path: root/javax/swing/JTree.java

/* JTree.java --
   Copyright (C) 2002, 2004, 2005  Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

GNU Classpath is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU Classpath; see the file COPYING.  If not, write to the
Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA.

Linking this library statically or dynamically with other modules is
making a combined work based on this library.  Thus, the terms and
conditions of the GNU General Public License cover the whole
combination.

As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
modules, and to copy and distribute the resulting executable under
terms of your choice, provided that you also meet, for each linked
independent module, the terms and conditions of the license of that
module.  An independent module is a module which is not derived from
or based on this library.  If you modify this library, you may extend
this exception to your version of the library, but you are not
obligated to do so.  If you do not wish to do so, delete this
exception statement from your version. */


package javax.swing;

import java.awt.Dimension;
import java.awt.Rectangle;
import java.io.Serializable;
import java.util.Enumeration;
import java.util.Hashtable;
import java.util.Iterator;
import java.util.Vector;

import javax.accessibility.Accessible;
import javax.accessibility.AccessibleContext;
import javax.swing.event.TreeExpansionEvent;
import javax.swing.event.TreeExpansionListener;
import javax.swing.event.TreeModelEvent;
import javax.swing.event.TreeModelListener;
import javax.swing.event.TreeSelectionEvent;
import javax.swing.event.TreeSelectionListener;
import javax.swing.event.TreeWillExpandListener;
import javax.swing.plaf.TreeUI;
import javax.swing.text.Position;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeCellRenderer;
import javax.swing.tree.DefaultTreeModel;
import javax.swing.tree.DefaultTreeSelectionModel;
import javax.swing.tree.ExpandVetoException;
import javax.swing.tree.TreeCellEditor;
import javax.swing.tree.TreeCellRenderer;
import javax.swing.tree.TreeModel;
import javax.swing.tree.TreeNode;
import javax.swing.tree.TreePath;
import javax.swing.tree.TreeSelectionModel;


public class JTree extends JComponent
  implements Scrollable, Accessible
{
  /**
   * Listens to the model of the JTree and updates the property
   * <code>expandedState</code> if nodes are removed or changed.
   */
  protected class TreeModelHandler
    implements TreeModelListener
  {

    /**
     * Creates a new instance of TreeModelHandler.
     */
    protected TreeModelHandler()
    {
    }

    /**
     * Notifies when a node has changed in some ways. This does not include
     * that a node has changed its location or changed it's children. It
     * only means that some attributes of the node have changed that might
     * affect its presentation.
     *
     * This method is called after the actual change occured.
     *
     * @param ev the TreeModelEvent describing the change
     */
    public void treeNodesChanged(TreeModelEvent ev)
    {
      // nothing to do here
    }

    /**
     * Notifies when a node is inserted into the tree.
     *
     * This method is called after the actual change occured.
     *
     * @param ev the TreeModelEvent describing the change
     */
    public void treeNodesInserted(TreeModelEvent ev)
    {
      // nothing to do here
    }

    /**
     * Notifies when a node is removed from the tree.
     *
     * This method is called after the actual change occured.
     *
     * @param ev the TreeModelEvent describing the change
     */
    public void treeNodesRemoved(TreeModelEvent ev)
    {
      // TODO: The API docs suggest that this method should do something
      // but I cannot really see what has to be done here ...
    }

    /**
     * Notifies when the structure of the tree is changed.
     *
     * This method is called after the actual change occured.
     *
     * @param ev the TreeModelEvent describing the change
     */
    public void treeStructureChanged(TreeModelEvent ev)
    {
      // set state of new path
      TreePath path = ev.getTreePath();
      setExpandedState(path, isExpanded(path));
    }
  } // TreeModelHandler

  /**
   * This redirects TreeSelectionEvents and rewrites the source of it
   * to be this JTree. This is typically done when the tree model
   * generates an event, but the JTree object associated with that model
   * should be listed as the actual source of the event.
   */
  protected class TreeSelectionRedirector
    implements TreeSelectionListener, Serializable
  {
    /** The serial version UID. */
    private static final long serialVersionUID = -3505069663646241664L;

    /**
     * Creates a new instance of TreeSelectionRedirector
     */
    protected TreeSelectionRedirector()
    {
    }

    /**
     * Notifies when the tree selection changes.
     *
     * @param ev the TreeSelectionEvent that describes the change
     */
    public void valueChanged(TreeSelectionEvent ev)
    {
      TreeSelectionEvent rewritten =
        (TreeSelectionEvent) ev.cloneWithSource(JTree.this);
      fireValueChanged(rewritten);
    }
  } // TreeSelectionRedirector

  /**
   * A TreeModel that does not allow anything to be selected.
   */
  protected static class EmptySelectionModel
    extends DefaultTreeSelectionModel
  {
    /** The serial version UID. */
    private static final long serialVersionUID = -5815023306225701477L;

    /**
     * The shared instance of this model.
     */
    protected static final EmptySelectionModel sharedInstance =
    new EmptySelectionModel();

    /**
     * Creates a new instance of EmptySelectionModel.
     */
    protected EmptySelectionModel()
    {
    }

    /**
     * Returns the shared instance of EmptySelectionModel.
     *
     * @return the shared instance of EmptySelectionModel
     */
    public static EmptySelectionModel sharedInstance()
    {
      return sharedInstance;
    }

    /**
     * This catches attempts to set a selection and sets nothing
     * instead.
     *
     * @param paths not used here
     */
    public void setSelectionPaths(TreePath[] paths)
    {
      // we don't allow selections in this class
    }

