/*
 * Copyright 2008 Sun Microsystems, Inc.  All Rights Reserved.
 *
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 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   - Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 *   - Neither the name of Sun Microsystems nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

import java.awt.*;
import java.awt.event.*;
import java.awt.font.*;
import java.net.*;
import javax.swing.*;
import netscape.javascript.JSObject;
import netscape.javascript.JSException;

/** Simple example of dragging applets to the desktop illustrating:
 * <UL>
 * <LI> Customization of the drag gesture via <CODE>isAppletDragStart</CODE>
 * <LI> Customization of the close button via <CODE>setAppletCloseListener</CODE>
 * <LI> Fallback of applet services like <CODE>showDocument</CODE> and <CODE>showStatus</CODE>
 * <LI> Creation of desktop shortcuts via the <CODE>&lt;shortcut&gt;</CODE> tag
 * </UL>
 *
 * Compile this example with <CODE>plugin.jar</CODE> on the compilation classpath.
 */

public class DragExample extends JApplet {
    private URL documentURL;
    private int statusCount;
    private ContentPanel panel;
    private ActionListener closeListener;

    private static final int  DRAG_BAR_HEIGHT = 12;
    private static final Font DRAG_BAR_FONT = new Font("SansSerif", Font.PLAIN, 10);
    private static final String TEXT = "Click And Drag Here";

    class ContentPanel extends JPanel {
        private boolean gotTextWidth;
        private int textWidth;

        public ContentPanel() {
            super();
            setBackground(Color.GRAY);
            addMouseListener(new MouseAdapter() {
                    public void mouseClicked(MouseEvent e) {
                        if (closeListener != null) {
                            if (e.getButton() == MouseEvent.BUTTON1 &&
                                e.getY() <= DRAG_BAR_HEIGHT &&
                                e.getX() >= (getWidth() - DRAG_BAR_HEIGHT)) {
                                // Shut ourselves down
                                closeListener.actionPerformed(null);
                            }
                        }
                    }
                });
        }

        protected void paintComponent(Graphics graphics) {
            super.paintComponent(graphics);
            Graphics2D g = (Graphics2D) graphics;
            int width = getWidth();
            int height = getHeight();
            // Draw the red bar and text
            g.setColor(Color.RED);
            g.fillRect(0, 0, width, DRAG_BAR_HEIGHT);
            g.setColor(Color.WHITE);
            g.setFont(DRAG_BAR_FONT);
            if (!gotTextWidth) {
                FontMetrics fm = g.getFontMetrics();
                textWidth = fm.charsWidth(TEXT.toCharArray(), 0, TEXT.length());
                gotTextWidth = true;
            }
            g.drawString(TEXT, (width - textWidth) / 2, DRAG_BAR_HEIGHT - 1);

            // Draw the close region
            int xLeft   = getWidth() - DRAG_BAR_HEIGHT + 1;
            int xRight  = getWidth() - 2;
            int xTop    = 1;
            int xBottom = DRAG_BAR_HEIGHT - 2;

            g.drawLine(xLeft, xTop, xRight, xBottom);
            g.drawLine(xLeft, xBottom, xRight, xTop);
        }

        public boolean isAppletDragStart(MouseEvent e) {
            // Change the drag gesture to be left-click and drag with
            // no modifier keys
            return ((e.getSource() == this ||
                     ((e.getSource() instanceof Container) &&
                      (((Container) e.getSource()).isAncestorOf(this)))) &&
                    e.getY() <= DRAG_BAR_HEIGHT &&
                    e.getX() < (getWidth() - DRAG_BAR_HEIGHT) &&
                    !e.isAltDown() &&
                    !e.isAltGraphDown() &&
                    !e.isControlDown() &&
                    !e.isMetaDown() &&
                    !e.isShiftDown());
        }
    }

    public void init() {
        try {
            try {
                JSObject win = JSObject.getWindow(this);
                documentURL =
                    new URL((String) win.eval("document.URL"));
            } catch (JSException e) {
                // When running in disconnected mode, we can't talk
                // back to the browser, so provide a reasonable
                // default
                documentURL = new URL("https://jdk6.dev.java.net/plugin2/");
            }
            SwingUtilities.invokeLater(new Runnable() {
                    public void run() {
                        // Note that if the applet has been dragged to
                        // the desktop, but the original web page of
                        // the applet is still visible, then clicking
                        // this button will replace the current web
                        // page (effectively forcing a reload),
                        // causing the applet to be disconnected. If
                        // the applet has already been disconnected,
                        // clicking this button will cause the page to
                        // be opened in a new browser window via an
                        // invocation of the system web browser. This
                        // illustrates that the
                        // AppletContext.showDocument() functionality
                        // gracefully falls back to an implementation
                        // standalone from the web browser as the
                        // applet is disconnected from the browser.
                        JButton button = new JButton("Reopen Web Page");
                        button.addActionListener(new ActionListener() {
                                public void actionPerformed(ActionEvent e) {
                                    getAppletContext().showDocument(documentURL);
                                }
                            });
                        panel = new ContentPanel();
                        panel.setLayout(new BoxLayout(panel, BoxLayout.Y_AXIS));
                        panel.add(Box.createVerticalGlue());
                        panel.add(createCenteredButton(button));
                        panel.add(Box.createVerticalGlue());

                        // Note that as long as the web page
                        // originally containing the applet is still
                        // visible, clicking this button will display
                        // the status message in the browser's status
                        // bar. Once the applet has been disconnected
                        // from the browser, the status message will
                        // be displayed in the Java Console.
                        button = new JButton("Show Applet Status");
                        button.addActionListener(new ActionListener() {
                                public void actionPerformed(ActionEvent e) {
                                    getAppletContext().showStatus("Showng Applet Status: " +
                                                                  (++statusCount));
                                }
                            });
                        panel.add(createCenteredButton(button));
                        panel.add(Box.createVerticalGlue());
                        add(panel);
                    }
                });
        } catch (MalformedURLException e) {
            throw new RuntimeException(e);
        }
    }

    private static Component createCenteredButton(JButton button) {
        Box box = Box.createHorizontalBox();
        box.add(Box.createHorizontalGlue());
        box.add(button);
        box.add(Box.createHorizontalGlue());
        return box;
    }

    //----------------------------------------------------------------------
    // Methods for interacting with the drag-and-drop support
    //

    public boolean isAppletDragStart(MouseEvent e) {
        if (panel == null) {
            return false;
        }
            
        return panel.isAppletDragStart(e);
    }

    public void setAppletCloseListener(ActionListener l) {
        closeListener = l;
    }

    public void appletRestored() {
        closeListener = null;
    }
}