jlabel.java

gcc的组建

/* JLabel.java --
   Copyright (C) 2002, 2004, 2005  Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

GNU Classpath 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 for more details.

You should have received a copy of the GNU General Public License
along with GNU Classpath; see the file COPYING.  If not, write to the
Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA.

Linking this library statically or dynamically with other modules is
making a combined work based on this library.  Thus, the terms and
conditions of the GNU General Public License cover the whole
combination.

As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
modules, and to copy and distribute the resulting executable under
terms of your choice, provided that you also meet, for each linked
independent module, the terms and conditions of the license of that
module.  An independent module is a module which is not derived from
or based on this library.  If you modify this library, you may extend
this exception to your version of the library, but you are not
obligated to do so.  If you do not wish to do so, delete this
exception statement from your version. */


package javax.swing;

import java.awt.Component;
import java.awt.Font;
import java.awt.Image;
import java.awt.Point;
import java.awt.Rectangle;
import java.awt.event.KeyEvent;

import javax.accessibility.Accessible;
import javax.accessibility.AccessibleContext;
import javax.accessibility.AccessibleExtendedComponent;
import javax.accessibility.AccessibleText;
import javax.swing.plaf.LabelUI;
import javax.swing.text.AttributeSet;
import javax.swing.text.SimpleAttributeSet;

/**
 * A swing widget that displays a text message and/or an icon.
 */
public class JLabel extends JComponent implements Accessible, SwingConstants
{

  /**
   * Accessibility support for JLabel.
   */
  protected class AccessibleJLabel
    extends JComponent.AccessibleJComponent
    implements AccessibleText, AccessibleExtendedComponent
  {
    /**
     * Returns the selected text. This is an empty string since JLabels
     * are not selectable.
     *
     * @return the selected text
     */
    public String getSelectedText()
    {
      // We return "" here since JLabel's text is not selectable.
      return "";
    }

    /**
     * Returns the start index of the selected text.
     *
     * @return the start index of the selected text
     */
    public int getSelectionStart()
    {
      // TODO: Figure out what should be returned here, because JLabels don't
      // allow selection. I guess -1 for now.
      return -1;
    }

    /**
     * Returns the end index of the selected text.
     *
     * @return the end index of the selected text
     */
    public int getSelectionEnd()
    {
      // TODO: Figure out what should be returned here, because JLabels don't
      // allow selection. I guess -1 for now.
      return -1;
    }

    /**
     * Returns an {@link AttributeSet} that reflects the text attributes of
     * the specified character. We return an empty
     * <code>AttributeSet</code> here, because JLabels don't support text
     * attributes (at least not yet).
     *
     * @param index the index of the character
     *
     * @return an {@link AttributeSet} that reflects the text attributes of
     *         the specified character
     */
    public AttributeSet getCharacterAttribute(int index)
    {
      return new SimpleAttributeSet();
    }

    /**
     * Returns the character, word or sentence at the specified index. The
     * <code>part</code> parameter determines what is returned, the character,
     * word or sentence after the index.
     *
     * @param part one of {@link AccessibleText#CHARACTER},
     *             {@link AccessibleText#WORD} or
     *             {@link AccessibleText#SENTENCE}, specifying what is returned
     * @param index the index
     *
     * @return the character, word or sentence after <code>index</code>
     */
    public String getAtIndex(int part, int index)
    {
      String result = "";
      int startIndex = -1;
      int endIndex = -1;
      switch(part)
        {
        case AccessibleText.CHARACTER:
          result = String.valueOf(text.charAt(index));
          break;
        case AccessibleText.WORD:
          startIndex = text.lastIndexOf(' ', index);
          endIndex = text.indexOf(' ', startIndex + 1);
          if (endIndex == -1)
            endIndex = startIndex + 1;
          result = text.substring(startIndex + 1, endIndex);
          break;
        case AccessibleText.SENTENCE:
        default:
          startIndex = text.lastIndexOf('.', index);
          endIndex = text.indexOf('.', startIndex + 1);
          if (endIndex == -1)
            endIndex = startIndex + 1;
          result = text.substring(startIndex + 1, endIndex);
          break;
        }
      return result;
    }

    /**
     * Returns the character, word or sentence after the specified index. The
     * <code>part</code> parameter determines what is returned, the character,
     * word or sentence after the index.
     *
     * @param part one of {@link AccessibleText#CHARACTER},
     *             {@link AccessibleText#WORD} or
     *             {@link AccessibleText#SENTENCE}, specifying what is returned
     * @param index the index
     *
     * @return the character, word or sentence after <code>index</code>
     */
    public String getAfterIndex(int part, int index)
    {
      String result = "";
      int startIndex = -1;
      int endIndex = -1;
      switch(part)
        {
        case AccessibleText.CHARACTER:
          result = String.valueOf(text.charAt(index + 1));
          break;
        case AccessibleText.WORD:
          startIndex = text.indexOf(' ', index);
          endIndex = text.indexOf(' ', startIndex + 1);
          if (endIndex == -1)
            endIndex = startIndex + 1;
          result = text.substring(startIndex + 1, endIndex);
          break;
        case AccessibleText.SENTENCE:
        default:
          startIndex = text.indexOf('.', index);
          endIndex = text.indexOf('.', startIndex + 1);
          if (endIndex == -1)
            endIndex = startIndex + 1;
          result = text.substring(startIndex + 1, endIndex);
          break;
        }
      return result;
    }

