/*
 * @(#)JLabel.java	1.113 03/01/23
 *
 * Copyright 2003 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

package javax.swing;

import java.awt.Component;
import java.awt.Font;
import java.awt.Image;
import java.awt.*;
import java.text.*;
import java.awt.geom.*;

import java.io.ObjectOutputStream;
import java.io.ObjectInputStream;
import java.io.IOException;

import javax.swing.plaf.LabelUI;
import javax.accessibility.*;
import javax.swing.text.*;
import javax.swing.text.html.*;
import javax.swing.plaf.basic.*;
import java.util.*;


/**
 * A display area for a short text string or an image, 
 * or both.
 * A label does not react to input events.
 * As a result, it cannot get the keyboard focus.
 * A label can, however, display a keyboard alternative
 * as a convenience for a nearby component
 * that has a keyboard alternative but can't display it.
 * <p>
 * A <code>JLabel</code> object can display
 * either text, an image, or both.
 * You can specify where in the label's display area
 * the label's contents are aligned
 * by setting the vertical and horizontal alignment.
 * By default, labels are vertically centered 
 * in their display area.
 * Text-only labels are leading edge aligned, by default;
 * image-only labels are horizontally centered, by default.
 * <p>
 * You can also specify the position of the text
 * relative to the image.
 * By default, text is on the trailing edge of the image,
 * with the text and image vertically aligned.
 * <p>
 * A label's leading and trailing edge are determined from the value of its
 * {@link java.awt.ComponentOrientation} property.  At present, the default 
 * ComponentOrientation setting maps the leading edge to left and the trailing
 * edge to right.  
 *
 * <p>
 * Finally, you can use the <code>setIconTextGap</code> method
 * to specify how many pixels
 * should appear between the text and the image.
 * The default is 4 pixels.
 * <p>
 * See <a href="http://java.sun.com/docs/books/tutorial/uiswing/components/label.html">How to Use Labels</a>
 * in <em>The Java Tutorial</em>
 * for further documentation.
 * <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.  As of 1.4, support for long term storage
 * of all JavaBeans<sup><font size="-2">TM</font></sup>
 * has been added to the <code>java.beans</code> package.
 * Please see {@link java.beans.XMLEncoder}.
 *
 * @beaninfo
 *   attribute: isContainer false
 * description: A component that displays a short string and an icon.
 * 
 * @version 1.113 01/23/03
 * @author Hans Muller
 */
public class JLabel extends JComponent implements SwingConstants, Accessible
{
    /**
     * @see #getUIClassID
     * @see #readObject
     */
    private static final String uiClassID = "LabelUI";

    private int mnemonic = '\0';
    private int mnemonicIndex = -1;

    private String text = "";         // "" rather than null, for BeanBox
    private Icon defaultIcon = null;
    private Icon disabledIcon = null;
    private boolean disabledIconSet = false;
            
    private int verticalAlignment = CENTER;
    private int horizontalAlignment = LEADING;
    private int verticalTextPosition = CENTER;
    private int horizontalTextPosition = TRAILING;
    private int iconTextGap = 4;

    protected Component labelFor = null;
    private AccessibleIcon accessibleIcon      = null;

    /**
     * Client property key used to determine what label is labeling the
     * component.  This is generally not used by labels, but is instead
     * used by components such as text areas that are being labeled by
     * labels.  When the labelFor property of a label is set, it will
     * automatically set the LABELED_BY_PROPERTY of the component being
     * labelled.
     *
     * @see #setLabelFor
     */
    static final String LABELED_BY_PROPERTY = "labeledBy";

    /**
     * Creates a <code>JLabel</code> instance with the specified
     * text, image, and horizontal alignment.
     * The label is centered vertically in its display area.
     * The text is on the trailing edge of the image.
     *
     * @param text  The text to be displayed by the label.
     * @param icon  The image to be displayed by the label.
     * @param horizontalAlignment  One of the following constants
     *           defined in <code>SwingConstants</code>:
     *           <code>LEFT</code>,
     *           <code>CENTER</code>,
     *           <code>RIGHT</code>,
     *           <code>LEADING</code> or
     *           <code>TRAILING</code>.
     */
    public JLabel(String text, Icon icon, int horizontalAlignment) {
        setText(text);
        setIcon(icon);
        setHorizontalAlignment(horizontalAlignment);
        updateUI();
        setAlignmentX(LEFT_ALIGNMENT);
    }
            
    /**
     * Creates a <code>JLabel</code> instance with the specified
     * text and horizontal alignment.
     * The label is centered vertically in its display area.
     *
     * @param text  The text to be displayed by the label.
     * @param horizontalAlignment  One of the following constants
     *           defined in <code>SwingConstants</code>:
     *           <code>LEFT</code>,
     *           <code>CENTER</code>,
     *           <code>RIGHT</code>,
     *           <code>LEADING</code> or
     *           <code>TRAILING</code>.
     */
    public JLabel(String text, int horizontalAlignment) {
        this(text, null, horizontalAlignment);
    }

    /**
     * Creates a <code>JLabel</code> instance with the specified text.
     * The label is aligned against the leading edge of its display area,
     * and centered vertically.
     *
     * @param text  The text to be displayed by the label.
     */
    public JLabel(String text) {
        this(text, null, LEADING);
    }

    /**
     * Creates a <code>JLabel</code> instance with the specified
     * image and horizontal alignment.
     * The label is centered vertically in its display area.
     *
     * @param image  The image to be displayed by the label.
     * @param horizontalAlignment  One of the following constants
     *           defined in <code>SwingConstants</code>:
     *           <code>LEFT</code>,
     *           <code>CENTER</code>, 
     *           <code>RIGHT</code>,
     *           <code>LEADING</code> or
     *           <code>TRAILING</code>.
     */
    public JLabel(Icon image, int horizontalAlignment) {
        this(null, image, horizontalAlignment);
    }

