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ToolTipManager.javaAPI DocJava SE 6 API29656Tue Jun 10 00:26:42 BST 2008javax.swing

ToolTipManager.java

/*
 * @(#)ToolTipManager.java	1.75 07/06/25
 *
 * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */


package javax.swing;

import java.awt.event.*;
import java.applet.*;
import java.awt.*;
import java.io.Serializable;
import sun.swing.UIAction;

/**
 * Manages all the <code>ToolTips</code> in the system.
 * <p>
 * ToolTipManager contains numerous properties for configuring how long it
 * will take for the tooltips to become visible, and how long till they
 * hide. Consider a component that has a different tooltip based on where
 * the mouse is, such as JTree. When the mouse moves into the JTree and
 * over a region that has a valid tooltip, the tooltip will become
 * visibile after <code>initialDelay</code> milliseconds. After
 * <code>dismissDelay</code> milliseconds the tooltip will be hidden. If
 * the mouse is over a region that has a valid tooltip, and the tooltip
 * is currently visible, when the mouse moves to a region that doesn't have
 * a valid tooltip the tooltip will be hidden. If the mouse then moves back
 * into a region that has a valid tooltip within <code>reshowDelay</code>
 * milliseconds, the tooltip will immediately be shown, otherwise the
 * tooltip will be shown again after <code>initialDelay</code> milliseconds.
 *
 * @see JComponent#createToolTip
 * @version 1.75 06/25/07
 * @author Dave Moore
 * @author Rich Schiavi
 */
public class ToolTipManager extends MouseAdapter implements MouseMotionListener  {
    Timer enterTimer, exitTimer, insideTimer;
    String toolTipText;
    Point  preferredLocation;
    JComponent insideComponent;
    MouseEvent mouseEvent;
    boolean showImmediately;
    final static ToolTipManager sharedInstance = new ToolTipManager();
    transient Popup tipWindow;
    /** The Window tip is being displayed in. This will be non-null if
     * the Window tip is in differs from that of insideComponent's Window.
     */
    private Window window;
    JToolTip tip;

    private Rectangle popupRect = null;
    private Rectangle popupFrameRect = null;

    boolean enabled = true;
    private boolean tipShowing = false;
   
    private KeyStroke postTip,hideTip;
    private Action postTipAction, hideTipAction;

    private FocusListener focusChangeListener = null;
    private MouseMotionListener moveBeforeEnterListener = null;

    // PENDING(ges)
    protected boolean lightWeightPopupEnabled = true;
    protected boolean heavyWeightPopupEnabled = false;

    ToolTipManager() {
        enterTimer = new Timer(750, new insideTimerAction());
        enterTimer.setRepeats(false);
        exitTimer = new Timer(500, new outsideTimerAction());
        exitTimer.setRepeats(false);
        insideTimer = new Timer(4000, new stillInsideTimerAction());
        insideTimer.setRepeats(false);

	// create accessibility actions 
	postTip = KeyStroke.getKeyStroke(KeyEvent.VK_F1,Event.CTRL_MASK);
	postTipAction = new Actions(Actions.SHOW);
	hideTip = KeyStroke.getKeyStroke(KeyEvent.VK_ESCAPE,0);
	hideTipAction = new Actions(Actions.HIDE);

	moveBeforeEnterListener = new MoveBeforeEnterListener();
    }

    /**
     * Enables or disables the tooltip.
     *
     * @param flag  true to enable the tip, false otherwise
     */
    public void setEnabled(boolean flag) {
        enabled = flag;
        if (!flag) {
            hideTipWindow();
        }
    }

    /**
     * Returns true if this object is enabled.
     *
     * @return true if this object is enabled, false otherwise
     */
    public boolean isEnabled() {
        return enabled;
    }

