defaultcaret.java

来自「linux下建立JAVA虚拟机的源码KAFFE」· Java 代码 · 共 1,104 行 · 第 1/2 页

   * <code>MouseEvent</code>.
   *
   * @param event the <code>MouseEvent</code> from which to fetch the position
   */
  protected void positionCaret(MouseEvent event)
  {
    int newDot = getComponent().viewToModel(event.getPoint());
    setDot(newDot);
  }

  /**
   * Deinstalls this <code>Caret</code> from the specified
   * <code>JTextComponent</code>. This removes any listeners that have been
   * registered by this <code>Caret</code>.
   *
   * @param c the text component from which to install this caret
   */
  public void deinstall(JTextComponent c)
  {
    textComponent.removeFocusListener(this);
    textComponent.removeMouseListener(this);
    textComponent.removeMouseMotionListener(this);
    textComponent.getDocument().removeDocumentListener(documentListener);
    documentListener = null;
    textComponent.removePropertyChangeListener(propertyChangeListener);
    propertyChangeListener = null;
    textComponent = null;

    // Deinstall blink timer if present.
    if (blinkTimer != null)
      blinkTimer.stop();
    blinkTimer = null;
  }

  /**
   * Installs this <code>Caret</code> on the specified
   * <code>JTextComponent</code>. This registers a couple of listeners
   * on the text component.
   *
   * @param c the text component on which to install this caret
   */
  public void install(JTextComponent c)
  {
    textComponent = c;
    textComponent.addFocusListener(this);
    textComponent.addMouseListener(this);
    textComponent.addMouseMotionListener(this);
    propertyChangeListener = new PropertyChangeHandler();
    textComponent.addPropertyChangeListener(propertyChangeListener);
    documentListener = new DocumentHandler();
    textComponent.getDocument().addDocumentListener(documentListener);

    repaint();
  }

  /**
   * Sets the current visual position of this <code>Caret</code>.
   *
   * @param p the Point to use for the saved location. May be <code>null</code>
   *        to indicate that there is no visual location
   */
  public void setMagicCaretPosition(Point p)
  {
    magicCaretPosition = p;
  }

  /**
   * Returns the current visual position of this <code>Caret</code>.
   *
   * @return the current visual position of this <code>Caret</code>
   *
   * @see #setMagicCaretPosition
   */
  public Point getMagicCaretPosition()
  {
    return magicCaretPosition;
  }

  /**
   * Returns the current position of the <code>mark</code>. The
   * <code>mark</code> marks the location in the <code>Document</code> that
   * is the end of a selection. If there is no selection, the <code>mark</code>
   * is the same as the <code>dot</code>.
   *
   * @return the current position of the mark
   */
  public int getMark()
  {
    return mark;
  }
  
  private void clearHighlight()
  {
    Highlighter highlighter = textComponent.getHighlighter();
    
    if (highlighter == null)
      return;
    
    if (selectionVisible)
      {
    try
      {
        if (highlightEntry == null)
          highlightEntry = highlighter.addHighlight(0, 0, getSelectionPainter());
        else
          highlighter.changeHighlight(highlightEntry, 0, 0);
        
        // Free the global variable which stores the text component with an active
        // selection.
        if (componentWithSelection == textComponent)
          componentWithSelection = null;
      }
    catch (BadLocationException e)
      {
        // This should never happen.
        throw new InternalError();
      }
      }
    else
      {
    if (highlightEntry != null)
      {
        highlighter.removeHighlight(highlightEntry);
        highlightEntry = null;
      }
      }
  }
  
  private void handleHighlight()
  {
    Highlighter highlighter = textComponent.getHighlighter();
    
    if (highlighter == null)
      return;
    
    int p0 = Math.min(dot, mark);
    int p1 = Math.max(dot, mark);
    
    if (selectionVisible)
      {
	try
	  {
	    if (highlightEntry == null)
	      highlightEntry = highlighter.addHighlight(p0, p1, getSelectionPainter());
	    else
	      highlighter.changeHighlight(highlightEntry, p0, p1);
            
            // If another component currently has a text selection clear that selection
            // first.
            if (componentWithSelection != null)
              if (componentWithSelection != textComponent)
                {
                  Caret c = componentWithSelection.getCaret();
                  c.setDot(c.getDot());
                }
            componentWithSelection = textComponent;
            
	  }
	catch (BadLocationException e)
	  {
	    // This should never happen.
	    throw new InternalError();
	  }
      }
    else
      {
	if (highlightEntry != null)
	  {
	    highlighter.removeHighlight(highlightEntry);
	    highlightEntry = null;
	  }
      }
  }

