/*
 * @(#)JTree.java	1.111 01/11/29
 *
 * Copyright 2002 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

package javax.swing;

import java.awt.*;
import java.awt.event.*;
import java.beans.*;
import java.io.*;
import java.util.*;
import javax.swing.event.*;
import javax.swing.plaf.TreeUI;
import javax.swing.tree.*;
import javax.accessibility.*;


/**
 * A control that displays a set of hierarchical data as an outline.
 * A specific node can be identified either by a TreePath (an object
 * that encapsulates a node and all of its ancestors), or by its
 * display row, where each row in the display area displays one node.
 * <p>
 * An <i>expanded</i> node is one displays its children. A <i>collapsed</i>
 * node is one which hides them. A <i>hidden</i> node is one which is
 * under a collapsed parent. A <i>viewable</i> node is under a collapsed 
 * parent, but may or may not be displayed. A <i>displayed</i> node
 * is both viewable and in the display area, where it can be seen.
 * <p>
 * These JTree methods use "visible" to mean "displayed":<ul>
 * <li><code>isRootVisible()</code>
 * <li><code>setRootVisible()</code>
 * <li><code>scrollPathToVisible()</code>
 * <li><code>scrollRowToVisible()</code>
 * <li><code>getVisibleRowCount()</code>
 * <li><code>setVisibleRowCount()</code>
 * </ul>
 * <p>
 * These JTree methods use "visible" to mean "viewable" (under an
 * expanded parent):<ul>
 * <li><code>isVisible()</code>
 * <li><code>makeVisible()</code>
 * </ul>
 * <p>
 * If you are interested in knowing when the selection changes implement
 * the TreeSelectionListener interface and add the instance using the
 * method addTreeSelectionListener. valueChanged will be invoked when the
 * selection changes, that is if the user clicks twice on the same
 * node valueChanged will only be invoked once.
 * <p>
 * If you are interested in knowing either double clicks events or when
 * a user clicks on a node, regardless of whether or not it was selected
 * it is recommended you do the following:
 * <pre>
 * final JTree tree = ...;
 *
 * MouseListener ml = new MouseAdapter() {
 *     public void <b>mouseClicked</b>(MouseEvent e) {
 *         int selRow = tree.getRowForLocation(e.getX(), e.getY());
 *         TreePath selPath = tree.getPathForLocation(e.getX(), e.getY());
 *         if(selRow != -1) {
 *             if(e.getClickCount() == 1) {
 *                 mySingleClick(selRow, selPath);
 *             }
 *             else if(e.getClickCount() == 2) {
 *                 myDoubleClick(selRow, selPath);
 *             }
 *         }
 *     }
 * };
 * tree.addMouseListener(ml);
 * </pre>
 * NOTE: This example obtains both the path and row, but you only need to
 * get the one you're interested in.
 * <p>
 * To use JTree to display compound nodes (for example, nodes containing both
 * a graphic icon and text), subclass {@link TreeCellRenderer} and use 
 * {@link #setTreeCellRenderer} to tell the tree to use it. To edit such nodes,
 * subclass {@link TreeCellEditor} and use {@link #setTreeCellEditor}.
 * <p>
 * Like all JComponent classes, you can use {@link JComponent#registerKeyboardAction}
 * to associate an {@link Action} object with a {@link KeyStroke} and execute the
 * action under specified conditions.
 * <p>
 * See <a href="http://java.sun.com/docs/books/tutorial/ui/swing/tree.html">How to Use Trees</a>
 * in <a href="http://java.sun.com/Series/Tutorial/index.html"><em>The Java Tutorial</em></a>
 * for further documentation.
 * <p>
 * For the keyboard keys used by this component in the standard Look and
 * Feel (L&F) renditions, see the
 * <a href="doc-files/Key-Index.html#JTree">JTree</a> key assignments.
 * <p>
 * <strong>Warning:</strong>
 * Serialized objects of this class will not be compatible with
 * future Swing releases.  The current serialization support is appropriate
 * for short term storage or RMI between applications running the same
 * version of Swing.  A future release of Swing will provide support for
 * long term persistence.
 *
 * @beaninfo
 *   attribute: isContainer false
 *
 * @version 1.78 05/11/98
 * @author Rob Davis
 * @author Ray Ryan
 * @author Scott Violet
 */
public class JTree extends JComponent implements Scrollable, Accessible
{
    /**
     * @see #getUIClassID
     * @see #readObject
     */
    private static final String uiClassID = "TreeUI";

    /**
     * The model that defines the tree displayed by this object.
     */
    transient protected TreeModel        treeModel;

    /**
     * Models the set of selected nodes in this tree.
     */
    transient protected TreeSelectionModel selectionModel;

    /**
     * True if the root node is displayed, false if its children are
     * the highest visible nodes.
     */
    protected boolean                    rootVisible;

    /**
     * The cell used to draw nodes. If null, the UI uses a default
     * cellRenderer.
     */
    transient protected TreeCellRenderer  cellRenderer;

    /**
     * Height to use for each display row. If this is <= 0 the renderer 
     * determines the height for each row.
     */
    protected int                         rowHeight;

    /**
     * Maps from TreePath to Boolean indicating whether or not the
     * particular path is expanded. This ONLY indicates whether a 
     * given path is expanded, and NOT if it is visible or not. That
     * information must be determined by visiting all the parent
     * paths and seeing if they are visible.
     */
    transient private Hashtable           expandedState;


    /**
     * True if handles are displayed at the topmost level of the tree.
     * <p>
     * A handle is a small icon that displays adjacent to the node which 
     * allows the user to click once to expand or collapse the node. A
     * common interface shows a plus sign (+) for a node which can be
     * expanded and a minus sign (-) for a node which can be collapsed.
     * Handles are always shown for nodes below the topmost level.
     * <p>
     * If the <code>rootVisible</code> setting specifies that the root 
     * node is to be displayed, then that is the only node at the topmost
     * level. If the root node is not displayed, then all of its 
     * children are at the topmost level of the tree. Handles are 
     * always displayed for nodes other than the topmost.
     * <p> 
     * If the root node isn't visible, it is generally a good to make 
     * this value true. Otherwise, the tree looks exactly like a list,
     * and users may not know that the "list entries" are actually
     * tree nodes.
     *
     * @see #rootVisible
     */
    protected boolean           showsRootHandles;

