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.awt.AWTPermissions;
29
30 /**
31 * <code>MouseInfo</code> provides methods for getting information about the mouse,
32 * such as mouse pointer location and the number of mouse buttons.
33 *
34 * @author Roman Poborchiy
35 * @since 1.5
36 */
37
38 public class MouseInfo {
39
40 /**
41 * Private constructor to prevent instantiation.
42 */
43 private MouseInfo() {
44 }
45
46 /**
47 * Returns a <code>PointerInfo</code> instance that represents the current
48 * location of the mouse pointer.
49 * The <code>GraphicsDevice</code> stored in this <code>PointerInfo</code>
50 * contains the mouse pointer. The coordinate system used for the mouse position
51 * depends on whether or not the <code>GraphicsDevice</code> is part of a virtual
52 * screen device.
53 * For virtual screen devices, the coordinates are given in the virtual
54 * coordinate system, otherwise they are returned in the coordinate system
55 * of the <code>GraphicsDevice</code>. See {@link GraphicsConfiguration}
56 * for more information about the virtual screen devices.
57 * On systems without a mouse, returns <code>null</code>.
58 * <p>
59 * If there is a security manager, its <code>checkPermission</code> method
60 * is called with an <code>AWTPermission("watchMousePointer")</code>
61 * permission before creating and returning a <code>PointerInfo</code>
62 * object. This may result in a <code>SecurityException</code>.
63 *
64 * @exception HeadlessException if GraphicsEnvironment.isHeadless() returns true
65 * @exception SecurityException if a security manager exists and its
66 * <code>checkPermission</code> method doesn't allow the operation
67 * @see GraphicsConfiguration
68 * @see SecurityManager#checkPermission
69 * @see java.awt.AWTPermission
70 * @return location of the mouse pointer
71 * @since 1.5
72 */
73 public static PointerInfo getPointerInfo() throws HeadlessException {
74 if (GraphicsEnvironment.isHeadless()) {
75 throw new HeadlessException();
76 }
77
78 SecurityManager security = System.getSecurityManager();
79 if (security != null) {
80 security.checkPermission(AWTPermissions.WATCH_MOUSE_PERMISSION);
81 }
82
83 Point point = new Point(0, 0);
84 int deviceNum = Toolkit.getDefaultToolkit().getMouseInfoPeer().fillPointWithCoords(point);
85 GraphicsDevice[] gds = GraphicsEnvironment.getLocalGraphicsEnvironment().
86 getScreenDevices();
87 PointerInfo retval = null;
88 if (areScreenDevicesIndependent(gds)) {
89 retval = new PointerInfo(gds[deviceNum], point);
90 } else {
91 for (int i = 0; i < gds.length; i++) {
92 GraphicsConfiguration gc = gds[i].getDefaultConfiguration();
93 Rectangle bounds = gc.getBounds();
94 if (bounds.contains(point)) {
95 retval = new PointerInfo(gds[i], point);
96 }
97 }
98 }
99
100 return retval;
101 }
102
103 private static boolean areScreenDevicesIndependent(GraphicsDevice[] gds) {
104 for (int i = 0; i < gds.length; i++) {
105 Rectangle bounds = gds[i].getDefaultConfiguration().getBounds();
106 if (bounds.x != 0 || bounds.y != 0) {
107 return false;
108 }
109 }
110 return true;
111 }
112
113 /**
114 * Returns the number of buttons on the mouse.
115 * On systems without a mouse, returns <code>-1</code>.
116 * The number of buttons is obtained from the AWT Toolkit
117 * by requesting the {@code "awt.mouse.numButtons"} desktop property
118 * which is set by the underlying native platform.
119 *
120 * @exception HeadlessException if GraphicsEnvironment.isHeadless() returns true
121 * @return number of buttons on the mouse
122 * @see Toolkit#getDesktopProperty
123 * @since 1.5
124 */
125 public static int getNumberOfButtons() throws HeadlessException {
126 if (GraphicsEnvironment.isHeadless()) {
127 throw new HeadlessException();
128 }
129 Object prop = Toolkit.getDefaultToolkit().
130 getDesktopProperty("awt.mouse.numButtons");
131 if (prop instanceof Integer) {
132 return ((Integer)prop).intValue();
133 }
134
135 // This should never happen.
136 assert false : "awt.mouse.numButtons is not an integer property";
137 return 0;
138 }
139
140 }