  /**
   * Sets the visiblity state of the selection.
   *
   * @param v <code>true</code> if the selection should be visible,
   *        <code>false</code> otherwise
   */
  public void setSelectionVisible(boolean v)
  {
    if (selectionVisible == v)
      return;
    
    selectionVisible = v;
    handleHighlight();
    repaint();
  }

  /**
   * Returns <code>true</code> if the selection is currently visible,
   * <code>false</code> otherwise.
   *
   * @return <code>true</code> if the selection is currently visible,
   *         <code>false</code> otherwise
   */
  public boolean isSelectionVisible()
  {
    return selectionVisible;
  }

  /**
   * Causes the <code>Caret</code> to repaint itself.
   */
  protected final void repaint()
  {
    getComponent().repaint(x, y, width, height);
  }

  /**
   * Paints this <code>Caret</code> using the specified <code>Graphics</code>
   * context.
   *
   * @param g the graphics context to use
   */
  public void paint(Graphics g)
  {
    JTextComponent comp = getComponent();
    if (comp == null)
      return;

    // Make sure the dot has a sane position.
    dot = Math.min(dot, textComponent.getDocument().getLength());
    dot = Math.max(dot, 0);

    Rectangle rect = null;

    try
      {
        rect = textComponent.modelToView(dot);
      }
    catch (BadLocationException e)
      {
    	AssertionError ae;
    	ae = new AssertionError("Unexpected bad caret location: " + dot);
    	ae.initCause(e);
    	throw ae;
      }

    if (rect == null)
      return;

    // Check if paint has possibly been called directly, without a previous
    // call to damage(). In this case we need to do some cleanup first.
    if ((x != rect.x) || (y != rect.y))
      {
        repaint(); // Erase previous location of caret.
        x = rect.x;
        y = rect.y;
        width = 1;
        height = rect.height;
      }

    // Now draw the caret on the new position if visible.
    if (visible)
      {
        g.setColor(textComponent.getCaretColor());
        g.drawLine(rect.x, rect.y, rect.x, rect.y + rect.height);
      }
  }

  /**
   * Returns all registered event listeners of the specified type.
   *
   * @param listenerType the type of listener to return
   *
   * @return all registered event listeners of the specified type
   */
  public EventListener[] getListeners(Class listenerType)
  {
    return listenerList.getListeners(listenerType);
  }

  /**
   * Registers a {@link ChangeListener} that is notified whenever that state
   * of this <code>Caret</code> changes.
   *
   * @param listener the listener to register to this caret
   */
  public void addChangeListener(ChangeListener listener)
  {
    listenerList.add(ChangeListener.class, listener);
  }

  /**
   * Removes a {@link ChangeListener} from the list of registered listeners.
   *
   * @param listener the listener to remove
   */
  public void removeChangeListener(ChangeListener listener)
  {
    listenerList.remove(ChangeListener.class, listener);
  }

  /**
   * Returns all registered {@link ChangeListener}s of this <code>Caret</code>.
   *
   * @return all registered {@link ChangeListener}s of this <code>Caret</code>
   */
  public ChangeListener[] getChangeListeners()
  {
    return (ChangeListener[]) getListeners(ChangeListener.class);
  }

  /**
   * Notifies all registered {@link ChangeListener}s that the state
   * of this <code>Caret</code> has changed.
   */
  protected void fireStateChanged()
  {
    ChangeListener[] listeners = getChangeListeners();

    for (int index = 0; index < listeners.length; ++index)
      listeners[index].stateChanged(changeEvent);
  }

  /**
   * Returns the <code>JTextComponent</code> on which this <code>Caret</code>
   * is installed.
   *
   * @return the <code>JTextComponent</code> on which this <code>Caret</code>
   *         is installed
   */
  protected final JTextComponent getComponent()
  {
    return textComponent;
  }

  /**
   * Returns the blink rate of this <code>Caret</code> in milliseconds.
   * A value of <code>0</code> means that the caret does not blink.
   *
   * @return the blink rate of this <code>Caret</code> or <code>0</code> if
   *         this caret does not blink
   */
  public int getBlinkRate()
  {
    return blinkRate;
  }

  /**
   * Sets the blink rate of this <code>Caret</code> in milliseconds.
   * A value of <code>0</code> means that the caret does not blink.
   *
   * @param rate the new blink rate to set
   */
  public void setBlinkRate(int rate)
  {
    if (blinkTimer != null)
      blinkTimer.setDelay(rate);
    blinkRate = rate;
  }

  /**
   * Returns the current position of this <code>Caret</code> within the
   * <code>Document</code>.
   *
   * @return the current position of this <code>Caret</code> within the
   *         <code>Document</code>
   */
  public int getDot()
  {
    return dot;
  }