    /**
     * When displaying the <code>JToolTip</code>, the
     * <code>ToolTipManager</code> chooses to use a lightweight
     * <code>JPanel</code> if it fits. This method allows you to
     * disable this feature. You have to do disable it if your
     * application mixes light weight and heavy weights components.
     *
     * @param aFlag true if a lightweight panel is desired, false otherwise
     *
     */
    public void setLightWeightPopupEnabled(boolean aFlag){
        lightWeightPopupEnabled = aFlag;
    }
    
    /**
     * Returns true if lightweight (all-Java) <code>Tooltips</code>
     * are in use, or false if heavyweight (native peer)
     * <code>Tooltips</code> are being used.
     *
     * @return true if lightweight <code>ToolTips</code> are in use
     */
    public boolean isLightWeightPopupEnabled() { 
        return lightWeightPopupEnabled;
    }


    /**
     * Specifies the initial delay value.
     *
     * @param milliseconds  the number of milliseconds to delay
     *        (after the cursor has paused) before displaying the
     *        tooltip
     * @see #getInitialDelay
     */
    public void setInitialDelay(int milliseconds) {
        enterTimer.setInitialDelay(milliseconds);
    }

    /**
     * Returns the initial delay value.
     *
     * @return an integer representing the initial delay value,
     *		in milliseconds
     * @see #setInitialDelay
     */
    public int getInitialDelay() {
        return enterTimer.getInitialDelay();
    }

    /**
     * Specifies the dismissal delay value.
     *
     * @param milliseconds  the number of milliseconds to delay
     *        before taking away the tooltip
     * @see #getDismissDelay
     */
    public void setDismissDelay(int milliseconds) {
        insideTimer.setInitialDelay(milliseconds);
    }

    /**
     * Returns the dismissal delay value.
     *
     * @return an integer representing the dismissal delay value, 
     *		in milliseconds
     * @see #setDismissDelay
     */
    public int getDismissDelay() {
        return insideTimer.getInitialDelay();
    }

    /**
     * Used to specify the amount of time before the user has to wait
     * <code>initialDelay</code> milliseconds before a tooltip will be
     * shown. That is, if the tooltip is hidden, and the user moves into
     * a region of the same Component that has a valid tooltip within
     * <code>milliseconds</code> milliseconds the tooltip will immediately
     * be shown. Otherwise, if the user moves into a region with a valid
     * tooltip after <code>milliseconds</code> milliseconds, the user
     * will have to wait an additional <code>initialDelay</code>
     * milliseconds before the tooltip is shown again.
     *
     * @param milliseconds time in milliseconds
     * @see #getReshowDelay
     */
    public void setReshowDelay(int milliseconds) {
        exitTimer.setInitialDelay(milliseconds);
    }

    /**
     * Returns the reshow delay property.
     *
     * @return reshown delay property
     * @see #setReshowDelay
     */
    public int getReshowDelay() {
        return exitTimer.getInitialDelay();
    }

    void showTipWindow() {
        if(insideComponent == null || !insideComponent.isShowing())
            return;
        String mode = UIManager.getString("ToolTipManager.enableToolTipMode");
        if ("activeApplication".equals(mode)) {
            KeyboardFocusManager kfm = 
                    KeyboardFocusManager.getCurrentKeyboardFocusManager();
            if (kfm.getFocusedWindow() == null) {
                return;
            }
        }
        if (enabled) {
            Dimension size;
            Point screenLocation = insideComponent.getLocationOnScreen();
            Point location = new Point();
            GraphicsConfiguration gc;
            gc = insideComponent.getGraphicsConfiguration();
            Rectangle sBounds = gc.getBounds();
            Insets screenInsets = Toolkit.getDefaultToolkit()
                                             .getScreenInsets(gc);
            // Take into account screen insets, decrease viewport
            sBounds.x += screenInsets.left;
            sBounds.y += screenInsets.top;
            sBounds.width -= (screenInsets.left + screenInsets.right);
            sBounds.height -= (screenInsets.top + screenInsets.bottom);
        boolean leftToRight
                = SwingUtilities.isLeftToRight(insideComponent);