    /**
     * Creates a <code>JLabel</code> instance with the specified image.
     * The label is centered vertically and horizontally
     * in its display area.
     *
     * @param image  The image to be displayed by the label.
     */
    public JLabel(Icon image) {
        this(null, image, CENTER);
    }

    /**
     * Creates a <code>JLabel</code> instance with 
     * no image and with an empty string for the title.
     * The label is centered vertically 
     * in its display area.
     * The label's contents, once set, will be displayed on the leading edge 
     * of the label's display area.
     */
    public JLabel() {
        this("", null, LEADING);
    }


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


    /**
     * Sets the L&F object that renders this component.
     *
     * @param ui  the LabelUI L&F object
     * @see UIDefaults#getUI
     * @beaninfo
     *        bound: true
     *       hidden: true
     *    attribute: visualUpdate true
     *  description: The UI object that implements the Component's LookAndFeel. 
     */
    public void setUI(LabelUI ui) {
        super.setUI(ui);
    }


    /**
     * Resets the UI property to a value from the current look and feel.
     *
     * @see JComponent#updateUI
     */
    public void updateUI() {
        setUI((LabelUI)UIManager.getUI(this));
    }


    /**
     * Returns a string that specifies the name of the l&f class
     * that renders this component.
     *
     * @return String "LabelUI"
     *
     * @see JComponent#getUIClassID
     * @see UIDefaults#getUI
     */
    public String getUIClassID() {
        return uiClassID;
    }


    /** 
     * Returns the text string that the label displays.
     *
     * @return a String
     * @see #setText
     */
    public String getText() {
        return text;
    }


    /**
     * Defines the single line of text this component will display.  If
     * the value of text is null or empty string, nothing is displayed.
     * <p>
     * The default value of this property is null.
     * <p>
     * This is a JavaBeans bound property.  
     * 
     * @see #setVerticalTextPosition
     * @see #setHorizontalTextPosition
     * @see #setIcon
     * @beaninfo
     *    preferred: true
     *        bound: true
     *    attribute: visualUpdate true
     *  description: Defines the single line of text this component will display.
     */
    public void setText(String text) {

        String oldAccessibleName = null;
        if (accessibleContext != null) {
            oldAccessibleName = accessibleContext.getAccessibleName();
        }

        String oldValue = this.text;
        this.text = text;
        firePropertyChange("text", oldValue, text);

        setDisplayedMnemonicIndex(
                      SwingUtilities.findDisplayedMnemonicIndex(
                                          text, getDisplayedMnemonic()));

        if ((accessibleContext != null) 
            && (accessibleContext.getAccessibleName() != oldAccessibleName)) {
                accessibleContext.firePropertyChange(
                        AccessibleContext.ACCESSIBLE_VISIBLE_DATA_PROPERTY, 
                        oldAccessibleName,
                        accessibleContext.getAccessibleName());
        }
        if (text == null || oldValue == null || !text.equals(oldValue)) {
            revalidate();
            repaint();
        }
    }

    
    /**
     * Returns the graphic image (glyph, icon) that the label displays.
     *
     * @return an Icon
     * @see #setIcon
     */
    public Icon getIcon() {
        return defaultIcon;
    }

    /**
     * Defines the icon this component will display.  If
     * the value of icon is null, nothing is displayed.
     * <p>
     * The default value of this property is null.
     * <p>
     * This is a JavaBeans bound property.  
     * 
     * @see #setVerticalTextPosition
     * @see #setHorizontalTextPosition
     * @see #getIcon
     * @beaninfo
     *    preferred: true
     *        bound: true
     *    attribute: visualUpdate true
     *  description: The icon this component will display.
     */
    public void setIcon(Icon icon) {
        Icon oldValue = defaultIcon;
        defaultIcon = icon;

        /* If the default icon has really changed and we had
         * generated the disabled icon for this component
         * (in other words, setDisabledIcon() was never called), then 
         * clear the disabledIcon field.
         */
        if ((defaultIcon != oldValue) && !disabledIconSet) {
            disabledIcon = null;
        }

        firePropertyChange("icon", oldValue, defaultIcon);

        if ((accessibleContext != null) && (oldValue != defaultIcon)) {
                accessibleContext.firePropertyChange(
                        AccessibleContext.ACCESSIBLE_VISIBLE_DATA_PROPERTY, 
                        oldValue, defaultIcon);
        }

        /* If the default icon has changed and the new one is 
         * a different size, then revalidate.   Repaint if the
         * default icon has changed.
         */
        if (defaultIcon != oldValue) {
            if ((defaultIcon == null) || 
                (oldValue == null) ||
                (defaultIcon.getIconWidth() != oldValue.getIconWidth()) ||
                (defaultIcon.getIconHeight() != oldValue.getIconHeight())) {
                revalidate();
            } 
            repaint();
        }

	// set the accessible icon
	accessibleIcon = null;
	if (defaultIcon instanceof Accessible) {
	    AccessibleContext ac = 
		((Accessible)defaultIcon).getAccessibleContext();
	    if (ac != null && ac instanceof AccessibleIcon) {
		accessibleIcon = (AccessibleIcon)ac;
	    }
	} 
    }


    /**
     * Returns the value of the disabledIcon property if it's been set,
     * If it hasn't been set and the value of the icon property is
     * an ImageIcon, we compute a "grayed out" version of the icon and
     * update the disabledIcon property with that.
     * 
     * @return The value of the disabledIcon property.
     * @see #setDisabledIcon
     * @see ImageIcon
     */
    public Icon getDisabledIcon() 
    {
        if(!disabledIconSet && 
           (disabledIcon == null) &&
           (defaultIcon != null) && 
           (defaultIcon instanceof ImageIcon)) {
            Image grayImage = GrayFilter.createDisabledImage(((ImageIcon)defaultIcon).getImage());
            disabledIcon = new ImageIcon(grayImage);
            firePropertyChange("disabledIcon", null, disabledIcon);
        }
        return disabledIcon;
    }