    /**
     * Creates a new event and passed it off the selectionListeners.
     */
    protected transient TreeSelectionRedirector selectionRedirector;

    /**
     * Editor for the entries.  Default is null (tree is not editable).
     */
    transient protected TreeCellEditor          cellEditor;

    /**
     * Is the tree editable? Default is false.
     */
    protected boolean                 editable;

    /**
     * Is this tree a large model? This is a code-optimization setting.
     * A large model can be used when the cell height is the same for all
     * nodes. The UI will then cache very little information and instead
     * continually message the model. Without a large model the UI caches 
     * most of the information, resulting in fewer method calls to the model.
     * <p>
     * This value is only a suggestion to the UI. Not all UIs will
     * take advantage of it. Default value is false.
     */
    protected boolean                 largeModel;

    /**
     * Number of rows to make visible at one time. This value is used for
     * the Scrollable interface. It determines the preferred size of the 
     * display area.
     */
    protected int                     visibleRowCount;

    /**
     * If true, when editing is to be stopped by way of selection changing,
     * data in tree changing or other means stopCellEditing is invoked, and
     * changes are saved. If false, cancelCellEditing is invoked, and changes
     * are discarded. Default is false.
     */
    protected boolean                 invokesStopCellEditing;

    /**
     * If true, when a node is expanded, as many of the descendants are 
     * scrolled to be visible.
     */
    protected boolean                 scrollsOnExpand;

    /**
     * Number of mouse clicks before a node is expanded.
     */
    protected int                     toggleClickCount;

    /**
     * Updates the expandedState.
     */
    transient protected TreeModelListener       treeModelListener;

    /**
     * Used when setExpandedState is invoked, will be a Stack of Stacks.
     */
    transient private Stack           expandedStack;

    /**
     * Max number of stacks to keep around.
     */
    private static int                TEMP_STACK_SIZE = 11;

    //
    // Bound propery names
    //
    /** Bound property name for cellRenderer. */
    public final static String        CELL_RENDERER_PROPERTY = "cellRenderer";
    /** Bound property name for treeModel. */
    public final static String        TREE_MODEL_PROPERTY = "treeModel";
    /** Bound property name for rootVisible. */
    public final static String        ROOT_VISIBLE_PROPERTY = "rootVisible";
    /** Bound property name for showsRootHandles. */
    public final static String        SHOWS_ROOT_HANDLES_PROPERTY = "showsRootHandles";
    /** Bound property name for rowHeight. */
    public final static String        ROW_HEIGHT_PROPERTY = "rowHeight";
    /** Bound property name for cellEditor. */
    public final static String        CELL_EDITOR_PROPERTY = "cellEditor";
    /** Bound property name for editable. */
    public final static String        EDITABLE_PROPERTY = "editable";
    /** Bound property name for largeModel. */
    public final static String        LARGE_MODEL_PROPERTY = "largeModel";
    /** Bound property name for selectionModel. */
    public final static String        SELECTION_MODEL_PROPERTY = "selectionModel";
    /** Bound property name for visibleRowCount. */
    public final static String        VISIBLE_ROW_COUNT_PROPERTY = "visibleRowCount";
    /** Bound property name for messagesStopCellEditing. */
    public final static String        INVOKES_STOP_CELL_EDITING_PROPERTY = "messagesStopCellEditing";
    /** Bound property name for scrollsOnExpand. */
    public final static String        SCROLLS_ON_EXPAND_PROPERTY = "scrollsOnExpand";
    /** Bound property name for toggleClickCount. */
    //public final static String        TOGGLE_CLICK_COUNT_PROPERTY = "toggleClickCount";


    /**
     * Creates and returns a sample TreeModel. Used primarily for beanbuilders.
     * to show something interesting.
     *
     * @return the default TreeModel
     */
    protected static TreeModel getDefaultTreeModel() {
        DefaultMutableTreeNode      root = new DefaultMutableTreeNode("JTree");
	DefaultMutableTreeNode      parent;

	parent = new DefaultMutableTreeNode("colors");
	root.add(parent);
	parent.add(new DefaultMutableTreeNode("blue"));
	parent.add(new DefaultMutableTreeNode("violet"));
	parent.add(new DefaultMutableTreeNode("red"));
	parent.add(new DefaultMutableTreeNode("yellow"));

	parent = new DefaultMutableTreeNode("sports");
	root.add(parent);
	parent.add(new DefaultMutableTreeNode("basketball"));
	parent.add(new DefaultMutableTreeNode("soccer"));
	parent.add(new DefaultMutableTreeNode("football"));
	parent.add(new DefaultMutableTreeNode("hockey"));

	parent = new DefaultMutableTreeNode("food");
	root.add(parent);
	parent.add(new DefaultMutableTreeNode("hot dogs"));
	parent.add(new DefaultMutableTreeNode("pizza"));
	parent.add(new DefaultMutableTreeNode("ravioli"));
	parent.add(new DefaultMutableTreeNode("bananas"));
        return new DefaultTreeModel(root);
    }

    /**
     * Returns a TreeModel wrapping the specified object. If the object
     * is:<ul>
     * <li>an array of Objects,
     * <li>a Hashtable, or
     * <li>a Vector
     * </ul>then a new root node is created with each of the incoming 
     * objects as children. Otherwise, a new root is created with the 
     * specified object as its value.
     *
     * @param value  the Object used as the foundation for the TreeModel
     * @return a TreeModel wrapping the specified object
     */
    protected static TreeModel createTreeModel(Object value) {
        DefaultMutableTreeNode           root;

        if((value instanceof Object[]) || (value instanceof Hashtable) ||
           (value instanceof Vector)) {
            root = new DefaultMutableTreeNode("root");
            DynamicUtilTreeNode.createChildren(root, value);
        }
        else {
            root = new DynamicUtilTreeNode("root", value);
        }
        return new DefaultTreeModel(root, false);
    }

