/*
 * @(#)BasicTreeUI.java	1.122 00/02/02
 *
 * Copyright 1997-2000 Sun Microsystems, Inc. All Rights Reserved.
 * 
 * This software is the proprietary information of Sun Microsystems, Inc.  
 * Use is subject to license terms.
 * 
 */

package javax.swing.plaf.basic;

import javax.swing.*;
import javax.swing.event.*;
import javax.swing.text.DefaultTextUI;
import java.awt.*;
import java.awt.event.*;
import java.beans.*;
import java.io.*;
import java.util.Enumeration;
import java.util.Hashtable;
import javax.swing.plaf.ActionMapUIResource;
import javax.swing.plaf.ComponentUI;
import javax.swing.plaf.UIResource;
import javax.swing.plaf.TreeUI;
import javax.swing.tree.*;

/**
 * The basic L&F for a hierarchical data structure.
 * <p>
 *
 * @version 1.113 07/20/99
 * @author Scott Violet
 */

public class BasicTreeUI extends TreeUI
{
    static private final Insets EMPTY_INSETS = new Insets(0, 0, 0, 0);

    transient protected Icon        collapsedIcon;
    transient protected Icon        expandedIcon;

    /** Color used to draw hash marks.  If null no hash marks will be
      * drawn. */
    private Color hashColor;

    /** Distance between left margin and where verical dashes will be
      * drawn. */
    protected int               leftChildIndent;
    /** Distance to add to leftChildIndent to determine where cell
      * contents will be drawn. */
    protected int               rightChildIndent;
    /** Total distance that will be indented.  The sum of leftChildIndent
      * and rightChildIndent. */
    protected int               totalChildIndent;

    /** Minimum preferred size. */
    protected Dimension         preferredMinSize;

    /** Index of the row that was last selected. */
    protected int               lastSelectedRow;

    /** Component that we're going to be drawing into. */
    protected JTree             tree;

    /** Renderer that is being used to do the actual cell drawing. */
    transient protected TreeCellRenderer   currentCellRenderer;

    /** Set to true if the renderer that is currently in the tree was
     * created by this instance. */
    protected boolean           createdRenderer;

    /** Editor for the tree. */
    transient protected TreeCellEditor     cellEditor;

    /** Set to true if editor that is currently in the tree was
     * created by this instance. */
    protected boolean           createdCellEditor;

    /** Set to false when editing and shouldSelectCell() returns true meaning
      * the node should be selected before editing, used in completeEditing. */
    protected boolean           stopEditingInCompleteEditing;

    /** Used to paint the TreeCellRenderer. */
    protected CellRendererPane  rendererPane;

    /** Size needed to completely display all the nodes. */
    protected Dimension         preferredSize;

    /** Is the preferredSize valid? */
    protected boolean           validCachedPreferredSize;

    /** Object responsible for handling sizing and expanded issues. */
    protected AbstractLayoutCache  treeState;


    /** Used for minimizing the drawing of vertical lines. */
    protected Hashtable         drawingCache;

    /** True if doing optimizations for a largeModel. Subclasses that
     * don't support this may wish to override createLayoutCache to not
     * return a FixedHeightLayoutCache instance. */
    protected boolean           largeModel;

    /** Reponsible for telling the TreeState the size needed for a node. */
    protected AbstractLayoutCache.NodeDimensions     nodeDimensions;

    /** Used to determine what to display. */
    protected TreeModel         treeModel;

    /** Model maintaing the selection. */
    protected TreeSelectionModel treeSelectionModel;

    /** How much the depth should be offset to properly calculate
     * x locations. This is based on whether or not the root is visible,
     * and if the root handles are visible. */
    protected int               depthOffset;

    /** Last width the tree was at when painted. This is used when
     * !leftToRigth to notice the bounds have changed so that we can instruct
     * the TreeState to relayout. */
    private int                 lastWidth;

    // Following 4 ivars are only valid when editing.

    /** When editing, this will be the Component that is doing the actual
      * editing. */
    protected Component         editingComponent;

    /** Path that is being edited. */
    protected TreePath          editingPath;

    /** Row that is being edited. Should only be referenced if
     * editingComponent is not null. */
    protected int               editingRow;

    /** Set to true if the editor has a different size than the renderer. */
    protected boolean           editorHasDifferentSize;

    /** Row correspondin to lead path. */
    private int                 leadRow;
    /** If true, the property change event for LEAD_SELECTION_PATH_PROPERTY,
     * or ANCHOR_SELECTION_PATH_PROPERTY will not generate a repaint. */
    private boolean             ignoreLAChange;

    /** Indicates the orientation. */
    private boolean             leftToRight;

    // Cached listeners
    private PropertyChangeListener propertyChangeListener;
    private PropertyChangeListener selectionModelPropertyChangeListener;
    private MouseListener mouseListener;
    private FocusListener focusListener;
    private KeyListener keyListener;
    /** Used for large models, listens for moved/resized events and
     * updates the validCachedPreferredSize bit accordingly. */
    private ComponentListener   componentListener;
    /** Listens for CellEditor events. */
    private CellEditorListener  cellEditorListener;
    /** Updates the display when the selection changes. */
    private TreeSelectionListener treeSelectionListener;
    /** Is responsible for updating the display based on model events. */
    private TreeModelListener treeModelListener;
    /** Updates the treestate as the nodes expand. */
    private TreeExpansionListener treeExpansionListener;

    public static ComponentUI createUI(JComponent x) {
	return new BasicTreeUI();
    }

    public BasicTreeUI() {
	super();
    }

    protected Color getHashColor() {
        return hashColor;
    }

    protected void setHashColor(Color color) {
        hashColor = color;
    }

    public void setLeftChildIndent(int newAmount) {
	leftChildIndent = newAmount;
	totalChildIndent = leftChildIndent + rightChildIndent;
	if(treeState != null)
	    treeState.invalidateSizes();
	updateSize();
    }

    public int getLeftChildIndent() {
	return leftChildIndent;
    }

    public void setRightChildIndent(int newAmount) {
	rightChildIndent = newAmount;
	totalChildIndent = leftChildIndent + rightChildIndent;
	if(treeState != null)
	    treeState.invalidateSizes();
	updateSize();
    }

    public int getRightChildIndent() {
	return rightChildIndent;
    }

    public void setExpandedIcon(Icon newG) {
	expandedIcon = newG;
    }

    public Icon getExpandedIcon() {
	return expandedIcon;
    }

    public void setCollapsedIcon(Icon newG) {
	collapsedIcon = newG;
    }

    public Icon getCollapsedIcon() {
	return collapsedIcon;
    }

    //
    // Methods for configuring the behavior of the tree. None of them
    // push the value to the JTree instance. You should really only
    // call these methods on the JTree.
    //

