jfilechooser.java

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	/** Implements the ActionListener interface. Handles button-presses,
	 * and the ENTER keystroke in the Pathname field.
	 */
	public void actionPerformed(ActionEvent e_) {
	    Object source = e_.getSource();
	    if (source == _parentButton) {
		_doParentDirectoryAction();
	    }
	    else if (source == _newButton) {
		_doNewDirectoryAction();
	    }
	    else if (source == _approveButton) {
		_doApproveAction();
	    }
	    else if (source == _cancelButton) {
		_doCancelAction();
	    }
	    else if (source == _locationField) {
		_doApproveAction();
	    }
	}

	/** Implements the KeyListener interface
	 */
	public void keyPressed(KeyEvent e_) {
	    int key = e_.getKeyCode();
	    if (key == PARENT_DIRECTORY_ACCELERATOR) {
		_doParentDirectoryAction(); 
	    }
	    else if (key == NEW_DIRECTORY_ACCELERATOR) {
		_doNewDirectoryAction();
	    }
	    else if (key == APPROVE_ACCELERATOR) {
		_doApproveAction(); 
	    }
	    else if (key == CANCEL_ACCELERATOR) {
		_doCancelAction(); 
	    }
	}

	/** Implements the KeyListener interface
	 */
	public void keyTyped(KeyEvent e_) {
	}

	/** Implements KeyListener interface; is never called.
	 */
	public void keyReleased(KeyEvent e_) { }

	/** Implements the ListSelectionListener interface.
	 */
	public void valueChanged(ListSelectionEvent e_) {
	    String listitem = (String) _dirList.getSelectedValue();
	    if (listitem == null) {
		// The selection is empty; so there must have been a 
		// file selected, but it has just been deselected.
		_locationField.setText(_currentDirectory.getAbsolutePath());
		return;
	    }

	    /* Strip the trailing "/"
	     */
	    if (listitem.endsWith("/"))
		listitem = listitem.substring(0, listitem.length()-1);

	    File file = new File(_currentDirectory, listitem);
	    if (file.canRead() == false) {
		String[] msgs = {
		    "File or directory not readable:",
		    file.getAbsolutePath() };
		JOptionPane.showMessageDialog(
			this, msgs, "Error", JOptionPane.ERROR_MESSAGE);
		return;
	    }
	    else if (file.isDirectory() == false) {
		if (_fileSelectionMode == DIRECTORIES_ONLY) {
		    String[] msgs = {
			"Not a directory:",
			file.getAbsolutePath() };
		    JOptionPane.showMessageDialog(
			    this, msgs, "Error", JOptionPane.ERROR_MESSAGE);
		}
		else {
		    _locationField.setText(file.getAbsolutePath());
		}
		return;
	    }

	    // The selected file is a directory.
	    setCurrentDirectory(file);
	    displayCurrentDirectory();
	    repaint();

	    _scrollPane.getViewport().setViewPosition(new Point(0,0));
	    _scrollPane.repaint();

	    /* If the newly selected directory is a root directory,
	     * don't allow the Parent button to be pressed.
	     */
	    if (_isRoot(_currentDirectory) == false)
		_parentButton.setEnabled(true);
	}

	/** Implements the FileChooserListener interface.
	 */
	public void fileChanged(FileChooserEvent e)
	{
	    displayCurrentDirectory();
	    repaint();
	}

	private void _doNewDirectoryAction() {
	    JFileChooser.NewDirDialog dlg = 
		new NewDirDialog(this, _currentDirectory);

	    dlg.setLocation(getLocation().addOffset(2, 2));
	    dlg.show();
	    File newdir = dlg.getDirectory();
	    if (newdir != null)
		setCurrentDirectory(newdir);
	    	displayCurrentDirectory();
	    	repaint();
	}

	private void _doParentDirectoryAction() {
	    if (_isRoot(_currentDirectory)) {
		// We are already in a root directory.  Display the 
		// filesystem roots in the listbox. The list of 
		// root directories is system-dependent; on Windows it 
		// would be A:, B:, C: etc.  On Unix it would be "/".
	    	File[] roots = File.listRoots();
	    	for (int i=0; i<roots.length; i++) {
	    	    DefaultListModel listModel = 
		    	(DefaultListModel) _dirList.getModel();
	    	    listModel.addElement(roots[i].getAbsolutePath());
	    	}
	    	_location = "";
	    }
	    else {
		File parent = _currentDirectory.getParentFile();
		if (_isRoot(parent)) {
		    _parentButton.setEnabled(false);
		    _dirList.requestFocus();
		}
		setCurrentDirectory(parent);
	    	displayCurrentDirectory();
	    	repaint();
	    }
	}

