scrollpane.java

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}

/*************************************************************************/

/**
  * Returns the width of a vertical scrollbar.
  *
  * @return The width of a vertical scrollbar.
  */
public int
getVScrollbarWidth()
{
  ScrollPanePeer spp = (ScrollPanePeer)getPeer();
  if (spp != null)
    return(spp.getVScrollbarWidth());
  else
    return(0); // FIXME: What to do here?
}

/*************************************************************************/

/**
  * Returns the current scroll position of the viewport.
  *
  * @return The current scroll position of the viewport.
  */
public Point
getScrollPosition()
{
  int x = 0;
  int y = 0;

  Adjustable v = getVAdjustable();
  Adjustable h = getHAdjustable();

  if (v != null)
    y = v.getValue();
  if (h != null)
    x = h.getValue();

  return(new Point(x, y));
}

/*************************************************************************/

/**
  * Sets the scroll position to the specified value.
  *
  * @param scrollPosition The new scrollPosition.
  *
  * @exception IllegalArgumentException If the specified value is outside
  * the legal scrolling range.
  */
public void
setScrollPosition(Point scrollPosition) throws IllegalArgumentException
{
  setScrollPosition(scrollPosition.x, scrollPosition.y);
}

/*************************************************************************/

/**
  * Sets the scroll position to the specified value.
  *
  * @param x The new X coordinate of the scroll position.
  * @param y The new Y coordinate of the scroll position.
  *
  * @exception IllegalArgumentException If the specified value is outside
  * the legal scrolling range.
  */
public void
setScrollPosition(int x, int y)
{
  Adjustable h = getHAdjustable();
  Adjustable v = getVAdjustable();

  if (h != null)
    h.setValue(x);
  if (v != null)
    v.setValue(y);

  ScrollPanePeer spp = (ScrollPanePeer)getPeer();
  if (spp != null)
    spp.setScrollPosition(x, y);
}

/*************************************************************************/

/**
  * Notifies this object that it should create its native peer.
  */
public void
addNotify()
{
  if (peer != null)
    return;

  setPeer((ComponentPeer)getToolkit().createScrollPane(this));
  super.addNotify();

  Component[] list = getComponents();
  if (list != null && list.length > 0 && ! (list[0] instanceof Panel))
  {
    Panel panel = new Panel();
    panel.setLayout(new BorderLayout());
    panel.add(list[0], BorderLayout.CENTER);
    add(panel);
  }
}

/*************************************************************************/

/**
  * Notifies this object that it should destroy its native peers.
  */
public void
removeNotify()
{
  super.removeNotify();
}

/*************************************************************************/

/**
  * Adds the specified child component to this container.  A 
  * <code>ScrollPane</code> can have at most one child, so if a second
  * one is added, then first one is removed.
  *
  * @param component The component to add to this container.
  * @param constraints A list of layout constraints for this object.
  * @param index The index at which to add the child, which is ignored
  * in this implementation.
  */
  protected final void addImpl (Component component, Object constraints,
				int index)
{
  Component[] list = getComponents();
  if ((list != null) && (list.length > 0))
    remove(list[0]);

  super.addImpl(component, constraints, -1);

  doLayout();
}

/*************************************************************************/

/**
  * Lays out this component.  This consists of resizing the sole child
  * component to its perferred size.
  */
public void
doLayout()
{
  layout ();
}

/*************************************************************************/

/**
  * Lays out this component.  This consists of resizing the sole child
  * component to its perferred size.
  *
  * @deprecated This method is deprecated in favor of
  * <code>doLayout()</code>.
  */
public void
layout()
{
  Component[] list = getComponents ();
  if ((list != null) && (list.length > 0))
    {
      Dimension dim = list[0].getPreferredSize ();
      Dimension vp = getViewportSize ();

      if (dim.width < vp.width)
	dim.width = vp.width;

      if (dim.height < vp.height)
	dim.height = vp.height;

      ScrollPanePeer peer = (ScrollPanePeer) getPeer ();
      if (peer != null)
	peer.childResized (dim.width, dim.height);

      list[0].setSize (dim);

      Point p = getScrollPosition ();
      if (p.x > dim.width)
        p.x = dim.width;
      if (p.y > dim.height)
        p.y = dim.height;

      setScrollPosition (p);
    }
}

/*************************************************************************/

/**
  * This method overrides its superclass method to ensure no layout
  * manager is set for this container.  <code>ScrollPane</code>'s do
  * not have layout managers.
  *
  * @param layoutManager Ignored
  */
public final void
setLayout(LayoutManager layoutManager)
{
  return;
}

/*************************************************************************/

/**
  * Prints all of the components in this container.
  *
  * @param graphics The desired graphics context for printing.
  */
public void
printComponents(Graphics graphics)
{
  super.printComponents(graphics);
}

/*************************************************************************/

/**
  * Returns a debug string for this object.
  *
  * @return A debug string for this object.
  */
public String
paramString()
{
  Insets insets = getInsets();
  return getName() + ","
         + getX() + ","
         + getY() + ","
         + getWidth() + "x" + getHeight() + ","
         + "ScrollPosition=(" + scrollPosition.getX() + "," 
                              + scrollPosition.getY() + "),"
         + "Insets=(" + insets.top + ","
                      + insets.left + ","
                      + insets.bottom + ","
                      + insets.right + "),"
         + "ScrollbarDisplayPolicy=" + getScrollbarDisplayPolicy() + ","
         + "wheelScrollingEnabled=" + isWheelScrollingEnabled();
}

  /**
   * Tells whether or not an event is enabled.
   *
   * @since 1.4
   */
  protected boolean eventTypeEnabled (int type)
  {
    if (type == MouseEvent.MOUSE_WHEEL)
      return wheelScrollingEnabled;

    return super.eventTypeEnabled (type);
  }

  /**
   * Tells whether or not wheel scrolling is enabled.
   *
   * @since 1.4
   */
  public boolean isWheelScrollingEnabled ()
  {
    return wheelScrollingEnabled;
  }

  /**
   * Enables/disables wheel scrolling.
   *
   * @since 1.4
   */
  public void setWheelScrollingEnabled (boolean enable)
  {
    wheelScrollingEnabled = enable;
  }
  
  protected class AccessibleAWTScrollPane extends AccessibleAWTContainer
  {
    private static final long serialVersionUID = 6100703663886637L;

    public AccessibleRole getAccessibleRole()
    {
      return AccessibleRole.SCROLL_PANE;
    }
  }

  /**
   * Gets the AccessibleContext associated with this <code>ScrollPane</code>.
   * The context is created, if necessary.
   *
   * @return the associated context
   */
  public AccessibleContext getAccessibleContext()
  {
    /* Create the context if this is the first request */
    if (accessibleContext == null)
      accessibleContext = new AccessibleAWTScrollPane();
    return accessibleContext;
  }
} // class ScrollPane