    /**
     * Set the icon to be displayed if this JLabel is "disabled"
     * (JLabel.setEnabled(false)).
     * <p>
     * The default value of this property is null.
     * 
     * @param disabledIcon the Icon to display when the component is disabled
     * @see #getDisabledIcon
     * @see #setEnabled
     * @beaninfo
     *        bound: true
     *    attribute: visualUpdate true
     *  description: The icon to display if the label is disabled.
     */
    public void setDisabledIcon(Icon disabledIcon) {
        Icon oldValue = this.disabledIcon;
        this.disabledIcon = disabledIcon;
        disabledIconSet = (disabledIcon != null);
        firePropertyChange("disabledIcon", oldValue, disabledIcon);
        if (disabledIcon != oldValue) {
            if (disabledIcon == null || oldValue == null ||
                disabledIcon.getIconWidth() != oldValue.getIconWidth() ||
                disabledIcon.getIconHeight() != oldValue.getIconHeight()) {
                revalidate();
            } 
            if (!isEnabled()) {
                repaint();
            }
        }
    }


    /**
     * Specify a keycode that indicates a mnemonic key.
     * This property is used when the label is part of a larger component.  
     * If the labelFor property of the label is not null, the label will
     * call the requestFocus method of the component specified by the
     * labelFor property when the mnemonic is activated.
     *
     * @see #getLabelFor
     * @see #setLabelFor
     * @beaninfo
     *        bound: true
     *    attribute: visualUpdate true
     *  description: The mnemonic keycode.
     */
    public void setDisplayedMnemonic(int key) {
        int oldKey = mnemonic;
        mnemonic = key;
        firePropertyChange("displayedMnemonic", oldKey, mnemonic);

        setDisplayedMnemonicIndex(
            SwingUtilities.findDisplayedMnemonicIndex(getText(), mnemonic));

        if (key != oldKey) {
            revalidate();
            repaint();
        }
    }


    /**
     * Specifies the displayedMnemonic as a char value.
     *
     * @param aChar  a char specifying the mnemonic to display
     * @see #setDisplayedMnemonic(int)
     */
    public void setDisplayedMnemonic(char aChar) {
        int vk = (int) aChar;
        if(vk >= 'a' && vk <='z')
            vk -= ('a' - 'A');
        setDisplayedMnemonic(vk);
    }


    /**
     * Return the keycode that indicates a mnemonic key.
     * This property is used when the label is part of a larger component.
     * If the labelFor property of the label is not null, the label will
     * call the requestFocus method of the component specified by the
     * labelFor property when the mnemonic is activated.
     *
     * @return int value for the mnemonic key
     *
     * @see #getLabelFor
     * @see #setLabelFor
     */
    public int getDisplayedMnemonic() {
        return mnemonic;
    }

    /**
     * Provides a hint to the look and feel as to which character in the
     * text should be decorated to represent the mnemonic. Not all look and
     * feels may support this. A value of -1 indicates either there is no
     * mnemonic, the mnemonic character is not contained in the string, or
     * the developer does not wish the mnemonic to be displayed.
     * <p>
     * The value of this is updated as the properties relating to the
     * mnemonic change (such as the mnemonic itself, the text...).
     * You should only ever have to call this if
     * you do not wish the default character to be underlined. For example, if
     * the text was 'Save As', with a mnemonic of 'a', and you wanted the 'A'
     * to be decorated, as 'Save <u>A</u>s', you would have to invoke
     * <code>setDisplayedMnemonicIndex(5)</code> after invoking
     * <code>setMnemonic(KeyEvent.VK_A)</code>.
     *
     * @since 1.4
     * @param index Index into the String to underline
     * @exception IllegalArgumentException will be thrown if <code>index</code
     *            is >= length of the text, or < -1
     *
     * @beaninfo
     *        bound: true
     *    attribute: visualUpdate true
     *  description: the index into the String to draw the keyboard character
     *               mnemonic at
     */
    public void setDisplayedMnemonicIndex(int index)
                                             throws IllegalArgumentException {
        int oldValue = mnemonicIndex;
        if (index == -1) {
            mnemonicIndex = -1;
        } else {
            String text = getText();
            int textLength = (text == null) ? 0 : text.length();
            if (index < -1 || index >= textLength) {  // index out of range
                throw new IllegalArgumentException("index == " + index);
            }
        }
        mnemonicIndex = index;
        firePropertyChange("displayedMnemonicIndex", oldValue, index);
        if (index != oldValue) {
            revalidate();
            repaint();
        }
    }

    /**
     * Returns the character, as an index, that the look and feel should
     * provide decoration for as representing the mnemonic character.
     *
     * @since 1.4
     * @return index representing mnemonic character
     * @see #setDisplayedMnemonicIndex
     */
    public int getDisplayedMnemonicIndex() {
        return mnemonicIndex;
    }

    /**
     * Verify that key is a legal value for the horizontalAlignment properties.
     *
     * @param key the property value to check
     * @param message the IllegalArgumentException detail message 
     * @exception IllegalArgumentException if key isn't LEFT, CENTER, RIGHT,
     * LEADING or TRAILING.
     * @see #setHorizontalTextPosition
     * @see #setHorizontalAlignment
     */
    protected int checkHorizontalKey(int key, String message) {
        if ((key == LEFT) ||
            (key == CENTER) ||
            (key == RIGHT) ||
            (key == LEADING) ||
            (key == TRAILING)) {
            return key;
        }
        else {
            throw new IllegalArgumentException(message);
        }
    }


    /**
     * Verify that key is a legal value for the 
     * verticalAlignment or verticalTextPosition properties.
     *
     * @param key the property value to check
     * @param message the IllegalArgumentException detail message 
     * @exception IllegalArgumentException if key isn't TOP, CENTER, or BOTTOM.
     * @see #setVerticalAlignment
     * @see #setVerticalTextPosition
     */
    protected int checkVerticalKey(int key, String message) {
        if ((key == TOP) || (key == CENTER) || (key == BOTTOM)) {
            return key;
        }
        else {
            throw new IllegalArgumentException(message);
        }
    }