    /**
     * Returns the character, word or sentence before the specified index. The
     * <code>part</code> parameter determines what is returned, the character,
     * word or sentence before the index.
     *
     * @param part one of {@link AccessibleText#CHARACTER},
     *             {@link AccessibleText#WORD} or
     *             {@link AccessibleText#SENTENCE}, specifying what is returned
     * @param index the index
     *
     * @return the character, word or sentence before <code>index</code>
     */
    public String getBeforeIndex(int part, int index)
    {
      String result = "";
      int startIndex = -1;
      int endIndex = -1;
      switch(part)
        {
        case AccessibleText.CHARACTER:
          result = String.valueOf(text.charAt(index - 1));
          break;
        case AccessibleText.WORD:
          endIndex = text.lastIndexOf(' ', index);
          if (endIndex == -1)
            endIndex = 0;
          startIndex = text.lastIndexOf(' ', endIndex - 1);
          result = text.substring(startIndex + 1, endIndex);
          break;
        case AccessibleText.SENTENCE:
        default:
          endIndex = text.lastIndexOf('.', index);
          if (endIndex == -1)
            endIndex = 0;
          startIndex = text.lastIndexOf('.', endIndex - 1);
          result = text.substring(startIndex + 1, endIndex);
          break;
        }
      return result;
    }

    /**
     * Returns the caret position. This method returns -1 because JLabel don't
     * have a caret.
     *
     * @return the caret position
     */
    public int getCaretPosition()
    {
      return -1;
    }

    /**
     * Returns the number of characters that are displayed by the JLabel.
     *
     * @return the number of characters that are displayed by the JLabel
     */
    public int getCharCount()
    {
      return text.length();
    }

    /**
     * Returns the bounding box of the character at the specified index.
     *
     * @param index the index of the character that we return the
     *        bounds for
     *
     * @return the bounding box of the character at the specified index
     */
    public Rectangle getCharacterBounds(int index)
    {
      // FIXME: Implement this correctly.
      return new Rectangle();
    }

    /**
     * Returns the index of the character that is located at the specified
     * point.
     *
     * @param point the location that we lookup the character for
     *
     * @return the index of the character that is located at the specified
     *         point
     */
    public int getIndexAtPoint(Point point)
    {
      // FIXME: Implement this correctly.
      return 0;
    }
  }

  /** DOCUMENT ME! */
  private static final long serialVersionUID = 5496508283662221534L;

  /**
   * The Component the label will give focus to when its mnemonic is
   * activated.
   */
  protected Component labelFor;

  /** The label's text. */
  transient String text;

  /** Where the label will be positioned horizontally. */
  private transient int horizontalAlignment = LEADING;

  /** Where the label text will be placed horizontally relative to the icon. */
  private transient int horizontalTextPosition = TRAILING;

  /** Where the label will be positioned vertically. */
  private transient int verticalAlignment = CENTER;

  /** Where the label text will be place vertically relative to the icon. */
  private transient int verticalTextPosition = CENTER;

  /** The icon painted when the label is enabled. */
  private transient Icon icon;

  /** The icon painted when the label is disabled. */
  private transient Icon disabledIcon;

  /** The label's mnemnonic key. */
  private transient int displayedMnemonic = KeyEvent.VK_UNDEFINED;

  /** The index of the menemonic character in the text. */
  private transient int displayedMnemonicIndex = -1;

  /** The gap between the icon and the text. */
  private transient int iconTextGap = 4;

  /**
   * Creates a new vertically centered, horizontally on the leading edge
   * JLabel object with text and no icon.
   */
  public JLabel()
  {
    this(null, null, LEADING);
  }

  /**
   * Creates a new vertically and horizontally centered
   * JLabel object with no text and the given icon.
   *
   * @param image The icon to use with the label.
   */
  public JLabel(Icon image)
  {
    this(null, image, CENTER);
  }

  /**
   * Creates a new vertically centered JLabel object with no text and the
   * given icon and horizontal alignment. By default, the text is TRAILING
   * the image.
   *
   * @param image The icon to use with the label.
   * @param horizontalAlignment The horizontal alignment of the label.
   */
  public JLabel(Icon image, int horizontalAlignment)
  {
    this(null, image, horizontalAlignment);
  }

  /**
   * Creates a new horizontally leading and vertically centered JLabel 
   * object with no icon and the given text.
   *
   * @param text The text to use with the label.
   */
  public JLabel(String text)
  {
    this(text, null, LEADING);
  }

  /**
   * Creates a new vertically centered JLabel object with no icon and the
   * given text and horizontal alignment.
   *
   * @param text The text to use with the label.
   * @param horizontalAlignment The horizontal alignment of the label.
   */
  public JLabel(String text, int horizontalAlignment)
  {
    this(text, null, horizontalAlignment);
  }

  /**
   * Creates a new vertically centered JLabel object with the given text,
   * icon, and horizontal alignment.
   *
   * @param text The text to use with the label.
   * @param icon The icon to use with the label.
   * @param horizontalAlignment The horizontal alignment of the label.
   */
  public JLabel(String text, Icon icon, int horizontalAlignment)
  {
    this.text = text;
    this.icon = icon;
    this.horizontalAlignment = horizontalAlignment;
    setAlignmentX(0.0F);
    updateUI();
  }

  /**
   * This method returns the label's UI delegate.
   *
   * @return The label's UI delegate.
   */
  public LabelUI getUI()
  {
    return (LabelUI) ui;
  }

  /**
   * This method sets the label's UI delegate.
   *
   * @param ui The label's UI delegate.
   */
  public void setUI(LabelUI ui)
  {
    super.setUI(ui);
  }

  /**
   * This method resets the label's UI delegate to the default UI for the
   * current look and feel.
   */
  public void updateUI()
  {
    setUI((LabelUI) UIManager.getUI(this));
  }

  /**
   * This method returns a name to identify which look and feel class will be
   * the UI delegate for this label.
   *
   * @return The UIClass identifier. "LabelUI"
   */
  public String getUIClassID()
  {
    return "LabelUI";
  }

  /**