basictextui.java

gcc的组建

    textComponent.removeFocusListener(focuslistener);
    textComponent.getDocument().removeDocumentListener(documentHandler);
  }

  /**
   * Uninstalls all keyboard actions that have previously been installed by
   * this UI.
   */
  protected void uninstallKeyboardActions()
  {
    // FIXME: Uninstall keyboard actions here.
  }

  /**
   * Returns the property prefix by which the text component's UIDefaults
   * are looked up.
   *
   * @return the property prefix by which the text component's UIDefaults
   *     are looked up
   */
  protected abstract String getPropertyPrefix();

  /**
   * Returns the preferred size of the text component.
   *
   * @param c not used here
   *
   * @return the preferred size of the text component
   */
  public Dimension getPreferredSize(JComponent c)
  {
    View v = getRootView(textComponent);

    float w = v.getPreferredSpan(View.X_AXIS);
    float h = v.getPreferredSpan(View.Y_AXIS);

    return new Dimension((int) w, (int) h);
  }

  /**
   * Returns the maximum size for text components that use this UI.
   *
   * This returns (Integer.MAX_VALUE, Integer.MAX_VALUE).
   *
   * @param c not used here
   *
   * @return the maximum size for text components that use this UI
   */
  public Dimension getMaximumSize(JComponent c)
  {
    // Sun's implementation returns Integer.MAX_VALUE here, so do we.
    return new Dimension(Integer.MAX_VALUE, Integer.MAX_VALUE);
  }

  /**
   * Returns the minimum size for text components. This returns the size
   * of the component's insets.
   *
   * @return the minimum size for text components
   */
  public Dimension getMinimumSize(JComponent c)
  {
    Insets i = c.getInsets();
    return new Dimension(i.left + i.right, i.top + i.bottom);
  }

  /**
   * Paints the text component.
   *
   * @param g the <code>Graphics</code> context to paint to
   * @param c not used here
   */
  public final void paint(Graphics g, JComponent c)
  {
    paintSafely(g);
  }

  /**
   * Actually performs the painting.
   *
   * @param g the <code>Graphics</code> context to paint to
   */
  protected void paintSafely(Graphics g)
  {
    Caret caret = textComponent.getCaret();
    Highlighter highlighter = textComponent.getHighlighter();

    if (textComponent.isOpaque())
      paintBackground(g);

    if (highlighter != null
	&& textComponent.getSelectionStart() != textComponent.getSelectionEnd())
      highlighter.paint(g);

    rootView.paint(g, getVisibleEditorRect());

    if (caret != null && textComponent.hasFocus())
      caret.paint(g);
  }

  /**
   * Paints the background of the text component.
   *
   * @param g the <code>Graphics</code> context to paint to
   */
  protected void paintBackground(Graphics g)
  {
    // This method does nothing. All the background filling is done by the
    // ComponentUI update method. However, the method is called by paint
    // to provide a way for subclasses to draw something different (e.g.
    // background images etc) on the background.
  }

  /**
   * Marks the specified range inside the text component's model as
   * damaged and queues a repaint request.
   *
   * @param t the text component
   * @param p0 the start location inside the document model of the range that
   *        is damaged
   * @param p1 the end location inside the document model of the range that
   *        is damaged
   */
  public void damageRange(JTextComponent t, int p0, int p1)
  {
    damageRange(t, p0, p1, null, null);
  }

  /**
   * Marks the specified range inside the text component's model as
   * damaged and queues a repaint request. This variant of this method
   * allows a {@link Position.Bias} object to be specified for the start
   * and end location of the range.
   *
   * @param t the text component
   * @param p0 the start location inside the document model of the range that
   *        is damaged
   * @param p1 the end location inside the document model of the range that
   *        is damaged
   * @param firstBias the bias for the start location
   * @param secondBias the bias for the end location
   */
  public void damageRange(JTextComponent t, int p0, int p1,
                          Position.Bias firstBias, Position.Bias secondBias)
  {
    // TODO: Implement me.
  }

  /**
   * Returns the {@link EditorKit} used for the text component that is managed
   * by this UI.
   *
   * @param t the text component
   *
   * @return the {@link EditorKit} used for the text component that is managed
   *         by this UI
   */
  public EditorKit getEditorKit(JTextComponent t)
  {
    return kit;
  }

  /**
   * Gets the next position inside the document model that is visible on
   * screen, starting from <code>pos</code>.
   *
   * @param t the text component
   * @param pos the start positionn
   * @param b the bias for pos
   * @param direction the search direction
   * @param biasRet filled by the method to indicate the bias of the return
   *        value
   *
   * @return the next position inside the document model that is visible on
   *         screen
   */
  public int getNextVisualPositionFrom(JTextComponent t, int pos,
                                       Position.Bias b, int direction,
                                       Position.Bias[] biasRet)
    throws BadLocationException
  {
    return 0; // TODO: Implement me.
  }

  /**
   * Returns the root {@link View} of a text component.
   *
   * @return the root {@link View} of a text component
   */
  public View getRootView(JTextComponent t)
  {
    return rootView;
  }