    /**
     * Returns the amount of space between the text and the icon
     * displayed in this label.
     *
     * @return an int equal to the number of pixels between the text
     *         and the icon.
     * @see #setIconTextGap
     */
    public int getIconTextGap() {
        return iconTextGap;
    }


    /**
     * If both the icon and text properties are set, this property
     * defines the space between them.  
     * <p>
     * The default value of this property is 4 pixels.
     * <p>
     * This is a JavaBeans bound property.
     * 
     * @see #getIconTextGap
     * @beaninfo
     *        bound: true
     *    attribute: visualUpdate true
     *  description: If both the icon and text properties are set, this
     *               property defines the space between them.
     */
    public void setIconTextGap(int iconTextGap) {
        int oldValue = this.iconTextGap;
        this.iconTextGap = iconTextGap;
        firePropertyChange("iconTextGap", oldValue, iconTextGap);
        if (iconTextGap != oldValue) {
            revalidate();
            repaint();
        }
    }



    /**
     * Returns the alignment of the label's contents along the Y axis.
     *
     * @return   The value of the verticalAlignment property, one of the 
     *           following constants defined in <code>SwingConstants</code>:
     *           <code>TOP</code>,
     *           <code>CENTER</code>, or
     *           <code>BOTTOM</code>.
     *
     * @see SwingConstants
     * @see #setVerticalAlignment
     */
    public int getVerticalAlignment() {
        return verticalAlignment;
    }


    /**
     * Sets the alignment of the label's contents along the Y axis.  
     * <p>
     * The default value of this property is CENTER.
     * 
     * @param alignment One of the following constants
     *           defined in <code>SwingConstants</code>:
     *           <code>TOP</code>,
     *           <code>CENTER</code> (the default), or
     *           <code>BOTTOM</code>.
     *
     * @see SwingConstants
     * @see #getVerticalAlignment
     * @beaninfo
     *        bound: true
     *         enum: TOP    SwingConstants.TOP
     *               CENTER SwingConstants.CENTER
     *               BOTTOM SwingConstants.BOTTOM
     *    attribute: visualUpdate true
     *  description: The alignment of the label's contents along the Y axis.  
     */
    public void setVerticalAlignment(int alignment) {
        if (alignment == verticalAlignment) return;
        int oldValue = verticalAlignment;
        verticalAlignment = checkVerticalKey(alignment, "verticalAlignment");
        firePropertyChange("verticalAlignment", oldValue, verticalAlignment); 
        repaint();
    }


    /**
     * Returns the alignment of the label's contents along the X axis.
     *
     * @return   The value of the horizontalAlignment property, one of the 
     *           following constants defined in <code>SwingConstants</code>:
     *           <code>LEFT</code>,
     *           <code>CENTER</code>, 
     *           <code>RIGHT</code>,
     *           <code>LEADING</code> or
     *           <code>TRAILING</code>.
     *
     * @see #setHorizontalAlignment
     * @see SwingConstants
     */
    public int getHorizontalAlignment() {
        return horizontalAlignment;
    }

    /**
     * Sets the alignment of the label's contents along the X axis.
     * <p>
     * This is a JavaBeans bound property.
     *
     * @param alignment  One of the following constants
     *           defined in <code>SwingConstants</code>:
     *           <code>LEFT</code>,
     *           <code>CENTER</code> (the default for image-only labels),
     *           <code>RIGHT</code>,
     *           <code>LEADING</code> (the default for text-only labels) or
     *           <code>TRAILING</code>.
     *
     * @see SwingConstants
     * @see #getHorizontalAlignment
     * @beaninfo
     *        bound: true
     *         enum: LEFT     SwingConstants.LEFT
     *               CENTER   SwingConstants.CENTER
     *               RIGHT    SwingConstants.RIGHT
     *               LEADING  SwingConstants.LEADING
     *               TRAILING SwingConstants.TRAILING
     *    attribute: visualUpdate true
     *  description: The alignment of the label's content along the X axis.
     */
    public void setHorizontalAlignment(int alignment) {
        if (alignment == horizontalAlignment) return;
        int oldValue = horizontalAlignment;
        horizontalAlignment = checkHorizontalKey(alignment,
                                                 "horizontalAlignment");
        firePropertyChange("horizontalAlignment",
                           oldValue, horizontalAlignment);
        repaint();
    }


    /**
     * Returns the vertical position of the label's text,
     * relative to its image.
     *
     * @return   One of the following constants
     *           defined in <code>SwingConstants</code>:
     *           <code>TOP</code>,
     *           <code>CENTER</code>, or
     *           <code>BOTTOM</code>.
     *
     * @see #setVerticalTextPosition
     * @see SwingConstants
     */
    public int getVerticalTextPosition() {
        return verticalTextPosition;
    }


    /**
     * Sets the vertical position of the label's text,
     * relative to its image.
     * <p>
     * The default value of this property is CENTER.
     * <p>
     * This is a JavaBeans bound property.
     *
     * @param textPosition  One of the following constants
     *           defined in <code>SwingConstants</code>:
     *           <code>TOP</code>,
     *           <code>CENTER</code> (the default), or
     *           <code>BOTTOM</code>.
     *
     * @see SwingConstants
     * @see #getVerticalTextPosition
     * @beaninfo
     *        bound: true
     *         enum: TOP    SwingConstants.TOP
     *               CENTER SwingConstants.CENTER
     *               BOTTOM SwingConstants.BOTTOM
     *       expert: true
     *    attribute: visualUpdate true
     *  description: The vertical position of the text relative to it's image.
     */
    public void setVerticalTextPosition(int textPosition) {
        if (textPosition == verticalTextPosition) return;
        int old = verticalTextPosition;
        verticalTextPosition = checkVerticalKey(textPosition,
                                                "verticalTextPosition");
        firePropertyChange("verticalTextPosition", old, verticalTextPosition);
        repaint();
    }