    /**
     * Updates the componentListener, if necessary.
     */
    protected void setLargeModel(boolean largeModel) {
	if(getRowHeight() < 1)
	    largeModel = false;
	if(this.largeModel != largeModel) {
	    completeEditing();
	    this.largeModel = largeModel;
	    treeState = createLayoutCache();
	    configureLayoutCache();
	    updateLayoutCacheExpandedNodes();
	    updateSize();
	}
    }

    protected boolean isLargeModel() {
	return largeModel;
    }

    /**
     * Sets the row height, this is forwarded to the treeState.
     */
    protected void setRowHeight(int rowHeight) {
	completeEditing();
	if(treeState != null) {
	    setLargeModel(tree.isLargeModel());
	    treeState.setRowHeight(rowHeight);
	    updateSize();
	}
    }

    protected int getRowHeight() {
	return (tree == null) ? -1 : tree.getRowHeight();
    }

    /**
     * Sets the TreeCellRenderer to <code>tcr</code>. This invokes
     * <code>updateRenderer</code>.
     */
    protected void setCellRenderer(TreeCellRenderer tcr) {
	completeEditing();
	updateRenderer();
	if(treeState != null) {
	    treeState.invalidateSizes();
	    updateSize();
	}
    }

    /**
     * Return currentCellRenderer, which will either be the trees
     * renderer, or defaultCellRenderer, which ever wasn't null.
     */
    protected TreeCellRenderer getCellRenderer() {
	return currentCellRenderer;
    }

    /**
     * Sets the TreeModel.
     */
    protected void setModel(TreeModel model) {
	completeEditing();
	if(treeModel != null && treeModelListener != null)
	    treeModel.removeTreeModelListener(treeModelListener);
	treeModel = model;
	if(treeModel != null) {
	    if(treeModelListener != null)
		treeModel.addTreeModelListener(treeModelListener);
	}
	if(treeState != null) {
	    treeState.setModel(model);
	    updateLayoutCacheExpandedNodes();
	    updateSize();
	}
    }

    protected TreeModel getModel() {
	return treeModel;
    }

    /**
     * Sets the root to being visible.
     */
    protected void setRootVisible(boolean newValue) {
	completeEditing();
	updateDepthOffset();
	if(treeState != null) {
	    treeState.setRootVisible(newValue);
	    treeState.invalidateSizes();
	    updateSize();
	}
    }

    protected boolean isRootVisible() {
	return (tree != null) ? tree.isRootVisible() : false;
    }

    /**
     * Determines whether the node handles are to be displayed.
     */
    protected void setShowsRootHandles(boolean newValue) {
	completeEditing();
	updateDepthOffset();
	if(treeState != null) {
	    treeState.invalidateSizes();
	    updateSize();
	}
    }

    protected boolean getShowsRootHandles() {
	return (tree != null) ? tree.getShowsRootHandles() : false;
    }

    /**
     * Sets the cell editor.
     */
    protected void setCellEditor(TreeCellEditor editor) {
	updateCellEditor();
    }

    protected TreeCellEditor getCellEditor() {
	return (tree != null) ? tree.getCellEditor() : null;
    }

    /**
     * Configures the receiver to allow, or not allow, editing.
     */
    protected void setEditable(boolean newValue) {
	updateCellEditor();
    }

    protected boolean isEditable() {
	return (tree != null) ? tree.isEditable() : false;
    }

    /**
     * Resets the selection model. The appropriate listener are installed
     * on the model.
     */
    protected void setSelectionModel(TreeSelectionModel newLSM) {
	completeEditing();
	if(selectionModelPropertyChangeListener != null &&
	   treeSelectionModel != null)
	    treeSelectionModel.removePropertyChangeListener
		              (selectionModelPropertyChangeListener);
	if(treeSelectionListener != null && treeSelectionModel != null)
	    treeSelectionModel.removeTreeSelectionListener
		               (treeSelectionListener);
	treeSelectionModel = newLSM;
	if(treeSelectionModel != null) {
	    if(selectionModelPropertyChangeListener != null)
		treeSelectionModel.addPropertyChangeListener
		              (selectionModelPropertyChangeListener);
	    if(treeSelectionListener != null)
		treeSelectionModel.addTreeSelectionListener
		                   (treeSelectionListener);
	    if(treeState != null)
		treeState.setSelectionModel(treeSelectionModel);
	}
	else if(treeState != null)
	    treeState.setSelectionModel(null);
	if(tree != null)
	    tree.repaint();
    }

    protected TreeSelectionModel getSelectionModel() {
	return treeSelectionModel;
    }

    //
    // TreeUI methods
    //

    /**
      * Returns the Rectangle enclosing the label portion that the
      * last item in path will be drawn into.  Will return null if
      * any component in path is currently valid.
      */
    public Rectangle getPathBounds(JTree tree, TreePath path) {
	if(tree != null && treeState != null) {
	    Insets           i = tree.getInsets();
	    Rectangle        bounds = treeState.getBounds(path, null);

	    if(bounds != null && i != null) {
		bounds.x += i.left;
		bounds.y += i.top;
	    }
	    return bounds;
	}
	return null;
    }

    /**
      * Returns the path for passed in row.  If row is not visible
      * null is returned.
      */
    public TreePath getPathForRow(JTree tree, int row) {
	return (treeState != null) ? treeState.getPathForRow(row) : null;
    }

    /**
      * Returns the row that the last item identified in path is visible
      * at.  Will return -1 if any of the elements in path are not
      * currently visible.
      */
    public int getRowForPath(JTree tree, TreePath path) {
	return (treeState != null) ? treeState.getRowForPath(path) : -1;
    }

    /**
      * Returns the number of rows that are being displayed.
      */
    public int getRowCount(JTree tree) {
	return (treeState != null) ? treeState.getRowCount() : 0;
    }

    /**
      * Returns the path to the node that is closest to x,y.  If
      * there is nothing currently visible this will return null, otherwise
      * it'll always return a valid path.  If you need to test if the
      * returned object is exactly at x, y you should get the bounds for
      * the returned path and test x, y against that.
      */
    public TreePath getClosestPathForLocation(JTree tree, int x, int y) {
	if(tree != null && treeState != null) {
	    Insets          i = tree.getInsets();

	    if(i == null)
		i = EMPTY_INSETS;

	    return treeState.getPathClosestTo(x - i.left, y - i.top);
	}
	return null;
    }

    /**
      * Returns true if the tree is being edited.  The item that is being
      * edited can be returned by getEditingPath().
      */
    public boolean isEditing(JTree tree) {
	return (editingComponent != null);
    }

