Java example source code file (ScreenMenu.java)

This example Java source code file (ScreenMenu.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

awt, cmenuitem, component, componentevent, event, gui, hashtable, icon, jmenuitem, jseparator, menucomponentpeer, mouseevent, override, rectangle, runnable, screenmenu, string, swing, util

The ScreenMenu.java Java example source code

/*
 * Copyright (c) 2011, 2013, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package com.apple.laf;

import java.awt.*;
import java.awt.event.*;
import java.awt.peer.MenuComponentPeer;
import java.util.Hashtable;

import javax.swing.*;

import sun.awt.SunToolkit;
import sun.lwawt.LWToolkit;
import sun.lwawt.macosx.*;

final class ScreenMenu extends Menu
        implements ContainerListener, ComponentListener,
                   ScreenMenuPropertyHandler {

    static {
        java.security.AccessController.doPrivileged(
            new java.security.PrivilegedAction<Void>() {
                public Void run() {
                    System.loadLibrary("awt");
                    return null;
                }
            });
    }

    // screen menu stuff
    private static native long addMenuListeners(ScreenMenu listener, long nativeMenu);
    private static native void removeMenuListeners(long modelPtr);

    private transient long fModelPtr;

    private final Hashtable<Component, MenuItem> fItems;
    private final JMenu fInvoker;

    private Component fLastMouseEventTarget;
    private Rectangle fLastTargetRect;
    private volatile Rectangle[] fItemBounds;

    private ScreenMenuPropertyListener fPropertyListener;

    // Array of child hashes used to see if we need to recreate the Menu.
    private int childHashArray[];

    ScreenMenu(final JMenu invoker) {
        super(invoker.getText());
        fInvoker = invoker;

        int count = fInvoker.getMenuComponentCount();
        if (count < 5) count = 5;
        fItems = new Hashtable<Component, MenuItem>(count);
        setEnabled(fInvoker.isEnabled());
        updateItems();
    }

    /**
     * Determine if we need to tear down the Menu and re-create it, since the contents may have changed in the Menu opened listener and
     * we do not get notified of it, because EDT is busy in our code. We only need to update if the menu contents have changed in some
     * way, such as the number of menu items, the text of the menuitems, icon, shortcut etc.
     */
    private static boolean needsUpdate(final Component items[], final int childHashArray[]) {
      if (items == null || childHashArray == null) {
        return true;
      }
      if (childHashArray.length != items.length) {
       return true;
      }
      for (int i = 0; i < items.length; i++) {
          final int hashCode = getHashCode(items[i]);
          if (hashCode != childHashArray[i]) {
            return true;
          }
      }
      return false;
    }

    /**
     * Used to recreate the AWT based Menu structure that implements the Screen Menu.
     * Also computes hashcode and stores them so that we can compare them later in needsUpdate.
     */
    private void updateItems() {
        final int count = fInvoker.getMenuComponentCount();
        final Component[] items = fInvoker.getMenuComponents();
        if (needsUpdate(items, childHashArray)) {
            removeAll();
            if (count <= 0) return;

            childHashArray = new int[count];
            for (int i = 0; i < count; i++) {
                addItem(items[i]);
                childHashArray[i] = getHashCode(items[i]);
            }
        }
    }

    /**
     * Callback from JavaMenuUpdater.m -- called when menu first opens
     */
    public void invokeOpenLater() {
        final JMenu invoker = fInvoker;
        if (invoker == null) {
            System.err.println("invoker is null!");
            return;
        }

        try {
            LWCToolkit.invokeAndWait(new Runnable() {
                public void run() {
                    invoker.setSelected(true);
                    invoker.validate();
                    updateItems();
                    fItemBounds = new Rectangle[invoker.getMenuComponentCount()];
                }
            }, invoker);
        } catch (final Exception e) {
            System.err.println(e);
            e.printStackTrace();
        }
    }

    /**
     * Callback from JavaMenuUpdater.m -- called when menu closes.
     */
    public void invokeMenuClosing() {
        final JMenu invoker = fInvoker;
        if (invoker == null) return;

        try {
            LWCToolkit.invokeAndWait(new Runnable() {
                public void run() {
                    invoker.setSelected(false);
                    // Null out the tracking rectangles and the array.
                    if (fItemBounds != null) {
                        for (int i = 0; i < fItemBounds.length; i++) {
                            fItemBounds[i] = null;
                        }
                    }
                    fItemBounds = null;
                }
            }, invoker);
        } catch (final Exception e) {
            e.printStackTrace();
        }
    }