    /**
     * Returns the horizontal position of the label's text,
     * relative to its image.
     *
     * @return   One of the following constants
     *           defined in <code>SwingConstants</code>:
     *           <code>LEFT</code>,
     *           <code>CENTER</code>, 
     *           <code>RIGHT</code>,
     *           <code>LEADING</code> or
     *           <code>TRAILING</code>.
     *
     * @see SwingConstants
     */
    public int getHorizontalTextPosition() {
        return horizontalTextPosition;
    }


    /**
     * Sets the horizontal position of the label's text,
     * relative to its image.
     *
     * @param textPosition  One of the following constants
     *           defined in <code>SwingConstants</code>:
     *           <code>LEFT</code>,
     *           <code>CENTER</code>,
     *           <code>RIGHT</code>,
     *           <code>LEADING</code>, or
     *           <code>TRAILING</code> (the default).
     * @exception IllegalArgumentException
     *
     * @see SwingConstants
     * @beaninfo
     *       expert: true
     *        bound: true
     *         enum: LEFT     SwingConstants.LEFT
     *               CENTER   SwingConstants.CENTER
     *               RIGHT    SwingConstants.RIGHT
     *               LEADING  SwingConstants.LEADING
     *               TRAILING SwingConstants.TRAILING
     *    attribute: visualUpdate true
     *  description: The horizontal position of the label's text, 
     *               relative to its image.
     */
    public void setHorizontalTextPosition(int textPosition) {
        int old = horizontalTextPosition;
        this.horizontalTextPosition = checkHorizontalKey(textPosition,
                                                "horizontalTextPosition");
        firePropertyChange("horizontalTextPosition",
                           old, horizontalTextPosition);
        repaint();
    }


    /**
     * This is overridden to return false if the current Icon's Image is
     * not equal to the passed in Image <code>img</code>.
     *
     * @see     java.awt.image.ImageObserver
     * @see     java.awt.Component#imageUpdate(java.awt.Image, int, int, int, int, int)
     */
    public boolean imageUpdate(Image img, int infoflags,
			       int x, int y, int w, int h) {
        // Don't use getDisabledIcon, will trigger creation of icon if icon
        // not set.
	if (!isShowing() ||
            !SwingUtilities.doesIconReferenceImage(getIcon(), img) &&
            !SwingUtilities.doesIconReferenceImage(disabledIcon, img)) {

	    return false;
	}
	return super.imageUpdate(img, infoflags, x, y, w, h);
    }


    /** 
     * See readObject() and writeObject() in JComponent for more 
     * information about serialization in Swing.
     */
    private void writeObject(ObjectOutputStream s) throws IOException {
        s.defaultWriteObject();
        if (getUIClassID().equals(uiClassID)) {
            byte count = JComponent.getWriteObjCounter(this);
            JComponent.setWriteObjCounter(this, --count);
            if (count == 0 && ui != null) {
                ui.installUI(this);
            }
        }
    }


    /**
     * Returns a string representation of this JLabel. This method 
     * is intended to be used only for debugging purposes, and the 
     * content and format of the returned string may vary between      
     * implementations. The returned string may be empty but may not 
     * be <code>null</code>.
     * 
     * @return  a string representation of this JLabel.
     */
    protected String paramString() {
	String textString = (text != null ?
			     text : "");
	String defaultIconString = ((defaultIcon != null) 
				    && (defaultIcon != this)  ?
				    defaultIcon.toString() : "");
	String disabledIconString = ((disabledIcon != null) 
				     && (disabledIcon != this) ?
				     disabledIcon.toString() : "");
	String labelForString = (labelFor  != null ?
				 labelFor.toString() : "");
        String verticalAlignmentString;
        if (verticalAlignment == TOP) {
            verticalAlignmentString = "TOP";
        } else if (verticalAlignment == CENTER) {
            verticalAlignmentString = "CENTER";
        } else if (verticalAlignment == BOTTOM) {
            verticalAlignmentString = "BOTTOM";
        } else verticalAlignmentString = "";
        String horizontalAlignmentString;
        if (horizontalAlignment == LEFT) {
            horizontalAlignmentString = "LEFT";
        } else if (horizontalAlignment == CENTER) {
            horizontalAlignmentString = "CENTER";
        } else if (horizontalAlignment == RIGHT) {
            horizontalAlignmentString = "RIGHT";
        } else if (horizontalAlignment == LEADING) {
            horizontalAlignmentString = "LEADING";
        } else if (horizontalAlignment == TRAILING) {
            horizontalAlignmentString = "TRAILING";
        } else horizontalAlignmentString = "";
        String verticalTextPositionString;
        if (verticalTextPosition == TOP) {
            verticalTextPositionString = "TOP";
        } else if (verticalTextPosition == CENTER) {
            verticalTextPositionString = "CENTER";
        } else if (verticalTextPosition == BOTTOM) {
            verticalTextPositionString = "BOTTOM";
        } else verticalTextPositionString = "";
        String horizontalTextPositionString;
        if (horizontalTextPosition == LEFT) {
            horizontalTextPositionString = "LEFT";
        } else if (horizontalTextPosition == CENTER) {
            horizontalTextPositionString = "CENTER";
        } else if (horizontalTextPosition == RIGHT) {
            horizontalTextPositionString = "RIGHT";
        } else if (horizontalTextPosition == LEADING) {
            horizontalTextPositionString = "LEADING";
        } else if (horizontalTextPosition == TRAILING) {
            horizontalTextPositionString = "TRAILING";
        } else horizontalTextPositionString = "";

	return super.paramString() +
	",defaultIcon=" + defaultIconString +
	",disabledIcon=" + disabledIconString +
	",horizontalAlignment=" + horizontalAlignmentString +
	",horizontalTextPosition=" + horizontalTextPositionString +
	",iconTextGap=" + iconTextGap +
	",labelFor=" + labelForString +
	",text=" + textString +
	",verticalAlignment=" + verticalAlignmentString +
	",verticalTextPosition=" + verticalTextPositionString;
    }

