Home » openjdk-7 » java » awt » [javadoc | source]

    1   /*
    2    * Copyright (c) 2003, 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 sun.security.util.SecurityConstants;
   29   /**
   30    * <code>MouseInfo</code>  provides methods for getting information about the mouse,
   31    * such as mouse pointer location and the number of mouse buttons.
   32    *
   33    * @author     Roman Poborchiy
   34    * @since 1.5
   35    */
   36   
   37   public class MouseInfo {
   38   
   39       /**
   40        * Private constructor to prevent instantiation.
   41        */
   42       private MouseInfo() {
   43       }
   44   
   45       /**
   46        * Returns a <code>PointerInfo</code> instance that represents the current
   47        * location of the mouse pointer.
   48        * The <code>GraphicsDevice</code> stored in this <code>PointerInfo</code>
   49        * contains the mouse pointer. The coordinate system used for the mouse position
   50        * depends on whether or not the <code>GraphicsDevice</code> is part of a virtual
   51        * screen device.
   52        * For virtual screen devices, the coordinates are given in the virtual
   53        * coordinate system, otherwise they are returned in the coordinate system
   54        * of the <code>GraphicsDevice</code>. See {@link GraphicsConfiguration}
   55        * for more information about the virtual screen devices.
   56        * On systems without a mouse, returns <code>null</code>.
   57        * <p>
   58        * If there is a security manager, its <code>checkPermission</code> method
   59        * is called with an <code>AWTPermission("watchMousePointer")</code>
   60        * permission before creating and returning a <code>PointerInfo</code>
   61        * object. This may result in a <code>SecurityException</code>.
   62        *
   63        * @exception HeadlessException if GraphicsEnvironment.isHeadless() returns true
   64        * @exception SecurityException if a security manager exists and its
   65        *            <code>checkPermission</code> method doesn't allow the operation
   66        * @see       GraphicsConfiguration
   67        * @see       SecurityManager#checkPermission
   68        * @see       java.awt.AWTPermission
   69        * @return    location of the mouse pointer
   70        * @since     1.5
   71        */
   72       public static PointerInfo getPointerInfo() throws HeadlessException {
   73           if (GraphicsEnvironment.isHeadless()) {
   74               throw new HeadlessException();
   75           }
   76   
   77           SecurityManager security = System.getSecurityManager();
   78           if (security != null) {
   79               security.checkPermission(SecurityConstants.AWT.WATCH_MOUSE_PERMISSION);
   80           }
   81   
   82           Point point = new Point(0, 0);
   83           int deviceNum = Toolkit.getDefaultToolkit().getMouseInfoPeer().fillPointWithCoords(point);
   84           GraphicsDevice[] gds = GraphicsEnvironment.getLocalGraphicsEnvironment().
   85                                      getScreenDevices();
   86           PointerInfo retval = null;
   87           if (areScreenDevicesIndependent(gds)) {
   88               retval = new PointerInfo(gds[deviceNum], point);
   89           } else {
   90               for (int i = 0; i < gds.length; i++) {
   91                   GraphicsConfiguration gc = gds[i].getDefaultConfiguration();
   92                   Rectangle bounds = gc.getBounds();
   93                   if (bounds.contains(point)) {
   94                       retval = new PointerInfo(gds[i], point);
   95                   }
   96               }
   97           }
   98   
   99           return retval;
  100       }
  101   
  102       private static boolean areScreenDevicesIndependent(GraphicsDevice[] gds) {
  103           for (int i = 0; i < gds.length; i++) {
  104               Rectangle bounds = gds[i].getDefaultConfiguration().getBounds();
  105               if (bounds.x != 0 || bounds.y != 0) {
  106                   return false;
  107               }
  108           }
  109           return true;
  110       }
  111   
  112       /**
  113        * Returns the number of buttons on the mouse.
  114        * On systems without a mouse, returns <code>-1</code>.
  115        *
  116        * @exception HeadlessException if GraphicsEnvironment.isHeadless() returns true
  117        * @return number of buttons on the mouse
  118        * @since 1.5
  119        */
  120       public static int getNumberOfButtons() throws HeadlessException {
  121           if (GraphicsEnvironment.isHeadless()) {
  122               throw new HeadlessException();
  123           }
  124           Object prop = Toolkit.getDefaultToolkit().
  125                                 getDesktopProperty("awt.mouse.numButtons");
  126           if (prop instanceof Integer) {
  127               return ((Integer)prop).intValue();
  128           }
  129   
  130           // This should never happen.
  131           assert false : "awt.mouse.numButtons is not an integer property";
  132           return 0;
  133       }
  134   
  135   }

Home » openjdk-7 » java » awt » [javadoc | source]