            // Just to be paranoid
            hideTipWindow();

            tip = insideComponent.createToolTip();
            tip.setTipText(toolTipText);
            size = tip.getPreferredSize();

            if(preferredLocation != null) {
                location.x = screenLocation.x + preferredLocation.x;
                location.y = screenLocation.y + preferredLocation.y;
        if (!leftToRight) {
            location.x -= size.width;
        }
            } else {
                location.x = screenLocation.x + mouseEvent.getX();
                location.y = screenLocation.y + mouseEvent.getY() + 20;
        if (!leftToRight) {
            if(location.x - size.width>=0) {
                location.x -= size.width;
            }
        }

            }

        // we do not adjust x/y when using awt.Window tips
        if (popupRect == null){
        popupRect = new Rectangle();
        }
        popupRect.setBounds(location.x,location.y,
                size.width,size.height);

        // Fit as much of the tooltip on screen as possible
            if (location.x < sBounds.x) {
                location.x = sBounds.x;
            }
            else if (location.x - sBounds.x + size.width > sBounds.width) {
                location.x = sBounds.x + Math.max(0, sBounds.width - size.width)
;
            }
            if (location.y < sBounds.y) {
                location.y = sBounds.y;
            }
            else if (location.y - sBounds.y + size.height > sBounds.height) {
                location.y = sBounds.y + Math.max(0, sBounds.height - size.height);
            }

            PopupFactory popupFactory = PopupFactory.getSharedInstance();

            if (lightWeightPopupEnabled) {
        int y = getPopupFitHeight(popupRect, insideComponent);
        int x = getPopupFitWidth(popupRect,insideComponent);
        if (x>0 || y>0) {
            popupFactory.setPopupType(PopupFactory.MEDIUM_WEIGHT_POPUP);
        } else {
            popupFactory.setPopupType(PopupFactory.LIGHT_WEIGHT_POPUP);
        }
            }
            else {
                popupFactory.setPopupType(PopupFactory.MEDIUM_WEIGHT_POPUP);
            }
        tipWindow = popupFactory.getPopup(insideComponent, tip,
                          location.x,
                          location.y);
            popupFactory.setPopupType(PopupFactory.LIGHT_WEIGHT_POPUP);

        tipWindow.show();

            Window componentWindow = SwingUtilities.windowForComponent(
                                                    insideComponent);

            window = SwingUtilities.windowForComponent(tip);
            if (window != null && window != componentWindow) {
                window.addMouseListener(this);
            }
            else {
                window = null;
            }

            insideTimer.start();
        tipShowing = true;
        }
    }

    void hideTipWindow() {
        if (tipWindow != null) {
            if (window != null) {
                window.removeMouseListener(this);
                window = null;
            }
            tipWindow.hide();
	    tipWindow = null;
	    tipShowing = false;
            tip = null;
            insideTimer.stop();
        } 
    }

    /**
     * Returns a shared <code>ToolTipManager</code> instance.
     *
     * @return a shared <code>ToolTipManager</code> object
     */
    public static ToolTipManager sharedInstance() {
        return sharedInstance;
    }

    // add keylistener here to trigger tip for access
    /**
     * Registers a component for tooltip management.
     * <p>
     * This will register key bindings to show and hide the tooltip text
     * only if <code>component</code> has focus bindings. This is done
     * so that components that are not normally focus traversable, such
     * as <code>JLabel</code>, are not made focus traversable as a result
     * of invoking this method.
     *
     * @param component  a <code>JComponent</code> object to add
     * @see JComponent#isFocusTraversable
     */
    public void registerComponent(JComponent component) {
        component.removeMouseListener(this);
        component.addMouseListener(this);
        component.removeMouseMotionListener(moveBeforeEnterListener);
	component.addMouseMotionListener(moveBeforeEnterListener);

	if (shouldRegisterBindings(component)) {
	    // register our accessibility keybindings for this component
	    // this will apply globally across L&F
	    // Post Tip: Ctrl+F1
	    // Unpost Tip: Esc and Ctrl+F1
	    InputMap inputMap = component.getInputMap(JComponent.WHEN_FOCUSED);
	    ActionMap actionMap = component.getActionMap();

	    if (inputMap != null && actionMap != null) {
		inputMap.put(postTip, "postTip");
		inputMap.put(hideTip, "hideTip");
		actionMap.put("postTip", postTipAction);
		actionMap.put("hideTip", hideTipAction);
	    }
	}
    }