    /**
     * This catches attempts to add something to the selection.
     *
     * @param paths not used here
     */
    public void addSelectionPaths(TreePath[] paths)
    {
      // we don't allow selections in this class
    }

    /**
     * This catches attempts to remove something from the selection.
     *
     * @param paths not used here
     */
    public void removeSelectionPaths(TreePath[] paths)
    {
      // we don't allow selections in this class
    }
  }// EmptySelectionModel

  private static final long serialVersionUID = 7559816092864483649L;

  public static final String CELL_EDITOR_PROPERTY = "cellEditor";
  public static final String CELL_RENDERER_PROPERTY = "cellRenderer";
  public static final String EDITABLE_PROPERTY = "editable";
  public static final String INVOKES_STOP_CELL_EDITING_PROPERTY = "invokesStopCellEditing";
  public static final String LARGE_MODEL_PROPERTY = "largeModel";
  public static final String ROOT_VISIBLE_PROPERTY = "rootVisible";
  public static final String ROW_HEIGHT_PROPERTY = "rowHeight";
  public static final String SCROLLS_ON_EXPAND_PROPERTY = "scrollsOnExpand";
  public static final String SELECTION_MODEL_PROPERTY = "selectionModel";
  public static final String SHOWS_ROOT_HANDLES_PROPERTY = "showsRootHandles";
  public static final String TOGGLE_CLICK_COUNT_PROPERTY = "toggleClickCount";
  public static final String TREE_MODEL_PROPERTY = "model";
  public static final String VISIBLE_ROW_COUNT_PROPERTY = "visibleRowCount";

  /** @since 1.3 */
  public static final String ANCHOR_SELECTION_PATH_PROPERTY = "anchorSelectionPath";
  /** @since 1.3 */
  public static final String LEAD_SELECTION_PATH_PROPERTY = "leadSelectionPath";
  /** @since 1.3 */
  public static final String EXPANDS_SELECTED_PATHS_PROPERTY = "expandsSelectedPaths";

  private static final Object EXPANDED = new Object();
  private static final Object COLLAPSED = new Object();
  
  private boolean dragEnabled;
  private boolean expandsSelectedPaths;
  private TreePath anchorSelectionPath;
  private TreePath leadSelectionPath;

  /*
   * This contains the state of all nodes in the tree. Al/ entries map the
   * TreePath of a note to to its state. Valid states are EXPANDED and
   * COLLAPSED.  Nodes not in this Hashtable are assumed state COLLAPSED.
   */
  private Hashtable nodeStates;

  protected transient TreeCellEditor cellEditor;
  protected transient TreeCellRenderer cellRenderer;
  protected boolean editable;
  protected boolean invokesStopCellEditing;
  protected boolean largeModel;
  protected boolean rootVisible;
  protected int rowHeight;
  protected boolean scrollsOnExpand;
  protected transient TreeSelectionModel selectionModel;
  protected boolean showsRootHandles;
  protected int toggleClickCount;
  protected transient TreeModel treeModel;
  protected int visibleRowCount;

  /**
   * Handles TreeModelEvents to update the expandedState.
   */
  protected transient TreeModelListener treeModelListener;

  /**
   * Redirects TreeSelectionEvents so that the source is this JTree.
   */
  protected TreeSelectionRedirector selectionRedirector =
    new TreeSelectionRedirector();

  /**
   * Creates a new <code>JTree</code> object.
   */
  public JTree()
  {
    this(createTreeModel(null));
  }

  /**
   * Creates a new <code>JTree</code> object.
   *
   * @param value the initial nodes in the tree
   */
  public JTree(Hashtable value)
  {
    this(createTreeModel(value));
  }

  /**
   * Creates a new <code>JTree</code> object.
   *
   * @param value the initial nodes in the tree
   */
  public JTree(Object[] value)
  {
    this(createTreeModel(value));
  }

  /**
   * Creates a new <code>JTree</code> object.
   *
   * @param model the model to use
   */
  public JTree(TreeModel model)
  {
    setModel(model);
    setSelectionModel(EmptySelectionModel.sharedInstance());
    selectionModel.addTreeSelectionListener(selectionRedirector);
    setCellRenderer(new DefaultTreeCellRenderer());
    updateUI();
  }

  /**
   * Creates a new <code>JTree</code> object.
   *
   * @param root the root node
   */
  public JTree(TreeNode root)
  {
    this(root, false);
  }

  /**
   * Creates a new <code>JTree</code> object.
   *
   * @param root the root node
   * @param asksAllowChildren if false, all nodes without children are leaf nodes.
   * If true, only nodes that do not allow children are leaf nodes.
   */
  public JTree(TreeNode root, boolean asksAllowChildren)
  {
    this(new DefaultTreeModel(root, asksAllowChildren));
  }

  /**
   * Creates a new <code>JTree</code> object.
   *
   * @param value the initial nodes in the tree
   */
  public JTree(Vector value)
  {
    this(createTreeModel(value));
  }

  public static class DynamicUtilTreeNode 
    extends DefaultMutableTreeNode
  {
    protected Object childValue;
    protected boolean loadedChildren;