	private void _doApproveAction() {
	    File file = new File(_locationField.getText());
	    String errmsg = null;

	    if (_fileSelectionMode == DIRECTORIES_ONLY && 
		file.isDirectory() == false) {

		errmsg = "Entry is not a directory: ";
	    }
	    else if (_fileSelectionMode == FILES_ONLY &&
		file.isDirectory()) {

		setCurrentDirectory(file);
		displayCurrentDirectory();
		repaint();
		return;
	    }

	    if (errmsg != null) {
		String[] msgs = { errmsg, _locationField.getText() };
		JOptionPane.showMessageDialog(
		    this, msgs, "Error", JOptionPane.ERROR_MESSAGE);
		return;
	    }

	    _cancelWasPressed = false;
	    _location = _locationField.getText();
	    hide();
	}

	private void _doCancelAction() {
	    _cancelWasPressed = true;
	    hide();
	}

	/** Returns true if the specified file is a root directory.
	 */
	private boolean _isRoot(File dir_) {
	    String dirname = dir_.getAbsolutePath();

	    File[] roots = File.listRoots();
	    for (int i=0; i<roots.length; i++) {
		if (roots[i].getAbsolutePath().equals(dirname))
		    return true;
	    }
	    return false;
	}


	/**
	 * Causes the JFileChooser to scan its file list for the current
	 * directory, using the currently selected file filter if applicable.
	 * Note that this method does not cause the file chooser to be redrawn.
	 */
	private void displayCurrentDirectory()
	{
	    /* Clear the list of Files in the current dir
	     */
	    _dirList.clear();

	    DefaultListModel listModel = (DefaultListModel) _dirList.getModel();

	    /* Add all the current directory's children into the list.
	     */
	    File[] files = _currentDirectory.listFiles();

	    /* Define and instantiate an anonymous class that implements
	     * the Comparator interface. This will be used by the TreeSet
	     * to keep the filenames in lexicographical order.
	     */
	    Comparator fileSorter = new Comparator() {
		public int compare(Object obj1, Object obj2) {
		    String file1 = (String) obj1;
		    String file2 = (String) obj2;
		    return file1.compareTo(file2);
		}
	    };

	    TreeSet dirs = new TreeSet(fileSorter);
	    int numEntries = 0;
	    for (int i=0; i<files.length; i++) {
		if (files[i].isDirectory()) {
		    dirs.add(files[i].getName() + "/");
		}
		else if ((_fileSelectionMode != DIRECTORIES_ONLY) &&
			 (_fileFilter == null ||
			  _fileFilter.accept(files[i]))) {
		    /* This is a regular file, and either there is no
		     * file filter or the file is accepted by the
		     * filter.
		     */
		    dirs.add(files[i].getName());
		}
		numEntries++;
	    }

	    /* Copy the filenames from the TreeSet to the JList widget
	     */
	    Iterator iter = dirs.iterator();
	    while (iter.hasNext()) {
		listModel.addElement(iter.next());
	    }
	    _locationField.setText(_location);
	}

	private JScrollPane _scrollPane;
	protected JButton _cancelButton = new JButton("Cancel");
	protected JButton _approveButton = new JButton("Open");
	protected JButton _parentButton = new JButton("Parent Directory");
	protected JButton _newButton = new JButton("New Directory");
	private JTextField _locationField = new JTextField(35);
    }

    /*====================================================================
     * This is a non-static inner class used by the JFileChooser 
     * to implement a sorted list of directory names. The user can
     * find a directory quickly by entering the first few characters
     * of the directory name.
     */
    private class DirList
	extends JList
    {
	DirList() {
	    super();
	    setVisibleRowCount(10);
	    setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
	}

	/** Clears the list of files displayed by this JList. 
	 * Does not generate any ListSelectionEvents. (?)
	 */
	void clear() {
	    // Clear the selection model without notifying any 
	    // ListSelectionListeners.
	    int min = getSelectionModel().getMinSelectionIndex();
	    if (min != -1) {
	    	int max = getSelectionModel().getMaxSelectionIndex();
		getSelectionModel().removeIndexInterval(min, max);
	    }