    /**
     * Removes a component from tooltip control.
     *
     * @param component  a <code>JComponent</code> object to remove
     */
    public void unregisterComponent(JComponent component) {
        component.removeMouseListener(this);
	component.removeMouseMotionListener(moveBeforeEnterListener);

	if (shouldRegisterBindings(component)) {
	    InputMap inputMap = component.getInputMap(JComponent.WHEN_FOCUSED);
	    ActionMap actionMap = component.getActionMap();

	    if (inputMap != null && actionMap != null) {
		inputMap.remove(postTip);
		inputMap.remove(hideTip);
		actionMap.remove("postTip");
		actionMap.remove("hideTip");
	    }
	}
    }

    /**
     * Returns whether or not bindings should be registered on the given
     * <code>JComponent</code>. This is implemented to return true if the
     * tool tip manager has a binding in any one of the
     * <code>InputMaps</code> registered under the condition
     * <code>WHEN_FOCUSED</code>.
     * <p>
     * This does not use <code>isFocusTraversable</code> as
     * some components may override <code>isFocusTraversable</code> and
     * base the return value on something other than bindings. For example,
     * <code>JButton</code> bases its return value on its enabled state.
     *
     * @param component  the <code>JComponent</code> in question
     */
    private boolean shouldRegisterBindings(JComponent component) {
	InputMap inputMap = component.getInputMap(JComponent.WHEN_FOCUSED,
						  false);
	while (inputMap != null && inputMap.size() == 0) {
	    inputMap = inputMap.getParent();
	}
	return (inputMap != null);
    }

    // implements java.awt.event.MouseListener
    /**
     *  Called when the mouse enters the region of a component.
     *  This determines whether the tool tip should be shown.
     *
     *  @param event  the event in question
     */
    public void mouseEntered(MouseEvent event) {
        initiateToolTip(event);
    }

    private void initiateToolTip(MouseEvent event) {
        if (event.getSource() == window) {
            return;
        }
        JComponent component = (JComponent)event.getSource();
	component.removeMouseMotionListener(moveBeforeEnterListener);

        exitTimer.stop();

	Point location = event.getPoint();
	// ensure tooltip shows only in proper place
	if (location.x < 0 || 
	    location.x >=component.getWidth() ||
	    location.y < 0 ||
	    location.y >= component.getHeight()) {
	    return;
	}

        if (insideComponent != null) {
            enterTimer.stop();
        }
	// A component in an unactive internal frame is sent two
	// mouseEntered events, make sure we don't end up adding
	// ourselves an extra time.
        component.removeMouseMotionListener(this);
        component.addMouseMotionListener(this);

        boolean sameComponent = (insideComponent == component);

        insideComponent = component;
    if (tipWindow != null){
            mouseEvent = event;
            if (showImmediately) {
                String newToolTipText = component.getToolTipText(event);
                Point newPreferredLocation = component.getToolTipLocation(
                                                         event);
                boolean sameLoc = (preferredLocation != null) ?
                            preferredLocation.equals(newPreferredLocation) :
                            (newPreferredLocation == null);

                if (!sameComponent || !toolTipText.equals(newToolTipText) || 
                         !sameLoc) {
                    toolTipText = newToolTipText;
                    preferredLocation = newPreferredLocation;
                    showTipWindow();
                }
            } else {
                enterTimer.start();
            }
        }
    }