    /**
      * Stops the current editing session.  This has no effect if the
      * tree isn't being edited.  Returns true if the editor allows the
      * editing session to stop.
      */
    public boolean stopEditing(JTree tree) {
	if(editingComponent != null && cellEditor.stopCellEditing()) {
	    completeEditing(false, false, true);
	    return true;
	}
	return false;
    }

    /**
      * Cancels the current editing session.
      */
    public void cancelEditing(JTree tree) {
	if(editingComponent != null) {
	    completeEditing(false, true, false);
	}
    }

    /**
      * Selects the last item in path and tries to edit it.  Editing will
      * fail if the CellEditor won't allow it for the selected item.
      */
    public void startEditingAtPath(JTree tree, TreePath path) {
	tree.scrollPathToVisible(path);
	if(path != null && tree.isVisible(path))
	    startEditing(path, null);
    }

    /**
     * Returns the path to the element that is being edited.
     */
    public TreePath getEditingPath(JTree tree) {
	return editingPath;
    }

    //
    // Install methods
    //

    public void installUI(JComponent c) {
        if ( c == null ) {
	    throw new NullPointerException( "null component passed to BasicTreeUI.installUI()" );
        }

	tree = (JTree)c;

	prepareForUIInstall();

	// Boilerplate install block
	installDefaults();
	installListeners();
	installKeyboardActions();
	installComponents();

	completeUIInstall();
    }

    /**
     * Invoked after the <code>tree</code> instance variable has been
     * set, but before any defaults/listeners have been installed.
     */
    protected void prepareForUIInstall() {
	drawingCache = new Hashtable(7);

	// Data member initializations
	leftToRight = BasicGraphicsUtils.isLeftToRight(tree);
	lastWidth = tree.getWidth();
	stopEditingInCompleteEditing = true;
	lastSelectedRow = -1;
	leadRow = -1;
	preferredSize = new Dimension();
	tree.setRowHeight(UIManager.getInt("Tree.rowHeight"));

	Object     b = UIManager.get("Tree.scrollsOnExpand");

	if(b != null)
	    tree.setScrollsOnExpand(((Boolean)b).booleanValue());

	largeModel = tree.isLargeModel();
	if(getRowHeight() <= 0)
	    largeModel = false;
	setModel(tree.getModel());
    }

    /**
     * Invoked from installUI after all the defaults/listeners have been
     * installed.
     */
    protected void completeUIInstall() {
	// Custom install code

	this.setShowsRootHandles(tree.getShowsRootHandles());

	updateRenderer();

	updateDepthOffset();

	setSelectionModel(tree.getSelectionModel());

	// Create, if necessary, the TreeState instance.
	treeState = createLayoutCache();
	configureLayoutCache();

	updateSize();
    }

    protected void installDefaults() {
	if(tree.getBackground() == null ||
	   tree.getBackground() instanceof UIResource) {
	    tree.setBackground(UIManager.getColor("Tree.background"));
	} 
	if(getHashColor() == null || getHashColor() instanceof UIResource) {
	    setHashColor(UIManager.getColor("Tree.hash"));
	}
	if (tree.getFont() == null || tree.getFont() instanceof UIResource)
	    tree.setFont( UIManager.getFont("Tree.font") );

	setExpandedIcon( (Icon)UIManager.get( "Tree.expandedIcon" ) );
	setCollapsedIcon( (Icon)UIManager.get( "Tree.collapsedIcon" ) );

	setLeftChildIndent(((Integer)UIManager.get("Tree.leftChildIndent")).
			   intValue());
	setRightChildIndent(((Integer)UIManager.get("Tree.rightChildIndent")).
			   intValue());
    }

    protected void installListeners() {
        if ( (propertyChangeListener = createPropertyChangeListener())
	     != null ) {
	    tree.addPropertyChangeListener(propertyChangeListener);
	}
        if ( (mouseListener = createMouseListener()) != null ) {
	    tree.addMouseListener(mouseListener);
	}
        if ((focusListener = createFocusListener()) != null ) {
	    tree.addFocusListener(focusListener);
	}
        if ((keyListener = createKeyListener()) != null) {
	    tree.addKeyListener(keyListener);
	}
	if((treeExpansionListener = createTreeExpansionListener()) != null) {
	    tree.addTreeExpansionListener(treeExpansionListener);
	}
	if((treeModelListener = createTreeModelListener()) != null &&
	   treeModel != null) {
	    treeModel.addTreeModelListener(treeModelListener);
	}
	if((selectionModelPropertyChangeListener =
	    createSelectionModelPropertyChangeListener()) != null &&
	   treeSelectionModel != null) {
	    treeSelectionModel.addPropertyChangeListener
		(selectionModelPropertyChangeListener);
	}
	if((treeSelectionListener = createTreeSelectionListener()) != null &&
	   treeSelectionModel != null) {
	    treeSelectionModel.addTreeSelectionListener(treeSelectionListener);
	}
    }

    protected void installKeyboardActions() {
	InputMap km = getInputMap(JComponent.
				  WHEN_ANCESTOR_OF_FOCUSED_COMPONENT);

	SwingUtilities.replaceUIInputMap(tree, JComponent.
					 WHEN_ANCESTOR_OF_FOCUSED_COMPONENT,
					 km);
	km = getInputMap(JComponent.WHEN_FOCUSED);
	SwingUtilities.replaceUIInputMap(tree, JComponent.WHEN_FOCUSED, km);
	ActionMap am = getActionMap();

	SwingUtilities.replaceUIActionMap(tree, am);
    }

    InputMap getInputMap(int condition) {
	if (condition == JComponent.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT) {
	    return (InputMap)UIManager.get("Tree.ancestorInputMap");
	}
	else if (condition == JComponent.WHEN_FOCUSED) {
	    return (InputMap)UIManager.get("Tree.focusInputMap");
	}
	return null;
    }

