java/11 : java.desktop/javax/swing/JLabel.java

JLabel
https://openjdk.java.net/
GPLv2 + Classpath Exception
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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package javax.swing;

import java.awt.Component;
import java.awt.Image;
import java.awt.*;
import java.text.*;
import java.awt.geom.*;
import java.beans.JavaBean;
import java.beans.BeanProperty;
import java.beans.Transient;

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

import javax.swing.plaf.LabelUI;
import javax.accessibility.*;
import javax.swing.text.*;

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.

A JLabel 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.

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.
 A label's leading and trailing edge are determined from the value of its ComponentOrientation property. At present, the default ComponentOrientation setting maps the leading edge to left and the trailing edge to right. 

Finally, you can use the setIconTextGap method
to specify how many pixels
should appear between the text and the image.
The default is 4 pixels.

See How to Use Labels
in The Java Tutorial
for further documentation.

Warning: Swing is not thread safe. For more
information see Swing's Threading
Policy.

Warning:
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™
has been added to the java.beans package. Please see XMLEncoder. 
Author: Hans Muller
Since: 1.2/**
 * 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://docs.oracle.com/javase/tutorial/uiswing/components/label.html">How to Use Labels</a>
 * in <em>The Java Tutorial</em>
 * for further documentation.
 * <p>
 * <strong>Warning:</strong> Swing is not thread safe. For more
 * information see <a
 * href="package-summary.html#threading">Swing's Threading
 * Policy</a>.
 * <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&trade;
 * has been added to the <code>java.beans</code> package.
 * Please see {@link java.beans.XMLEncoder}.
 *
 * @author Hans Muller
 * @since 1.2
 */
@JavaBean(defaultProperty = "UI", description = "A component that displays a short string and an icon.")
@SwingContainer(false)
@SuppressWarnings("serial")
public class JLabel extends JComponent implements SwingConstants, Accessible
{
    See Also: getUIClassID
JComponent.readObject/**
     * @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;

    The Component this label is for; null if the label
is not the label for a component
/**
     * The Component this label is for; null if the label
     * is not the label for a component
     */
    protected Component labelFor = 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 Also: setLabelFor/**
     * 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 JLabel 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.
Params: text –  The text to be displayed by the label.
icon –  The image to be displayed by the label.
horizontalAlignment –  One of the following constants
          defined in SwingConstants:
          LEFT,
          CENTER,
          RIGHT,
          LEADING or
          TRAILING./**
     * 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 JLabel instance with the specified
text and horizontal alignment.
The label is centered vertically in its display area.
Params: text –  The text to be displayed by the label.
horizontalAlignment –  One of the following constants
          defined in SwingConstants:
          LEFT,
          CENTER,
          RIGHT,
          LEADING or
          TRAILING./**
     * 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 JLabel instance with the specified text.
The label is aligned against the leading edge of its display area,
and centered vertically.
Params: text –  The text to be displayed by the label./**
     * 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 JLabel instance with the specified
image and horizontal alignment.
The label is centered vertically in its display area.
Params: image –  The image to be displayed by the label.
horizontalAlignment –  One of the following constants
          defined in SwingConstants:
          LEFT,
          CENTER,
          RIGHT,
          LEADING or
          TRAILING./**
     * 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 JLabel instance with the specified image.
The label is centered vertically and horizontally
in its display area.
Params: image –  The image to be displayed by the label./**
     * 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 JLabel 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.
/**
     * 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.
Returns: LabelUI object/**
     * Returns the L&amp;F object that renders this component.
     *
     * @return LabelUI object
     */
    public LabelUI getUI() {
        return (LabelUI)ui;
    }