    // implements java.awt.event.MouseListener
    /**
     *  Called when the mouse exits the region of a component.
     *  Any tool tip showing should be hidden.
     *
     *  @param event  the event in question
     */
    public void mouseExited(MouseEvent event) {
        boolean shouldHide = true;
        if (insideComponent == null) {
            // Drag exit
        } 
        if (window != null && event.getSource() == window) {
	  // if we get an exit and have a heavy window
	  // we need to check if it if overlapping the inside component
            Container insideComponentWindow = insideComponent.getTopLevelAncestor();
            // insideComponent may be removed after tooltip is made visible 
            if (insideComponentWindow != null) {
                Point location = event.getPoint();
                SwingUtilities.convertPointToScreen(location, window);

                location.x -= insideComponentWindow.getX();
                location.y -= insideComponentWindow.getY();

                location = SwingUtilities.convertPoint(null, location, insideComponent);
                if (location.x >= 0 && location.x < insideComponent.getWidth() &&
                        location.y >= 0 && location.y < insideComponent.getHeight()) {
                    shouldHide = false;
                } else {
                    shouldHide = true;
                }
            }
        } else if(event.getSource() == insideComponent && tipWindow != null) {
	    Window win = SwingUtilities.getWindowAncestor(insideComponent);
	    if (win != null) {	// insideComponent may have been hidden (e.g. in a menu)
		Point location = SwingUtilities.convertPoint(insideComponent,
							     event.getPoint(),
							     win);
		Rectangle bounds = insideComponent.getTopLevelAncestor().getBounds();
		location.x += bounds.x;
		location.y += bounds.y;
		
		Point loc = new Point(0, 0);
		SwingUtilities.convertPointToScreen(loc, tip);
		bounds.x = loc.x;
		bounds.y = loc.y;
		bounds.width = tip.getWidth();
		bounds.height = tip.getHeight();
		
		if (location.x >= bounds.x && location.x < (bounds.x + bounds.width) &&
		    location.y >= bounds.y && location.y < (bounds.y + bounds.height)) {
		    shouldHide = false;
		} else {
		    shouldHide = true;
		}
	    }
        } 
        
        if (shouldHide) {        
            enterTimer.stop();
        if (insideComponent != null) {
	        insideComponent.removeMouseMotionListener(this);
	    }
            insideComponent = null;
            toolTipText = null;
            mouseEvent = null;
            hideTipWindow();
            exitTimer.restart();
        }
    }

    // implements java.awt.event.MouseListener
    /**
     *  Called when the mouse is pressed.
     *  Any tool tip showing should be hidden.
     *
     *  @param event  the event in question
     */
    public void mousePressed(MouseEvent event) {
        hideTipWindow();
        enterTimer.stop();
        showImmediately = false;
        insideComponent = null;
        mouseEvent = null;
    }

    // implements java.awt.event.MouseMotionListener
    /**
     *  Called when the mouse is pressed and dragged.
     *  Does nothing.
     *
     *  @param event  the event in question
     */
    public void mouseDragged(MouseEvent event) {
    }

    // implements java.awt.event.MouseMotionListener
    /**
     *  Called when the mouse is moved.
     *  Determines whether the tool tip should be displayed.
     *
     *  @param event  the event in question
     */
    public void mouseMoved(MouseEvent event) {
        if (tipShowing) {
            checkForTipChange(event);
        }
        else if (showImmediately) {
            JComponent component = (JComponent)event.getSource();
            toolTipText = component.getToolTipText(event);
            if (toolTipText != null) {
                preferredLocation = component.getToolTipLocation(event);
                mouseEvent = event;
                insideComponent = component;
                exitTimer.stop();
                showTipWindow();
            }
        }
        else {
            // Lazily lookup the values from within insideTimerAction
            insideComponent = (JComponent)event.getSource();
            mouseEvent = event;
            toolTipText = null;
            enterTimer.restart();
        }
    }