    ActionMap getActionMap() {
	return createActionMap();
    }

    ActionMap createActionMap() {
	ActionMap map = new ActionMapUIResource();

	map.put("selectPrevious", new TreeIncrementAction(-1, "selectPrevious",
							  false, true));
	map.put("selectPreviousChangeLead", new TreeIncrementAction
		(-1, "selectPreviousLead", false, false));
	map.put("selectPreviousExtendSelection", new TreeIncrementAction
		(-1, "selectPreviousExtendSelection", true, true));

	map.put("selectNext", new TreeIncrementAction
		(1, "selectNext", false, true));
	map.put("selectNextChangeLead", new TreeIncrementAction
		(1, "selectNextLead", false, false));
	map.put("selectNextExtendSelection", new TreeIncrementAction
		(1, "selectNextExtendSelection", true, true));

	map.put("selectChild", new TreeTraverseAction
		(1, "selectChild", true));
	map.put("selectChildChangeLead", new TreeTraverseAction
		(1, "selectChildLead", false));

	map.put("selectParent", new TreeTraverseAction
		(-1, "selectParent", true));
	map.put("selectParentChangeLead", new TreeTraverseAction
		(-1, "selectParentLead", false));	

	map.put("scrollUpChangeSelection", new TreePageAction
		(-1, "scrollUpChangeSelection", false, true));
	map.put("scrollUpChangeLead", new TreePageAction
		(-1, "scrollUpChangeLead", false, false));
	map.put("scrollUpExtendSelection", new TreePageAction
		(-1, "scrollUpExtendSelection", true, true));

	map.put("scrollDownChangeSelection", new TreePageAction
		(1, "scrollDownChangeSelection", false, true));
	map.put("scrollDownExtendSelection", new TreePageAction
		(1, "scrollDownExtendSelection", true, true));
	map.put("scrollDownChangeLead", new TreePageAction
		(1, "scrollDownChangeLead", false, false));

	map.put("selectFirst", new TreeHomeAction
		(-1, "selectFirst", false, true));
	map.put("selectFirstChangeLead", new TreeHomeAction
		(-1, "selectFirst", false, false));
	map.put("selectFirstExtendSelection",new TreeHomeAction
		(-1, "selectFirstExtendSelection", true, true));

	map.put("selectLast", new TreeHomeAction
		(1, "selectLast", false, true));
	map.put("selectLastChangeLead", new TreeHomeAction
		(1, "selectLast", false, false));
	map.put("selectLastExtendSelection", new TreeHomeAction
		(1, "selectLastExtendSelection", true, true));

	map.put("toggle", new TreeToggleAction("toggle"));

	map.put("cancel", new TreeCancelEditingAction("cancel"));

	map.put("startEditing", new TreeEditAction("startEditing"));

	map.put("selectAll", new TreeSelectAllAction("selectAll", true));

	map.put("clearSelection", new TreeSelectAllAction
		("clearSelection", false));

	map.put("toggleSelectionPreserveAnchor",
		new TreeAddSelectionAction("toggleSelectionPreserveAnchor",
					   false));
	map.put("toggleSelection",
		new TreeAddSelectionAction("toggleSelection", true));

	map.put("extendSelection", new TreeExtendSelectionAction
		("extendSelection"));

	map.put("scrollLeft", new ScrollAction
		(tree, SwingConstants.HORIZONTAL, -10));
	map.put("scrollLeftExtendSelection", new TreeScrollLRAction
		(-1, "scrollLeftExtendSelection", true, true));
	map.put("scrollRight", new ScrollAction
		(tree, SwingConstants.HORIZONTAL, 10));
	map.put("scrollRightExtendSelection", new TreeScrollLRAction
		(1, "scrollRightExtendSelection", true, true));

	map.put("scrollRightChangeLead", new TreeScrollLRAction
		(1, "scrollRightChangeLead", false, false));
	map.put("scrollLeftChangeLead", new TreeScrollLRAction
		(-1, "scrollLeftChangeLead", false, false));
	return map;
    }

    /**
     * Intalls the subcomponents of the tree, which is the renderer pane.
     */
    protected void installComponents() {
	if ((rendererPane = createCellRendererPane()) != null) {
	    tree.add( rendererPane );
	}
    }

    //
    // Create methods.
    //

    /**
     * Creates an instance of NodeDimensions that is able to determine
     * the size of a given node in the tree.
     */
    protected AbstractLayoutCache.NodeDimensions createNodeDimensions() {
	return new NodeDimensionsHandler();
    }

    /**
     * Creates a listener that is responsible that updates the UI based on
     * how the tree changes.
     */
    protected PropertyChangeListener createPropertyChangeListener() {
        return new PropertyChangeHandler();
    }

    /**
     * Creates the listener responsible for updating the selection based on
     * mouse events.
     */
    protected MouseListener createMouseListener() {
        return new MouseHandler();
    }

    /**
     * Creates a listener that is responsible for updating the display
     * when focus is lost/gained.
     */
    protected FocusListener createFocusListener() {
        return new FocusHandler();
    }

    /**
     * Creates the listener reponsible for getting key events from
     * the tree.
     */
    protected KeyListener createKeyListener() {
        return new KeyHandler();
    }

    /**
     * Creates the listener responsible for getting property change
     * events from the selection model.
     */
    protected PropertyChangeListener createSelectionModelPropertyChangeListener() {
	return new SelectionModelPropertyChangeHandler();
    }

    /**
     * Creates the listener that updates the display based on selection change
     * methods.
     */
    protected TreeSelectionListener createTreeSelectionListener() {
	return new TreeSelectionHandler();
    }

    /**
     * Creates a listener to handle events from the current editor.
     */
    protected CellEditorListener createCellEditorListener() {
	return new CellEditorHandler();
    }

    /**
     * Creates and returns a new ComponentHandler. This is used for
     * the large model to mark the validCachedPreferredSize as invalid
     * when the component moves.
     */
    protected ComponentListener createComponentListener() {
	return new ComponentHandler();
    }

    /**
     * Creates and returns the object responsible for updating the treestate
     * when nodes expanded state changes.
     */
    protected TreeExpansionListener createTreeExpansionListener() {
	return new TreeExpansionHandler();
    }

    /**
     * Creates the object responsible for managing what is expanded, as
     * well as the size of nodes.
     */
    protected AbstractLayoutCache createLayoutCache() {
	if(isLargeModel() && getRowHeight() > 0) {
	    return new FixedHeightLayoutCache();
	}
	return new VariableHeightLayoutCache();
    }

    /**
     * Returns the renderer pane that renderer components are placed in.
     */
    protected CellRendererPane createCellRendererPane() {
        return new CellRendererPane();
    }

