jpopupmenu.java

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  public boolean isVisible()
  {
    return visible;
  }

  /**
   * Sets visibility property of this popup menu. If the property is
   * set to true then popup menu will be dispayed and popup menu will
   * hide itself if visible property is set to false.
   *
   * @param visible true if popup menu will become visible and false otherwise.
   */
  public void setVisible(boolean visible)
  {
    if (visible == isVisible())
      return;

    boolean old = isVisible();
    this.visible = visible;
    if (old != isVisible())
      {
	firePropertyChange("visible", old, isVisible());
	if (visible)
	  {
	    firePopupMenuWillBecomeVisible();
	    Container rootContainer = (Container) SwingUtilities.getRoot(invoker);

	    boolean fit = true;
	    Dimension size;

	    // Determine the size of the popup menu
	    if (this.getSize().width == 0 && this.getSize().width == 0)
	      size = this.getPreferredSize();
	    else
	      size = this.getSize();

	    if ((size.width > (rootContainer.getWidth() - popupLocation.x))
	        || (size.height > (rootContainer.getHeight() - popupLocation.y)))
	      fit = false;
	    if (lightWeightPopupEnabled && fit)
	      popup = new LightWeightPopup(this);
	    else
	      {
		if (fit)
		  popup = new MediumWeightPopup(this);
		else
		  popup = new HeavyWeightPopup(this);
	      }
	    if (popup instanceof LightWeightPopup
	        || popup instanceof MediumWeightPopup)
	      {
		JLayeredPane layeredPane;
		layeredPane = SwingUtilities.getRootPane(invoker)
		                            .getLayeredPane();
		Point p = new Point(popupLocation.x, popupLocation.y);
		SwingUtilities.convertPointFromScreen(p, layeredPane);
		popup.show(p.x, p.y, size.width, size.height);  
	      }
	    else
	      {
		// Subtract insets of the top-level container if popup menu's
		// top-left corner is inside it.
		Insets insets = rootContainer.getInsets();
		popup.show(popupLocation.x - insets.left,
		           popupLocation.y - insets.top, size.width,
		           size.height);
	      }
	  }
	else
	  {
	    firePopupMenuWillBecomeInvisible();
	    popup.hide();
	  }
      }
  }

  /**
   * Sets location of the popup menu.
   *
   * @param x X coordinate of the popup menu's location
   * @param y Y coordinate of the popup menu's location
   */
  public void setLocation(int x, int y)
  {
    if (popupLocation == null)
      popupLocation = new Point();

    popupLocation.x = x;
    popupLocation.y = y;
  }

  /**
   * Returns popup menu's invoker.
   *
   * @return popup menu's invoker
   */
  public Component getInvoker()
  {
    return invoker;
  }

  /**
   * Sets popup menu's invoker.
   *
   * @param component The new invoker of this popup menu
   */
  public void setInvoker(Component component)
  {
    invoker = component;
  }

  /**
   * This method displays JPopupMenu on the screen at the specified
   * location. Note that x and y coordinates given to this method
   * should be expressed in terms of the popup menus' invoker.
   *
   * @param component Invoker for this popup menu
   * @param x x-coordinate of the popup menu relative to the specified invoker
   * @param y y-coordiate of the popup menu relative to the specified invoker
   */
  public void show(Component component, int x, int y)
  {
    setInvoker(component);
    Point p = new Point(x, y);
    SwingUtilities.convertPointToScreen(p, component);
    setLocation(p.x, p.y);
    setVisible(true);
  }

  /**
   * Returns component located at the specified index in the popup menu
   *
   * @param index index of the component to return
   *
   * @return component located at the specified index in the popup menu
   *
   * @deprecated Replaced by getComponent(int)
   */
  public Component getComponentAtIndex(int index)
  {
    return getComponent(index);
  }

  /**
   * Returns index of the specified component in the popup menu
   *
   * @param component Component to look for
   *
   * @return index of the specified component in the popup menu
   */
  public int getComponentIndex(Component component)
  {
    Component[] items = getComponents();

    for (int i = 0; i < items.length; i++)
      {
	if (items[i].equals(component))
	  return i;
      }

    return -1;
  }

  /**
   * Sets size of the popup
   *
   * @param size Dimensions representing new size of the popup menu
   */
  public void setPopupSize(Dimension size)
  {
    super.setSize(size);
  }

  /**
   * Sets size of the popup menu
   *
   * @param width width for the new size
   * @param height height for the new size
   */
  public void setPopupSize(int width, int height)
  {
    super.setSize(width, height);
  }