	    // Clear the contents of the data model.
	    ((DefaultListModel) getModel()).clear();
	    _currentRow = 0;
	    _matchbuf.setLength(0);
	}

	/** Overrides corresponding method in JList, and allows the
	 * user to find a directory quickly by typing the first few letters
	 * of the filename.
	 */
	public void processKeyEvent(KeyEvent evt_)
	{
	    int key = evt_.getKeyCode();
	    ListModel listmodel = super.getModel();
	    if (listmodel.getSize() > 0 && 
		    (key == KeyEvent.VK_BACK_SPACE || 
			(key > ' ' && key < 255))) {

		if (key == KeyEvent.VK_BACK_SPACE) {
		    if (_matchbuf.length() > 0)	    // truncate
			_matchbuf.setLength(_matchbuf.length() - 1);
		    else
			Toolkit.getDefaultToolkit().beep();
		}
		else
		    _matchbuf.append((char) key);

		/* Scan through the items in the list until we get
		 * to an item that is lexicographically greater than the
		 * pattern we have typed.
		 */
		String matchstring = _matchbuf.toString();
		int i;
		for (i=0; i<listmodel.getSize(); i++) {
		    if (matchstring.compareTo(listmodel.getElementAt(i)) <= 0) {
			break;
		    }
		}
		if (i == listmodel.getSize())
		    i--;    // the loop completed.

		String item = (String) listmodel.getElementAt(i);
		if ( ! item.startsWith(matchstring))
		    Toolkit.getDefaultToolkit().beep();

		_currentRow = i;
		super.ensureIndexIsVisible(i);
	    }
	    super.processKeyEvent(evt_);
	}

	// INSTANCE VARIABLE
	private StringBuffer _matchbuf = new StringBuffer();
    }

    /*====================================================================
     * This is a non-static inner class used by the JFileChooser 
     * to get the name of the new directory to create.
     */
    private class NewDirDialog
	extends JDialog
	implements ActionListener
    {
	NewDirDialog(Dialog owner_, File parent_) {
	    super(owner_);

	    setTitle("Enter the new directory name");
	    _parentFile = parent_;
	    setSize(60, 10);

	    JPanel midpan = new JPanel();
	    midpan.setBorder(new EmptyBorder(2,2,2,2));
	    midpan.add(new JLabel("Directory name:"));
	    _dirnameField = new JTextField(35);
	    _dirnameField.setActionCommand("dirname");
	    _dirnameField.addActionListener(this);
	    midpan.add(_dirnameField);
	    add(midpan, BorderLayout.CENTER);

	    _okButton = new JButton("OK");
	    _okButton.addActionListener(this);
	    _cancelButton = new JButton("Cancel");
	    _cancelButton.addActionListener(this);
	    JPanel southpan = new JPanel();
	    southpan.setLayout(new FlowLayout(FlowLayout.RIGHT, 1, 1));
	    southpan.add(_okButton);
	    southpan.add(_cancelButton);
	    add(southpan, BorderLayout.SOUTH);
	    pack();
	}

	public void actionPerformed(ActionEvent e_) {
	    String cmd = e_.getActionCommand();
	    if (cmd.equals("OK") || cmd.equals("dirname")) {
		if (_parentFile.canWrite() == false) {
		    String[] msgs = {"Permission denied"};
		    JOptionPane.showMessageDialog(
			    this, msgs, "Error", JOptionPane.ERROR_MESSAGE);
		    return;
		}

		File newdir = new File(_parentFile, _dirnameField.getText());
		boolean ok = newdir.mkdir();
		if (ok == false) {
		    String[] msgs = {"Invalid directory"};
		    JOptionPane.showMessageDialog(
			    this, msgs, "Error", JOptionPane.ERROR_MESSAGE);
		}
		else {
		    _directory = newdir;
		    hide();
		}
	    }
	    else if (cmd.equals("Cancel")) {
		_directory = null;
		hide();
	    }
	}

	File getDirectory() { return _directory; }

	private File _parentFile;
	private JButton _okButton;
	private JButton _cancelButton;
	private JTextField _dirnameField;
	private File _directory = null;

    }

    // end of inner class NewDirDialog

    private interface FileChooserListener 
	extends EventListener
    {
	public void fileChanged(FileChooserEvent e);
    }

    private class FileChooserEvent
	extends java.util.EventObject
    {
	public FileChooserEvent(Object source_)
	{
	    super(source_);
	}
    }
}