Высокоуровневое Отбрасывание

/**
 * Demonstration of the top-level {@code TransferHandler}
 * support on {@code JFrame}.
 *
 * @author Shannon Hickey
 */
public class TopLevelTransferHandlerDemo extends JFrame {
    
    private static boolean DEMO = false;

    private JDesktopPane dp = new JDesktopPane();
    private DefaultListModel listModel = new DefaultListModel();
    private JList list = new JList(listModel);
    private static int left;
    private static int top;
    private JCheckBoxMenuItem copyItem;
    private JCheckBoxMenuItem nullItem;
    private JCheckBoxMenuItem thItem;

    private class Doc extends InternalFrameAdapter implements ActionListener {
        String name;
        JInternalFrame frame;
        TransferHandler th;
        JTextArea area;

        public Doc(File file) {
            this.name = file.getName();
            try {
                init(file.toURI().toURL());
            } catch (MalformedURLException e) {
                e.printStackTrace();
            }
        }
        
        public Doc(String name) {
            this.name = name;
            init(getClass().getResource(name));
        }
        
        private void init(URL url) {
            frame = new JInternalFrame(name);
            frame.addInternalFrameListener(this);
            listModel.add(listModel.size(), this);

            area = new JTextArea();
            area.setMargin(new Insets(5, 5, 5, 5));

            try {
                BufferedReader reader = new BufferedReader(new InputStreamReader(url.openStream()));
                String in;
                while ((in = reader.readLine()) != null) {
                    area.append(in);
                    area.append("\n");
                }
                reader.close();
            } catch (Exception e) {
                e.printStackTrace();
                return;
            }

            th = area.getTransferHandler();
            area.setFont(new Font("monospaced", Font.PLAIN, 12));
            area.setCaretPosition(0);
            area.setDragEnabled(true);
            area.setDropMode(DropMode.INSERT);
            frame.getContentPane().add(new JScrollPane(area));
            dp.add(frame);
            frame.show();
            if (DEMO) {
                frame.setSize(300, 200);
            } else {
                frame.setSize(400, 300);
            }
            frame.setResizable(true);
            frame.setClosable(true);
            frame.setIconifiable(true);
            frame.setMaximizable(true);
            frame.setLocation(left, top);
            incr();
            SwingUtilities.invokeLater(new Runnable() {
                public void run() {
                    select();
                }
            });
            nullItem.addActionListener(this);
            setNullTH();
        }

        public void internalFrameClosing(InternalFrameEvent event) {
            listModel.removeElement(this);
            nullItem.removeActionListener(this);
        }

        public void internalFrameOpened(InternalFrameEvent event) {
            int index = listModel.indexOf(this);
            list.getSelectionModel().setSelectionInterval(index, index);
        }

        public void internalFrameActivated(InternalFrameEvent event) {
            int index = listModel.indexOf(this);
            list.getSelectionModel().setSelectionInterval(index, index);
        }

        public String toString() {
            return name;
        }
        
        public void select() {
            try {
                frame.toFront();
                frame.setSelected(true);
            } catch (java.beans.PropertyVetoException e) {}
        }
        
        public void actionPerformed(ActionEvent ae) {
            setNullTH();
        }
        
        public void setNullTH() {
            if (nullItem.isSelected()) {
                area.setTransferHandler(null);
            } else {
                area.setTransferHandler(th);
            }
        }
    }

    private TransferHandler handler = new TransferHandler() {
        public boolean canImport(TransferHandler.TransferSupport support) {
            if (!support.isDataFlavorSupported(DataFlavor.javaFileListFlavor)) {
                return false;
            }

            if (copyItem.isSelected()) {
                boolean copySupported = (COPY & support.getSourceDropActions()) == COPY;

                if (!copySupported) {
                    return false;
                }

                support.setDropAction(COPY);
            }

            return true;
        }

        public boolean importData(TransferHandler.TransferSupport support) {
            if (!canImport(support)) {
                return false;
            }
            
