Java tutorial
/* From http://java.sun.com/docs/books/tutorial/index.html */ /* * Copyright (c) 2006 Sun Microsystems, Inc. All Rights Reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * -Redistribution of source code must retain the above copyright notice, this * list of conditions and the following disclaimer. * * -Redistribution 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, Inc. or the names of contributors may * be used to endorse or promote products derived from this software without * specific prior written permission. * * This software is provided "AS IS," without a warranty of any kind. ALL * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING * ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE * OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN MIDROSYSTEMS, INC. ("SUN") * AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE * AS A RESULT OF USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS * DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE FOR ANY LOST * REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL, * INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY * OF LIABILITY, ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE, * EVEN IF SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. * * You acknowledge that this software is not designed, licensed or intended * for use in the design, construction, operation or maintenance of any * nuclear facility. */ /* * DragFileDemo.java is a 1.4 example that requires the following file: * FileAndTextTransferHandler.java TabbedPaneController.java */ import java.awt.BorderLayout; import java.awt.Component; import java.awt.Dimension; import java.awt.Insets; import java.awt.datatransfer.DataFlavor; import java.awt.datatransfer.StringSelection; import java.awt.datatransfer.Transferable; import java.awt.datatransfer.UnsupportedFlavorException; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.io.BufferedReader; import java.io.File; import java.io.FileReader; import java.io.IOException; import javax.swing.BorderFactory; import javax.swing.JButton; import javax.swing.JComponent; import javax.swing.JFileChooser; import javax.swing.JFrame; import javax.swing.JPanel; import javax.swing.JScrollPane; import javax.swing.JSplitPane; import javax.swing.JTabbedPane; import javax.swing.JTextArea; import javax.swing.TransferHandler; import javax.swing.text.BadLocationException; import javax.swing.text.Document; import javax.swing.text.JTextComponent; import javax.swing.text.Position; public class DragFileDemo extends JPanel implements ActionListener { JTextArea fileArea; JFileChooser fc; JButton clear; TabbedPaneController tpc; public DragFileDemo() { super(new BorderLayout()); fc = new JFileChooser(); ; fc.setMultiSelectionEnabled(true); fc.setDragEnabled(true); fc.setControlButtonsAreShown(false); JPanel fcPanel = new JPanel(new BorderLayout()); fcPanel.add(fc, BorderLayout.CENTER); clear = new JButton("Clear All"); clear.addActionListener(this); JPanel buttonPanel = new JPanel(new BorderLayout()); buttonPanel.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5)); buttonPanel.add(clear, BorderLayout.LINE_END); JPanel upperPanel = new JPanel(new BorderLayout()); upperPanel.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5)); upperPanel.add(fcPanel, BorderLayout.CENTER); upperPanel.add(buttonPanel, BorderLayout.PAGE_END); //The TabbedPaneController manages the panel that //contains the tabbed pane. When there are no files //the panel contains a plain text area. Then, as //files are dropped onto the area, the tabbed panel //replaces the file area. JTabbedPane tabbedPane = new JTabbedPane(); JPanel tabPanel = new JPanel(new BorderLayout()); tabPanel.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5)); tpc = new TabbedPaneController(tabbedPane, tabPanel); JSplitPane splitPane = new JSplitPane(JSplitPane.VERTICAL_SPLIT, upperPanel, tabPanel); splitPane.setDividerLocation(400); splitPane.setPreferredSize(new Dimension(530, 650)); add(splitPane, BorderLayout.CENTER); } public void setDefaultButton() { getRootPane().setDefaultButton(clear); } public void actionPerformed(ActionEvent e) { if (e.getSource() == clear) { tpc.clearAll(); } } /** * Create the GUI and show it. For thread safety, this method should be * invoked from the event-dispatching thread. */ private static void createAndShowGUI() { //Make sure we have nice window decorations. JFrame.setDefaultLookAndFeelDecorated(true); //Create and set up the window. JFrame frame = new JFrame("DragFileDemo"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); //Create and set up the menu bar and content pane. DragFileDemo demo = new DragFileDemo(); demo.setOpaque(true); //content panes must be opaque frame.setContentPane(demo); //Display the window. frame.pack(); frame.setVisible(true); demo.setDefaultButton(); } public static void main(String[] args) { //Schedule a job for the event-dispatching thread: //creating and showing this application's GUI. javax.swing.SwingUtilities.invokeLater(new Runnable() { public void run() { createAndShowGUI(); } }); } } /* * TabbedPaneController.java is used by the 1.4 DragFileDemo.java example. */ /* * Class that manages area where the contents of files are displayed. When no * files are present, there is a simple JTextArea instructing users to drop a * file. As soon as a file is dropped, a JTabbedPane is placed into the window * and each file is displayed under its own tab. When all the files are removed, * the JTabbedPane is removed from the window and the simple JTextArea is again * displayed. */ class TabbedPaneController { JPanel tabbedPanel = null; JTabbedPane tabbedPane; JPanel emptyFilePanel = null; JTextArea emptyFileArea = null; FileAndTextTransferHandler transferHandler; boolean noFiles = true; String fileSeparator; public TabbedPaneController(JTabbedPane tb, JPanel tp) { tabbedPane = tb; tabbedPanel = tp; transferHandler = new FileAndTextTransferHandler(this); fileSeparator = System.getProperty("file.separator"); //The split method in the String class uses //regular expressions to define the text used for //the split. The forward slash "\" is a special //character and must be escaped. Some look and feels, //such as Microsoft Windows, use the forward slash to //delimit the path. if ("\\".equals(fileSeparator)) { fileSeparator = "\\\\"; } init(); } public JTextArea addTab(String filename) { if (noFiles) { tabbedPanel.remove(emptyFilePanel); tabbedPanel.add(tabbedPane, BorderLayout.CENTER); noFiles = false; } String[] str = filename.split(fileSeparator); return makeTextPanel(str[str.length - 1], filename); } //Remove all tabs and their components, then put the default //file area back. public void clearAll() { if (noFiles == false) { tabbedPane.removeAll(); tabbedPanel.remove(tabbedPane); } init(); } private void init() { String defaultText = "Select one or more files from the file chooser and drop here..."; noFiles = true; if (emptyFilePanel == null) { emptyFileArea = new JTextArea(20, 15); emptyFileArea.setEditable(false); emptyFileArea.setDragEnabled(true); emptyFileArea.setTransferHandler(transferHandler); emptyFileArea.setMargin(new Insets(5, 5, 5, 5)); JScrollPane fileScrollPane = new JScrollPane(emptyFileArea); emptyFilePanel = new JPanel(new BorderLayout(), false); emptyFilePanel.add(fileScrollPane, BorderLayout.CENTER); } tabbedPanel.add(emptyFilePanel, BorderLayout.CENTER); tabbedPanel.repaint(); emptyFileArea.setText(defaultText); } protected JTextArea makeTextPanel(String name, String toolTip) { JTextArea fileArea = new JTextArea(20, 15); fileArea.setDragEnabled(true); fileArea.setTransferHandler(transferHandler); fileArea.setMargin(new Insets(5, 5, 5, 5)); JScrollPane fileScrollPane = new JScrollPane(fileArea); tabbedPane.addTab(name, null, (Component) fileScrollPane, toolTip); tabbedPane.setSelectedComponent((Component) fileScrollPane); return fileArea; } } /* * FileAndTextTransferHandler.java is used by the 1.4 DragFileDemo.java example. */ class FileAndTextTransferHandler extends TransferHandler { private DataFlavor fileFlavor, stringFlavor; private TabbedPaneController tpc; private JTextArea source; private boolean shouldRemove; protected String newline = "\n"; //Start and end position in the source text. //We need this information when performing a MOVE //in order to remove the dragged text from the source. Position p0 = null, p1 = null; FileAndTextTransferHandler(TabbedPaneController t) { tpc = t; fileFlavor = DataFlavor.javaFileListFlavor; stringFlavor = DataFlavor.stringFlavor; } public boolean importData(JComponent c, Transferable t) { JTextArea tc; if (!canImport(c, t.getTransferDataFlavors())) { return false; } //A real application would load the file in another //thread in order to not block the UI. This step //was omitted here to simplify the code. try { if (hasFileFlavor(t.getTransferDataFlavors())) { String str = null; java.util.List files = (java.util.List) t.getTransferData(fileFlavor); for (int i = 0; i < files.size(); i++) { File file = (File) files.get(i); //Tell the tabbedpane controller to add //a new tab with the name of this file //on the tab. The text area that will //display the contents of the file is returned. tc = tpc.addTab(file.toString()); BufferedReader in = null; try { in = new BufferedReader(new FileReader(file)); while ((str = in.readLine()) != null) { tc.append(str + newline); } } catch (IOException ioe) { System.out.println("importData: Unable to read from file " + file.toString()); } finally { if (in != null) { try { in.close(); } catch (IOException ioe) { System.out.println("importData: Unable to close file " + file.toString()); } } } } return true; } else if (hasStringFlavor(t.getTransferDataFlavors())) { tc = (JTextArea) c; if (tc.equals(source) && (tc.getCaretPosition() >= p0.getOffset()) && (tc.getCaretPosition() <= p1.getOffset())) { shouldRemove = false; return true; } String str = (String) t.getTransferData(stringFlavor); tc.replaceSelection(str); return true; } } catch (UnsupportedFlavorException ufe) { System.out.println("importData: unsupported data flavor"); } catch (IOException ieo) { System.out.println("importData: I/O exception"); } return false; } protected Transferable createTransferable(JComponent c) { source = (JTextArea) c; int start = source.getSelectionStart(); int end = source.getSelectionEnd(); Document doc = source.getDocument(); if (start == end) { return null; } try { p0 = doc.createPosition(start); p1 = doc.createPosition(end); } catch (BadLocationException e) { System.out.println("Can't create position - unable to remove text from source."); } shouldRemove = true; String data = source.getSelectedText(); return new StringSelection(data); } public int getSourceActions(JComponent c) { return COPY_OR_MOVE; } //Remove the old text if the action is a MOVE. //However, we do not allow dropping on top of the selected text, //so in that case do nothing. protected void exportDone(JComponent c, Transferable data, int action) { if (shouldRemove && (action == MOVE)) { if ((p0 != null) && (p1 != null) && (p0.getOffset() != p1.getOffset())) { try { JTextComponent tc = (JTextComponent) c; tc.getDocument().remove(p0.getOffset(), p1.getOffset() - p0.getOffset()); } catch (BadLocationException e) { System.out.println("Can't remove text from source."); } } } source = null; } public boolean canImport(JComponent c, DataFlavor[] flavors) { if (hasFileFlavor(flavors)) { return true; } if (hasStringFlavor(flavors)) { return true; } return false; } private boolean hasFileFlavor(DataFlavor[] flavors) { for (int i = 0; i < flavors.length; i++) { if (fileFlavor.equals(flavors[i])) { return true; } } return false; } private boolean hasStringFlavor(DataFlavor[] flavors) { for (int i = 0; i < flavors.length; i++) { if (stringFlavor.equals(flavors[i])) { return true; } } return false; } }