    Sets the L&F object that renders this component.
Params: ui –  the LabelUI L&F object
See Also: UIDefaults.getUI/**
     * Sets the L&amp;F object that renders this component.
     *
     * @param ui  the LabelUI L&amp;F object
     * @see UIDefaults#getUI
     */
    @BeanProperty(hidden = true, visualUpdate = true, description
            = "The UI object that implements the Component's LookAndFeel.")
    public void setUI(LabelUI ui) {
        super.setUI(ui);
        // disabled icon is generated by LF so it should be unset here
        if (!disabledIconSet && disabledIcon != null) {
            setDisabledIcon(null);
        }
    }


    Resets the UI property to a value from the current look and feel.
See Also: updateUI.updateUI/**
     * 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.
See Also: JComponent.getUIClassID
UIDefaults.getUI
Returns: String "LabelUI"/**
     * Returns a string that specifies the name of the l&amp;f class
     * that renders this component.
     *
     * @return String "LabelUI"
     *
     * @see JComponent#getUIClassID
     * @see UIDefaults#getUI
     */
    @BeanProperty(bound = false)
    public String getUIClassID() {
        return uiClassID;
    }


    Returns the text string that the label displays.
See Also: setText
Returns: a String/**
     * 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.

The default value of this property is null.

This is a JavaBeans bound property.
Params: text –  the single line of text this component will display
See Also: setVerticalTextPosition
setHorizontalTextPosition
setIcon/**
     * 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.
     *
     * @param text  the single line of text this component will display
     * @see #setVerticalTextPosition
     * @see #setHorizontalTextPosition
     * @see #setIcon
     */
    @BeanProperty(preferred = true, 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.
See Also: setIcon
Returns: an Icon/**
     * 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.

The default value of this property is null.

This is a JavaBeans bound property.
Params: icon –  the default icon this component will display
See Also: setVerticalTextPosition
setHorizontalTextPosition
getIcon/**
     * 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.
     *
     * @param icon  the default icon this component will display
     * @see #setVerticalTextPosition
     * @see #setHorizontalTextPosition
     * @see #getIcon
     */
    @BeanProperty(preferred = true, 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();
        }
    }


    Returns the icon used by the label when it's disabled.
If no disabled icon has been set this will forward the call to
the look and feel to construct an appropriate disabled Icon.

Some look and feels might not render the disabled Icon, in which
case they will ignore this.
See Also: setDisabledIcon
LookAndFeel.getDisabledIcon
ImageIcon
Returns: the disabledIcon property/**
     * Returns the icon used by the label when it's disabled.
     * If no disabled icon has been set this will forward the call to
     * the look and feel to construct an appropriate disabled Icon.
     * <p>
     * Some look and feels might not render the disabled Icon, in which
     * case they will ignore this.
     *
     * @return the <code>disabledIcon</code> property
     * @see #setDisabledIcon
     * @see javax.swing.LookAndFeel#getDisabledIcon
     * @see ImageIcon
     */
    @Transient
    public Icon getDisabledIcon() {
        if (!disabledIconSet && disabledIcon == null && defaultIcon != null) {
            disabledIcon = UIManager.getLookAndFeel().getDisabledIcon(this, defaultIcon);
            if (disabledIcon != null) {
                firePropertyChange("disabledIcon", null, disabledIcon);
            }
        }
        return disabledIcon;
    }


    Set the icon to be displayed if this JLabel is "disabled"
(JLabel.setEnabled(false)).

The default value of this property is null.
Params: disabledIcon – the Icon to display when the component is disabled
See Also: getDisabledIcon
JComponent.setEnabled/**
     * 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
     */
    @BeanProperty(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.
Params: key –  a keycode that indicates a mnemonic key
See Also: getLabelFor
setLabelFor/**
     * 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.
     *
     * @param key  a keycode that indicates a mnemonic key
     * @see #getLabelFor
     * @see #setLabelFor
     */
    @BeanProperty(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.
Params: aChar –  a char specifying the mnemonic to display
See Also: setDisplayedMnemonic(int)/**
     * 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 = java.awt.event.KeyEvent.getExtendedKeyCodeForChar(aChar);
        if (vk != java.awt.event.KeyEvent.VK_UNDEFINED) {
            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.
See Also: getLabelFor
setLabelFor
Returns: int value for the mnemonic key/**
     * 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.