    /**
     * Currently not set or used by this class.
     * It might be set and used in later versions of this class.
     */
    protected boolean hasChildren;
    
    public DynamicUtilTreeNode(Object value,
                               Object children) 
    {
      super(value);
      childValue = children;
      loadedChildren = false;
    }

    public int getChildCount()
    {
      loadChildren();
      return super.getChildCount();
    }

    protected void loadChildren()
    {
      if (!loadedChildren)
        {
          createChildren(this, childValue);
          loadedChildren = true;
        }
    }
    
    public Enumeration children()
    {
      loadChildren();
      return super.children();
    }

    /**
     * Returns the child node at position <code>pos</code>. Subclassed here
     * to load the children if necessary.
     *
     * @param pos the position of the child node to fetch
     *
     * @return the childnode at the specified position
     */
    public TreeNode getChildAt(int pos)
    {
      loadChildren();
      return super.getChildAt(pos);
    }

    public boolean isLeaf() 
    {
      return (childValue == null || 
              !(childValue instanceof Hashtable
               || childValue instanceof Vector
               || childValue.getClass().isArray()));
    }

    public static void createChildren(DefaultMutableTreeNode parent,
                                      Object children)
    {
      if (children instanceof Hashtable)
        {
          Hashtable tab = (Hashtable) children;
          Enumeration e = tab.keys();
          while (e.hasMoreElements()) 
            {
              Object key = e.nextElement();
              Object val = tab.get(key);
              parent.add(new DynamicUtilTreeNode(key, val));
            }
        }
      else if (children instanceof Vector)
        {
          Iterator i = ((Vector)children).iterator();
          while (i.hasNext())
            {
              Object n = i.next();
              parent.add(new DynamicUtilTreeNode(n,n));
            }
        }
      else if (children.getClass().isArray())
        {
          Object[] arr = (Object[]) children;
          for (int i = 0; i < arr.length; ++i)
            parent.add(new DynamicUtilTreeNode(arr[i], arr[i]));
      }
    }
  }

  public int getRowForPath(TreePath path)
  {
    TreeUI ui = getUI();

    if (ui != null)
      return ui.getRowForPath(this, path);

    return -1;
  }
  
  public TreePath getPathForRow(int row)
  {
    TreeUI ui = getUI();
    return ui != null ? ui.getPathForRow(this, row) : null;
  }

  protected TreePath[] getPathBetweenRows(int index0, int index1)
  {
    TreeUI ui = getUI();
    
    if (ui == null)
      return null;
    
    int minIndex = Math.min(index0, index1);
    int maxIndex = Math.max(index0, index1);
    TreePath[] paths = new TreePath[maxIndex - minIndex + 1];
    
    for (int i = minIndex; i <= maxIndex; ++i)
      paths[i - minIndex] = ui.getPathForRow(this, i);

    return paths;
  }
  
  /**
   * Creates a new <code>TreeModel</code> object.
   *
   * @param value the values stored in the model
   */
  protected static TreeModel createTreeModel(Object value)
  {
    return new DefaultTreeModel(new DynamicUtilTreeNode(value, value));
  }

  /**
   * Return the UI associated with this <code>JTree</code> object.
   *
   * @return the associated <code>TreeUI</code> object
   */
  public TreeUI getUI()
  {
    return (TreeUI) ui;
  }

  /**
   * Sets the UI associated with this <code>JTree</code> object.
   *
   * @param ui the <code>TreeUI</code> to associate
   */
  public void setUI(TreeUI ui)
  {
    super.setUI(ui);
  }

  /**
   * This method resets the UI used to the Look and Feel defaults..
   */
  public void updateUI()
  {
    setUI((TreeUI) UIManager.getUI(this));
    revalidate();
    repaint();
  }

  /**
   * This method returns the String ID of the UI class of  Separator.
   *
   * @return The UI class' String ID.
   */
  public String getUIClassID()
  {
    return "TreeUI";
  }

  /**
   * Gets the AccessibleContext associated with this <code>JToggleButton</code>.
   *
   * @return the associated context
   */
  public AccessibleContext getAccessibleContext()
  {
    return null;
  }

  /**
   * Returns the preferred viewport size..
   *
   * @return the preferred size
   */
  public Dimension getPreferredScrollableViewportSize()
  {
    return null;
  }

  public int getScrollableUnitIncrement(Rectangle visibleRect,
                                        int orientation, int direction)
  {
    return 1;
  }

  public int getScrollableBlockIncrement(Rectangle visibleRect,
                                         int orientation, int direction)
  {
    return 1;
  }

  public boolean getScrollableTracksViewportWidth()
  {
    return false;
  }

  public boolean getScrollableTracksViewportHeight()
  {
    return false;
  }

  /**
   * Adds a <code>TreeExpansionListener</code> object to the tree.
   *
   * @param listener the listener to add
   */
  public void addTreeExpansionListener(TreeExpansionListener listener)
  {
    listenerList.add(TreeExpansionListener.class, listener);
  }

  /**
   * Removes a <code>TreeExpansionListener</code> object from the tree.
   *
   * @param listener the listener to remove
   */
  public void removeTreeExpansionListener(TreeExpansionListener listener)
  {
    listenerList.remove(TreeExpansionListener.class, listener);
  }

  /**
   * Returns all added <code>TreeExpansionListener</code> objects.
   *
   * @return an array of listeners
   */
  public TreeExpansionListener[] getTreeExpansionListeners()
  {
    return (TreeExpansionListener[]) getListeners(TreeExpansionListener.class);
  }

