gcc/libjava/classpath/javax/swing/plaf/basic/BasicMenuUI.java

/* BasicMenuUI.java
   Copyright (C) 2002, 2004, 2005  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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General Public License for more details.

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Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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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permission to link this library with independent modules to produce an
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package javax.swing.plaf.basic;

import java.awt.Dimension;
import java.awt.event.MouseEvent;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;

import javax.swing.JComponent;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JPopupMenu;
import javax.swing.MenuSelectionManager;
import javax.swing.UIDefaults;
import javax.swing.UIManager;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
import javax.swing.event.MenuDragMouseEvent;
import javax.swing.event.MenuDragMouseListener;
import javax.swing.event.MenuEvent;
import javax.swing.event.MenuKeyEvent;
import javax.swing.event.MenuKeyListener;
import javax.swing.event.MenuListener;
import javax.swing.event.MouseInputListener;
import javax.swing.plaf.ComponentUI;

/**
 * UI Delegate for JMenu
 */
public class BasicMenuUI extends BasicMenuItemUI
{
  protected ChangeListener changeListener;

  /* MenuListener listens to MenuEvents fired by JMenu */
  protected MenuListener menuListener;

  /* PropertyChangeListner that listens to propertyChangeEvents occuring in JMenu*/
  protected PropertyChangeListener propertyChangeListener;

  /**
   * Creates a new BasicMenuUI object.
   */
  public BasicMenuUI()
  {
    mouseInputListener = createMouseInputListener((JMenu) menuItem);
    menuListener = createMenuListener((JMenu) menuItem);
    propertyChangeListener = createPropertyChangeListener((JMenu) menuItem);
  }

  /**
   * This method creates a new ChangeListener.
   *
   * @return A new ChangeListener.
   */
  protected ChangeListener createChangeListener(JComponent c)
  {
    return new ChangeHandler();
  }

  /**
   * This method creates new MenuDragMouseListener to listen to mouse dragged events
   * occuring in the Menu
   *
   * @param c the menu to listen to
   *
   * @return The MenuDrageMouseListener
   */
  protected MenuDragMouseListener createMenuDragMouseListener(JComponent c)
  {
    return new MenuDragMouseHandler();
  }

  /**
   * This method creates new MenuDragKeyListener to listen to key events
   *
   * @param c the menu to listen to
   *
   * @return The MenuKeyListener
   */
  protected MenuKeyListener createMenuKeyListener(JComponent c)
  {
    return new MenuKeyHandler();
  }

  /**
   * This method creates new MenuListener to listen to menu events
   * occuring in the Menu
   *
   * @param c the menu to listen to
   *
   * @return The MenuListener
   */
  protected MenuListener createMenuListener(JComponent c)
  {
    return new MenuHandler();
  }

  /**
   * This method creates new MouseInputListener to listen to mouse input events
   * occuring in the Menu
   *
   * @param c the menu to listen to
   *
   * @return The MouseInputListener
   */
  protected MouseInputListener createMouseInputListener(JComponent c)
  {
    return new MouseInputHandler();
  }

  /**
   * This method creates newPropertyChangeListener to listen to property changes
   * occuring in the Menu
   *
   * @param c the menu to listen to
   *
   * @return The PropertyChangeListener
   */
  protected PropertyChangeListener createPropertyChangeListener(JComponent c)
  {
    return new PropertyChangeHandler();
  }

  /**
   * This method creates a new BasicMenuUI.
   *
   * @param c The JComponent to create a UI for.
   *
   * @return A new BasicMenuUI.
   */
  public static ComponentUI createUI(JComponent c)
  {
    return new BasicMenuUI();
  }

  /**
   * Get the component's maximum size.
   *
   * @param c The JComponent for which to get maximum size
   *
   * @return The maximum size of the component
   */
  public Dimension getMaximumSize(JComponent c)
  {
    // If this menu is in a popup menu, treat it like a regular JMenuItem
    if (!((JMenu)c).isTopLevelMenu())
      {
        JMenuItem menuItem = new JMenuItem(((JMenu)c).getText(), ((JMenu)c).getIcon());
        return menuItem.getMaximumSize();
      }
    return c.getPreferredSize();
  }

  /**
   * Returns the prefix for entries in the {@link UIDefaults} table.
   *
   * @return "Menu"
   */
  protected String getPropertyPrefix()
  {
    return "Menu";
  }

