Imported GNU Classpath 0.90

[official-gcc.git] / libjava / classpath / javax / swing / text / DefaultCaret.java

/* DefaultCaret.java --
   Copyright (C) 2002, 2004, 2005, 2006 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
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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
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As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
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package javax.swing.text;

import java.awt.Graphics;
import java.awt.Point;
import java.awt.Rectangle;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.FocusEvent;
import java.awt.event.FocusListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseMotionListener;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.util.EventListener;

import javax.swing.JComponent;
import javax.swing.SwingUtilities;
import javax.swing.Timer;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
import javax.swing.event.DocumentEvent;
import javax.swing.event.DocumentListener;
import javax.swing.event.EventListenerList;

/**
 * The default implementation of the {@link Caret} interface.
 *
 * @author orgininal author unknown
 * @author Roman Kennke (roman@kennke.org)
 */
public class DefaultCaret extends Rectangle
  implements Caret, FocusListener, MouseListener, MouseMotionListener
{

  /**
   * Controls the blinking of the caret.
   *
   * @author Roman Kennke (kennke@aicas.com)
   * @author Audrius Meskauskas (AudriusA@Bioinformatics.org)
   */
  private class BlinkTimerListener implements ActionListener
  {
    /**
     * Forces the next event to be ignored. The next event should be ignored
     * if we force the caret to appear. We do not know how long will it take
     * to fire the comming event; this may be near immediately. Better to leave
     * the caret visible one iteration longer.
     */
    boolean ignoreNextEvent;
    
    /**
     * Receives notification when the blink timer fires and updates the visible
     * state of the caret.
     * 
     * @param event the action event
     */
    public void actionPerformed(ActionEvent event)
    {
      if (ignoreNextEvent)
        ignoreNextEvent = false;
      else
        {
          visible = !visible;
          repaint();
        }
    }
  }

  /**
   * Listens for changes in the text component's document and updates the
   * caret accordingly.
   * 
   * @author Roman Kennke (kennke@aicas.com)
   */
  private class DocumentHandler implements DocumentListener
  {
    /**
     * Receives notification that some text attributes have changed. No action
     * is taken here.
     *
     * @param event the document event
     */
    public void changedUpdate(DocumentEvent event)
    {
      // Nothing to do here.
    }

    /**
     * Receives notification that some text has been inserted from the text
     * component. The caret is moved forward accordingly.
     *
     * @param event the document event
     */
    public void insertUpdate(DocumentEvent event)
    {
      if (policy == ALWAYS_UPDATE || 
          (SwingUtilities.isEventDispatchThread() && 
           policy == UPDATE_WHEN_ON_EDT))
        {        
          int dot = getDot();
          setDot(dot + event.getLength());
        }
    }

    /**
     * Receives notification that some text has been removed into the text
     * component. The caret is moved backwards accordingly.
     *
     * @param event the document event
     */
    public void removeUpdate(DocumentEvent event)
    {
      if (policy == ALWAYS_UPDATE
          || (SwingUtilities.isEventDispatchThread()
              && policy == UPDATE_WHEN_ON_EDT))
        {
          int dot = getDot();
          setDot(dot - event.getLength());
        }
      else if (policy == NEVER_UPDATE
               || (! SwingUtilities.isEventDispatchThread()
                   && policy == UPDATE_WHEN_ON_EDT))
        {
          int docLength = event.getDocument().getLength();
          if (getDot() > docLength)
            setDot(docLength);
        }
    }
  }

  /**
   * Listens for property changes on the text document. This is used to add and
   * remove our document listener, if the document of the text component has
   * changed.
   *
   * @author Roman Kennke (kennke@aicas.com)
   */
  private class PropertyChangeHandler implements PropertyChangeListener
  {

    /**
     * Receives notification when a property has changed on the text component.
     * This adds/removes our document listener from the text component's
     * document when the document changes.
     *
     * @param e the property change event
     */
    public void propertyChange(PropertyChangeEvent e)
    {
      if (e.getPropertyName().equals("document"))
        {
          Document oldDoc = (Document) e.getOldValue();
          oldDoc.removeDocumentListener(documentListener);
          Document newDoc = (Document) e.getNewValue();
          newDoc.addDocumentListener(documentListener);
        }
    }
    
  }

  /** The serialization UID (compatible with JDK1.5). */
  private static final long serialVersionUID = 4325555698756477346L;
  