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 As', you would have to invoke
setDisplayedMnemonicIndex(5) after invoking
setDisplayedMnemonic(KeyEvent.VK_A).
Params: index – Index into the String to underline
Throws: IllegalArgumentException – will be thrown if index
           is >= length of the text, or < -1
Since: 1.4/**
     * 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>setDisplayedMnemonic(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 &gt;= length of the text, or &lt; -1
     */
    @BeanProperty(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.
See Also: setDisplayedMnemonicIndex
Since: 1.4
Returns: index representing mnemonic character/**
     * 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.
Params: key – the property value to check
message – the IllegalArgumentException detail message
Throws: IllegalArgumentException – if key isn't LEFT, CENTER, RIGHT,
LEADING or TRAILING.
See Also: setHorizontalTextPosition
setHorizontalAlignment
Returns: the key value if key is a a legal value for the horizontalAlignment properties/**
     * Verify that key is a legal value for the horizontalAlignment properties.
     *
     * @param key the property value to check
     * @param message the IllegalArgumentException detail message
     * @return the key value if {@code key} is a a legal value for the
     *         horizontalAlignment properties
     * @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.
Params: key – the property value to check
message – the IllegalArgumentException detail message
Throws: IllegalArgumentException – if key isn't TOP, CENTER, or BOTTOM.
See Also: setVerticalAlignment
setVerticalTextPosition
Returns: the key value if key is a legal value for the verticalAlignment or verticalTextPosition properties/**
     * 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
     * @return the key value if {@code key} is a legal value for the
     *         verticalAlignment or verticalTextPosition properties
     * @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.
See Also: setIconTextGap
Returns: an int equal to the number of pixels between the text
        and the icon./**
     * 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.

The default value of this property is 4 pixels.

This is a JavaBeans bound property.
Params: iconTextGap –  the space between the icon and text properties
See Also: getIconTextGap/**
     * 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.
     *
     * @param iconTextGap  the space between the icon and text properties
     * @see #getIconTextGap
     */
    @BeanProperty(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.
See Also: SwingConstants
setVerticalAlignment
Returns:   The value of the verticalAlignment property, one of the
          following constants defined in SwingConstants:
          TOP,
          CENTER, or
          BOTTOM./**
     * 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.

The default value of this property is CENTER.
Params: alignment – One of the following constants
          defined in SwingConstants:
          TOP,
          CENTER (the default), or
          BOTTOM.
See Also: SwingConstants
getVerticalAlignment/**
     * 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
     */
    @BeanProperty(visualUpdate = true, enumerationValues = {
            "SwingConstants.TOP",
            "SwingConstants.CENTER",
            "SwingConstants.BOTTOM"},
            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.
See Also: setHorizontalAlignment
SwingConstants
Returns:   The value of the horizontalAlignment property, one of the
          following constants defined in SwingConstants:
          LEFT,
          CENTER,
          RIGHT,
          LEADING or
          TRAILING./**
     * 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.

This is a JavaBeans bound property.
Params: alignment –  One of the following constants
          defined in SwingConstants:
          LEFT,
          CENTER (the default for image-only labels),
          RIGHT,
          LEADING (the default for text-only labels) or
          TRAILING.
See Also: SwingConstants
getHorizontalAlignment/**
     * 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
     */
    @BeanProperty(visualUpdate = true, enumerationValues = {
            "SwingConstants.LEFT",
            "SwingConstants.CENTER",
            "SwingConstants.RIGHT",
            "SwingConstants.LEADING",
            "SwingConstants.TRAILING"}, 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.
See Also: setVerticalTextPosition
SwingConstants
Returns:   One of the following constants
          defined in SwingConstants:
          TOP,
          CENTER, or
          BOTTOM./**
     * 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.

The default value of this property is CENTER.