    /**
      * Creates a default cell editor.
      */
    protected TreeCellEditor createDefaultCellEditor() {
	if(currentCellRenderer != null &&
	   (currentCellRenderer instanceof DefaultTreeCellRenderer)) {
	    DefaultTreeCellEditor editor = new DefaultTreeCellEditor
		        (tree, (DefaultTreeCellRenderer)currentCellRenderer);

	    return editor;
	}
	return new DefaultTreeCellEditor(tree, null);
    }

    /**
      * Returns the default cell renderer that is used to do the
      * stamping of each node.
      */
    protected TreeCellRenderer createDefaultCellRenderer() {
	return new DefaultTreeCellRenderer();
    }

    /**
     * Returns a listener that can update the tree when the model changes.
     */
    protected TreeModelListener createTreeModelListener() {
	return new TreeModelHandler();
    }

    //
    // Uninstall methods
    //

    public void uninstallUI(JComponent c) {
	completeEditing();

	prepareForUIUninstall();

	uninstallDefaults();
	uninstallListeners();
	uninstallKeyboardActions();
	uninstallComponents();

	completeUIUninstall();
    }

    protected void prepareForUIUninstall() {
    }

    protected void completeUIUninstall() {
	if(createdRenderer) {
	    tree.setCellRenderer(null);
	}
	if(createdCellEditor) {
	    tree.setCellEditor(null);
	}
	cellEditor = null;
	currentCellRenderer = null;
	rendererPane = null;
        componentListener = null;
	propertyChangeListener = null;
	mouseListener = null;
	focusListener = null;
	keyListener = null;
	setSelectionModel(null);
	treeState = null;
	drawingCache = null;
	selectionModelPropertyChangeListener = null;
	tree = null;
	treeModel = null;
	treeSelectionModel = null;
	treeSelectionListener = null;
	treeExpansionListener = null;
    }

    protected void uninstallDefaults() {
    }

    protected void uninstallListeners() {
	if(componentListener != null) {
	    tree.removeComponentListener(componentListener);
	}
        if (propertyChangeListener != null) {
	    tree.removePropertyChangeListener(propertyChangeListener);
	}
        if (mouseListener != null) {
	    tree.removeMouseListener(mouseListener);
	}
        if (focusListener != null) {
	    tree.removeFocusListener(focusListener);
	}
        if (keyListener != null) {
	    tree.removeKeyListener(keyListener);
	}
	if(treeExpansionListener != null) {
	    tree.removeTreeExpansionListener(treeExpansionListener);
	}
	if(treeModel != null && treeModelListener != null) {
	    treeModel.removeTreeModelListener(treeModelListener);
	}
	if(selectionModelPropertyChangeListener != null &&
	   treeSelectionModel != null) {
	    treeSelectionModel.removePropertyChangeListener
		(selectionModelPropertyChangeListener);
	}
	if(treeSelectionListener != null && treeSelectionModel != null) {
	    treeSelectionModel.removeTreeSelectionListener
		               (treeSelectionListener);
	}
    }

    protected void uninstallKeyboardActions() {
	SwingUtilities.replaceUIActionMap(tree, null);
	SwingUtilities.replaceUIInputMap(tree, JComponent.
					 WHEN_ANCESTOR_OF_FOCUSED_COMPONENT,
					 null);
	SwingUtilities.replaceUIInputMap(tree, JComponent.WHEN_FOCUSED, null);
    }

    /**
     * Uninstalls the renderer pane.
     */
    protected void uninstallComponents() {
	if(rendererPane != null) {
	    tree.remove(rendererPane);
	}
    }

    /**
     * Recomputes the right margin, and invalidates any tree states
     */
    private void redoTheLayout() {
	if (treeState != null) {
	    treeState.invalidateSizes();
	}
    }

    //
    // Painting routines.
    //

    public void paint(Graphics g, JComponent c) {
	if (tree != c) {
	    throw new InternalError("incorrect component");
	}

	// Should never happen if installed for a UI
	if(treeState == null) {
	    return;
	}

	// Update the lastWidth if necessary.
	// This should really come from a ComponentListener installed on
	// the JTree, but for the time being it is here.
	int              width = tree.getWidth();

	if (width != lastWidth) {
	    lastWidth = width;
	    if (!leftToRight) {
		// For RTL when the size changes, we have to refresh the
		// cache as the X position is based off the width.
		redoTheLayout();
		updateSize();
	    }
	}

	Rectangle        paintBounds = g.getClipBounds();
	Insets           insets = tree.getInsets();

	if(insets == null)
	    insets = EMPTY_INSETS;

	TreePath         initialPath = getClosestPathForLocation
	                               (tree, 0, paintBounds.y);
	Enumeration      paintingEnumerator = treeState.getVisiblePathsFrom
	                                      (initialPath);
	int              row = treeState.getRowForPath(initialPath);
	int              endY = paintBounds.y + paintBounds.height;

	drawingCache.clear();

	if(initialPath != null && paintingEnumerator != null) {
	    TreePath   parentPath = initialPath;

	    // Draw the lines, knobs, and rows

	    // Find each parent and have them draw a line to their last child
	    parentPath = parentPath.getParentPath();
	    while(parentPath != null) {
		paintVerticalPartOfLeg(g, paintBounds, insets, parentPath);
		drawingCache.put(parentPath, Boolean.TRUE);
		parentPath = parentPath.getParentPath();
	    }

	    boolean         done = false;
	    // Information for the node being rendered.
	    boolean         isExpanded;
	    boolean         hasBeenExpanded;
	    boolean         isLeaf;
	    Rectangle       boundsBuffer = new Rectangle();
	    Rectangle       bounds;
	    TreePath        path;
	    boolean         rootVisible = isRootVisible();