    /**
     * --- Accessibility Support ---
     */

    /**
     * Get the component this is labelling.
     *
     * @return the Component this is labelling.  Can be null if this
     * does not label a Component.  If the displayedMnemonic 
     * property is set and the labelFor property is also set, the label 
     * will call the requestFocus method of the component specified by the
     * labelFor property when the mnemonic is activated.
     *
     * @see #getDisplayedMnemonic
     * @see #setDisplayedMnemonic
     */
    public Component getLabelFor() {
        return labelFor;
    }

    /**
     * Set the component this is labelling.  Can be null if this does not 
     * label a Component.  If the displayedMnemonic property is set
     * and the labelFor property is also set, the label will
     * call the requestFocus method of the component specified by the
     * labelFor property when the mnemonic is activated.
     *
     * @param c  the Component this label is for, or null if the label is
     *           not the label for a component
     *
     * @see #getDisplayedMnemonic
     * @see #setDisplayedMnemonic
     * 
     * @beaninfo
     *        bound: true
     *  description: The component this is labelling.
     */
    public void setLabelFor(Component c) {
        Component oldC = labelFor;
        labelFor = c;
        firePropertyChange("labelFor", oldC, c);        

        if (oldC instanceof JComponent) {
            ((JComponent)oldC).putClientProperty(LABELED_BY_PROPERTY, null);
        }
        if (c instanceof JComponent) {
            ((JComponent)c).putClientProperty(LABELED_BY_PROPERTY, this);
        }
    }

    /** 
     * Get the AccessibleContext of this object 
     *
     * @return the AccessibleContext of this object
     * @beaninfo
     *       expert: true
     *  description: The AccessibleContext associated with this Label.
     */
    public AccessibleContext getAccessibleContext() {
        if (accessibleContext == null) {
            accessibleContext = new AccessibleJLabel();
        }
        return accessibleContext;
    }

    /**
     * The class used to obtain the accessible role for this object.
     * <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.  As of 1.4, support for long term storage
     * of all JavaBeans<sup><font size="-2">TM</font></sup>
     * has been added to the <code>java.beans</code> package.
     * Please see {@link java.beans.XMLEncoder}.
     */
    protected class AccessibleJLabel extends AccessibleJComponent
        implements AccessibleText, AccessibleExtendedComponent {

        /**
         * Get the accessible name of this object.  
         * 
         * @return the localized name of the object -- can be null if this 
         * object does not have a name
         * @see AccessibleContext#setAccessibleName
         */
        public String getAccessibleName() {
            if (accessibleName != null) {
                return accessibleName;
            } else {
                if (JLabel.this.getText() == null) {
                    return super.getAccessibleName();
                } else {
                    return JLabel.this.getText();
                }
            }
        }

        /**
         * Get the role of this object.
         *
         * @return an instance of AccessibleRole describing the role of the 
         * object
         * @see AccessibleRole
         */
        public AccessibleRole getAccessibleRole() {
            return AccessibleRole.LABEL;
        }

	/**
	 * Get the AccessibleIcons associated with this object if one
	 * or more exist.  Otherwise return null.
	 */
	public AccessibleIcon [] getAccessibleIcon() {
	    if (JLabel.this.accessibleIcon == null) {
		return null; 
	    } else {
		AccessibleIcon [] ac = new AccessibleIcon[1];
		ac[0] = JLabel.this.accessibleIcon;
		return ac;
	    }
	}

        /**
         * Get the AccessibleRelationSet associated with this object if one
         * exists.  Otherwise return null.
         * @see AccessibleRelation
         */
        public AccessibleRelationSet getAccessibleRelationSet() {
	    // Check where the AccessibleContext's relation
	    // set already contains a LABEL_FOR relation.
	    AccessibleRelationSet relationSet 
		= super.getAccessibleRelationSet();

	    if (!relationSet.contains(AccessibleRelation.LABEL_FOR)) {
		Component c = JLabel.this.getLabelFor();
		if (c != null) {
		    AccessibleRelation relation 
			= new AccessibleRelation(AccessibleRelation.LABEL_FOR);
		    relation.setTarget(c);
		    relationSet.add(relation);
		}
	    }
	    return relationSet;
        }


	/* AccessibleText ---------- */

	public AccessibleText getAccessibleText() {
	    View view = (View)JLabel.this.getClientProperty("html");
	    if (view != null) {
		return this;
	    } else {
		return null;
	    }
	}

	/**
	 * Given a point in local coordinates, return the zero-based index
	 * of the character under that Point.  If the point is invalid,
	 * this method returns -1.
	 *
	 * @param p the Point in local coordinates
	 * @return the zero-based index of the character under Point p; if 
	 * Point is invalid returns -1.
	 */
	public int getIndexAtPoint(Point p) {
	    View view = (View) JLabel.this.getClientProperty("html");
	    if (view != null) {
		Rectangle r = getTextRectangle();
                if (r == null) {
                    return -1;
                }
		Rectangle2D.Float shape = 
		    new Rectangle2D.Float(r.x, r.y, r.width, r.height);
		Position.Bias bias[] = new Position.Bias[1];
		return view.viewToModel(p.x, p.y, shape, bias);
	    } else {
		return -1;
	    }
	}
	
	/**
	 * Determine the bounding box of the character at the given 
	 * index into the string.  The bounds are returned in local
	 * coordinates.  If the index is invalid an empty rectangle is 
	 * returned.
	 *
	 * @param i the index into the String
	 * @return the screen coordinates of the character's the bounding box,
	 * if index is invalid returns an empty rectangle.
	 */
	public Rectangle getCharacterBounds(int i) {
	    View view = (View) JLabel.this.getClientProperty("html");
	    if (view != null) {
		Rectangle r = getTextRectangle();
        if (r == null) {
            return null;
        }
		Rectangle2D.Float shape = 
		    new Rectangle2D.Float(r.x, r.y, r.width, r.height);
		try {
		    Shape charShape = 
			view.modelToView(i, shape, Position.Bias.Forward);
		    return charShape.getBounds();
		} catch (BadLocationException e) {
		    return null;
		}
	    } else {
		return null;
	    }
	}
	