  /**
   * Notifies all listeners that the tree was collapsed.
   *
   * @param path the path to the node that was collapsed
   */
  public void fireTreeCollapsed(TreePath path)
  {
    TreeExpansionEvent event = new TreeExpansionEvent(this, path);
    TreeExpansionListener[] listeners = getTreeExpansionListeners();

    for (int index = 0; index < listeners.length; ++index)
      listeners[index].treeCollapsed(event);
  }
  
  /**
   * Notifies all listeners that the tree was expanded.
   *
   * @param path the path to the node that was expanded
   */
  public void fireTreeExpanded(TreePath path)
  {
    TreeExpansionEvent event = new TreeExpansionEvent(this, path);
    TreeExpansionListener[] listeners = getTreeExpansionListeners();

    for (int index = 0; index < listeners.length; ++index)
      listeners[index].treeExpanded(event);
  }

  /**
   * Adds a <code>TreeSelctionListener</code> object to the tree.
   *
   * @param listener the listener to add
   */
  public void addTreeSelectionListener(TreeSelectionListener listener)
  {
    listenerList.add(TreeSelectionListener.class, listener);
  }

  /**
   * Removes a <code>TreeSelectionListener</code> object from the tree.
   *
   * @param listener the listener to remove
   */
  public void removeTreeSelectionListener(TreeSelectionListener listener)
  {
    listenerList.remove(TreeSelectionListener.class, listener);
  }

  /**
   * Returns all added <code>TreeSelectionListener</code> objects.
   *
   * @return an array of listeners
   */
  public TreeSelectionListener[] getTreeSelectionListeners()
  {
    return (TreeSelectionListener[]) getListeners(TreeSelectionListener.class);
  }

  /**
   * Notifies all listeners when the selection of the tree changed.
   *
   * @param event the event to send
   */
  protected void fireValueChanged(TreeSelectionEvent event)
  {
    TreeSelectionListener[] listeners = getTreeSelectionListeners();

    for (int index = 0; index < listeners.length; ++index)
      listeners[index].valueChanged(event);
  }

  /**
   * Adds a <code>TreeWillExpandListener</code> object to the tree.
   *
   * @param listener the listener to add
   */
  public void addTreeWillExpandListener(TreeWillExpandListener listener)
  {
    listenerList.add(TreeWillExpandListener.class, listener);
  }

  /**
   * Removes a <code>TreeWillExpandListener</code> object from the tree.
   *
   * @param listener the listener to remove
   */
  public void removeTreeWillExpandListener(TreeWillExpandListener listener)
  {
    listenerList.remove(TreeWillExpandListener.class, listener);
  }

  /**
   * Returns all added <code>TreeWillExpandListener</code> objects.
   *
   * @return an array of listeners
   */
  public TreeWillExpandListener[] getTreeWillExpandListeners()
  {
    return (TreeWillExpandListener[]) getListeners(TreeWillExpandListener.class);
  }

  /**
   * Notifies all listeners that the tree will collapse.
   *
   * @param path the path to the node that will collapse
   */
  public void fireTreeWillCollapse(TreePath path)
    throws ExpandVetoException
  {
    TreeExpansionEvent event = new TreeExpansionEvent(this, path);
    TreeWillExpandListener[] listeners = getTreeWillExpandListeners();

    for (int index = 0; index < listeners.length; ++index)
      listeners[index].treeWillCollapse(event);
  }

  /**
   * Notifies all listeners that the tree will expand.
   *
   * @param path the path to the node that will expand
   */
  public void fireTreeWillExpand(TreePath path)
    throws ExpandVetoException
  {
    TreeExpansionEvent event = new TreeExpansionEvent(this, path);
    TreeWillExpandListener[] listeners = getTreeWillExpandListeners();

    for (int index = 0; index < listeners.length; ++index)
      listeners[index].treeWillExpand(event);
  }

  /**
   * Returns the model of this <code>JTree</code> object.
   *
   * @return the associated <code>TreeModel</code>
   */
  public TreeModel getModel()
  {
    return treeModel;
  }

  /**
   * Sets the model to use in <code>JTree</code>.
   *
   * @param model the <code>TreeModel</code> to use
   */
  public void setModel(TreeModel model)
  {
    if (treeModel == model)
      return;

    TreeModel oldValue = treeModel;
    treeModel = model;
    firePropertyChange(TREE_MODEL_PROPERTY, oldValue, model);

    // add treeModelListener to the new model
    if (treeModelListener == null)
      treeModelListener = createTreeModelListener();
    model.addTreeModelListener(treeModelListener);
  }

  /**
   * Checks if this <code>JTree</code> object is editable.
   *
   * @return <code>true</code> if this tree object is editable,
   * <code>false</code> otherwise
   */
  public boolean isEditable()
  {
    return editable;
  }

  /**
   * Sets the <code>editable</code> property.
   *
   * @param flag <code>true</code> to make this tree object editable,
   * <code>false</code> otherwise
   */
  public void setEditable(boolean flag)
  {
    if (editable == flag)
      return;

    boolean oldValue = editable;
    editable = flag;
    firePropertyChange(EDITABLE_PROPERTY, oldValue, editable);
  }