  /**
   * Initializes any default properties that this UI has from the defaults for
   * the Basic look and feel.
   */
  protected void installDefaults()
  {
    UIDefaults defaults = UIManager.getLookAndFeelDefaults();

    menuItem.setBackground(defaults.getColor("Menu.background"));
    menuItem.setBorder(defaults.getBorder("Menu.border"));
    menuItem.setFont(defaults.getFont("Menu.font"));
    menuItem.setForeground(defaults.getColor("Menu.foreground"));
    menuItem.setMargin(defaults.getInsets("Menu.margin"));
    acceleratorFont = defaults.getFont("Menu.acceleratorFont");
    acceleratorForeground = defaults.getColor("Menu.acceleratorForeground");
    acceleratorSelectionForeground = defaults.getColor("Menu.acceleratorSelectionForeground");
    selectionBackground = defaults.getColor("Menu.selectionBackground");
    selectionForeground = defaults.getColor("Menu.selectionForeground");
    arrowIcon = defaults.getIcon("Menu.arrowIcon");
    oldBorderPainted = defaults.getBoolean("Menu.borderPainted");
    menuItem.setOpaque(true);
  }

  /**
   * Installs any keyboard actions. The list of keys that need to be bound are
   * listed in Basic look and feel's defaults.
   *
   */
  protected void installKeyboardActions()
  {
    // FIXME: Need to implement
  }

  /**
   * Creates and registers all the listeners for this UI delegate.
   */
  protected void installListeners()
  {
    ((JMenu) menuItem).addMouseListener(mouseInputListener);
    ((JMenu) menuItem).addMouseMotionListener(mouseInputListener);
    ((JMenu) menuItem).addMenuListener(menuListener);
    ((JMenu) menuItem).addMenuDragMouseListener(menuDragMouseListener);
  }

  protected void setupPostTimer(JMenu menu)
  {
  }

  /**
   * This method uninstalls the defaults and sets any objects created during
   * install to null
   */
  protected void uninstallDefaults()
  {
    menuItem.setBackground(null);
    menuItem.setBorder(null);
    menuItem.setFont(null);
    menuItem.setForeground(null);
    menuItem.setMargin(null);
    acceleratorFont = null;
    acceleratorForeground = null;
    acceleratorSelectionForeground = null;
    selectionBackground = null;
    selectionForeground = null;
    arrowIcon = null;
  }

  /**
   * Uninstalls any keyboard actions. The list of keys used  are listed in
   * Basic look and feel's defaults.
   */
  protected void uninstallKeyboardActions()
  {
    // FIXME: Need to implement
  }

  /**
   * Unregisters all the listeners that this UI delegate was using. In
   * addition, it will also null any listeners that it was using.
   */
  protected void uninstallListeners()
  {
    ((JMenu) menuItem).removeMouseListener(mouseInputListener);
    ((JMenu) menuItem).removeMenuListener(menuListener);
    ((JMenu) menuItem).removePropertyChangeListener(propertyChangeListener);
  }

  /**
   * This class is used by menus to handle mouse events occuring in the
   * menu.
   */
  protected class MouseInputHandler implements MouseInputListener
  {
    public void mouseClicked(MouseEvent e)
    {
      MenuSelectionManager manager = MenuSelectionManager.defaultManager();
      manager.processMouseEvent(e);
    }

    public void mouseDragged(MouseEvent e)
    {
      MenuSelectionManager manager = MenuSelectionManager.defaultManager();
      manager.processMouseEvent(e);
    }

    private boolean popupVisible()
    {
      JMenuBar mb = (JMenuBar) ((JMenu) menuItem).getParent();
      // check if mb.isSelected because if no menus are selected
      // we don't have to look through the list for popup menus
      if (!mb.isSelected())
        return false;
      for (int i = 0; i < mb.getMenuCount(); i++)
      {
         JMenu m = mb.getMenu(i);
        if (m != null && m.isPopupMenuVisible())
          return true;
      }
      return false;
    }

    public void mouseEntered(MouseEvent e)
    {
      /* When mouse enters menu item, it should be considered selected

       if (i) if this menu is a submenu in some other menu
          (ii) or if this menu is in a menu bar and some other menu in a 
          menu bar was just selected and has its popup menu visible. 
               (If nothing was selected, menu should be pressed before
               it will be selected)
      */
      JMenu menu = (JMenu) menuItem;

      // NOTE: the following if used to require !menu.isArmed but I could find
      // no reason for this and it was preventing some JDK-compatible behaviour.
      // Specifically, if a menu is selected but its popup menu not visible,
      // and then another menu is selected whose popup menu IS visible, when
      // the mouse is moved over the first menu, its popup menu should become
      // visible.

      if (! menu.isTopLevelMenu() || popupVisible())
        {
	  // set new selection and forward this event to MenuSelectionManager
	  MenuSelectionManager manager = MenuSelectionManager.defaultManager();
	  manager.setSelectedPath(getPath());
	  manager.processMouseEvent(e);
        }
    }

    public void mouseExited(MouseEvent e)
    {
      MenuSelectionManager manager = MenuSelectionManager.defaultManager();
      manager.processMouseEvent(e);
    }

    public void mouseMoved(MouseEvent e)
    {
    }

    public void mousePressed(MouseEvent e)
    {
      MenuSelectionManager manager = MenuSelectionManager.defaultManager();
      JMenu menu = (JMenu) menuItem;
      manager.processMouseEvent(e);