This is a JavaBeans bound property.
Params: textPosition –  One of the following constants
          defined in SwingConstants:
          TOP,
          CENTER (the default), or
          BOTTOM.
See Also: SwingConstants
getVerticalTextPosition/**
     * 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
     */
    @BeanProperty(expert = true, visualUpdate = true, enumerationValues = {
            "SwingConstants.TOP",
            "SwingConstants.CENTER",
            "SwingConstants.BOTTOM"},
            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);
        revalidate();
        repaint();
    }


    Returns the horizontal position of the label's text,
relative to its image.
See Also: SwingConstants
Returns:   One of the following constants
          defined in SwingConstants:
          LEFT,
          CENTER,
          RIGHT,
          LEADING or
          TRAILING./**
     * 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.
Params: textPosition –  One of the following constants
          defined in SwingConstants:
          LEFT,
          CENTER,
          RIGHT,
          LEADING, or
          TRAILING (the default).
See Also: SwingConstants/**
     * 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).
     *
     * @see SwingConstants
     */
    @BeanProperty(expert = true, visualUpdate = true, enumerationValues = {
            "SwingConstants.LEFT",
            "SwingConstants.CENTER",
            "SwingConstants.RIGHT",
            "SwingConstants.LEADING",
            "SwingConstants.TRAILING"}, 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);
        revalidate();
        repaint();
    }


    This is overridden to return false if the current Icon's Image is
not equal to the passed in Image img.
See Also: ImageObserver
Component.imageUpdate(Image, int, int, int, int, int)/**
     * 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.
/**
     * 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 null.
Returns:  a string representation of this JLabel./**
     * 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.
See Also: getDisplayedMnemonic
setDisplayedMnemonic
Returns: 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./**
     * 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.
Params: c –  the Component this label is for, or null if the label is
          not the label for a component
See Also: getDisplayedMnemonic
setDisplayedMnemonic/**
     * 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
     */
    @BeanProperty(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
Returns: the AccessibleContext of this object/**
     * Get the AccessibleContext of this object
     *
     * @return the AccessibleContext of this object
     */
    @BeanProperty(bound = false, 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.

Warning:
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™
has been added to the java.beans package. Please see XMLEncoder. /**
     * 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&trade;
     * has been added to the <code>java.beans</code> package.
     * Please see {@link java.beans.XMLEncoder}.
     */
    @SuppressWarnings("serial")
    protected class AccessibleJLabel extends AccessibleJComponent
        implements AccessibleText, AccessibleExtendedComponent {

        Get the accessible name of this object.
See Also: AccessibleContext.setAccessibleName
Returns: the localized name of the object -- can be null if this
object does not have a name/**
         * 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() {
            String name = accessibleName;

            if (name == null) {
                name = (String)getClientProperty(AccessibleContext.ACCESSIBLE_NAME_PROPERTY);
            }
            if (name == null) {
                name = JLabel.this.getText();
            }
            if (name == null) {
                name = super.getAccessibleName();
            }
            return name;
        }

        Get the role of this object.
See Also: AccessibleRole
Returns: an instance of AccessibleRole describing the role of the
object/**
         * 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.
Since: 1.3/**
         * Get the AccessibleIcons associated with this object if one
         * or more exist.  Otherwise return null.
         * @since 1.3
         */
        public AccessibleIcon [] getAccessibleIcon() {
            Icon icon = getIcon();
            if (icon instanceof Accessible) {
                AccessibleContext ac =
                ((Accessible)icon).getAccessibleContext();
                if (ac != null && ac instanceof AccessibleIcon) {
                    return new AccessibleIcon[] { (AccessibleIcon)ac };
                }
            }
            return null;
        }

        Get the AccessibleRelationSet associated with this object if one
exists.  Otherwise return null.
See Also: AccessibleRelation
Since: 1.3/**
         * Get the AccessibleRelationSet associated with this object if one
         * exists.  Otherwise return null.
         * @see AccessibleRelation
         * @since 1.3
         */
        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.
Params: p – the Point in local coordinates
Returns: the zero-based index of the character under Point p; if
Point is invalid returns -1.
Since: 1.3/**
         * 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.
         * @since 1.3
         */
        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;
            }
        }