	    while(!done && paintingEnumerator.hasMoreElements()) {
		path = (TreePath)paintingEnumerator.nextElement();
		if(path != null) {
		    isLeaf = treeModel.isLeaf(path.getLastPathComponent());
		    if(isLeaf)
			isExpanded = hasBeenExpanded = false;
		    else {
			isExpanded = treeState.getExpandedState(path);
			hasBeenExpanded = tree.hasBeenExpanded(path);
		    }
		    bounds = treeState.getBounds(path, boundsBuffer);
		    if(bounds == null)
			// This will only happen if the model changes out
			// from under us (usually in another thread).
			// Swing isn't multithreaded, but I'll put this
			// check in anyway.
			return;
		    bounds.x += insets.left;
		    bounds.y += insets.top;
		    // See if the vertical line to the parent has been drawn.
		    parentPath = path.getParentPath();
		    if(parentPath != null) {
			if(drawingCache.get(parentPath) == null) {
			    paintVerticalPartOfLeg(g, paintBounds,
						   insets, parentPath);
			    drawingCache.put(parentPath, Boolean.TRUE);
			}
			paintHorizontalPartOfLeg(g, paintBounds, insets,
						 bounds, path, row,
						 isExpanded,
						 hasBeenExpanded, isLeaf);
		    }
		    else if(rootVisible && row == 0) {
			paintHorizontalPartOfLeg(g, paintBounds, insets,
						 bounds, path, row,
						 isExpanded,
						 hasBeenExpanded, isLeaf);
		    }
		    if(shouldPaintExpandControl(path, row, isExpanded,
						hasBeenExpanded, isLeaf)) {
			paintExpandControl(g, paintBounds, insets, bounds,
					   path, row, isExpanded,
					   hasBeenExpanded, isLeaf);
		    }
                    //This is the quick fix for bug 4259260.  Somewhere we
                    //are out by 4 pixels in the RTL layout.  Its probably
                    //due to built in right-side padding in some icons.  Rather
                    //than ferret out problem at the source, this compensates. 
            	    if (!leftToRight) {
                        bounds.x +=4;
                    }
		    paintRow(g, paintBounds, insets, bounds, path,
				 row, isExpanded, hasBeenExpanded, isLeaf);
		    if((bounds.y + bounds.height) >= endY)
			done = true;
		}
		else {
		    done = true;
		}
		row++;
	    }
	}
	// Empty out the renderer pane, allowing renderers to be gc'ed.
	rendererPane.removeAll();
    }

    /**
     * Paints the horizontal part of the leg. The reciever should
     * NOT modify <code>clipBounds</code>, or <code>insets</code>.<p>
     * NOTE: <code>parentRow</code> can be -1 if the root is not visible.
     */
    protected void paintHorizontalPartOfLeg(Graphics g, Rectangle clipBounds,
					    Insets insets, Rectangle bounds,
					    TreePath path, int row,
					    boolean isExpanded,
					    boolean hasBeenExpanded, boolean
					    isLeaf) {
	int clipLeft = clipBounds.x;
	int clipRight = clipBounds.x + (clipBounds.width - 1);
	int clipTop = clipBounds.y;
	int clipBottom = clipBounds.y + (clipBounds.height - 1);
	int lineY = bounds.y + bounds.height / 2;
	// Offset leftX from parents indent.
	if (leftToRight) {
	    int leftX = bounds.x - getRightChildIndent();
	    int nodeX = bounds.x - getHorizontalLegBuffer();
	
	    if(lineY > clipTop && lineY < clipBottom && nodeX > clipLeft &&
	                                              leftX < clipRight ) {
	        leftX = Math.max(leftX, clipLeft);
		nodeX = Math.min(nodeX, clipRight);

		g.setColor(getHashColor());
		paintHorizontalLine(g, tree, lineY, leftX, nodeX);
	    }
	}
	else {
	    int leftX = bounds.x + bounds.width + getRightChildIndent();
	    int nodeX = bounds.x + bounds.width + 
	                                  getHorizontalLegBuffer() - 1;

	    if(lineY > clipTop && lineY < clipBottom &&
	       leftX > clipLeft && nodeX < clipRight) {
	        leftX = Math.min(leftX, clipRight);
		nodeX = Math.max(nodeX, clipLeft);

		g.setColor(getHashColor());
		paintHorizontalLine(g, tree, lineY, nodeX, leftX);
	    }
	}
    }

    /**
     * Paints the vertical part of the leg. The reciever should
     * NOT modify <code>clipBounds</code>, <code>insets</code>.<p>
     */
    protected void paintVerticalPartOfLeg(Graphics g, Rectangle clipBounds,
					  Insets insets, TreePath path) {
	int lineX;
	if (leftToRight) {
	    lineX = ((path.getPathCount() + depthOffset) *
		     totalChildIndent) - getRightChildIndent() + insets.left;
	}
	else {
	    lineX = lastWidth - ((path.getPathCount() - 1 + depthOffset) *
				                       totalChildIndent) - 9;
	}
	int clipLeft = clipBounds.x;
	int clipRight = clipBounds.x + (clipBounds.width - 1);

	if (lineX > clipLeft && lineX < clipRight) {
	    int clipTop = clipBounds.y;
	    int clipBottom = clipBounds.y + clipBounds.height;
	    Rectangle parentBounds = getPathBounds(tree, path);
	    Rectangle lastChildBounds = getPathBounds(tree,
						     getLastChildPath(path));

	    if(lastChildBounds == null)
		// This shouldn't happen, but if the model is modified
		// in another thread it is possible for this to happen.
		// Swing isn't multithreaded, but I'll add this check in
		// anyway.
		return;

	    int       top;

	    if(parentBounds == null) {
		top = Math.max(insets.top + getVerticalLegBuffer(),
			       clipTop);
	    }
	    else
		top = Math.max(parentBounds.y + parentBounds.height +
			       getVerticalLegBuffer(), clipTop);
	    if(path.getPathCount() == 1 && !isRootVisible()) {
		TreeModel      model = getModel();

		if(model != null) {
		    Object        root = model.getRoot();

		    if(model.getChildCount(root) > 0) {
			parentBounds = getPathBounds(tree, path.
				  pathByAddingChild(model.getChild(root, 0)));
			if(parentBounds != null)
			    top = Math.max(insets.top + getVerticalLegBuffer(),
					   parentBounds.y +
					   parentBounds.height / 2);
		    }
		}
	    }

	    int bottom = Math.min(lastChildBounds.y +
				  (lastChildBounds.height / 2), clipBottom);

	    g.setColor(getHashColor());
	    paintVerticalLine(g, tree, lineX, top, bottom);
	}
    }

    /**
     * Paints the expand (toggle) part of a row. The reciever should
     * NOT modify <code>clipBounds</code>, or <code>insets</code>.
     */
    protected void paintExpandControl(Graphics g,
				      Rectangle clipBounds, Insets insets,
				      Rectangle bounds, TreePath path,
				      int row, boolean isExpanded,
				      boolean hasBeenExpanded,
				      boolean isLeaf) {
	Object       value = path.getLastPathComponent();

