimension dialogDim = getSize ();
    Dimension frameDim = frame.getSize ();
    Dimension screenSize = getToolkit ().getScreenSize ();
    Point location = frame.getLocation ();
    location.translate (
             (frameDim.width-dialogDim.width)/2,
             (frameDim.height-dialogDim.height)/2);
    location.x = Math.max ( 0, Math.min (location.x,
                             screenSize.width-getSize ().width));
    location.y = Math.max (0, Math.min (location.y,
                             screenSize.height-getSize ().height));

    setLocation (location.x, location.y);

    setVisible (true);
  } // ctor

  //-------------------------------------------------------addGB----------------
  public void addGB (Component component, int x, int y) {
    fGBC.gridx=x; fGBC.gridy = y;
    fGridBag.setConstraints (component, fGBC);
    fContainer.add (component);
  } // addGB

  //-------------------------------------------------------actionPerformed------
  /** When the OK button on the dialog box is clicked. **/
  public void actionPerformed (ActionEvent e) {
    if (e.getSource () == fButtonOK)  {
        fUrlData = fUrlField.getText ().trim ();

        // Check the entry for proper length and form.
        if (fUrlData.length () == 0) {
            JOptionPane.showMessageDialog (null,
               "Empty URL entry!", "Input Error",
            JOptionPane.ERROR_MESSAGE);
            return;
        }

        // Use the URL class to determine if the URL
        // entry is in proper form.
        try {
          java.net.URL url = new java.net.URL (fUrlData);
        }
        catch (java.net.MalformedURLException ex) {
           JOptionPane.showMessageDialog (null,
             "Malformed URL entry!", "Input Error",
              JOptionPane.ERROR_MESSAGE);
           return;
        }

        // Pass the URL back to the caller. Use the fTextID
        // number to let caller know what type of text is being
        // passed.
        fUrlRequestor.setText (fTextID, fUrlData);

    } else if (e.getSource () == fButtonHelp) {
        JOptionPane.showMessageDialog (null,
                   "Help message...");
        return; // Don't close dialog
    }
    // Close dialog after OK or Cancel button clicked
    this.dispose ();
  } // actionPerformed

} // GetUrlDialog

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