  /**
   * Checks if the root element is visible.
   *
   * @return <code>true</code> if the root element is visible,
   * <code>false</code> otherwise
   */
  public boolean isRootVisible()
  {
    return rootVisible;
  }

  public void setRootVisible(boolean flag)
  {
    if (rootVisible == flag)
      return;
    
    boolean oldValue = rootVisible;
    rootVisible = flag;
    firePropertyChange(ROOT_VISIBLE_PROPERTY, oldValue, flag);
  }

  public boolean getShowsRootHandles()
  {
    return showsRootHandles;
  }

  public void setShowsRootHandles(boolean flag)
  {
    if (showsRootHandles == flag)
      return;

    boolean oldValue = showsRootHandles;
    showsRootHandles = flag;
    firePropertyChange(SHOWS_ROOT_HANDLES_PROPERTY, oldValue, flag);
  }

  public TreeCellEditor getCellEditor()
  {
    return cellEditor;
  }

  public void setCellEditor(TreeCellEditor editor)
  {
    if (cellEditor == editor)
      return;

    TreeCellEditor oldValue = cellEditor;
    cellEditor = editor;
    firePropertyChange(CELL_EDITOR_PROPERTY, oldValue, editor);
  }
  
  public TreeCellRenderer getCellRenderer()
  {
    return cellRenderer;
  }
  
  public void setCellRenderer(TreeCellRenderer newRenderer)
  {
    if (cellRenderer == newRenderer)
      return;

    TreeCellRenderer oldValue = cellRenderer;
    cellRenderer = newRenderer;
    firePropertyChange(CELL_RENDERER_PROPERTY, oldValue, newRenderer);
  }

  public TreeSelectionModel getSelectionModel()
  {
    return selectionModel;
  }

  public void setSelectionModel(TreeSelectionModel model)
  {
    if (selectionModel == model)
      return;
    
    TreeSelectionModel oldValue = selectionModel;
    selectionModel = model;
    firePropertyChange(SELECTION_MODEL_PROPERTY, oldValue, model);
  }

  public int getVisibleRowCount()
  {
    return visibleRowCount;
  }

  public void setVisibleRowCount(int rows)
  {
    if (visibleRowCount == rows)
      return;

    int oldValue = visibleRowCount;
    visibleRowCount = rows;
    firePropertyChange(VISIBLE_ROW_COUNT_PROPERTY, oldValue, rows);
  }

  public boolean isLargeModel()
  {
    return largeModel;
  }

  public void setLargeModel(boolean large)
  {
    if (largeModel == large)
      return;

    boolean oldValue = largeModel;
    largeModel = large;
    firePropertyChange(LARGE_MODEL_PROPERTY, oldValue, large);
  }

  public int getRowHeight()
  {
    return rowHeight;
  }

  public void setRowHeight(int height)
  {
    if (rowHeight == height)
      return;
    
    int oldValue = rowHeight;
    rowHeight = height;
    firePropertyChange(ROW_HEIGHT_PROPERTY, oldValue, height);
  }

  public boolean isFixedRowHeight()
  {
    return rowHeight > 0;
  }

  public boolean getInvokesStopCellEditing()
  {
    return invokesStopCellEditing;
  }

  public void setInvokesStopCellEditing(boolean invoke)
  {
    if (invokesStopCellEditing == invoke)
     return;

    boolean oldValue = invokesStopCellEditing;
    invokesStopCellEditing = invoke;
    firePropertyChange(INVOKES_STOP_CELL_EDITING_PROPERTY, oldValue, invoke);
  }

  /**
   * @since 1.3
   */
  public int getToggleClickCount()
  {
    return toggleClickCount;
  }

  /**
   * @since 1.3
   */
  public void setToggleClickCount(int count)
  {
    if (toggleClickCount == count)
      return;
    
    int oldValue = toggleClickCount;
    toggleClickCount = count;
    firePropertyChange(TOGGLE_CLICK_COUNT_PROPERTY, oldValue, count);
  }

  public void scrollPathToVisible(TreePath path)
  {
    if (path == null)
      return;

    Rectangle rect = getPathBounds(path);

    if (rect == null)
      return;

    scrollRectToVisible(rect);
  }

  public void scrollRowToVisible(int row)
  {
    scrollPathToVisible(getPathForRow(row));
  }
  
  public boolean getScrollsOnExpand()
  {
    return scrollsOnExpand;
  }

  public void setScrollsOnExpand(boolean scroll)
  {
    if (scrollsOnExpand == scroll)
      return;

    boolean oldValue = scrollsOnExpand;
    scrollsOnExpand = scroll;
    firePropertyChange(SCROLLS_ON_EXPAND_PROPERTY, oldValue, scroll);
  }

  public void setSelectionPath(TreePath path)
  {
    selectionModel.setSelectionPath(path);
  }

  public void setSelectionPaths(TreePath[] paths)
  {
    selectionModel.setSelectionPaths(paths);
  }
  
  public void setSelectionRow(int row)
  {
    TreePath path = getPathForRow(row);

    if (path != null)
      selectionModel.setSelectionPath(path);
  }

  public void setSelectionRows(int[] rows)
  {
    // Make sure we have an UI so getPathForRow() does not return null.
    if (rows == null || getUI() == null)
      return;

    TreePath[] paths = new TreePath[rows.length];

    for (int i = rows.length - 1; i >= 0; --i)
      paths[i] = getPathForRow(rows[i]);

    setSelectionPaths(paths);
  }

  public void setSelectionInterval(int index0, int index1)
  {
    TreePath[] paths = getPathBetweenRows(index0, index1);

    if (paths != null)
      setSelectionPaths(paths);
  }

  public void addSelectionPath(TreePath path)
  {
    selectionModel.addSelectionPath(path);
  }

  public void addSelectionPaths(TreePath[] paths)
  {
    selectionModel.addSelectionPaths(paths);
  }

  public void addSelectionRow(int row)
  {
    TreePath path = getPathForRow(row);

    if (path != null)
      selectionModel.addSelectionPath(path);
  }

  public void addSelectionRows(int[] rows)
  {
    // Make sure we have an UI so getPathForRow() does not return null.
    if (rows == null || getUI() == null)
      return;