    /**
     * Returns a JTree with a sample model.
     * The default model used by the tree defines a leaf node as any node without
     * children.
     *
     * @return a JTree with the default model, which defines a leaf node
     *         as any node without children.
     * @see DefaultTreeModel#asksAllowsChildren
     */
    public JTree() {
        this(getDefaultTreeModel());
    }

    /**
     * Returns a JTree with each element of the specified array as the
     * child of a new root node which is not displayed.
     * By default, the tree defines a leaf node as any node without
     * children.
     *
     * @param value  an array of Objects
     * @return a JTree with the contents of the array as children of
     *         the root node
     * @see DefaultTreeModel#asksAllowsChildren
     */
    public JTree(Object[] value) {
        this(createTreeModel(value));
        this.setRootVisible(false);
        this.setShowsRootHandles(true);
    }

    /**
     * Returns a JTree with each element of the specified Vector as the
     * child of a new root node which is not displayed. By default, the
     * tree defines a leaf node as any node without children.
     *
     * @param value  a Vector
     * @return a JTree with the contents of the Vector as children of
     *         the root node
     * @see DefaultTreeModel#asksAllowsChildren
     */
    public JTree(Vector value) {
        this(createTreeModel(value));
        this.setRootVisible(false);
        this.setShowsRootHandles(true);
    }

    /**
     * Returns a JTree created from a Hashtable which does not display
     * the root. Each value-half of the key/value pairs in the HashTable
     * becomes a child of the new root node. By default, the tree defines
     * a leaf node as any node without children.
     *
     * @param value  a Hashtable
     * @return a JTree with the contents of the Hashtable as children of
     *         the root node
     * @see DefaultTreeModel#asksAllowsChildren
     */
    public JTree(Hashtable value) {
        this(createTreeModel(value));
        this.setRootVisible(false);
        this.setShowsRootHandles(true);
    }

    /**
     * Returns a JTree with the specified TreeNode as its root, which  
     * displays the root node. By default, the tree defines a leaf node as any node
     * without children.
     *
     * @param root  a TreeNode object
     * @return a JTree with the specified root node
     * @see DefaultTreeModel#asksAllowsChildren
     */
    public JTree(TreeNode root) {
        this(root, false);
    }

    /**
     * Returns a JTree with the specified TreeNode as its root, which 
     * displays the root node and which decides whether a node is a 
     * leaf node in the specified manner.
     *
     * @param root  a TreeNode object
     * @param asksAllowsChildren  if false, any node without children is a 
     *              leaf node. If true, only nodes that do not allow 
     *              children are leaf nodes.
     * @return a JTree with the specified root node
     * @see DefaultTreeModel#asksAllowsChildren
     */
    public JTree(TreeNode root, boolean asksAllowsChildren) {
        this(new DefaultTreeModel(root, asksAllowsChildren));
    }

    /**
     * Returns an instance of JTree which displays the root node 
     * -- the tree is created using the specified data model.
     *
     * @param newModel  the TreeModel to use as the data model
     * @return a JTree based on the TreeModel
     */
    public JTree(TreeModel newModel) {
        super();
	expandedStack = new Stack();
	toggleClickCount = 2;
	expandedState = new Hashtable();
        setLayout(null);
        rowHeight = 16;
        visibleRowCount = 20;
        rootVisible = true;
        selectionModel = new DefaultTreeSelectionModel();
        cellRenderer = null;
	scrollsOnExpand = true;
        setOpaque(true);
        updateUI();
        setModel(newModel);
    }

    /**
     * Returns the L&F object that renders this component.
     *
     * @return the TreeUI object that renders this component
     */
    public TreeUI getUI() {
        return (TreeUI)ui;
    }

    /**
     * Sets the L&F object that renders this component.
     *
     * @param ui  the TreeUI L&F object
     * @see UIDefaults#getUI
     */
    public void setUI(TreeUI ui) {
        if ((TreeUI)this.ui != ui) {
            super.setUI(ui);
            repaint();
        }
    }

    /**
     * Notification from the UIManager that the L&F has changed. 
     * Replaces the current UI object with the latest version from the 
     * UIManager.
     *
     * @see JComponent#updateUI
     */
    public void updateUI() {
        setUI((TreeUI)UIManager.getUI(this));
        invalidate();
    }


    /**
     * Returns the name of the L&F class that renders this component.
     *
     * @return "TreeUI"
     * @see JComponent#getUIClassID
     * @see UIDefaults#getUI
     */
    public String getUIClassID() {
        return uiClassID;
    }


    /**
     * Returns the current TreeCellRenderer that is rendering each cell.
     *
     * @return the TreeCellRenderer that is rendering each cell
     */
    public TreeCellRenderer getCellRenderer() {
        return cellRenderer;
    }

    /**
     * Sets the TreeCellRenderer that will be used to draw each cell.
     *
     * @param x  the TreeCellRenderer that is to render each cell
     * @beaninfo
     *        bound: true
     *  description: The TreeCellRenderer that will be used to draw
     *               each cell.
     */
    public void setCellRenderer(TreeCellRenderer x) {
        TreeCellRenderer oldValue = cellRenderer;

        cellRenderer = x;
        firePropertyChange(CELL_RENDERER_PROPERTY, oldValue, cellRenderer);
        invalidate();
    }

