URL page = item.getPage();                if (! page.equals(pageItem.getPage())) {                    setPage(page);                }            }        }    }    /**     * Load URL into the current page item.  If the cached page item exists for     * the given URL, use it; otherwise create new page item.     */    void setPage(URL url) {        PageItem item = pageCache.get(url);        if (item == null) {            item = createPageItem(url);            pageCache.put(url, item);        }        if (pageItem != null) {            Container p = pageItem.getParent();            if (p != null) {                p.remove(pageItem);                p.add(item);            }        }        pageItem = item;        updateSelectedPages();    }    /**     * Synchronize the selection in the print list with the current page item.     * If the current page item isn't in the print list, clear selection.     */    void updateSelectedPages() {        ListModel pages = selectedPages.getModel();        int n = pages.getSize();        if (n > 0) {            URL page = pageItem.getPage();            int index = selectedPages.getSelectedIndex();            if (index >= 0) {                PageItem selected = (PageItem) pages.getElementAt(index);                if (page.equals(selected.getPage())) {                    // Currently displayed page is selected in the print list.                    return;                }            }            for (int i = 0; i < n; i++) {                PageItem pi = (PageItem) pages.getElementAt(i);                if (page.equals(pi.getPage())) {                    // Currently displayed page is in the print list, select it.                    selectedPages.setSelectedIndex(i);                    return;                }            }            // Currently displayed page is not in the print list.             selectedPages.clearSelection();        }    }    /* Part 3: Initialization and setup.  */        /**     * Create and return a page item initialized with the given URL.     */    PageItem createPageItem(URL url) {        PageItem item = new PageItem();        item.setPreferredSize(new Dimension(800, 600));        item.setEditable(false);        item.addHyperlinkListener(this);        try {            item.setPage(url);        } catch (IOException ioe) {            messageArea.setText("Error loading " + url + ": " + ioe);        }        return item;    }    /**     * Create and return a menu item with the specified action, mnemonics and     * keyboad accelerator.     */    JMenuItem createMenuItem(Action action, int mnemonics, KeyStroke accel) {        JMenuItem item = new JMenuItem(action);        item.setMnemonic(mnemonics);        item.setAccelerator(accel);        return item;    }        /**     * Create and display the main application frame.     */    void createAndShowGUI() {        messageArea = new JLabel(defaultMessage);                selectedPages = new JList(new DefaultListModel());        selectedPages.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);        selectedPages.addListSelectionListener(this);                setPage(homePage);                JSplitPane pane = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT,                new JScrollPane(pageItem), new JScrollPane(selectedPages));                JMenu fileMenu = new JMenu("File");        fileMenu.setMnemonic(KeyEvent.VK_F);        /** Menu item and keyboard shortcuts for the "add page" command.  */        fileMenu.add(createMenuItem(                new AbstractAction("Add Page") {                    public void actionPerformed(ActionEvent e) {                        DefaultListModel pages =                                (DefaultListModel) selectedPages.getModel();                        pages.addElement(pageItem);                        selectedPages.setSelectedIndex(pages.getSize() - 1);                   }                },                KeyEvent.VK_A,                 KeyStroke.getKeyStroke(KeyEvent.VK_A, ActionEvent.ALT_MASK)));        /** Menu item and keyboard shortcuts for the "print selected" command.*/        fileMenu.add(createMenuItem(                new AbstractAction("Print Selected") {                    public void actionPerformed(ActionEvent e) {                        printSelectedPages();                    }                },                KeyEvent.VK_P,                 KeyStroke.getKeyStroke(KeyEvent.VK_P, ActionEvent.ALT_MASK)));        /** Menu item and keyboard shortcuts for the "clear selected" command.*/        fileMenu.add(createMenuItem(                new AbstractAction("Clear Selected") {                    public void actionPerformed(ActionEvent e) {                        DefaultListModel pages =                                (DefaultListModel) selectedPages.getModel();                        pages.removeAllElements();                    }                },                KeyEvent.VK_C,                 KeyStroke.getKeyStroke(KeyEvent.VK_C, ActionEvent.ALT_MASK)));        fileMenu.addSeparator();        /** Menu item and keyboard shortcuts for the "home page" command.  */        fileMenu.add(createMenuItem(                new AbstractAction("Home Page") {                    public void actionPerformed(ActionEvent e) {                        setPage(homePage);                    }                },                KeyEvent.VK_H,                 KeyStroke.getKeyStroke(KeyEvent.VK_H, ActionEvent.ALT_MASK)));	/** Menu item and keyboard shortcuts for the "quit" command.  */        fileMenu.add(createMenuItem(                new AbstractAction("Quit") {                    public void actionPerformed(ActionEvent e) {                        for (Window w : Window.getWindows()) {                            w.dispose();                        }                    }                },                KeyEvent.VK_A,                 KeyStroke.getKeyStroke(KeyEvent.VK_Q, ActionEvent.ALT_MASK)));        JMenuBar menuBar = new JMenuBar();        menuBar.add(fileMenu);                JPanel contentPane = new JPanel();        contentPane.setLayout(new BoxLayout(contentPane, BoxLayout.Y_AXIS));        contentPane.add(pane);        contentPane.add(messageArea);        JFrame frame = new JFrame("Text Batch Printing Demo");        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);        frame.setJMenuBar(menuBar);        frame.setContentPane(contentPane);        frame.pack();        frame.setLocationRelativeTo(null);        frame.setVisible(true);        if (printService == null) {            // Actual printing is not possible, issue a warning message.            JOptionPane.showMessageDialog(frame, "No default print service",                            "Print Service Alert", JOptionPane.WARNING_MESSAGE);        }    }    public static void main(String[] args) {        final TextBatchPrintingDemo demo = new TextBatchPrintingDemo();        demo.homePage = demo.getClass().getResource(defaultPage);        // Custom home page can be specified on the command line.        if (args.length > 0) {            String pageName = args[0];            try {                URL url = new URL(pageName);                demo.homePage = url;            } catch (MalformedURLException e) {                System.out.println("Error parsing " + pageName + ": " + e);                // Home page is unchanged from the default value.            }        }        //Schedule a job for the event dispatch thread:        //creating and showing this application's GUI.        SwingUtilities.invokeLater(new Runnable() {            public void run() {                //Turn off metal's use of bold fonts                UIManager.put("swing.boldMetal", Boolean.FALSE);                demo.createAndShowGUI();            }        });    }}