1 /*
   2  * Copyright (c) 1996, 2016, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package java.awt;
  27 
  28 import java.awt.peer.PopupMenuPeer;
  29 
  30 import javax.accessibility.AccessibleContext;
  31 import javax.accessibility.AccessibleRole;
  32 
  33 import sun.awt.AWTAccessor;
  34 
  35 /**
  36  * A class that implements a menu which can be dynamically popped up
  37  * at a specified position within a component.
  38  * <p>
  39  * As the inheritance hierarchy implies, a {@code PopupMenu}
  40  *  can be used anywhere a {@code Menu} can be used.
  41  * However, if you use a {@code PopupMenu} like a {@code Menu}
  42  * (e.g., you add it to a {@code MenuBar}), then you <b>cannot</b>
  43  * call {@code show} on that {@code PopupMenu}.
  44  *
  45  * @author      Amy Fowler
  46  */
  47 public class PopupMenu extends Menu {
  48 
  49     private static final String base = "popup";
  50     static int nameCounter = 0;
  51 
  52     transient volatile boolean isTrayIconPopup;
  53 
  54     static {
  55         AWTAccessor.setPopupMenuAccessor(
  56             new AWTAccessor.PopupMenuAccessor() {
  57                 public boolean isTrayIconPopup(PopupMenu popupMenu) {
  58                     return popupMenu.isTrayIconPopup;
  59                 }
  60             });
  61     }
  62 
  63     /*
  64      * JDK 1.1 serialVersionUID
  65      */
  66     private static final long serialVersionUID = -4620452533522760060L;
  67 
  68     /**
  69      * Creates a new popup menu with an empty name.
  70      * @exception HeadlessException if GraphicsEnvironment.isHeadless()
  71      * returns true.
  72      * @see java.awt.GraphicsEnvironment#isHeadless
  73      */
  74     public PopupMenu() throws HeadlessException {
  75         this("");
  76     }
  77 
  78     /**
  79      * Creates a new popup menu with the specified name.
  80      *
  81      * @param label a non-{@code null} string specifying
  82      *                the popup menu's label
  83      * @exception HeadlessException if GraphicsEnvironment.isHeadless()
  84      * returns true.
  85      * @see java.awt.GraphicsEnvironment#isHeadless
  86      */
  87     public PopupMenu(String label) throws HeadlessException {
  88         super(label);
  89     }
  90 
  91     /**
  92      * {@inheritDoc}
  93      */
  94     public MenuContainer getParent() {
  95         if (isTrayIconPopup) {
  96             return null;
  97         }
  98         return super.getParent();
  99     }
 100 
 101     /**
 102      * Constructs a name for this {@code MenuComponent}.
 103      * Called by {@code getName} when the name is {@code null}.
 104      */
 105     String constructComponentName() {
 106         synchronized (PopupMenu.class) {
 107             return base + nameCounter++;
 108         }
 109     }
 110 
 111     /**
 112      * Creates the popup menu's peer.
 113      * The peer allows us to change the appearance of the popup menu without
 114      * changing any of the popup menu's functionality.
 115      */
 116     public void addNotify() {
 117         synchronized (getTreeLock()) {
 118             // If our parent is not a Component, then this PopupMenu is
 119             // really just a plain, old Menu.
 120             if (parent != null && !(parent instanceof Component)) {
 121                 super.addNotify();
 122             }
 123             else {
 124                 if (peer == null)
 125                     peer = getComponentFactory().createPopupMenu(this);
 126                 int nitems = getItemCount();
 127                 for (int i = 0 ; i < nitems ; i++) {
 128                     MenuItem mi = getItem(i);
 129                     mi.parent = this;
 130                     mi.addNotify();
 131                 }
 132             }
 133         }
 134     }
 135 
 136    /**
 137      * Shows the popup menu at the x, y position relative to an origin
 138      * component.