    /**
      * Determines whether the tree is editable. Fires a property
      * change event if the new setting is different from the existing
      * setting.
      *
      * @param flag  a boolean value, true if the tree is editable
      * @beaninfo
      *        bound: true
      *  description: Whether the tree is editable.
      */
    public void setEditable(boolean flag) {
        boolean                 oldValue = this.editable;

        this.editable = flag;
        firePropertyChange(EDITABLE_PROPERTY, oldValue, flag);
        if (accessibleContext != null) {
            accessibleContext.firePropertyChange(
                AccessibleContext.ACCESSIBLE_STATE_PROPERTY, 
                (oldValue ? AccessibleState.EDITABLE : null),
                (flag ? AccessibleState.EDITABLE : null));
        }
    }

    /**
     * Returns true if the tree is editable.
     *
     * @return true if the tree is editable.
     */
    public boolean isEditable() {
        return editable;
    }

    /**
     * Sets the cell editor.  A null value implies that the
     * tree cannot be edited.  If this represents a change in the
     * cellEditor, the propertyChange method is invoked on all
     * listeners.
     *
     * @param cellEditor the TreeCellEditor to use
     * @beaninfo
     *        bound: true
     *  description: The cell editor. A null value implies the tree
     *               cannot be edited.
     */
    public void setCellEditor(TreeCellEditor cellEditor) {
        TreeCellEditor        oldEditor = this.cellEditor;

        this.cellEditor = cellEditor;
        firePropertyChange(CELL_EDITOR_PROPERTY, oldEditor, cellEditor);
        invalidate();
    }

    /**
     * Returns the editor used to edit entries in the tree.
     *
     * @return the TreeCellEditor in use, or null if the tree cannot
     *         be edited
     */
    public TreeCellEditor getCellEditor() {
        return cellEditor;
    }

    /**
     * Returns the TreeModel that is providing the data.
     *
     * @return the TreeModel that is providing the data
     */
    public TreeModel getModel() {
        return treeModel;
    }

    /**
     * Sets the TreeModel that will provide the data.
     *
     * @param newModel the TreeModel that is to provide the data
     * @beaninfo
     *        bound: true
     *  description: The TreeModel that will provide the data.
     */
    public void setModel(TreeModel newModel) {
        TreeModel oldModel = treeModel;

	if(treeModel != null && treeModelListener != null)
	    treeModel.removeTreeModelListener(treeModelListener);

        if (accessibleContext != null) {
	    if (treeModel != null) {
                treeModel.removeTreeModelListener((TreeModelListener)accessibleContext);
	    }
            if (newModel != null) {
	        newModel.addTreeModelListener((TreeModelListener)accessibleContext);
	    }
        }

        treeModel = newModel;
	clearToggledPaths();
	if(treeModel != null) {
	    if(treeModelListener == null)
		treeModelListener = createTreeModelListener();
	    if(treeModelListener != null)
		treeModel.addTreeModelListener(treeModelListener);
	    // Mark the root as expanded, if it isn't a leaf.
	    if(!treeModel.isLeaf(treeModel.getRoot()))
		expandedState.put(new TreePath(treeModel.getRoot()),
				  Boolean.TRUE);
	}
        firePropertyChange(TREE_MODEL_PROPERTY, oldModel, treeModel);
        invalidate();
    }

    /**
     * Returns true if the root node of the tree is displayed.
     *
     * @return true if the root node of the tree is displayed
     * @see #rootVisible
     */
    public boolean isRootVisible() {
        return rootVisible;
    }

    /**
     * Determines whether or not the root node from
     * the TreeModel is visible.
     *
     * @param rootVisible true if the root node of the tree is to be displayed
     * @see #rootVisible
     * @beaninfo
     *        bound: true
     *  description: Whether or not the root node 
     *               from the TreeModel is visible.
     */
    public void setRootVisible(boolean rootVisible) {
        boolean                oldValue = this.rootVisible;

        this.rootVisible = rootVisible;
        firePropertyChange(ROOT_VISIBLE_PROPERTY, oldValue, this.rootVisible);
        if (accessibleContext != null) {
            ((AccessibleJTree)accessibleContext).fireVisibleDataPropertyChange();
        }
    }

    /**
     * Determines whether the node handles are to be displayed.
     * 
     * @param newValue true if root handles are to be displayed
     * @see #showsRootHandles
     * @beaninfo
     *        bound: true
     *  description: Whether the node handles are to be
     *               displayed.
     */
    public void setShowsRootHandles(boolean newValue) {
        boolean                oldValue = showsRootHandles;
	TreeModel              model = getModel();

        showsRootHandles = newValue;
        firePropertyChange(SHOWS_ROOT_HANDLES_PROPERTY, oldValue,
                           showsRootHandles);
        if (accessibleContext != null) {
            ((AccessibleJTree)accessibleContext).fireVisibleDataPropertyChange();
        }
	// Make SURE the root is expanded
	if(model != null) {
	    expandPath(new TreePath(model.getRoot()));
	}
        invalidate();
    }

    /**
     * Returns true if handles for the root nodes are displayed.
     * 
     * @return true if root handles are displayed
     * @see #showsRootHandles
     */
    public boolean getShowsRootHandles()
    {
        return showsRootHandles;
    }

    /**
     * Sets the height of each cell.  If the specified value
     * is less than or equal to zero the current cell renderer is
     * queried for each row's height.
     *
     * @param rowHeight the height of each cell, in pixels
     * @beaninfo
     *        bound: true
     *  description: The height of each cell.
     */
    public void setRowHeight(int rowHeight)
    {
        int                oldValue = this.rowHeight;

        this.rowHeight = rowHeight;
        firePropertyChange(ROW_HEIGHT_PROPERTY, oldValue, this.rowHeight);
        invalidate();
    }

    /**
     * Returns the height of each row.  If the returned value is less than
     * or equal to 0 the height for each row is determined by the
     * renderer.
     *
     * @param the height of each cell, in pixels. Zero or negative if the
     *        height of each row is determined by the tree cell renderer
     */
    public int getRowHeight()
    {
        return rowHeight;
    }

    /**
     * Returns true if the height of each display row is a fixed size.
     *
     * @return true if the height of each row is a fixed size
     */
    public boolean isFixedRowHeight()
    {
        return (rowHeight > 0);
    }