  /**
   * Indicates the Caret position should always be updated after Document
   * changes even if the updates are not performed on the Event Dispatching
   * thread.
   * 
   * @since 1.5
   */
  public static final int ALWAYS_UPDATE = 2;

  /**
   * Indicates the Caret position should not be changed unless the Document
   * length becomes less than the Caret position, in which case the Caret
   * is moved to the end of the Document.
   * 
   * @since 1.5
   */
  public static final int NEVER_UPDATE = 1;
  
  /** 
   * Indicates the Caret position should be updated only if Document changes
   * are made on the Event Dispatcher thread.
   *  
   * @since 1.5
   */
  public static final int UPDATE_WHEN_ON_EDT = 0;
  
  /** Keeps track of the current update policy **/
  int policy = UPDATE_WHEN_ON_EDT;
    
  /**
   * The <code>ChangeEvent</code> that is fired by {@link #fireStateChanged()}.
   */
  protected ChangeEvent changeEvent = new ChangeEvent(this);

  /**
   * Stores all registered event listeners.
   */
  protected EventListenerList listenerList = new EventListenerList();

  /**
   * Our document listener.
   */
  DocumentListener documentListener;

  /**
   * Our property listener.
   */
  PropertyChangeListener propertyChangeListener;

  /**
   * The text component in which this caret is installed.
   */
  private JTextComponent textComponent;

  /**
   * Indicates if the selection should be visible or not.
   */
  private boolean selectionVisible = true;

  /**
   * The blink rate of this <code>Caret</code>.
   */
  private int blinkRate = 500;

  /**
   * The current dot position.
   */
  private int dot = 0;

  /**
   * The current mark position.
   */
  private int mark = 0;

  /**
   * The current visual caret position.
   */
  private Point magicCaretPosition = null;

  /**
   * Indicates if this <code>Caret</code> is currently visible or not. This is
   * package private to avoid an accessor method.
   */
  boolean visible = false;

  /**
   * The current highlight entry.
   */
  private Object highlightEntry;

  private Timer blinkTimer;
  
  private BlinkTimerListener blinkListener;

  /**
   * Creates a new <code>DefaultCaret</code> instance.
   */
  public DefaultCaret()
  {
    // Nothing to do here.
  }

  /**
   * Sets the Caret update policy.
   *    
   * @param policy the new policy.  Valid values are:
   * ALWAYS_UPDATE: always update the Caret position, even when Document
   * updates don't occur on the Event Dispatcher thread.
   * NEVER_UPDATE: don't update the Caret position unless the Document
   * length becomes less than the Caret position (then update the
   * Caret to the end of the Document).
   * UPDATE_WHEN_ON_EDT: update the Caret position when the 
   * Document updates occur on the Event Dispatcher thread.  This is the 
   * default.
   * 
   * @since 1.5
   * @throws IllegalArgumentException if policy is not one of the above.
   */
  public void setUpdatePolicy (int policy)
  {
    if (policy != ALWAYS_UPDATE && policy != NEVER_UPDATE
        && policy != UPDATE_WHEN_ON_EDT)
      throw new 
        IllegalArgumentException
        ("policy must be ALWAYS_UPDATE, NEVER__UPDATE, or UPDATE_WHEN_ON_EDT");
    this.policy = policy;
  }
  
  /**
   * Gets the caret update policy.
   * 
   * @return the caret update policy.
   * @since 1.5
   */
  public int getUpdatePolicy ()
  {
    return policy;
  }
  
  /**
   * Moves the caret position when the mouse is dragged over the text
   * component, modifying the selection accordingly.
   *
   * @param event the <code>MouseEvent</code> describing the drag operation
   */
  public void mouseDragged(MouseEvent event)
  {
    moveCaret(event);
  }

  /**
   * Indicates a mouse movement over the text component. Does nothing here.
   *
   * @param event the <code>MouseEvent</code> describing the mouse operation
   */
  public void mouseMoved(MouseEvent event)
  {
    // Nothing to do here.
  }