      // Menu should be displayed when the menu is pressed only if 
      // it is top-level menu
      if (menu.isTopLevelMenu())
        {
	  if (menu.getPopupMenu().isVisible())
	    // If menu is visible and menu button was pressed.. 
	    // then need to cancel the menu
	    manager.clearSelectedPath();
	  else
	    {
	      // Display the menu
	      int x = 0;
	      int y = menu.getHeight();

	      manager.setSelectedPath(getPath());

	      JMenuBar mb = (JMenuBar) menu.getParent();

	      // set selectedIndex of the selectionModel of a menuBar
	      mb.getSelectionModel().setSelectedIndex(mb.getComponentIndex(menu));
	    }
        }
    }

    public void mouseReleased(MouseEvent e)
    {
      MenuSelectionManager manager = MenuSelectionManager.defaultManager();
      manager.processMouseEvent(e);
    }
  }

  /**
   * This class handles MenuEvents fired by the JMenu
   */
  protected class MenuHandler implements MenuListener
  {
    /**
     * This method is called when menu is cancelled. The menu is cancelled
     * when its popup menu is closed without selection. It clears selected index
     * in the selectionModel of the menu parent.
     *
     * @param e The MenuEvent.
     */
    public void menuCanceled(MenuEvent e)
    {
      menuDeselected(e);
    }

    /**
     * This method is called when menu is deselected. It clears selected index
     * in the selectionModel of the menu parent.
     *
     * @param e The MenuEvent.
     */
    public void menuDeselected(MenuEvent e)
    {
      JMenu menu = (JMenu) menuItem;
      if (menu.isTopLevelMenu())
	((JMenuBar) menu.getParent()).getSelectionModel().clearSelection();
      else
	((JPopupMenu) menu.getParent()).getSelectionModel().clearSelection();
    }

    /**
     * This method is called when menu is selected.  It sets selected index
     * in the selectionModel of the menu parent.
     *
     * @param e The MenuEvent.
     */
    public void menuSelected(MenuEvent e)
    {
      JMenu menu = (JMenu) menuItem;
      if (menu.isTopLevelMenu())
	((JMenuBar) menu.getParent()).setSelected(menu);
      else
	((JPopupMenu) menu.getParent()).setSelected(menu);
    }
  }

  /**
   * This class handles PropertyChangeEvents fired from the JMenu
   */
  protected class PropertyChangeHandler implements PropertyChangeListener
  {
    /**
      * This method is called whenever one of the properties of the menu item
      * changes.
      *
      * @param e The PropertyChangeEvent.
      */
    public void propertyChange(PropertyChangeEvent e)
    {
    }
  }

  /**
   * @deprecated
   */
  public class ChangeHandler implements ChangeListener
  {
    public void stateChanged(ChangeEvent e)
    {
      // FIXME: It seems that this class is not used anywhere
    }
  }

  /**
   * This class handles mouse dragged events occuring in the menu.
   */
  protected class MenuDragMouseHandler implements MenuDragMouseListener
  {
    /**
     * This method is invoked when mouse is dragged over the menu item.
     *
     * @param e The MenuDragMouseEvent
     */
    public void menuDragMouseDragged(MenuDragMouseEvent e)
    {
      MenuSelectionManager manager = MenuSelectionManager.defaultManager();
      manager.setSelectedPath(e.getPath());
    }

    /**
     * This method is invoked when mouse enters the menu item while it is
     * being dragged.
     *
     * @param e The MenuDragMouseEvent
     */
    public void menuDragMouseEntered(MenuDragMouseEvent e)
    {
      MenuSelectionManager manager = MenuSelectionManager.defaultManager();
      manager.setSelectedPath(e.getPath());
    }

    /**
     * This method is invoked when mouse exits the menu item while
     * it is being dragged
     *
     * @param e The MenuDragMouseEvent
     */
    public void menuDragMouseExited(MenuDragMouseEvent e)
    {
    }

    /**
     * This method is invoked when mouse was dragged and released
     * inside the menu item.
     *
     * @param e The MenuDragMouseEvent
     */
    public void menuDragMouseReleased(MenuDragMouseEvent e)
    {
    }
  }

  /**
   * This class handles key events occuring when menu item is visible on the
   * screen.
   */
  protected class MenuKeyHandler implements MenuKeyListener
  {
    /**
     * This method is invoked when key has been pressed
     *
     * @param e A {@link MenuKeyEvent}.
     */
    public void menuKeyPressed(MenuKeyEvent e)
    {
    }

    /**
     * This method is invoked when key has been pressed
     *
     * @param e A {@link MenuKeyEvent}.
     */
    public void menuKeyReleased(MenuKeyEvent e)
    {
    }

    /**
     * This method is invoked when key has been typed
     * It handles the mnemonic key for the menu item.
     *
     * @param e A {@link MenuKeyEvent}.
     */
    public void menuKeyTyped(MenuKeyEvent e)
    {
    }
  }
}