  /**
   * Moves the <code>dot</code> location without touching the
   * <code>mark</code>. This is used when making a selection.
   *
   * @param dot the location where to move the dot
   *
   * @see #setDot(int)
   */
  public void moveDot(int dot)
  {
    if (dot >= 0)
      {
        Document doc = textComponent.getDocument();
        if (doc != null)
          this.dot = Math.min(dot, doc.getLength());
        this.dot = Math.max(this.dot, 0);
        
        handleHighlight();
        adjustVisibility(this);
        appear();
      }
  }

  /**
   * Sets the current position of this <code>Caret</code> within the
   * <code>Document</code>. This also sets the <code>mark</code> to the new
   * location.
   * 
   * @param dot
   *          the new position to be set
   * @see #moveDot(int)
   */
  public void setDot(int dot)
  {
    if (dot >= 0)
      {        
        Document doc = textComponent.getDocument();
        if (doc != null)
          this.dot = Math.min(dot, doc.getLength());
        this.dot = Math.max(this.dot, 0);
        this.mark = this.dot;
        
        clearHighlight();
        adjustVisibility(this);
        appear();
      }
  }
  
  /**
   * Show the caret (may be hidden due blinking) and adjust the timer not to
   * hide it (possibly immediately).
   * 
   * @author Audrius Meskauskas ([e-mail])
   */
  void appear()
  {
    // All machinery is only required if the carret is blinking.
    if (blinkListener != null)
      {
        blinkListener.ignoreNextEvent = true;

        // If the caret is visible, erase the current position by repainting
        // over.
        if (visible)
          repaint();

        // Draw the caret in the new position.
        visible = true;

        Rectangle area = null;
	int dot = getDot();
        try
          {
            area = getComponent().modelToView(dot);
          }
        catch (BadLocationException e)
          {
	    AssertionError ae;
	    ae = new AssertionError("Unexpected bad caret location: " + dot);
	    ae.initCause(e);
	    throw ae;
          }
        if (area != null)
          damage(area);
      }
    repaint();
  }  

  /**
   * Returns <code>true</code> if this <code>Caret</code> is currently visible,
   * and <code>false</code> if it is not.
   *
   * @return <code>true</code> if this <code>Caret</code> is currently visible,
   *         and <code>false</code> if it is not
   */
  public boolean isVisible()
  {
    return visible;
  }

  /**
   * Sets the visibility state of the caret. <code>true</code> shows the
   * <code>Caret</code>, <code>false</code> hides it.
   *
   * @param v the visibility to set
   */  
  public void setVisible(boolean v)
  {
    if (v != visible)
      {
        visible = v;
        updateTimerStatus();
        Rectangle area = null;
	int dot = getDot();
        try
          {            
            area = getComponent().modelToView(dot);
          }
        catch (BadLocationException e)
          {
	    AssertionError ae;
	    ae = new AssertionError("Unexpected bad caret location: " + dot);
	    ae.initCause(e);
	    throw ae;
          }
        if (area != null)
          damage(area);
      }
  }

  /**
   * Returns the {@link Highlighter.HighlightPainter} that should be used
   * to paint the selection.
   *
   * @return the {@link Highlighter.HighlightPainter} that should be used
   *         to paint the selection
   */
  protected Highlighter.HighlightPainter getSelectionPainter()
  {
    return DefaultHighlighter.DefaultPainter;
  }

  /**
   * Updates the carets rectangle properties to the specified rectangle and
   * repaints the caret.
   *
   * @param r the rectangle to set as the caret rectangle
   */
  protected void damage(Rectangle r)
  {
    if (r == null)
      return;
    x = r.x;
    y = r.y;
    width = 1;
    // height is normally set in paint and we leave it untouched. However, we
    // must set a valid value here, since otherwise the painting mechanism
    // sets a zero clip and never calls paint.
    if (height <= 0)
      height = getComponent().getHeight();
    repaint();
  }

  /**
   * Adjusts the text component so that the caret is visible. This default
   * implementation simply calls
   * {@link JComponent#scrollRectToVisible(Rectangle)} on the text component.
   * Subclasses may wish to change this.
   */
  protected void adjustVisibility(Rectangle rect)
  {
    getComponent().scrollRectToVisible(rect);
  }

  /**
   * Initializes the blink timer.
   */
  private void initBlinkTimer()
  {
    // Setup the blink timer.
    blinkListener = new BlinkTimerListener();
    blinkTimer = new Timer(getBlinkRate(), blinkListener);
    blinkTimer.setRepeats(true);
  }
}