    TreePath[] paths = new TreePath[rows.length];

    for (int i = rows.length - 1; i >= 0; --i)
      paths[i] = getPathForRow(rows[i]);

    addSelectionPaths(paths);
  }

  public void addSelectionInterval(int index0, int index1)
  {
    TreePath[] paths = getPathBetweenRows(index0, index1);

    if (paths != null)
      addSelectionPaths(paths);
  }

  public void removeSelectionPath(TreePath path)
  {
    selectionModel.removeSelectionPath(path);
  }

  public void removeSelectionPaths(TreePath[] paths)
  {
    selectionModel.removeSelectionPaths(paths);
  }

  public void removeSelectionRow(int row)
  {
    TreePath path = getPathForRow(row);

    if (path != null)
      selectionModel.removeSelectionPath(path);
  }

  public void removeSelectionRows(int[] rows)
  {
    // Make sure we have an UI so getPathForRow() does not return null.
    if (rows == null || getUI() == null)
      return;

    TreePath[] paths = new TreePath[rows.length];

    for (int i = rows.length - 1; i >= 0; --i)
      paths[i] = getPathForRow(rows[i]);

    removeSelectionPaths(paths);
  }

  public void removeSelectionInterval(int index0, int index1)
  {
    TreePath[] paths = getPathBetweenRows(index0, index1);

    if (paths != null)
      removeSelectionPaths(paths);
  }

  public void clearSelection()
  {
    selectionModel.clearSelection();
  }
  
  public TreePath getLeadSelectionPath()
  {
    return leadSelectionPath;
  }

  /**
   * @since 1.3
   */
  public void setLeadSelectionPath(TreePath path)
  {
    if (leadSelectionPath == path)
      return;

    TreePath oldValue = leadSelectionPath;
    leadSelectionPath = path;
    firePropertyChange(LEAD_SELECTION_PATH_PROPERTY, oldValue, path);
  }

  /**
   * @since 1.3
   */
  public TreePath getAnchorSelectionPath()
  {
    return anchorSelectionPath;
  }

  /**
   * @since 1.3
   */
  public void setAnchorSelectionPath(TreePath path)
  {
    if (anchorSelectionPath == path)
      return;

    TreePath oldValue = anchorSelectionPath;
    anchorSelectionPath = path;
    firePropertyChange(ANCHOR_SELECTION_PATH_PROPERTY, oldValue, path);
  }

  public int getLeadSelectionRow()
  {
    return selectionModel.getLeadSelectionRow();
  }

  public int getMaxSelectionRow()
  {
    return selectionModel.getMaxSelectionRow();
  }

  public int getMinSelectionRow()
  {
    return selectionModel.getMinSelectionRow();
  }

  public int getSelectionCount()
  {
    return selectionModel.getSelectionCount();
  }

  public TreePath getSelectionPath()
  {
    return selectionModel.getSelectionPath();
  }

  public TreePath[] getSelectionPaths()
  {
    return selectionModel.getSelectionPaths();
  }

  public int[] getSelectionRows()
  {
    return selectionModel.getSelectionRows();
  }

  public boolean isPathSelected(TreePath path)
  {
    return selectionModel.isPathSelected(path);
  }

  public boolean isRowSelected(int row)
  {
    return selectionModel.isRowSelected(row);
  }

  public boolean isSelectionEmpty()
  {
    return selectionModel.isSelectionEmpty();
  }
  
  /**
   * Return the value of the <code>dragEnabled</code> property.
   *
   * @return the value
   * 
   * @since 1.4
   */
  public boolean getDragEnabled()
  {
    return dragEnabled;
  }

  /**
   * Set the <code>dragEnabled</code> property.
   *
   * @param enabled new value
   * 
   * @since 1.4
   */
  public void setDragEnabled(boolean enabled)
  {
    dragEnabled = enabled;
  }

  public int getRowCount()
  {
    TreeUI ui = getUI();

    if (ui != null)
      return ui.getRowCount(this);
    
    return 0;
  }
  
  public void collapsePath(TreePath path)
  {
    setExpandedState(path, false);
  }
  
  public void collapseRow(int row)
  {
    if (row < 0 || row >= getRowCount())
      return;

    TreePath path = getPathForRow(row);

    if (path != null)
      collapsePath(path);
  }

  public void expandPath(TreePath path)
  {
    // Don't expand if last path component is a leaf node.
    if ((path == null)
        || (treeModel.isLeaf(path.getLastPathComponent())))
      return;

    setExpandedState(path, true);
  }
  
  public void expandRow(int row)
  {
    if (row < 0 || row >= getRowCount())
      return;

    TreePath path = getPathForRow(row);

    if (path != null)
      expandPath(path);
  }

  public boolean isCollapsed(TreePath path)
  {
    return ! isExpanded(path);
  }

  public boolean isCollapsed(int row)
  {
    if (row < 0 || row >= getRowCount())
      return false;

    TreePath path = getPathForRow(row);

    if (path != null)
      return isCollapsed(path);

    return false;
  }

  public boolean isExpanded(TreePath path)
  {
    if (path == null)
      return false;

    Object state = nodeStates.get(path);

    if ((state == null) || (state != EXPANDED))
      return false;