    /**
     * Callback from JavaMenuUpdater.m -- called when menu item is hilighted.
     *
     * @param inWhichItem The menu item selected by the user. -1 if mouse moves off the menu.
     * @param itemRectTop
     * @param itemRectLeft
     * @param itemRectBottom
     * @param itemRectRight Tracking rectangle coordinates.
     */
    public void handleItemTargeted(final int inWhichItem, final int itemRectTop, final int itemRectLeft, final int itemRectBottom, final int itemRectRight) {
        if (fItemBounds == null || inWhichItem < 0 || inWhichItem > (fItemBounds.length - 1)) return;
        final Rectangle itemRect = new Rectangle(itemRectLeft, itemRectTop, itemRectRight - itemRectLeft, itemRectBottom - itemRectTop);
        fItemBounds[inWhichItem] = itemRect;
    }

    /**
     * Callback from JavaMenuUpdater.m -- called when mouse event happens on the menu.
     */
    public void handleMouseEvent(final int kind, final int x, final int y, final int modifiers, final long when) {
        if (kind == 0) return;
        if (fItemBounds == null) return;

        SunToolkit.executeOnEventHandlerThread(fInvoker, new Runnable() {
            @Override
            public void run() {
                Component target = null;
                Rectangle targetRect = null;
                for (int i = 0; i < fItemBounds.length; i++) {
                    final Rectangle testRect = fItemBounds[i];
                    if (testRect != null) {
                        if (testRect.contains(x, y)) {
                            target = fInvoker.getMenuComponent(i);
                            targetRect = testRect;
                            break;
                        }
                    }
                }
                if (target == null && fLastMouseEventTarget == null) return;

                // Send a mouseExited to the previously hilited item, if it wasn't 0.
                if (target != fLastMouseEventTarget) {
                    if (fLastMouseEventTarget != null) {
                        LWToolkit.postEvent(new MouseEvent(fLastMouseEventTarget, MouseEvent.MOUSE_EXITED, when, modifiers, x - fLastTargetRect.x, y - fLastTargetRect.y, 0, false));
                    }
                    // Send a mouseEntered to the current hilited item, if it wasn't 0.
                    if (target != null) {
                        LWToolkit.postEvent(new MouseEvent(target, MouseEvent.MOUSE_ENTERED, when, modifiers, x - targetRect.x, y - targetRect.y, 0, false));
                    }
                    fLastMouseEventTarget = target;
                    fLastTargetRect = targetRect;
                }
                // Post a mouse event to the current item.
                if (target == null) return;
                LWToolkit.postEvent(new MouseEvent(target, kind, when, modifiers, x - targetRect.x, y - targetRect.y, 0, false));
            }
        });
    }

    @Override
    public void addNotify() {
        synchronized (getTreeLock()) {
            super.addNotify();
            if (fModelPtr == 0) {
                fInvoker.addContainerListener(this);
                fInvoker.addComponentListener(this);
                fPropertyListener = new ScreenMenuPropertyListener(this);
                fInvoker.addPropertyChangeListener(fPropertyListener);

                final Icon icon = fInvoker.getIcon();
                if (icon != null) {
                    setIcon(icon);
                }

                final String tooltipText = fInvoker.getToolTipText();
                if (tooltipText != null) {
                    setToolTipText(tooltipText);
                }
                final MenuComponentPeer peer = getPeer();
                if (peer instanceof CMenu) {
                    final CMenu menu = (CMenu) peer;
                    final long nativeMenu = menu.getNativeMenu();
                    fModelPtr = addMenuListeners(this, nativeMenu);
                }
            }
        }
    }

    @Override
    public void removeNotify() {
        synchronized (getTreeLock()) {
            // Call super so that the NSMenu has been removed, before we release
            // the delegate in removeMenuListeners
            super.removeNotify();
            fItems.clear();
            if (fModelPtr != 0) {
                removeMenuListeners(fModelPtr);
                fModelPtr = 0;
                fInvoker.removeContainerListener(this);
                fInvoker.removeComponentListener(this);
                fInvoker.removePropertyChangeListener(fPropertyListener);
            }
        }
    }

    /**
     * Invoked when a component has been added to the container.
     */
    @Override
    public void componentAdded(final ContainerEvent e) {
        addItem(e.getChild());
    }