        Returns the bounding box of the character at the given
index in the string.  The bounds are returned in local
coordinates. If the index is invalid, null is returned.
Params: i – the index into the String
Returns: the screen coordinates of the character's bounding box.
If the index is invalid, null is returned.
Since: 1.3/**
         * Returns the bounding box of the character at the given
         * index in the string.  The bounds are returned in local
         * coordinates. If the index is invalid, <code>null</code> is returned.
         *
         * @param i the index into the String
         * @return the screen coordinates of the character's bounding box.
         * If the index is invalid, <code>null</code> is returned.
         * @since 1.3
         */
        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)
Returns: the number of characters
Since: 1.3/**
         * Return the number of characters (valid indicies)
         *
         * @return the number of characters
         * @since 1.3
         */
        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).
Returns: the zero-based offset of the caret.
Since: 1.3/**
         * 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.
         * @since 1.3
         */
        public int getCaretPosition() {
            // There is no caret.
            return -1;
        }

        Returns the String at a given index.
Params: part – the AccessibleText.CHARACTER, AccessibleText.WORD,
or AccessibleText.SENTENCE to retrieve
index – an index within the text >= 0
Returns: the letter, word, or sentence,
  null for an invalid index or part
Since: 1.3/**
         * 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 &gt;= 0
         * @return the letter, word, or sentence,
         *   null for an invalid index or part
         * @since 1.3
         */
        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.
Params: part – the AccessibleText.CHARACTER, AccessibleText.WORD,
or AccessibleText.SENTENCE to retrieve
index – an index within the text >= 0
Returns: the letter, word, or sentence, null for an invalid
 index or part
Since: 1.3/**
         * 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 &gt;= 0
         * @return the letter, word, or sentence, null for an invalid
         *  index or part
         * @since 1.3
         */
        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.
Params: part – the AccessibleText.CHARACTER, AccessibleText.WORD,
  or AccessibleText.SENTENCE to retrieve
index – an index within the text >= 0
Returns: the letter, word, or sentence, null for an invalid index
 or part
Since: 1.3/**
         * 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 &gt;= 0
         * @return the letter, word, or sentence, null for an invalid index
         *  or part
         * @since 1.3
         */
        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
Params: i – the zero-based index into the text
Returns: the AttributeSet of the character
Since: 1.3/**
         * 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
         * @since 1.3
         */
        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.
Returns: the index into the text of the start of the selection
Since: 1.3/**
         * 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
         * @since 1.3
         */
        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.
Returns: the index into the text of the end of the selection
Since: 1.3/**
         * 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 the text of the end of the selection
         * @since 1.3
         */
        public int getSelectionEnd() {
            // Text cannot be selected.
            return -1;
        }

        Returns the portion of the text that is selected.
Returns: the String portion of the text that is selected
Since: 1.3/**
         * Returns the portion of the text that is selected.
         *
         * @return the String portion of the text that is selected
         * @since 1.3
         */
        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);

            String clippedText = SwingUtilities.layoutCompoundLabel(
                (JComponent)JLabel.this,
                getFontMetrics(getFont()),
                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
Returns: the AccessibleExtendedComponent/**
         * Returns the AccessibleExtendedComponent
         *
         * @return the AccessibleExtendedComponent
         */
        AccessibleExtendedComponent getAccessibleExtendedComponent() {
            return this;
        }

        Returns the tool tip text
Returns: the tool tip text, if supported, of the object;
otherwise, null
Since: 1.4/**
         * Returns the tool tip text
         *
         * @return the tool tip text, if supported, of the object;
         * otherwise, null
         * @since 1.4
         */
        public String getToolTipText() {
            return JLabel.this.getToolTipText();
        }