 139      * The origin component must be contained within the component
 140      * hierarchy of the popup menu's parent.  Both the origin and the parent
 141      * must be showing on the screen for this method to be valid.
 142      * <p>
 143      * If this {@code PopupMenu} is being used as a {@code Menu}
 144      * (i.e., it has a non-{@code Component} parent),
 145      * then you cannot call this method on the {@code PopupMenu}.
 146      *
 147      * @param origin the component which defines the coordinate space
 148      * @param x the x coordinate position to popup the menu
 149      * @param y the y coordinate position to popup the menu
 150      * @exception NullPointerException  if the parent is {@code null}
 151      * @exception IllegalArgumentException  if this {@code PopupMenu}
 152      *                has a non-{@code Component} parent
 153      * @exception IllegalArgumentException if the origin is not in the
 154      *                parent's hierarchy
 155      * @exception RuntimeException if the parent is not showing on screen
 156      */
 157     public void show(Component origin, int x, int y) {
 158         // Use localParent for thread safety.
 159         MenuContainer localParent = parent;
 160         if (localParent == null) {
 161             throw new NullPointerException("parent is null");
 162         }
 163         if (!(localParent instanceof Component)) {
 164             throw new IllegalArgumentException(
 165                 "PopupMenus with non-Component parents cannot be shown");
 166         }
 167         Component compParent = (Component)localParent;
 168         //Fixed 6278745: Incorrect exception throwing in PopupMenu.show() method
 169         //Exception was not thrown if compParent was not equal to origin and
 170         //was not Container
 171         if (compParent != origin) {
 172             if (compParent instanceof Container) {
 173                 if (!((Container)compParent).isAncestorOf(origin)) {
 174                     throw new IllegalArgumentException("origin not in parent's hierarchy");
 175                 }
 176             } else {
 177                 throw new IllegalArgumentException("origin not in parent's hierarchy");
 178             }
 179         }
 180         if (compParent.peer == null || !compParent.isShowing()) {
 181             throw new RuntimeException("parent not showing on screen");
 182         }
 183         if (peer == null) {
 184             addNotify();
 185         }
 186         synchronized (getTreeLock()) {
 187             if (peer != null) {
 188                 ((PopupMenuPeer)peer).show(
 189                     new Event(origin, 0, Event.MOUSE_DOWN, x, y, 0, 0));
 190             }
 191         }
 192     }
 193 
 194 
 195 /////////////////
 196 // Accessibility support
 197 ////////////////
 198 
 199     /**
 200      * Gets the {@code AccessibleContext} associated with this
 201      * {@code PopupMenu}.
 202      *
 203      * @return the {@code AccessibleContext} of this
 204      *                {@code PopupMenu}
 205      * @since 1.3
 206      */
 207     public AccessibleContext getAccessibleContext() {
 208         if (accessibleContext == null) {
 209             accessibleContext = new AccessibleAWTPopupMenu();
 210         }
 211         return accessibleContext;
 212     }
 213 
 214     /**
 215      * Inner class of PopupMenu used to provide default support for
 216      * accessibility.  This class is not meant to be used directly by
 217      * application developers, but is instead meant only to be
 218      * subclassed by menu component developers.
 219      * <p>
 220      * The class used to obtain the accessible role for this object.
 221      * @since 1.3
 222      */
 223     protected class AccessibleAWTPopupMenu extends AccessibleAWTMenu
 224     {
 225         /*
 226          * JDK 1.3 serialVersionUID
 227          */
 228         private static final long serialVersionUID = -4282044795947239955L;
 229 
 230         /**
 231          * Get the role of this object.
 232          *
 233          * @return an instance of AccessibleRole describing the role of the
 234          * object
 235          */
 236         public AccessibleRole getAccessibleRole() {
 237             return AccessibleRole.POPUP_MENU;
 238         }
 239 
 240     } // class AccessibleAWTPopupMenu
 241 
 242 }