    TreePath parent = path.getParentPath();

    if (parent != null)
      return isExpanded(parent);
    
    return true;
  }
  
  public boolean isExpanded(int row)
  {
    if (row < 0 || row >= getRowCount())
      return false;

    TreePath path = getPathForRow(row);

    if (path != null)
      return isExpanded(path);

    return false;
  }

  /**
   * @since 1.3
   */
  public boolean getExpandsSelectedPaths()
  {
    return expandsSelectedPaths;
  }

  /**
   * @since 1.3
   */
  public void setExpandsSelectedPaths(boolean flag)
  {
    if (expandsSelectedPaths == flag)
      return;

    boolean oldValue = expandsSelectedPaths;
    expandsSelectedPaths = flag;
    firePropertyChange(EXPANDS_SELECTED_PATHS_PROPERTY, oldValue, flag);
  }

  public Rectangle getPathBounds(TreePath path)
  {
    TreeUI ui = getUI();

    if (ui == null)
      return null;

    return ui.getPathBounds(this, path);
  }

  public Rectangle getRowBounds(int row)
  {
    TreePath path = getPathForRow(row);

    if (path != null)
      return getPathBounds(path);

    return null;
  }

  public boolean isEditing()
  {
    TreeUI ui = getUI();

    if (ui != null)
      return ui.isEditing(this);

    return false;
  }

  public boolean stopEditing()
  {
    TreeUI ui = getUI();

    if (ui != null)
      return ui.stopEditing(this);

   return false;
  }

  public void cancelEditing()
  {
    TreeUI ui = getUI();

    if (ui != null)
      ui.cancelEditing(this);
  }

  public void startEditingAtPath(TreePath path)
  {
    TreeUI ui = getUI();

    if (ui != null)
      ui.startEditingAtPath(this, path);
  }

  public TreePath getEditingPath()
  {
    TreeUI ui = getUI();

    if (ui != null)
      return ui.getEditingPath(this);

    return null;
  }

  public TreePath getPathForLocation(int x, int y)
  {
    TreePath path = getClosestPathForLocation(x, y);

    if (path != null)
      {
	 Rectangle rect = getPathBounds(path);

	 if ((rect != null) && rect.contains(x, y))
	   return path;
      }

    return null;
  }

  public int getRowForLocation(int x, int y)
  {
    TreePath path = getPathForLocation(x, y);

    if (path != null)
      return getRowForPath(path);

    return -1;
  }
  
  public TreePath getClosestPathForLocation(int x, int y)
  {
    TreeUI ui = getUI();

    if (ui != null)
      return ui.getClosestPathForLocation(this, x, y);
    
    return null;
  }

  public int getClosestRowForLocation(int x, int y)
  {
    TreePath path = getClosestPathForLocation(x, y);

    if (path != null)
      return getRowForPath(path);

    return -1;
  }

  public Object getLastSelectedPathComponent()
  {
    TreePath path = getSelectionPath();

    if (path != null)
      return path.getLastPathComponent();

    return null;
  }

  private void checkExpandParents(TreePath path)
    throws ExpandVetoException
  {
    TreePath parent = path.getParentPath();

    if (parent != null)
      checkExpandParents(parent);

    fireTreeWillExpand(path);
  }

  private void doExpandParents(TreePath path, boolean state)
  {
    TreePath parent = path.getParentPath();

    if (isExpanded(parent))
      return;
    
    if (parent != null)
      doExpandParents(parent, false);

    nodeStates.put(path, state ? EXPANDED : COLLAPSED);
  }
  
  protected void setExpandedState(TreePath path, boolean state)
  {
    if (path == null)
      return;

    TreePath parent = path.getParentPath();

    try
      {
	while (parent != null)
	  checkExpandParents(parent);
      }
    catch (ExpandVetoException e)
      {
	// Expansion vetoed.
	return;
      }

    doExpandParents(path, state);
  }

  protected void clearToggledPaths()
  {
    nodeStates.clear();
  }

  protected Enumeration getDescendantToggledPaths(TreePath parent)
  {
    if (parent == null)
      return null;

    Enumeration nodes = nodeStates.keys();
    Vector result = new Vector();

    while (nodes.hasMoreElements())
      {
        TreePath path = (TreePath) nodes.nextElement();

        if (path.isDescendant(parent))
          result.addElement(path);
      }
    
    return result.elements();
  }

  public boolean hasBeenExpanded(TreePath path)
  {
    if (path == null)
      return false;

    return nodeStates.get(path) != null;
  }

  public boolean isVisible(TreePath path)
  {
    if (path == null)
      return false;

    TreePath parent = path.getParentPath();

    if (parent == null)
      return true; // Is root node.

    return isExpanded(parent);
  }

  public void makeVisible(TreePath path)
  {
    if (path == null)
      return;

    expandPath(path.getParentPath());
  }

  public boolean isPathEditable(TreePath path)
  {    
    return isEditable();
  }

  /**
   * Creates and returns an instance of {@link TreeModelHandler}.
   *
   * @returns an instance of {@link TreeModelHandler}
   */
  protected TreeModelListener createTreeModelListener()
  {
    return new TreeModelHandler();
  }