    /**
     * Specifies whether the UI should use a large model.
     * (Not all UIs will implement this.) Fires a property change
     * for the LARGE_MODEL_PROPERTY.
     * 
     * @param newValue true to suggest a large model to the UI
     * @see #largeModel
     * @beaninfo
     *        bound: true
     *  description: Whether the UI should use a 
     *               large model.
     */
    public void setLargeModel(boolean newValue) {
        boolean                oldValue = largeModel;

        largeModel = newValue;
        firePropertyChange(LARGE_MODEL_PROPERTY, oldValue, newValue);
    }

    /**
     * Returns true if the tree is configured for a large model.
     * 
     * @return true if a large model is suggested
     * @see #largeModel
     */
    public boolean isLargeModel() {
        return largeModel;
    }

    /**
     * Determines what happens when editing is interrupted by selecting
     * another node in the tree, a change in the tree's data, or by some
     * other means. Setting this property to <code>true</code> causes the
     * changes to be automatically saved when editing is interrupted.
     * <p>
     * Fires a property change for the INVOKES_STOP_CELL_EDITING_PROPERTY.
     *
     * @param newValue true means that stopCellEditing is invoked when
     *        editing is interruped, and data is saved. False means that
     *        cancelCellEditing is invoked, and changes are lost.
     * @beaninfo
     *        bound: true
     *  description: Determines what happens when editing is interrupted,
     *               selecting another node in the tree, a change in the
     *               tree's data, or some other means.
     */
    public void setInvokesStopCellEditing(boolean newValue) {
        boolean                  oldValue = invokesStopCellEditing;

        invokesStopCellEditing = newValue;
        firePropertyChange(INVOKES_STOP_CELL_EDITING_PROPERTY, oldValue,
                           newValue);
    }

    /**
     * Returns the indicator that tells what happens when editing is 
     * interrupted.
     *
     * @return the indicator that tells what happens when editing is 
     *         interrupted
     * @see #setInvokesStopCellEditing
     */
    public boolean getInvokesStopCellEditing() {
        return invokesStopCellEditing;
    }

    /**
     * Determines whether or not when a node is expanded, as many of
     * the descendants are scrolled to be inside the viewport as
     * possible. The default is true.
     */
    public void setScrollsOnExpand(boolean newValue) {
	boolean           oldValue = scrollsOnExpand;

	scrollsOnExpand = newValue;
        firePropertyChange(SCROLLS_ON_EXPAND_PROPERTY, oldValue,
                           newValue);
    }

    /**
     * Returns true if the tree scrolls to show previously hidden children.
     * @return true if when a node is expanded as many of the descendants
     * as possible are scrolled to be visible.
     */
    public boolean getScrollsOnExpand() {
	return scrollsOnExpand;
    }

    // NOTE: This property will be enabled in a future release.
    /**
     * Sets the number of mouse clicks before a node will expand or close.
     * The default is two. 
     */
/*
    public void setToggleClickCount(int clickCount) {
	int         oldCount = toggleClickCount;

	toggleClickCount = clickCount;
	firePropertyChange(TOGGLE_CLICK_COUNT_PROPERTY, oldCount,
			   clickCount);
    }
*/

    /**
     * Returns the number of mouse clicks needed to expand or close a node.
     * @return number of mouse clicks before node is expanded.
     */
/*
    public int getToggleClickCount() {
	return toggleClickCount;
    }
*/

    /**
     * Returns <code>isEditable</code>. This is invoked from the UI before
     * editing begins to insure that the given path can be edited. This
     * is provided as an entry point for subclassers to add filtered
     * editing without having to resort to creating a new editor.
     *
     * @return true if every parent node and the node itself is editabled
     * @see #isEditable
     */
    public boolean isPathEditable(TreePath path) {
        return isEditable();
    }

    /**
     * Overrides JComponent's getToolTipText method in order to allow 
     * renderer's tips to be used if it has text set.
     * <p>
     * NOTE: For JTree to properly display tooltips of its renderers
     *       JTree must be a registered component with the ToolTipManager.
     *       This can be done by invoking
     *       <code>ToolTipManager.sharedInstance().registerComponent(tree)</code>.
     *       This is not done automaticly!
     *
     * @param event the MouseEvent that initiated the ToolTip display
     */
    public String getToolTipText(MouseEvent event) {
        if(event != null) {
            Point p = event.getPoint();
            int selRow = getRowForLocation(p.x, p.y);
            TreeCellRenderer       r = getCellRenderer();

            if(selRow != -1 && r != null) {
                TreePath     path = getPathForRow(selRow);
                Object       lastPath = path.getLastPathComponent();
                Component    rComponent = r.getTreeCellRendererComponent
                    (this, lastPath, isRowSelected(selRow),
                     isExpanded(selRow), getModel().isLeaf(lastPath), selRow,
                     true);

                if(rComponent instanceof JComponent) {
                    MouseEvent      newEvent;
                    Rectangle       pathBounds = getPathBounds(path);

                    p.translate(-pathBounds.x, -pathBounds.y);
                    newEvent = new MouseEvent(rComponent, event.getID(),
                                          event.getWhen(),
                                              event.getModifiers(),
                                              p.x, p.y, event.getClickCount(),
                                              event.isPopupTrigger());
                    
                    return ((JComponent)rComponent).getToolTipText(newEvent);
                }
            }
        }
        return null;
    }
    
    /**
     * Called by the renderers to convert the specified value to
     * text. This implementation returns value.toString(), ignoring
     * all other arguments. To control the conversion, subclass this 
     * method and use any of the arguments you need.
     * 
     * @param value the Object to convert to text
     * @param selected true if the node is selected
     * @param expanded true if the node is expanded
     * @param leaf  true if the node is a leaf node
     * @param row  an int specifying the node's display row, where 0 is 
     *             the first row in the display
     * @param hasFocus true if the node has the focus
     * @return the String representation of the node's value
     */
    public String convertValueToText(Object value, boolean selected,
                                     boolean expanded, boolean leaf, int row,
                                     boolean hasFocus) {
        if(value != null)
            return value.toString();
        return "";
    }