	/**
	 * Return the number of characters (valid indicies) 
	 *
	 * @return the number of characters
	 */
	public int getCharCount() {
	    View view = (View) JLabel.this.getClientProperty("html");
	    if (view != null) {
		Document d = view.getDocument();
		if (d instanceof StyledDocument) {
		    StyledDocument doc = (StyledDocument)d;
		    return doc.getLength();
		}
	    }
	    return accessibleContext.getAccessibleName().length();
	}
	
	/**
	 * Return the zero-based offset of the caret.
	 *
	 * Note: That to the right of the caret will have the same index
	 * value as the offset (the caret is between two characters).
	 * @return the zero-based offset of the caret.
	 */
	public int getCaretPosition() {
	    // There is no caret.
	    return -1;
	}
	
        /**
         * Returns the String at a given index. 
         *
         * @param part the AccessibleText.CHARACTER, AccessibleText.WORD,
         * or AccessibleText.SENTENCE to retrieve
         * @param index an index within the text >= 0
         * @return the letter, word, or sentence,
         *   null for an invalid index or part
         */
        public String getAtIndex(int part, int index) {
            if (index < 0 || index >= getCharCount()) {
                return null;
            }
            switch (part) {
            case AccessibleText.CHARACTER:
                try {
                    return getText(index, 1);
                } catch (BadLocationException e) {
                    return null;
                }
            case AccessibleText.WORD:
                try {
                    String s = getText(0, getCharCount());
                    BreakIterator words = BreakIterator.getWordInstance(getLocale());
                    words.setText(s);
                    int end = words.following(index);
                    return s.substring(words.previous(), end);
                } catch (BadLocationException e) {
                    return null;
                }
            case AccessibleText.SENTENCE:
                try {
                    String s = getText(0, getCharCount());
                    BreakIterator sentence = 
			BreakIterator.getSentenceInstance(getLocale());
                    sentence.setText(s);
                    int end = sentence.following(index);
                    return s.substring(sentence.previous(), end);
                } catch (BadLocationException e) {
                    return null;
                }
            default:
                return null;
            }
        }

        /**
         * Returns the String after a given index.
         *
         * @param part the AccessibleText.CHARACTER, AccessibleText.WORD,
         * or AccessibleText.SENTENCE to retrieve
         * @param index an index within the text >= 0
         * @return the letter, word, or sentence, null for an invalid
         *  index or part
         */
        public String getAfterIndex(int part, int index) {
            if (index < 0 || index >= getCharCount()) {
                return null;
            }
            switch (part) {
            case AccessibleText.CHARACTER:
		if (index+1 >= getCharCount()) {
		   return null;
		}
                try {
                    return getText(index+1, 1);
                } catch (BadLocationException e) {
                    return null;
                }
            case AccessibleText.WORD:
                try {
                    String s = getText(0, getCharCount());
                    BreakIterator words = BreakIterator.getWordInstance(getLocale());
                    words.setText(s);
                    int start = words.following(index);
		    if (start == BreakIterator.DONE || start >= s.length()) {
			return null;
		    }
		    int end = words.following(start);
		    if (end == BreakIterator.DONE || end >= s.length()) {
			return null;
		    }
                    return s.substring(start, end);
                } catch (BadLocationException e) {
                    return null;
                }
            case AccessibleText.SENTENCE:
                try {
                    String s = getText(0, getCharCount());
                    BreakIterator sentence = 
			BreakIterator.getSentenceInstance(getLocale());
                    sentence.setText(s);
                    int start = sentence.following(index);
		    if (start == BreakIterator.DONE || start >= s.length()) {
			return null;
		    }
		    int end = sentence.following(start);
		    if (end == BreakIterator.DONE || end >= s.length()) {
			return null;
		    }
                    return s.substring(start, end);
                } catch (BadLocationException e) {
                    return null;
                }
            default:
                return null;
            }
        }

        /**
         * Returns the String before a given index.
         *
         * @param part the AccessibleText.CHARACTER, AccessibleText.WORD,
         *   or AccessibleText.SENTENCE to retrieve
         * @param index an index within the text >= 0
         * @return the letter, word, or sentence, null for an invalid index
         *  or part
         */
        public String getBeforeIndex(int part, int index) {
            if (index < 0 || index > getCharCount()-1) {
                return null;
            }
            switch (part) {
            case AccessibleText.CHARACTER:
		if (index == 0) {
		    return null;
		}
                try {
                    return getText(index-1, 1);
                } catch (BadLocationException e) {
                    return null;
                }
            case AccessibleText.WORD:
                try {
                    String s = getText(0, getCharCount());
                    BreakIterator words = BreakIterator.getWordInstance(getLocale());
                    words.setText(s);
                    int end = words.following(index);
                    end = words.previous();
		    int start = words.previous();
		    if (start == BreakIterator.DONE) {
			return null;
		    }
                    return s.substring(start, end);
                } catch (BadLocationException e) {
                    return null;
                }
            case AccessibleText.SENTENCE:
                try {
                    String s = getText(0, getCharCount());
                    BreakIterator sentence = 
			BreakIterator.getSentenceInstance(getLocale());
                    sentence.setText(s);
                    int end = sentence.following(index);
                    end = sentence.previous();
		    int start = sentence.previous();
		    if (start == BreakIterator.DONE) {
			return null;
		    }
                    return s.substring(start, end);
                } catch (BadLocationException e) {
                    return null;
                }
            default:
                return null;
            }
        }

	/**
	 * Return the AttributeSet for a given character at a given index
	 *
	 * @param i the zero-based index into the text 
	 * @return the AttributeSet of the character
	 */
	public AttributeSet getCharacterAttribute(int i) {
	    View view = (View) JLabel.this.getClientProperty("html");
	    if (view != null) {
		Document d = view.getDocument();
		if (d instanceof StyledDocument) {
		    StyledDocument doc = (StyledDocument)d;
		    Element elem = doc.getCharacterElement(i);
		    if (elem != null) {
			return elem.getAttributes();
		    }
		}
	    }
	    return null;
	}