  /**
   * Returns a sample TreeModel that can be used in a JTree. This can
   * be used in Bean- or GUI-Builders to show something interesting.
   *
   * @return a sample TreeModel that can be used in a JTree
   */
  protected static TreeModel getDefaultTreeModel()
  {
    DefaultMutableTreeNode root = new DefaultMutableTreeNode("Root node");
    DefaultMutableTreeNode child1 = new DefaultMutableTreeNode("Child node 1");
    DefaultMutableTreeNode child11 =
      new DefaultMutableTreeNode("Child node 1.1");
    DefaultMutableTreeNode child12 =
      new DefaultMutableTreeNode("Child node 1.2");
    DefaultMutableTreeNode child13 =
      new DefaultMutableTreeNode("Child node 1.3");
    DefaultMutableTreeNode child2 = new DefaultMutableTreeNode("Child node 2");
    DefaultMutableTreeNode child21 =
      new DefaultMutableTreeNode("Child node 2.1");
    DefaultMutableTreeNode child22 =
      new DefaultMutableTreeNode("Child node 2.2");
    DefaultMutableTreeNode child23 =
      new DefaultMutableTreeNode("Child node 2.3");
    DefaultMutableTreeNode child24 =
      new DefaultMutableTreeNode("Child node 2.4");

    DefaultMutableTreeNode child3 = new DefaultMutableTreeNode("Child node 3");
    root.add(child1);
    root.add(child2);
    root.add(child3);
    child1.add(child11);
    child1.add(child12);
    child1.add(child13);
    child2.add(child21);
    child2.add(child22);
    child2.add(child23);
    child2.add(child24);
    return new DefaultTreeModel(root);
  }

  /**
   * Converts the specified value to a String. This is used by the
   * renderers of this JTree and its nodes.
   *
   * This implementation simply returns <code>value.toString()</code> and
   * ignores all other parameters.
   * Subclass this method to control the conversion.
   *
   * @param value the value that is converted to a String
   * @param selected indicates if that value is selected or not
   * @param expanded indicates if that value is expanded or not
   * @param leaf indicates if that value is a leaf node or not
   * @param row the row of the node
   * @param hasFocus indicates if that node has focus or not
   */
  public String convertValueToText(Object value, boolean selected,
                                   boolean expanded, boolean leaf, int row,
                                   boolean hasFocus)
  {
    return value.toString();
  }

  /**
   * A String representation of this JTree. This is intended to be used
   * for debugging. The returned string may be empty but may not be
   * <code>null</code>.
   *
   * @return a String representation of this JTree
   */
  public String paramString()
  {
    // TODO: this is completely legal, but it would possibly be nice
    // to return some more content, like the tree structure, some properties
    // etc ...
    return "";
  }

  /**
   * Returns all TreePath objects which are a descendants of 
   * the given path and are exapanded at the moment of the
   * execution of this method. If the state of any node 
   * is beeing toggled while this method is executing this 
   * change may be left unaccounted.
   *  
   * @param path The parent of this request
   * @return An Enumeration containing TreePath objects
   */
  public Enumeration getExpandedDescendants(TreePath path) 
  {
    Enumeration paths = nodeStates.keys();
    Vector relevantPaths = new Vector();
    while(paths.hasMoreElements())
      {
        TreePath nextPath = (TreePath) paths.nextElement();
        if(nodeStates.get(nextPath) == EXPANDED && 
           path.isDescendant(nextPath)) 
          {
            relevantPaths.add(nextPath);
          }
      }
    return relevantPaths.elements();
  }

  /**
   * Returns the next table element (beginning from the row
   * <code>startingRow</code>
   * that starts with <code>prefix</code>. Searching is done in the direction
   * specified by <code>bias</code>.
   *
   * @param prefix the prefix to search for in the cell values
   * @param startingRow the index of the row where to start searching from
   * @param bias the search direction, either {@link Position.Bias.Forward}
   *     or {@link Position.Bias.Backward}
   *
   * @return the path to the found element or -1 if no such element has
   *     been found
   *
   * @throws IllegalArgumentException if prefix is <code>null</code> or
   *     startingRow is not valid
   *
   * @since 1.4
   */
  public TreePath getNextMatch(String prefix, int startingRow,
                               Position.Bias bias)
  {
    if (prefix == null)
      throw new IllegalArgumentException("The argument 'prefix' must not be"
                                         + " null.");
    if (startingRow < 0)
      throw new IllegalArgumentException("The argument 'startingRow' must not"
                                         + " be less than zero.");

    int size = getRowCount();
    if (startingRow > size)
      throw new IllegalArgumentException("The argument 'startingRow' must not"
                                         + " be greater than the number of"
                                         + " elements in the TreeModel.");

    TreePath foundPath = null;
    if (bias == Position.Bias.Forward)
      {
        for (int i = startingRow; i < size; i++)
          {
            TreePath path = getPathForRow(i);
            Object o = path.getLastPathComponent();
            // FIXME: in the following call to convertValueToText the
            // last argument (hasFocus) should be done right.
            String item = convertValueToText(o, isRowSelected(i),
                                             isExpanded(i),
                                             treeModel.isLeaf(o), i, false);
            if (item.startsWith(prefix))
              {
                foundPath = path;
                break;
              }
          }
      }
    else
      {
        for (int i = startingRow; i >= 0; i--)
          {
            TreePath path = getPathForRow(i);
            Object o = path.getLastPathComponent();
            // FIXME: in the following call to convertValueToText the
            // last argument (hasFocus) should be done right.
            String item = convertValueToText(o, isRowSelected(i),
                                             isExpanded(i),
                                             treeModel.isLeaf(o), i, false);
            if (item.startsWith(prefix))
              {
                foundPath = path;
                break;
              }
          }
      }
    return foundPath;
  }
}