	// Draw icons if not a leaf and either hasn't been loaded,
	// or the model child count is > 0.
	if (!isLeaf && (!hasBeenExpanded ||
			treeModel.getChildCount(value) > 0)) {
	    int middleXOfKnob;
	    if (leftToRight) {
	        middleXOfKnob = bounds.x - (getRightChildIndent() - 1);
	    }
	    else {
	        middleXOfKnob = bounds.x + bounds.width + getRightChildIndent();
	    }
	    int middleYOfKnob = bounds.y + (bounds.height / 2);

	    if (isExpanded) {
		Icon expandedIcon = getExpandedIcon();
		if(expandedIcon != null)
		  drawCentered(tree, g, expandedIcon, middleXOfKnob,
			       middleYOfKnob );
	    }
	    else {
		Icon collapsedIcon = getCollapsedIcon();
		if(collapsedIcon != null)
		  drawCentered(tree, g, collapsedIcon, middleXOfKnob,
			       middleYOfKnob);
	    }
	}
    }

    /**
     * Paints the renderer part of a row. The reciever should
     * NOT modify <code>clipBounds</code>, or <code>insets</code>.
     */
    protected void paintRow(Graphics g, Rectangle clipBounds,
			    Insets insets, Rectangle bounds, TreePath path,
			    int row, boolean isExpanded,
			    boolean hasBeenExpanded, boolean isLeaf) {
	// Don't paint the renderer if editing this row.
	if(editingComponent != null && editingRow == row)
	    return;

	int leadIndex;

	if(tree.hasFocus()) {
	    leadIndex = getLeadSelectionRow();
	}
	else
	    leadIndex = -1;

	Component component;

	component = currentCellRenderer.getTreeCellRendererComponent
	              (tree, path.getLastPathComponent(),
		       tree.isRowSelected(row), isExpanded, isLeaf, row,
		       (leadIndex == row));
	
	rendererPane.paintComponent(g, component, tree, bounds.x, bounds.y,
				    bounds.width, bounds.height, true);	
    }

    /**
     * Returns true if the expand (toggle) control should be drawn for
     * the specified row.
     */
    protected boolean shouldPaintExpandControl(TreePath path, int row,
					       boolean isExpanded,
					       boolean hasBeenExpanded,
					       boolean isLeaf) {
	if(isLeaf)
	    return false;

	int              depth = path.getPathCount() - 1;

	if((depth == 0 || (depth == 1 && !isRootVisible())) &&
	   !getShowsRootHandles())
	    return false;
	return true;
    }

    /**
     * Paints a vertical line.
     */
    protected void paintVerticalLine(Graphics g, JComponent c, int x, int top,
				    int bottom) {
	g.drawLine(x, top, x, bottom);
    }

    /**
     * Paints a horizontal line.
     */
    protected void paintHorizontalLine(Graphics g, JComponent c, int y,
				      int left, int right) {
	g.drawLine(left, y, right, y);
    }

    /**
     * The vertical element of legs between nodes starts at the bottom of the
     * parent node by default.  This method makes the leg start below that.
     */
    protected int getVerticalLegBuffer() {
	return 0;
    } 

    /**
     * The horizontal element of legs between nodes starts at the
     * right of the left-hand side of the child node by default.  This
     * method makes the leg end before that.
     */
    protected int getHorizontalLegBuffer() {
	return 0;
    } 

    //
    // Generic painting methods
    //

    // Draws the icon centered at (x,y)
    protected void drawCentered(Component c, Graphics graphics, Icon icon,
				int x, int y) {
	icon.paintIcon(c, graphics, x - icon.getIconWidth()/2, y -
		       icon.getIconHeight()/2);
    }

    // This method is slow -- revisit when Java2D is ready.
    // assumes x1 <= x2
    protected void drawDashedHorizontalLine(Graphics g, int y, int x1, int x2){
	// Drawing only even coordinates helps join line segments so they
	// appear as one line.  This can be defeated by translating the
	// Graphics by an odd amount.
	x1 += (x1 % 2);

	for (int x = x1; x <= x2; x+=2) {
	    g.drawLine(x, y, x, y);
	}
    }

    // This method is slow -- revisit when Java2D is ready.
    // assumes y1 <= y2
    protected void drawDashedVerticalLine(Graphics g, int x, int y1, int y2) {
	// Drawing only even coordinates helps join line segments so they
	// appear as one line.  This can be defeated by translating the
	// Graphics by an odd amount.
	y1 += (y1 % 2);

	for (int y = y1; y <= y2; y+=2) {
	    g.drawLine(x, y, x, y);
	}
    }

    //
    // Various local methods
    //

    /**
     * Makes all the nodes that are expanded in JTree expanded in LayoutCache.
     * This invokes updateExpandedDescendants with the root path.
     */
    protected void updateLayoutCacheExpandedNodes() {
	if(treeModel != null)
	    updateExpandedDescendants(new TreePath(treeModel.getRoot()));
    }

    /**
     * Updates the expanded state of all the descendants of <code>path</code>
     * by getting the expanded descendants from the tree and forwarding
     * to the tree state.
     */
    protected void updateExpandedDescendants(TreePath path) {
	completeEditing();
	if(treeState != null) {
	    treeState.setExpandedState(path, true);

	    Enumeration   descendants = tree.getExpandedDescendants(path);

	    if(descendants != null) {
		while(descendants.hasMoreElements()) {
		    path = (TreePath)descendants.nextElement();
		    treeState.setExpandedState(path, true);
		}
	    }
	    updateLeadRow();
	    updateSize();
	}
    }

    /**
     * Returns a path to the last child of <code>parent</code>.
     */
    protected TreePath getLastChildPath(TreePath parent) {
	if(treeModel != null) {
	    int         childCount = treeModel.getChildCount
		(parent.getLastPathComponent());
	    
	    if(childCount > 0)
		return parent.pathByAddingChild(treeModel.getChild
			   (parent.getLastPathComponent(), childCount - 1));
	}
	return null;
    }

    /**
     * Updates how much each depth should be offset by.
     */
    protected void updateDepthOffset() {
	if(isRootVisible()) {
	    if(getShowsRootHandles())
		depthOffset = 1;
	    else
		depthOffset = 0;
	}
	else if(!getShowsRootHandles())
	    depthOffset = -1;
	else
	    depthOffset = 0;
    }