  /**
   * When the click is received from Button 1 then the following actions
   * are performed here:
   *
   * <ul>
   * <li>If we receive a double click, the caret position (dot) is set
   *   to the position associated to the mouse click and the word at
   *   this location is selected. If there is no word at the pointer
   *   the gap is selected instead.</li>
   * <li>If we receive a triple click, the caret position (dot) is set
   *   to the position associated to the mouse click and the line at
   *   this location is selected.</li>
   * </ul>
   *
   * @param event the <code>MouseEvent</code> describing the click operation
   */
  public void mouseClicked(MouseEvent event)
  {
    int count = event.getClickCount();
    
    if (count >= 2)
      {
        int newDot = getComponent().viewToModel(event.getPoint());
        JTextComponent t = getComponent();

        try
          {
            if (count == 3)
              t.select(Utilities.getRowStart(t, newDot), Utilities.getRowEnd(t, newDot));
            else
              {
                int nextWord = Utilities.getNextWord(t, newDot);
                
                // When the mouse points at the offset of the first character
                // in a word Utilities().getPreviousWord will not return that
                // word but we want to select that. We have to use
                // Utilities.nextWord() to get it.
                if (newDot == nextWord)
                  t.select(nextWord, Utilities.getNextWord(t, nextWord));
                else
                  {
                    int previousWord = Utilities.getPreviousWord(t, newDot);
                    int previousWordEnd = Utilities.getWordEnd(t, previousWord);
                    
                    // If the user clicked in the space between two words,
                    // then select the space.
                    if (newDot >= previousWordEnd && newDot <= nextWord)
                      t.select(previousWordEnd, nextWord);
                    // Otherwise select the word under the mouse pointer.
                    else
                      t.select(previousWord, previousWordEnd);
                  }
              }
          }
        catch(BadLocationException ble)
          {
            // TODO: Swallowing ok here?
          }
        
        dot = newDot;
      }
    
  }

  /**
   * Indicates that the mouse has entered the text component. Nothing is done
   * here.
   *
   * @param event the <code>MouseEvent</code> describing the mouse operation
   */
  public void mouseEntered(MouseEvent event)
  {
    // Nothing to do here.
  }

  /**
   * Indicates that the mouse has exited the text component. Nothing is done
   * here.
   *
   * @param event the <code>MouseEvent</code> describing the mouse operation
   */
  public void mouseExited(MouseEvent event)
  {
    // Nothing to do here.
  }

  /**
   * If the button 1 is pressed, the caret position is updated to the
   * position of the mouse click and the text component requests the input
   * focus if it is enabled. If the SHIFT key is held down, the caret will
   * be moved, which might select the text between the old and new location.
   *
   * @param event the <code>MouseEvent</code> describing the press operation
   */
  public void mousePressed(MouseEvent event)
  {
    if (event.isShiftDown())
      moveCaret(event);
    else
      positionCaret(event);
  }

  /**
   * Indicates that a mouse button has been released on the text component.
   * Nothing is done here.
   *
   * @param event the <code>MouseEvent</code> describing the mouse operation
   */
  public void mouseReleased(MouseEvent event)
  {
    // Nothing to do here.
  }

  /**
   * Sets the caret to <code>visible</code> if the text component is editable.
   *
   * @param event the <code>FocusEvent</code>
   */
  public void focusGained(FocusEvent event)
  {
    setVisible(true);    
    updateTimerStatus();
  }

  /**
   * Sets the caret to <code>invisible</code>.
   * 
   * @param event the <code>FocusEvent</code>
   */
  public void focusLost(FocusEvent event)
  {
    if (event.isTemporary() == false)
      {
        setVisible(false);
        // Stop the blinker, if running.
        if (blinkTimer != null && blinkTimer.isRunning())
          blinkTimer.stop();
      }
  }
  
  /**
   * Install (if not present) and start the timer, if the caret must blink. The
   * caret does not blink if it is invisible, or the component is disabled or
   * not editable.
   */
  private void updateTimerStatus()
  {
    if (textComponent.isEnabled() && textComponent.isEditable())
      {
        if (blinkTimer == null)
          initBlinkTimer();
        if (!blinkTimer.isRunning())
          blinkTimer.start();
      }
    else
      {
        if (blinkTimer != null)
          blinkTimer.stop();
      }
  }

  /**
   * Moves the caret to the position specified in the <code>MouseEvent</code>.
   * This will cause a selection if the dot and mark are different.
   *
   * @param event the <code>MouseEvent</code> from which to fetch the position
   */
  protected void moveCaret(MouseEvent event)
  {
    int newDot = getComponent().viewToModel(event.getPoint());
    moveDot(newDot);
  }

  /**
   * Repositions the caret to the position specified in the
   * <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);
      }
    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);
          }
        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 (AudriusA@Bioinformatics.org)
   */
  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);
  }
}