    /**
     * Checks to see if the tooltip needs to be changed in response to
     * the MouseMoved event <code>event</code>.
     */
    private void checkForTipChange(MouseEvent event) {
        JComponent component = (JComponent)event.getSource();
        String newText = component.getToolTipText(event);
        Point  newPreferredLocation = component.getToolTipLocation(event);

        if (newText != null || newPreferredLocation != null) {
            mouseEvent = event;
            if (((newText != null && newText.equals(toolTipText)) || newText == null) &&
                ((newPreferredLocation != null && newPreferredLocation.equals(preferredLocation)) 
                 || newPreferredLocation == null)) {
                if (tipWindow != null) {
                    insideTimer.restart();
                } else {
                    enterTimer.restart();
                }
            } else {
                toolTipText = newText;
                preferredLocation = newPreferredLocation;
                if (showImmediately) {
                    hideTipWindow();
                    showTipWindow();
                    exitTimer.stop();
                } else {
                    enterTimer.restart();
                }
            }
        } else {
            toolTipText = null;
            preferredLocation = null;
            mouseEvent = null;
            insideComponent = null;
            hideTipWindow();
            enterTimer.stop();
            exitTimer.restart();
        }
    }

    protected class insideTimerAction implements ActionListener {
        public void actionPerformed(ActionEvent e) {
            if(insideComponent != null && insideComponent.isShowing()) {
                // Lazy lookup
                if (toolTipText == null && mouseEvent != null) {
                    toolTipText = insideComponent.getToolTipText(mouseEvent);
                    preferredLocation = insideComponent.getToolTipLocation(
                                              mouseEvent);
                }
                if(toolTipText != null) {
                    showImmediately = true;
                    showTipWindow();
                }
                else {
                    insideComponent = null;
                    toolTipText = null;
                    preferredLocation = null;
                    mouseEvent = null;
                    hideTipWindow();
                }
            }
        }
    }

    protected class outsideTimerAction implements ActionListener {
        public void actionPerformed(ActionEvent e) {
            showImmediately = false;
        }
    }

    protected class stillInsideTimerAction implements ActionListener {
        public void actionPerformed(ActionEvent e) {
            hideTipWindow();
            enterTimer.stop();
            showImmediately = false;
            insideComponent = null;
            mouseEvent = null;
        }
    }

  /* This listener is registered when the tooltip is first registered
   * on a component in order to catch the situation where the tooltip
   * was turned on while the mouse was already within the bounds of
   * the component.  This way, the tooltip will be initiated on a
   * mouse-entered or mouse-moved, whichever occurs first.  Once the
   * tooltip has been initiated, we can remove this listener and rely
   * solely on mouse-entered to initiate the tooltip.
   */
    private class MoveBeforeEnterListener extends MouseMotionAdapter {
        public void mouseMoved(MouseEvent e) {
	    initiateToolTip(e);
	}
    }

    static Frame frameForComponent(Component component) {
        while (!(component instanceof Frame)) {
            component = component.getParent();
        }
        return (Frame)component;
    }

  private FocusListener createFocusChangeListener(){
    return new FocusAdapter(){
      public void focusLost(FocusEvent evt){
	hideTipWindow();
        insideComponent = null;
	JComponent c = (JComponent)evt.getSource();
	c.removeFocusListener(focusChangeListener);
      }
    };
  }

  // Returns: 0 no adjust
  //         -1 can't fit
  //         >0 adjust value by amount returned
  private int getPopupFitWidth(Rectangle popupRectInScreen, Component invoker){
    if (invoker != null){
      Container parent;
      for (parent = invoker.getParent(); parent != null; parent = parent.getParent()){
	// fix internal frame size bug: 4139087 - 4159012
	if(parent instanceof JFrame || parent instanceof JDialog ||
	   parent instanceof JWindow) { // no check for awt.Frame since we use Heavy tips
	  return getWidthAdjust(parent.getBounds(),popupRectInScreen);
	} else if (parent instanceof JApplet || parent instanceof JInternalFrame) {
	  if (popupFrameRect == null){
	    popupFrameRect = new Rectangle();
	  }
	  Point p = parent.getLocationOnScreen();
	  popupFrameRect.setBounds(p.x,p.y,
				   parent.getBounds().width,
				   parent.getBounds().height);
	  return getWidthAdjust(popupFrameRect,popupRectInScreen);
	}
      }
    }
    return 0;
  }