    /** 
      * Updates the cellEditor based on the editability of the JTree that
      * we're contained in.  If the tree is editable but doesn't have a
      * cellEditor, a basic one will be used.
      */
    protected void updateCellEditor() {
	TreeCellEditor        newEditor;

	completeEditing();
	if(tree == null)
	    newEditor = null;
	else {
	    if(tree.isEditable()) {
		newEditor = tree.getCellEditor();
		if(newEditor == null) {
		    newEditor = createDefaultCellEditor();
		    if(newEditor != null) {
			tree.setCellEditor(newEditor);
			createdCellEditor = true;
		    }
		}
	    }
	    else
		newEditor = null;
	}
	if(newEditor != cellEditor) {
	    if(cellEditor != null && cellEditorListener != null)
		cellEditor.removeCellEditorListener(cellEditorListener);
	    cellEditor = newEditor;
	    if(cellEditorListener == null)
		cellEditorListener = createCellEditorListener();
	    if(newEditor != null && cellEditorListener != null)
		newEditor.addCellEditorListener(cellEditorListener);
	    createdCellEditor = false;
	}
    }

    /**
      * Messaged from the tree we're in when the renderer has changed.
      */
    protected void updateRenderer() {
	if(tree != null) {
	    TreeCellRenderer      newCellRenderer;

	    newCellRenderer = tree.getCellRenderer();
	    if(newCellRenderer == null) {
		tree.setCellRenderer(createDefaultCellRenderer());
		createdRenderer = true;
	    }
	    else {
		createdRenderer = false;
		currentCellRenderer = newCellRenderer;
		if(createdCellEditor) {
		    tree.setCellEditor(null);
		}
	    }
	}
	else {
	    createdRenderer = false;
	    currentCellRenderer = null;
	}
	updateCellEditor();
    }

    /**
     * Resets the TreeState instance based on the tree we're providing the
     * look and feel for.
     */
    protected void configureLayoutCache() {
	if(treeState != null && tree != null) {
	    if(nodeDimensions == null)
		nodeDimensions = createNodeDimensions();
	    treeState.setNodeDimensions(nodeDimensions);
	    treeState.setRootVisible(tree.isRootVisible());
	    treeState.setRowHeight(tree.getRowHeight());
	    treeState.setSelectionModel(getSelectionModel());
	    // Only do this if necessary, may loss state if call with
	    // same model as it currently has.
	    if(treeState.getModel() != tree.getModel())
		treeState.setModel(tree.getModel());
	    updateLayoutCacheExpandedNodes();
	    // Create a listener to update preferred size when bounds
	    // changes, if necessary.
	    if(isLargeModel()) {
		if(componentListener == null) {
		    componentListener = createComponentListener();
		    if(componentListener != null)
			tree.addComponentListener(componentListener);
		}
	    }
	    else if(componentListener != null) {
		tree.removeComponentListener(componentListener);
		componentListener = null;
	    }
	}
	else if(componentListener != null) {
	    tree.removeComponentListener(componentListener);
	    componentListener = null;
	}
    }

    /**
     * Marks the cached size as being invalid, and messages the
     * tree with <code>treeDidChange</code>.
     */
    protected void updateSize() {
	validCachedPreferredSize = false;
	tree.treeDidChange();
    }

    /**
     * Updates the <code>preferredSize</code> instance variable,
     * which is returned from <code>getPreferredSize()</code>.<p>
     * For left to right orientations, the size is determined from the
     * current AbstractLayoutCache. For RTL orientations, the preferred size
     * becomes the width minus the minimum x position.
     */
    protected void updateCachedPreferredSize() {
	if(treeState != null) {
	    Insets               i = tree.getInsets();

	    if(isLargeModel()) {
		Rectangle            visRect = tree.getVisibleRect();

		if(i != null) {
		    visRect.x -= i.left;
		    visRect.y -= i.top;
		}
		if (leftToRight) {
		    preferredSize.width = treeState.getPreferredWidth(visRect);
		}
		else {
		    if (getRowCount(tree) == 0) {
			preferredSize.width = 0;
		    }
		    else {
			preferredSize.width = lastWidth - getMinX(visRect);
		    }
		}
	    }
	    else if (leftToRight) {
		preferredSize.width = treeState.getPreferredWidth(null);
	    }
	    else {
		Rectangle tempRect = null;
		int rowCount = tree.getRowCount();
		int width = 0;
		for (int counter = 0; counter < rowCount; counter++) {
		    tempRect = treeState.getBounds
			       (treeState.getPathForRow(counter), tempRect);
		    if (tempRect != null) {
			width = Math.max(lastWidth - tempRect.x, width);
		    }
		}
		preferredSize.width = width;
	    }
	    preferredSize.height = treeState.getPreferredHeight();
	    if(i != null) {
		preferredSize.width += i.left + i.right;
		preferredSize.height += i.top + i.bottom;
	    }
	}
	validCachedPreferredSize = true;
    }

    /**
     * Returns the minimum x location for the nodes in <code>bounds</code>.
     */
    private int getMinX(Rectangle bounds) {
	TreePath      firstPath;
	int           endY;

	if(bounds == null) {
	    firstPath = getPathForRow(tree, 0);
	    endY = Integer.MAX_VALUE;
	}
	else {
	    firstPath = treeState.getPathClosestTo(bounds.x, bounds.y);
	    endY = bounds.height + bounds.y;
	}

	Enumeration   paths = treeState.getVisiblePathsFrom(firstPath);
	int           minX = 0;

	if(paths != null && paths.hasMoreElements()) {
	    Rectangle   pBounds = treeState.getBounds
		                  ((TreePath)paths.nextElement(), null);
	    int         width;

	    if(pBounds != null) {
		minX = pBounds.x + pBounds.width;
		if (pBounds.y >= endY) {
		    return minX;
		}
	    }
	    while (pBounds != null && paths.hasMoreElements()) {
		pBounds = treeState.getBounds((TreePath)paths.nextElement(),
					      pBounds);
		if (pBounds != null && pBounds.y < endY) {
		    minX = Math.min(minX, pBounds.x);
		}
		else {
		    pBounds = null;
		}
	    }
	    return minX;
	}
	return minX;
    }

    /**
      * Messaged from the VisibleTreeNode after it has been expanded.
      */
    protected void pathWasExpanded(TreePath path) {
	if(tree != null) {
	    tree.fireTreeExpanded(path);
	}
    }

    /**
      * Messaged from the VisibleTreeNode after it has collapsed.
      */
    protected void pathWasCollapsed(TreePath path) {
	if(tree != null) {
	    tree.fireTreeCollapsed(path);
	}
    }

    /**
      * Ensures that the rows identified by beginRow through endRow are
      * visible.
      */
    protected void ensureRowsAreVisible(int beginRow, int endRow) {
	if(tree != null && beginRow >= 0 && endRow < getRowCount(tree))