  /**
   * Selects specified component in this popup menu.
   *
   * @param selected component to select
   */
  public void setSelected(Component selected)
  {
    int index = getComponentIndex(selected);
    selectionModel.setSelectedIndex(index);
  }

  /**
   * Checks if this popup menu paints its border.
   *
   * @return true if this popup menu paints its border and false otherwise.
   */
  public boolean isBorderPainted()
  {
    return borderPainted;
  }

  /**
   * Sets if the border of the popup menu should be
   * painter or not.
   *
   * @param painted true if the border should be painted and false otherwise
   */
  public void setBorderPainted(boolean painted)
  {
    borderPainted = painted;
  }

  /**
   * Returns margin for this popup menu.
   *
   * @return margin for this popup menu.
   */
  public Insets getMargin()
  {
    return margin;
  }

  /**
   * A string that describes this JPopupMenu. Normally only used
   * for debugging.
   *
   * @return A string describing this JMenuItem
   */
  protected String paramString()
  {
    StringBuffer sb = new StringBuffer();
    sb.append(super.paramString());
    sb.append(",label=");
    if (getLabel() != null)
      sb.append(getLabel());
    sb.append(",lightWeightPopupEnabled=").append(isLightWeightPopupEnabled());
    sb.append(",margin=");
    if (getMargin() != null)
      sb.append(margin);
    sb.append(",paintBorder=").append(isBorderPainted());
    return sb.toString();
  }

  /**
  * Process mouse events forwarded from MenuSelectionManager. This method 
  * doesn't do anything. It is here to conform to the MenuElement interface.
  *
  * @param event event forwarded from MenuSelectionManager
  * @param path path to the menu element from which event was generated
  * @param manager MenuSelectionManager for the current menu hierarchy
  */
  public void processMouseEvent(MouseEvent event, MenuElement[] path,
                                MenuSelectionManager manager)
  {
    // Empty Implementation. This method is needed for the implementation
    // of MenuElement interface
  }

  /**
   * Process key events forwarded from MenuSelectionManager. This method
   * doesn't do anything. It is here to conform to the MenuElement interface.
   *
   * @param event event forwarded from MenuSelectionManager
   * @param path path to the menu element from which event was generated
   * @param manager MenuSelectionManager for the current menu hierarchy
   *
   */
  public void processKeyEvent(KeyEvent event, MenuElement[] path,
                              MenuSelectionManager manager)
  {
    // Empty Implementation. This method is needed for the implementation
    // of MenuElement interface
  }

  /**
   * Method of MenuElement Interface. It is invoked when
   * popupMenu's selection has changed
   *
   * @param changed true if this popupMenu is part of current menu
   * hierarchy and false otherwise.
   */
  public void menuSelectionChanged(boolean changed)
  {
    if (! changed)
      setVisible(false);
  }

  /**
   * Return subcomonents of this popup menu. This method returns only
   * components that implement the <code>MenuElement</code> interface.
   *
   * @return array of menu items belonging to this popup menu
   */
  public MenuElement[] getSubElements()
  {
    Component[] items = getComponents();
    ArrayList subElements = new ArrayList();

    for (int i = 0; i < items.length; i++)
      if (items[i] instanceof MenuElement)
	subElements.add(items[i]);

    return (MenuElement[])
      subElements.toArray(new MenuElement[subElements.size()]);
  }

  /**
   * Method of the MenuElement interface. Returns reference to itself.
   *
   * @return Returns reference to itself
   */
  public Component getComponent()
  {
    return this;
  }

  /**
   * Checks if observing mouse event should trigger popup
   * menu to show on the screen.
   *
   * @param event MouseEvent to check
   *
   * @return true if the observing mouse event is popup trigger and false otherwise
   */
  public boolean isPopupTrigger(MouseEvent event)
  {
    return ((PopupMenuUI) getUI()).isPopupTrigger(event);
  }

  /**
   * DOCUMENT ME!
   *
   * @return DOCUMENT ME!
   */
  public AccessibleContext getAccessibleContext()
  {
    if (accessibleContext == null)
      accessibleContext = new AccessibleJPopupMenu();

    return accessibleContext;
  }

  /**
   * This interface is used to display menu items of the JPopupMenu
   */
  private interface Popup
  {
    /**
     * Displays container on the screen
     *
     * @param x x-coordinate of popup menu's location on the screen
     * @param y y-coordinate of popup menu's location on the screen
     * @param width width of the container that is used to display menu
     * item's for popup menu
     * @param height height of the container that is used to display menu
     * item's for popup menu
     */
    void show(int x, int y, int width, int height);