	/**
	 * Returns the start offset within the selected text.
	 * If there is no selection, but there is
	 * a caret, the start and end offsets will be the same.
	 *
	 * @return the index into the text of the start of the selection
	 */
	public int getSelectionStart() {
	    // Text cannot be selected.
	    return -1;
	}

	/**
	 * Returns the end offset within the selected text.
	 * If there is no selection, but there is
	 * a caret, the start and end offsets will be the same.
	 *
	 * @return the index into teh text of the end of the selection
	 */
	public int getSelectionEnd() {
	    // Text cannot be selected.
	    return -1;
	}

	/**
	 * Returns the portion of the text that is selected. 
	 *
	 * @return the String portion of the text that is selected
	 */
	public String getSelectedText() {
	    // Text cannot be selected.
	    return null;
	}

	/*
	 * Returns the text substring starting at the specified
	 * offset with the specified length.
	 */
	private String getText(int offset, int length) 
	    throws BadLocationException {

	    View view = (View) JLabel.this.getClientProperty("html");
	    if (view != null) {
		Document d = view.getDocument();
		if (d instanceof StyledDocument) {
		    StyledDocument doc = (StyledDocument)d;
		    return doc.getText(offset, length);
		}
	    }
	    return null;
	}

	/*
	 * Returns the bounding rectangle for the component text.
	 */
	private Rectangle getTextRectangle() {
	    
	    String text = JLabel.this.getText();
	    Icon icon = (JLabel.this.isEnabled()) ? JLabel.this.getIcon() : JLabel.this.getDisabledIcon();
	    
	    if ((icon == null) && (text == null)) {
		return null;
	    }

	    Rectangle paintIconR = new Rectangle();
	    Rectangle paintTextR = new Rectangle();
	    Rectangle paintViewR = new Rectangle();
	    Insets paintViewInsets = new Insets(0, 0, 0, 0);

	    paintViewInsets = JLabel.this.getInsets(paintViewInsets);
	    paintViewR.x = paintViewInsets.left;
	    paintViewR.y = paintViewInsets.top;
	    paintViewR.width = JLabel.this.getWidth() - (paintViewInsets.left + paintViewInsets.right);
	    paintViewR.height = JLabel.this.getHeight() - (paintViewInsets.top + paintViewInsets.bottom);
	    
            Graphics g = JLabel.this.getGraphics();
            if (g == null) {
                return null;
            }
	    String clippedText = SwingUtilities.layoutCompoundLabel(
	        (JComponent)JLabel.this,
		g.getFontMetrics(),
		text,
		icon,
		JLabel.this.getVerticalAlignment(),
		JLabel.this.getHorizontalAlignment(),
		JLabel.this.getVerticalTextPosition(),
		JLabel.this.getHorizontalTextPosition(),
		paintViewR,
		paintIconR,
		paintTextR,
		JLabel.this.getIconTextGap());

	    return paintTextR;
	}

        // ----- AccessibleExtendedComponent

	/**
	 * Returns the AccessibleExtendedComponent
	 *
	 * @return the AccessibleExtendedComponent
	 */
	AccessibleExtendedComponent getAccessibleExtendedComponent() {
	    return this;
	}

	/**
	 * Returns the tool tip text
	 *
	 * @return the tool tip text, if supported, of the object; 
	 * otherwise, null
	 */
	public String getToolTipText() {
	    return JLabel.this.getToolTipText();
	}
	
	/**
	 * Returns the titled border text
	 *
	 * @return the titled border text, if supported, of the object; 
	 * otherwise, null
	 */
	public String getTitledBorderText() {
	    return super.getTitledBorderText();
	}
	    
	/**
	 * Returns key bindings associated with this object
	 *
	 * @return the key bindings, if supported, of the object; 
	 * otherwise, null
	 * @see AccessibleKeyBinding
	 */
	public AccessibleKeyBinding getAccessibleKeyBinding() {
	    int mnemonic = JLabel.this.getDisplayedMnemonic();
	    if (mnemonic == 0) {
		return null;
	    }
	    return new LabelKeyBinding(mnemonic);
	}

	class LabelKeyBinding implements AccessibleKeyBinding {
	    int mnemonic;

	    LabelKeyBinding(int mnemonic) {
		this.mnemonic = mnemonic;
	    }

	    /**
	     * Returns the number of key bindings for this object
	     *
	     * @return the zero-based number of key bindings for this object
	     */
	    public int getAccessibleKeyBindingCount() {
		return 1;
	    }
	    
	    /**
	     * Returns a key binding for this object.  The value returned is an
	     * java.lang.Object which must be cast to appropriate type depending
	     * on the underlying implementation of the key.  For example, if the
	     * Object returned is a javax.swing.KeyStroke, the user of this
	     * method should do the following:
	     * <nf><code>
	     * Component c = <get the component that has the key bindings>
	     * AccessibleContext ac = c.getAccessibleContext();
	     * AccessibleKeyBinding akb = ac.getAccessibleKeyBinding();
	     * for (int i = 0; i < akb.getAccessibleKeyBindingCount(); i++) {
	     *     Object o = akb.getAccessibleKeyBinding(i);
	     *     if (o instanceof javax.swing.KeyStroke) {
	     *         javax.swing.KeyStroke keyStroke = (javax.swing.KeyStroke)o;
	     *         <do something with the key binding>
	     *     }
	     * }
	     * </code></nf>
	     *
	     * @param i zero-based index of the key bindings
	     * @return a javax.lang.Object which specifies the key binding
	     * @exception IllegalArgumentException if the index is
	     * out of bounds
	     * @see #getAccessibleKeyBindingCount
	     */
	    public java.lang.Object getAccessibleKeyBinding(int i) {
		if (i != 0) {
		    throw new IllegalArgumentException();
		}
		return KeyStroke.getKeyStroke(mnemonic, 0);
	    }
	}
	
    }  // AccessibleJComponent
}