    //
    // The following are convenience methods that get forwarded to the
    // current TreeUI.
    //

    /**
     * Returns the number of rows that are currently being displayed.
     *
     * @return the number of rows that are being displayed
     */
    public int getRowCount() {
        TreeUI            tree = getUI();

        if(tree != null)
            return tree.getRowCount(this);
        return 0;
    }

    /** 
     * Selects the node identified by the specified path.  If any
     * component of the path is hidden (under a collapsed node), it is 
     * exposed (made viewable).
     *
     * @param path the TreePath specifying the node to select
     */
    public void setSelectionPath(TreePath path) {
	makeVisible(path);
        getSelectionModel().setSelectionPath(path);
    }

    /** 
     * Selects the nodes identified by the specified array of paths.
     * If any component in any of the paths is hidden (under a collapsed
     * node), it is exposed (made viewable).
     *
     * @param paths an array of TreePath objects that specifies the nodes
     *        to select
     */
    public void setSelectionPaths(TreePath[] paths) {
	if(paths != null) {
	    for(int counter = paths.length - 1; counter >= 0; counter--)
		makeVisible(paths[counter]);
	}
        getSelectionModel().setSelectionPaths(paths);
    }

    /**
     * Selects the node at the specified row in the display.
     *
     * @param row  the row to select, where 0 is the first row in
     *             the display
     */
    public void setSelectionRow(int row) {
        int[]             rows = { row };

        setSelectionRows(rows);
    }

    /**
     * Selects the nodes corresponding to each of the specified rows
     * in the display. If a particular element of <code>rows</code> is
     * < 0 or >= getRowCount, it will be ignored. If none of the elements
     * in <code>rows</code> are valid rows, the selection will
     * be cleared. That is it will be as if <code>clearSelection</code>
     * was invoked.
     * 
     * @param rows  an array of ints specifying the rows to select,
     *              where 0 indicates the first row in the display
     */
    public void setSelectionRows(int[] rows) {
        TreeUI               ui = getUI();

        if(ui != null && rows != null) {
            int                  numRows = rows.length;
            TreePath[]           paths = new TreePath[numRows];

            for(int counter = 0; counter < numRows; counter++)
                paths[counter] = ui.getPathForRow(this, rows[counter]);
            setSelectionPaths(paths);
        }
    }

    /**
     * Adds the node identified by the specified TreePath to the current
     * selection. If any component of the path isn't viewable, it is 
     * made viewable.
     *
     * @param path the TreePath to add
     */
    public void addSelectionPath(TreePath path) {
	makeVisible(path);
        getSelectionModel().addSelectionPath(path);
    }

    /**
     * Adds each path in the array of paths to the current selection. If
     * any component of any of the paths isn't viewable, it is
     * made viewable.
     *
     * @param paths an array of TreePath objects that specifies the nodes
     *              to add
     */
    public void addSelectionPaths(TreePath[] paths) {
	if(paths != null) {
	    for(int counter = paths.length - 1; counter >= 0; counter--)
		makeVisible(paths[counter]);
	}
	getSelectionModel().addSelectionPaths(paths);
    }

    /**
     * Adds the path at the specified row to the current selection.
     *
     * @param row  an int specifying the row of the node to add,
     *             where 0 is the first row in the display
     */
    public void addSelectionRow(int row) {
        int[]      rows = { row };

        addSelectionRows(rows);
    }

    /**
     * Adds the paths at each of the specified rows to the current selection.
     * 
     * @param rows  an array of ints specifying the rows to add,
     *              where 0 indicates the first row in the display
     */
    public void addSelectionRows(int[] rows) {
        TreeUI             ui = getUI();

        if(ui != null && rows != null) {
            int                  numRows = rows.length;
            TreePath[]           paths = new TreePath[numRows];

            for(int counter = 0; counter < numRows; counter++)
                paths[counter] = ui.getPathForRow(this, rows[counter]);
            addSelectionPaths(paths);
        }
    }

    /**
     * Returns the last path component in the first node of the current 
     * selection.
     *
     * @return the last Object in the first selected node's TreePath,
     *         or null if nothing is selected
     * @see TreePath#getLastPathComponent
     */
    public Object getLastSelectedPathComponent() {
        TreePath     selPath = getSelectionModel().getSelectionPath();

        if(selPath != null)
            return selPath.getLastPathComponent();
        return null;
    }

    /**
     * Returns the path to the first selected node.
     *
     * @return the TreePath for the first selected node, or null if
     *         nothing is currently selected
     */
    public TreePath getSelectionPath() {
        return getSelectionModel().getSelectionPath();
    }

    /**
     * Returns the paths of all selected values.
     *
     * @return an array of TreePath objects indicating the selected
     *         nodes, or null if nothing is currently selected.
     */
    public TreePath[] getSelectionPaths() {
        return getSelectionModel().getSelectionPaths();
    }

    /**
     * Returns all of the currently selected rows. This method is simply
     * forwarded to the TreeSelectionModel. If nothing is selected null
     * or an empty array with be returned, based on the TreeSelectionModel
     * implementation.
     *
     * @return an array of ints that identifies all currently selected rows
     *         where 0 is the first row in the display
     */
    public int[] getSelectionRows() {
        return getSelectionModel().getSelectionRows();
    }

    /**
     * Returns the number of nodes selected.
     *
     * @return the number of nodes selected
     */
    public int getSelectionCount() {
        return selectionModel.getSelectionCount();
    }

    /**
     * Gets the first selected row.
     *
     * @return an int designating the first selected row, where 0 is the 
     *         first row in the display
     */
    public int getMinSelectionRow() {
        return getSelectionModel().getMinSelectionRow();
    }

    /**
     * Gets the last selected row.
     *
     * @return an int designating the last selected row, where 0 is the 
     *         first row in the display
     */
    public int getMaxSelectionRow() {
        return getSelectionModel().getMaxSelectionRow();
    }