    /**
     * Invoked when a component has been removed from the container.
     */
    @Override
    public void componentRemoved(final ContainerEvent e) {
        final Component child = e.getChild();
        final MenuItem sm = fItems.get(child);
        if (sm == null) return;

        remove(sm);
        fItems.remove(sm);
    }

    /**
     * Invoked when the component's size changes.
     */
    @Override
    public void componentResized(final ComponentEvent e) {}

    /**
     * Invoked when the component's position changes.
     */
    @Override
    public void componentMoved(final ComponentEvent e) {}

    /**
     * Invoked when the component has been made visible.
     * See componentHidden - we should still have a MenuItem
     * it just isn't inserted
     */
    @Override
    public void componentShown(final ComponentEvent e) {
        setVisible(true);
    }

    /**
     * Invoked when the component has been made invisible.
     * MenuComponent.setVisible does nothing,
     * so we remove the ScreenMenuItem from the ScreenMenu
     * but leave it in fItems
     */
    @Override
    public void componentHidden(final ComponentEvent e) {
        setVisible(false);
    }

    private void setVisible(final boolean b) {
        // Tell our parent to add/remove us
        final MenuContainer parent = getParent();

        if (parent != null) {
            if (parent instanceof ScreenMenu) {
                final ScreenMenu sm = (ScreenMenu)parent;
                sm.setChildVisible(fInvoker, b);
            }
        }
    }

    @Override
    public void setChildVisible(final JMenuItem child, final boolean b) {
        fItems.remove(child);
        updateItems();
    }

    @Override
    public void setAccelerator(final KeyStroke ks) {}

    // only check and radio items can be indeterminate
    @Override
    public void setIndeterminate(boolean indeterminate) { }

    @Override
    public void setToolTipText(final String text) {
        final MenuComponentPeer peer = getPeer();
        if (!(peer instanceof CMenuItem)) return;

        final CMenuItem cmi = (CMenuItem)peer;
        cmi.setToolTipText(text);
    }

    @Override
    public void setIcon(final Icon i) {
        final MenuComponentPeer peer = getPeer();
        if (!(peer instanceof CMenuItem)) return;

        final CMenuItem cmi = (CMenuItem)peer;
        Image img = null;

        if (i != null) {
            if (i.getIconWidth() > 0 && i.getIconHeight() > 0) {
                img = AquaIcon.getImageForIcon(i);
            }
        }
        cmi.setImage(img);
    }


    /**
     * Gets a hashCode for a JMenu or JMenuItem or subclass so that we can compare for
     * changes in the Menu.
     */
    private static int getHashCode(final Component m) {
        int hashCode = m.hashCode();

        if (m instanceof JMenuItem) {
            final JMenuItem mi = (JMenuItem) m;

            final String text = mi.getText();
            if (text != null) hashCode ^= text.hashCode();

            final Icon icon = mi.getIcon();
            if (icon != null) hashCode ^= icon.hashCode();

            final Icon disabledIcon = mi.getDisabledIcon();
            if (disabledIcon != null) hashCode ^= disabledIcon.hashCode();

            final Action action = mi.getAction();
            if (action != null) hashCode ^= action.hashCode();

            final KeyStroke ks = mi.getAccelerator();
            if (ks != null) hashCode ^= ks.hashCode();

            hashCode ^= Boolean.valueOf(mi.isVisible()).hashCode();
            hashCode ^= Boolean.valueOf(mi.isEnabled()).hashCode();
            hashCode ^= Boolean.valueOf(mi.isSelected()).hashCode();

        } else if (m instanceof JSeparator) {
            hashCode ^= "-".hashCode();
        }

        return hashCode;
    }

    private void addItem(final Component m) {
        if (!m.isVisible()) return;
        MenuItem sm = fItems.get(m);

        if (sm == null) {
            if (m instanceof JMenu) {
                sm = new ScreenMenu((JMenu)m);
            } else if (m instanceof JCheckBoxMenuItem) {
                sm = new ScreenMenuItemCheckbox((JCheckBoxMenuItem)m);
            } else if (m instanceof JRadioButtonMenuItem) {
                sm = new ScreenMenuItemCheckbox((JRadioButtonMenuItem)m);
            } else if (m instanceof JMenuItem) {
                sm = new ScreenMenuItem((JMenuItem)m);
            } else if (m instanceof JPopupMenu.Separator || m instanceof JSeparator) {
                sm = new MenuItem("-"); // This is what java.awt.Menu.addSeparator does
            }

            // Only place the menu item in the hashtable if we just created it.
            if (sm != null) {
                fItems.put(m, sm);
            }
        }

        if (sm != null) {
            add(sm);
        }
    }
}