            Transferable t = support.getTransferable();

            try {
                java.util.List<File> l =
                    (java.util.List<File>)t.getTransferData(DataFlavor.javaFileListFlavor);

                for (File f : l) {
                    new Doc(f);
                }
            } catch (UnsupportedFlavorException e) {
                return false;
            } catch (IOException e) {
                return false;
            }

            return true;
        }
    };

    private static void incr() {
        left += 30;
        top += 30;
        if (top == 150) {
            top = 0;
        }
    }

    public TopLevelTransferHandlerDemo() {
        super("TopLevelTransferHandlerDemo");
        setJMenuBar(createDummyMenuBar());
        getContentPane().add(createDummyToolBar(), BorderLayout.NORTH);

        JSplitPane sp = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT, list, dp);
        sp.setDividerLocation(120);
        getContentPane().add(sp);
        //new Doc("sample.txt");
        //new Doc("sample.txt");
        //new Doc("sample.txt");

        list.getSelectionModel().setSelectionMode(ListSelectionModel.SINGLE_SELECTION);

        list.addListSelectionListener(new ListSelectionListener() {
            public void valueChanged(ListSelectionEvent e) {
                if (e.getValueIsAdjusting()) {
                    return;
                }
                
                Doc val = (Doc)list.getSelectedValue();
                if (val != null) {
                    val.select();
                }
             }
        });
        
        final TransferHandler th = list.getTransferHandler();

        nullItem.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent ae) {
                if (nullItem.isSelected()) {
                    list.setTransferHandler(null);
                } else {
                    list.setTransferHandler(th);
                }
            }
        });
        thItem.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent ae) {
                if (thItem.isSelected()) {
                    setTransferHandler(handler);
                } else {
                    setTransferHandler(null);
                }
            }
        });
        dp.setTransferHandler(handler);
    }

    private static void createAndShowGUI(String[] args) {
        try {
            UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
        } catch (Exception e) {
        }

        TopLevelTransferHandlerDemo test = new TopLevelTransferHandlerDemo();
        test.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        if (DEMO) {
            test.setSize(493, 307);
        } else {
            test.setSize(800, 600);
        }
        test.setLocationRelativeTo(null);
        test.setVisible(true);
        test.list.requestFocus();
    }
    
    public static void main(final String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                //Turn off metal's use of bold fonts
                UIManager.put("swing.boldMetal", Boolean.FALSE);
                createAndShowGUI(args);
            }
        });
    }
    
    private JToolBar createDummyToolBar() {
        JToolBar tb = new JToolBar();
        JButton b;
        b = new JButton("New");
        b.setRequestFocusEnabled(false);
        tb.add(b);
        b = new JButton("Open");
        b.setRequestFocusEnabled(false);
        tb.add(b);
        b = new JButton("Save");
        b.setRequestFocusEnabled(false);
        tb.add(b);
        b = new JButton("Print");
        b.setRequestFocusEnabled(false);
        tb.add(b);
        b = new JButton("Preview");
        b.setRequestFocusEnabled(false);
        tb.add(b);
        tb.setFloatable(false);
        return tb;
    }
    
    private JMenuBar createDummyMenuBar() {
        JMenuBar mb = new JMenuBar();
        mb.add(createDummyMenu("File"));
        mb.add(createDummyMenu("Edit"));
        mb.add(createDummyMenu("Search"));
        mb.add(createDummyMenu("View"));
        mb.add(createDummyMenu("Tools"));
        mb.add(createDummyMenu("Help"));
        
        JMenu demo = new JMenu("Demo");
        demo.setMnemonic(KeyEvent.VK_D);
        mb.add(demo);

        thItem = new JCheckBoxMenuItem("Use Top-Level TransferHandler");
        thItem.setMnemonic(KeyEvent.VK_T);
        demo.add(thItem);

        nullItem = new JCheckBoxMenuItem("Remove TransferHandler from List and Text");
        nullItem.setMnemonic(KeyEvent.VK_R);
        demo.add(nullItem);

        copyItem = new JCheckBoxMenuItem("Use COPY Action");
        copyItem.setMnemonic(KeyEvent.VK_C);
        demo.add(copyItem);

        return mb;
    }
    
    private JMenu createDummyMenu(String str) {
        JMenu menu = new JMenu(str);
        JMenuItem item = new JMenuItem("[Empty]");
        item.setEnabled(false);
        menu.add(item);
        return menu;
    }
}