    /**
     * Returns the row index of the last node added to the selection.
     *
     * @return an int giving the row index of the last node added to the
     *         selection, where 0 is the first row in the display
     */
    public int getLeadSelectionRow() {
        return getSelectionModel().getLeadSelectionRow();
    }

    /**
     * Returns the path of the last node added to the selection.
     *
     * @return the TreePath of the last node added to the selection.
     */
    public TreePath getLeadSelectionPath() {
        return getSelectionModel().getLeadSelectionPath();
    }

    /**
     * Returns true if the item identified by the path is currently selected.
     *
     * @param path a TreePath identifying a node
     * @return true if the node is selected
     */
    public boolean isPathSelected(TreePath path) {
        return getSelectionModel().isPathSelected(path);
    }

    /**
     * Returns true if the node identitifed by row is selected.
     *
     * @param row  an int specifying a display row, where 0 is the first
     *             row in the display
     * @return true if the node is selected
     */
    public boolean isRowSelected(int row) {
        return getSelectionModel().isRowSelected(row);
    }

    /**
     * Returns an Enumeration of the descendants of <code>path</code> that
     * are currently expanded. If <code>path</code> is not currently
     * expanded, this will return null. If you expand/collapse nodes while
     * iterating over the returned Enumeration this may not return all
     * the expanded paths, or may return paths that are no longer expanded.
     */
    public Enumeration getExpandedDescendants(TreePath parent) {
	if(!isExpanded(parent))
	    return null;

	Enumeration       toggledPaths = expandedState.keys();
	Vector            elements = new Vector();
	TreePath          path;
	Object            value;

	if(toggledPaths != null) {
	    while(toggledPaths.hasMoreElements()) {
		path = (TreePath)toggledPaths.nextElement();
		value = expandedState.get(path);
		// Add the path if it is expanded, a descendant of parent,
		// and it is visible (all parents expanded). This is rather
		// expensive!
		if(value != null && ((Boolean)value).booleanValue() &&
		   parent.isDescendant(path) && isVisible(path)) {
		    elements.addElement(path);
		}
	    }
	}
	return elements.elements();
    }

    /**
     * Returns true if the node identified by the path has ever been
     * expanded.
     */
    public boolean hasBeenExpanded(TreePath path) {
	return (path != null && expandedState.get(path) != null);
    }

    /**
     * Returns true if the node identified by the path is currently expanded,
     * 
     * @param path  the TreePath specifying the node to check
     * @return false if any of the nodes in the node's path are collapsed, 
     *               true if all nodes in the path are expanded
     */
    public boolean isExpanded(TreePath path) {
	if(path == null)
	    return false;

	// Is this node expanded?
	Object          value = expandedState.get(path);

	if(value == null || !((Boolean)value).booleanValue())
	    return false;

	// It is, make sure its parent is also expanded.
	TreePath        parentPath = path.getParentPath();

	if(parentPath != null)
	    return isExpanded(parentPath);
        return true;
    }

    /**
     * Returns true if the node at the specified display row is currently
     * expanded.
     * 
     * @param row  the row to check, where 0 is the first row in the 
     *             display
     * @return true if the node is currently expanded, otherwise false
     */
    public boolean isExpanded(int row) {
        TreeUI                  tree = getUI();

        if(tree != null) {
	    TreePath         path = tree.getPathForRow(this, row);

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

    /**
     * Returns true if the value identified by path is currently collapsed,
     * this will return false if any of the values in path are currently
     * not being displayed.
     * 
     * @param path  the TreePath to check
     * @return true if any of the nodes in the node's path are collapsed, 
     *               false if all nodes in the path are expanded
     */
    public boolean isCollapsed(TreePath path) {
	return !isExpanded(path);
    }

    /**
     * Returns true if the node at the specified display row is collapsed.
     * 
     * @param row  the row to check, where 0 is the first row in the 
     *             display
     * @return true if the node is currently collapsed, otherwise false
     */
    public boolean isCollapsed(int row) {
	return !isExpanded(row);
    }

    /**
     * Ensures that the node identified by path is currently viewable.
     *
     * @param path  the TreePath to make visible
     */
    public void makeVisible(TreePath path) {
        if(path != null) {
	    TreePath        parentPath = path.getParentPath();

	    if(parentPath != null) {
		expandPath(parentPath);
	    }
        }
    }

    /**
     * Returns true if the value identified by path is currently viewable,
     * which means it is either the root or all of its parents are exapnded  ,
     * Otherwise, this method returns false. 
     *
     * @return true if the node is viewable, otherwise false
     */
    public boolean isVisible(TreePath path) {
        if(path != null) {
	    TreePath        parentPath = path.getParentPath();

	    if(parentPath != null)
		return isExpanded(parentPath);
	    // Root.
	    return true;
	}
        return false;
    }

    /**
     * Returns the Rectangle that the specified node will be drawn
     * into. Returns null if any component in the path is hidden
     * (under a collapsed parent).
     * <p>
     * Note:<br>
     * This method returns a valid rectangle, even if the specified
     * node is not currently displayed.
     *
     * @param path the TreePath identifying the node
     * @return the Rectangle the node is drawn in, or null 
     */
    public Rectangle getPathBounds(TreePath path) {
        TreeUI                   tree = getUI();

        if(tree != null)
            return tree.getPathBounds(this, path);
        return null;
    }

    /**
     * Returns the Rectangle that the node at the specified row is
     * drawn in.
     *
     * @param row  the row to be drawn, where 0 is the first row in the 
     *             display
     * @return the Rectangle the node is drawn in 
     */
    public Rectangle getRowBounds(int row) {
	TreePath          path = getPathForRow(row);

	return getPathBounds(getPathForRow(row));
    }

    /**
     * Makes sure all the path components in path are expanded (except
     * for the last path component) and scrolls so that the 
     * node identified by the path is displayed. Only works when this
     * JTree is contained in a JSrollPane.
     * 
     * @param path  the TreePath identifying the node to bring into view
     */
    public void scrollPathToVisible(TreePath path) {
	if(path != null) {
	    makeVisible(path);