    /**
     * Hides container used to display popup menu item's from the screen
     */
    void hide();
  }

  /**
   * This class represents Popup menu that uses light weight container
   * to display its contents.
   */
  private class LightWeightPopup extends Container implements Popup
  {
    /**
     * Creates a new LightWeightPopup menu
     *
     * @param c Container containing menu items
     */
    private Component c;

    public LightWeightPopup(Container c)
    {
      this.c = c;
    }

    /**
     * Displayes lightweight container with menu items to the screen
     *
     * @param x x-coordinate of lightweight container on the screen
     * @param y y-coordinate of lightweight container on the screen
     * @param width width of the lightweight container
     * @param height height of the lightweight container
     */
    public void show(int x, int y, int width, int height)
    {
      JLayeredPane layeredPane;
      layeredPane = SwingUtilities.getRootPane(invoker).getLayeredPane();
      c.setBounds(x, y, width, height);
      layeredPane.add(c, JLayeredPane.POPUP_LAYER, 0);
    }

    /**
     * Hides lightweight container from the screen
     */
    public void hide()
    {
      // FIXME: Right now the lightweight container is removed from JLayered
      // pane. It is probably would be better in order to improve performance
      // to make the container invisible instead of removing it everytime.
      JLayeredPane layeredPane;
      layeredPane = SwingUtilities.getRootPane(invoker).getLayeredPane();
      int index = layeredPane.getIndexOf(c);
      layeredPane.remove(index);
    }
  }

  /**
   * MediumWeightPopup is an AWT Panel with JPopupMenu's menu items.
   * It is used to display JPopupMenu's menu items on the screen
   */
  private class MediumWeightPopup extends Panel implements Popup
  {
    /**
     * Creates a new MediumWeightPopup object.
     *
     * @param c Container with JPopupMenu's menu items
     */
    public MediumWeightPopup(Container c)
    {
      this.add(c);
    }

    /**
     * Displays AWT Panel with its components on the screen
     *
     * @param x x-coordinate of the upper-left corner of the panel's
     * @param y y-coordinate of the upper-left corner of the panel's
     * @param width width of the panel
     * @param height height of the panel
     */
    public void show(int x, int y, int width, int height)
    {
      JLayeredPane layeredPane;
      layeredPane = SwingUtilities.getRootPane(invoker).getLayeredPane();
      layeredPane.add(this, JLayeredPane.POPUP_LAYER, 0);
      this.setBounds(x, y, width, height);
    }

    /**
     * Hides This panel from the screen
     */
    public void hide()
    {
      // FIXME: Right now the lightweight container is removed from JLayered
      // pane. It is probably would be better in order to improve performance
      // to make the container invisible instead of removing it everytime.
      JLayeredPane layeredPane;
      layeredPane = SwingUtilities.getRootPane(invoker).getLayeredPane();
      int index = layeredPane.getIndexOf(this);
      layeredPane.remove(index);
    }
  }

  /**
   * HeavyWeightPopup is JWindow that is used to display JPopupMenu menu item's
   * on the screen
   */
  private class HeavyWeightPopup extends JWindow implements Popup
  {
    /**
     * Creates a new HeavyWeightPopup object.
     *
     * @param c Container containing menu items
     */
    public HeavyWeightPopup(Container c)
    {
      this.setContentPane(c);
    }

    /**
     * Displays JWindow container JPopupMenu's menu items to the screen
     *
     * @param x x-coordinate of JWindow containing menu items
     * @param y y-coordinate of JWindow containing menu items
     * @param width width of the JWindow
     * @param height height of the JWindow
     */
    public void show(int x, int y, int width, int height)
    {
      this.setBounds(x, y, width, height);
      this.show();
    }
  }

  /**
   * This is the separator that can be used in popup menu.
   */
  public static class Separator extends JSeparator
  {
    public Separator()
    {
    }

    public String getUIClassID()
    {
      return "PopupMenuSeparatorUI";
    }
  }

  protected class AccessibleJPopupMenu extends AccessibleJComponent
  {
    private static final long serialVersionUID = 7423261328879849768L;

    protected AccessibleJPopupMenu()
    {
    }

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

  /* This class resizes popup menu and repaints popup menu appropriately if one
   of item's action has changed */
  protected class ActionChangeListener implements PropertyChangeListener
  {
    public void propertyChange(PropertyChangeEvent evt)
    {
      JPopupMenu.this.revalidate();
      JPopupMenu.this.repaint();
    }
  }
}