        Returns the titled border text
Returns: the titled border text, if supported, of the object;
otherwise, null
Since: 1.4/**
         * Returns the titled border text
         *
         * @return the titled border text, if supported, of the object;
         * otherwise, null
         * @since 1.4
         */
        public String getTitledBorderText() {
            return super.getTitledBorderText();
        }

        Returns key bindings associated with this object
See Also: AccessibleKeyBinding
Returns: the key bindings, if supported, of the object;
otherwise, null
Since: 1.4/**
         * Returns key bindings associated with this object
         *
         * @return the key bindings, if supported, of the object;
         * otherwise, null
         * @see AccessibleKeyBinding
         * @since 1.4
         */
        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
Returns: the zero-based number of key bindings for this object/**
             * 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:

Component c = 
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;
        
    }
}

Params: i – zero-based index of the key bindings
Throws: IllegalArgumentException – if the index is
out of bounds
See Also: getAccessibleKeyBindingCount
Returns: a javax.lang.Object which specifies the key binding/**
             * 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
}
Params:	ui – the LabelUI L&F object
See Also:	UIDefaults.getUI
See Also:	JComponent.getUIClassID UIDefaults.getUI
Returns:	String "LabelUI"
Params:	text – the single line of text this component will display
See Also:	setVerticalTextPosition setHorizontalTextPosition setIcon
Params:	icon – the default icon this component will display
See Also:	setVerticalTextPosition setHorizontalTextPosition getIcon
See Also:	setDisabledIcon LookAndFeel.getDisabledIcon ImageIcon
Returns:	the `disabledIcon` property
Params:	disabledIcon – the Icon to display when the component is disabled
See Also:	getDisabledIcon JComponent.setEnabled
Params:	key – a keycode that indicates a mnemonic key
See Also:	getLabelFor setLabelFor
Params:	aChar – a char specifying the mnemonic to display
See Also:	setDisplayedMnemonic(int)
Params:	index – Index into the String to underline
Throws:	IllegalArgumentException – will be thrown if `index` is >= length of the text, or < -1
Since:	1.4
See Also:	setDisplayedMnemonicIndex
Since:	1.4
Returns:	index representing mnemonic character
Params:	key – the property value to check message – the IllegalArgumentException detail message
Throws:	IllegalArgumentException – if key isn't LEFT, CENTER, RIGHT, LEADING or TRAILING.
See Also:	setHorizontalTextPosition setHorizontalAlignment
Returns:	the key value if `key` is a a legal value for the horizontalAlignment properties
See Also:	setIconTextGap
Returns:	an int equal to the number of pixels between the text and the icon.
Params:	iconTextGap – the space between the icon and text properties
See Also:	getIconTextGap
See Also:	SwingConstants setVerticalAlignment
Returns:	The value of the verticalAlignment property, one of the following constants defined in `SwingConstants`: `TOP`, `CENTER`, or `BOTTOM`.
Params:	alignment – One of the following constants defined in `SwingConstants`: `TOP`, `CENTER` (the default), or `BOTTOM`.
See Also:	SwingConstants getVerticalAlignment
See Also:	setHorizontalAlignment SwingConstants
Returns:	The value of the horizontalAlignment property, one of the following constants defined in `SwingConstants`: `LEFT`, `CENTER`, `RIGHT`, `LEADING` or `TRAILING`.
See Also:	setVerticalTextPosition SwingConstants
Returns:	One of the following constants defined in `SwingConstants`: `TOP`, `CENTER`, or `BOTTOM`.
Params:	textPosition – One of the following constants defined in `SwingConstants`: `TOP`, `CENTER` (the default), or `BOTTOM`.
See Also:	SwingConstants getVerticalTextPosition
See Also:	SwingConstants
Returns:	One of the following constants defined in `SwingConstants`: `LEFT`, `CENTER`, `RIGHT`, `LEADING` or `TRAILING`.
See Also:	getDisplayedMnemonic setDisplayedMnemonic
Returns:	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.
/

java/ 11/ java.desktop/javax/swing/JLabel.java