	    Rectangle          bounds = getPathBounds(path);

	    if(bounds != null) {
		scrollRectToVisible(bounds);
		if (accessibleContext != null) {
		    ((AccessibleJTree)accessibleContext).fireVisibleDataPropertyChange();
		}
	    }
	}
    }

    /**
     * Scrolls the item identified by row until it is displayed. The minimum
     * of amount of scrolling necessary to bring the row into view
     * is performed. Only works when this JTree is contained in a
     * JSrollPane.
     *
     * @param row  an int specifying the row to scroll, where 0 is the
     *             first row in the display
     */
    public void scrollRowToVisible(int row) {
	scrollPathToVisible(getPathForRow(row));
    }

    /**
     * Returns the path for the specified row.
     * <!-->If row is not visible null is returned.<-->
     *
     * @param row  an int specifying a row
     * @return the TreePath to the specified node, null if
     *         row < 0 or row > getRowCount()
     */
    public TreePath getPathForRow(int row) {
        TreeUI                  tree = getUI();

        if(tree != null)
            return tree.getPathForRow(this, row);
        return null;
    }

    /**
     * Returns the row that displays the node identified by the specified
     * path. 
     * 
     * @param path  the TreePath identifying a node
     * @return an int specifying the display row, where 0 is the first
     *         row in the display, or -1 if any of the elements in path
     *         are hidden under a collapsed parent.
     */
    public int getRowForPath(TreePath path) {
        TreeUI                  tree = getUI();

        if(tree != null)
            return tree.getRowForPath(this, path);
        return -1;
    }

    /**
     * Ensures that the node identified by the specified path is 
     * expanded and viewable.
     * 
     * @param path  the TreePath identifying a node
     */
    public void expandPath(TreePath path) {
	// Only expand if not leaf!
	TreeModel          model = getModel();

	if(path != null && model != null && 
	   !model.isLeaf(path.getLastPathComponent())) {
	    setExpandedState(path, true);
	}
    }

    /**
     * Ensures that the node in the specified row is expanded and
     * viewable. <p> If <code>row</code> is < 0 or >= getRowCount this
     * will have no effect.
     *
     * @param row  an int specifying a display row, where 0 is the
     *             first row in the display
     */
    public void expandRow(int row) {
	expandPath(getPathForRow(row));
    }

    /**
     * Ensures that the node identified by the specified path is 
     * collapsed and viewable.
     * 
     * @param path  the TreePath identifying a node
      */
    public void collapsePath(TreePath path) {
	setExpandedState(path, false);
    }

    /**
     * Ensures that the node in the specified row is collapsed.
     * <p> If <code>row</code> is < 0 or >= getRowCount this
     * will have no effect.
     *
     * @param row  an int specifying a display row, where 0 is the
     *             first row in the display
      */
    public void collapseRow(int row) {
	collapsePath(getPathForRow(row));
    }

    /**
     * Returns the path for the node at the specified location.
     *
     * @param x an int giving the number of pixels horizontally from
     *          the left edge of the display area, minus any left margin
     * @param y an int giving the number of pixels vertically from
     *          the top of the display area, minus any top margin
     * @return  the TreePath for the node at that location
     */
    public TreePath getPathForLocation(int x, int y) {
        TreePath          closestPath = getClosestPathForLocation(x, y);

        if(closestPath != null) {
            Rectangle       pathBounds = getPathBounds(closestPath);

            if(x >= pathBounds.x && x < (pathBounds.x + pathBounds.width) &&
               y >= pathBounds.y && y < (pathBounds.y + pathBounds.height))
                return closestPath;
        }
        return null;
    }

    /**
     * Returns the row for the specified location. 
     *
     * @param x an int giving the number of pixels horizontally from
     *          the left edge of the display area, minus any left margin
     * @param y an int giving the number of pixels vertically from
     *          the top of the display area, minus any top margin
     * @return the row corresponding to the location, or -1 if the
     *         location is not within the bounds of a displayed cell
     * @see #getClosestRowForLocation
     */
    public int getRowForLocation(int x, int y) {
	return getRowForPath(getPathForLocation(x, y));
    }

    /**
     * Returns the path to the node that is closest to x,y.  If
     * no nodes are currently viewable, or there is no model, returns
     * null, otherwise it always returns a valid path.  To test if
     * the node is exactly at x, y, get the node's bounds and
     * test x, y against that.
     *
     * @param x an int giving the number of pixels horizontally from
     *          the left edge of the display area, minus any left margin
     * @param y an int giving the number of pixels vertically from
     *          the top of the display area, minus any top margin
     * @return  the TreePath for the node closest to that location,
     *          null if nothing is viewable or there is no model
     *
     * @see #getPathForLocation
     * @see #getPathBounds
     */
    public TreePath getClosestPathForLocation(int x, int y) {
        TreeUI                  tree = getUI();

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

    /**
     * Returns the row to the node that is closest to x,y.  If no nodes
     * are viewable or there is no model, returns -1. Otherwise,
     * it always returns a valid row.  To test if the returned object is 
     * exactly at x, y, get the bounds for the node at the returned
     * row and test x, y against that.
     *
     * @param x an int giving the number of pixels horizontally from
     *          the left edge of the display area, minus any left margin
     * @param y an int giving the number of pixels vertically from
     *          the top of the display area, minus any top margin
     * @return the row closest to the location, -1 if nothing is
     *         viewable or there is no model
     *
     * @see #getRowForLocation
     * @see #getRowBounds
     */
    public int getClosestRowForLocation(int x, int y) {
	return getRowForPath(getClosestPathForLocation(x, y));
    }

    /**
     * Returns true if the tree is being edited. The item that is being
     * edited can be obtained using <code>getSelectionPath</code>.
     *
     * @return true if the user is currently editing