  /**
   * Maps a position in the document into the coordinate space of the View.
   * The output rectangle usually reflects the font height but has a width
   * of zero. A bias of {@link Position.Bias#Forward} is used in this method.
   *
   * @param t the text component
   * @param pos the position of the character in the model
   *
   * @return a rectangle that gives the location of the document position
   *         inside the view coordinate space
   *
   * @throws BadLocationException if <code>pos</code> is invalid
   * @throws IllegalArgumentException if b is not one of the above listed
   *         valid values
   */
  public Rectangle modelToView(JTextComponent t, int pos)
    throws BadLocationException
  {
    return modelToView(t, pos, Position.Bias.Forward);
  }

  /**
   * Maps a position in the document into the coordinate space of the View.
   * The output rectangle usually reflects the font height but has a width
   * of zero.
   *
   * @param t the text component
   * @param pos the position of the character in the model
   * @param bias either {@link Position.Bias#Forward} or
   *        {@link Position.Bias#Backward} depending on the preferred
   *        direction bias. If <code>null</code> this defaults to
   *        <code>Position.Bias.Forward</code>
   *
   * @return a rectangle that gives the location of the document position
   *         inside the view coordinate space
   *
   * @throws BadLocationException if <code>pos</code> is invalid
   * @throws IllegalArgumentException if b is not one of the above listed
   *         valid values
   */
  public Rectangle modelToView(JTextComponent t, int pos, Position.Bias bias)
    throws BadLocationException
  {
    return rootView.modelToView(pos, getVisibleEditorRect(), bias).getBounds();
  }

  /**
   * Maps a point in the <code>View</code> coordinate space to a position
   * inside a document model.
   *
   * @param t the text component
   * @param pt the point to be mapped
   *
   * @return the position inside the document model that corresponds to
   *     <code>pt</code>
   */
  public int viewToModel(JTextComponent t, Point pt)
  {
    return viewToModel(t, pt, null);
  }

  /**
   * Maps a point in the <code>View</code> coordinate space to a position
   * inside a document model.
   *
   * @param t the text component
   * @param pt the point to be mapped
   * @param biasReturn filled in by the method to indicate the bias of the
   *        return value
   *
   * @return the position inside the document model that corresponds to
   *     <code>pt</code>
   */
  public int viewToModel(JTextComponent t, Point pt, Position.Bias[] biasReturn)
  {
    return rootView.viewToModel(pt.x, pt.y, getVisibleEditorRect(), biasReturn);
  }

  /**
   * Creates a {@link View} for the specified {@link Element}.
   *
   * @param elem the <code>Element</code> to create a <code>View</code> for
   *
   * @see ViewFactory
   */
  public View create(Element elem)
  {
    // Subclasses have to implement this to get this functionality.
    return null;
  }

  /**
   * Creates a {@link View} for the specified {@link Element}.
   *
   * @param elem the <code>Element</code> to create a <code>View</code> for
   * @param p0 the start offset
   * @param p1 the end offset
   *
   * @see ViewFactory
   */
  public View create(Element elem, int p0, int p1)
  {
    // Subclasses have to implement this to get this functionality.
    return null;
  }

  /**
   * Returns the allocation to give the root view.
   *
   * @return the allocation to give the root view
   *
   * @specnote The allocation has nothing to do with visibility. According
   *           to the specs the naming of this method is unfortunate and
   *           has historical reasons
   */
  protected Rectangle getVisibleEditorRect()
  {
    JTextComponent textComponent = getComponent();
    int width = textComponent.getWidth();
    int height = textComponent.getHeight();

    if (width <= 0 || height <= 0)
      return new Rectangle(0, 0, 0, 0);
	
    Insets insets = textComponent.getInsets();
    return new Rectangle(insets.left, insets.top,
			 width - insets.left - insets.right,
			 height - insets.top - insets.bottom);
  }

  /**
   * Sets the root view for the text component.
   *
   * @param view the <code>View</code> to be set as root view
   */
  protected final void setView(View view)
  {
    rootView.setView(view);
    view.setParent(rootView);
    textComponent.revalidate();
    textComponent.repaint();
  }

  /**
   * Indicates that the model of a text component has changed. This
   * triggers a rebuild of the view hierarchy.
   */
  protected void modelChanged()
  {
    if (textComponent == null || rootView == null) 
      return;
    ViewFactory factory = rootView.getViewFactory();
    if (factory == null) 
      return;
    Document doc = textComponent.getDocument();
    if (doc == null)
      return;
    installDocumentListeners();
    Element elem = doc.getDefaultRootElement();
    if (elem == null)
      return;
    View view = factory.create(elem);
    setView(view);
  }

  /**
   * Receives notification whenever one of the text component's bound
   * properties changes. This default implementation does nothing.
   * It is a hook that enables subclasses to react to property changes
   * on the text component.
   *
   * @param ev the property change event
   */
  protected void propertyChange(PropertyChangeEvent ev)
  {
    // The default implementation does nothing.
  }
}