  // Returns:  0 no adjust
  //          >0 adjust by value return
  private int getPopupFitHeight(Rectangle popupRectInScreen, Component invoker){
    if (invoker != null){
      Container parent;
      for (parent = invoker.getParent(); parent != null; parent = parent.getParent()){
	if(parent instanceof JFrame || parent instanceof JDialog ||
	   parent instanceof JWindow) {
	  return getHeightAdjust(parent.getBounds(),popupRectInScreen);
	} else if (parent instanceof JApplet || parent instanceof JInternalFrame) {
	  if (popupFrameRect == null){
	    popupFrameRect = new Rectangle();
	  }
	  Point p = parent.getLocationOnScreen();
	  popupFrameRect.setBounds(p.x,p.y,
				   parent.getBounds().width,
				   parent.getBounds().height);
	  return getHeightAdjust(popupFrameRect,popupRectInScreen);
	}
      }
    }
    return 0;
  }

  private int getHeightAdjust(Rectangle a, Rectangle b){
    if (b.y >= a.y && (b.y + b.height) <= (a.y + a.height))
      return 0;
    else
      return (((b.y + b.height) - (a.y + a.height)) + 5);
  }

  // Return the number of pixels over the edge we are extending.
  // If we are over the edge the ToolTipManager can adjust.
  // REMIND: what if the Tooltip is just too big to fit at all - we currently will just clip
  private int getWidthAdjust(Rectangle a, Rectangle b){
    //    System.out.println("width b.x/b.width: " + b.x + "/" + b.width +
    //		       "a.x/a.width: " + a.x + "/" + a.width);
    if (b.x >= a.x && (b.x + b.width) <= (a.x + a.width)){
      return 0;
    }
    else {
      return (((b.x + b.width) - (a.x +a.width)) + 5);
    }
  }


    //
    // Actions
    //
    private void show(JComponent source) {
        if (tipWindow != null) { // showing we unshow
            hideTipWindow();
            insideComponent = null;
        }
        else {
            hideTipWindow(); // be safe
            enterTimer.stop();
            exitTimer.stop();
            insideTimer.stop();
            insideComponent = source;
            if (insideComponent != null){
                toolTipText = insideComponent.getToolTipText();
                preferredLocation = new Point(10,insideComponent.getHeight()+
                                              10);  // manual set
                showTipWindow();
                // put a focuschange listener on to bring the tip down
                if (focusChangeListener == null){
                    focusChangeListener = createFocusChangeListener();
                }
                insideComponent.addFocusListener(focusChangeListener); 
            }
        }
    }

    private void hide(JComponent source) {
        hideTipWindow();
        source.removeFocusListener(focusChangeListener);
        preferredLocation = null;
        insideComponent = null;
    }


    private static class Actions extends UIAction {
        private static String SHOW = "SHOW";
        private static String HIDE = "HIDE";

        Actions(String key) {
            super(key);
        }

        public void actionPerformed(ActionEvent e) {
            String key = getName();
            JComponent source = (JComponent)e.getSource();
            if (key == SHOW) {
                ToolTipManager.sharedInstance().show(source);
            }
            else if (key == HIDE) {
                ToolTipManager.sharedInstance().hide(source);
            }
        }

        public boolean isEnabled(Object sender) {
            if (getName() == SHOW) {
                return true;
            }
            return ToolTipManager.sharedInstance().tipShowing;
        }
    }
}