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| 1 | +/* | |
| 2 | + * Copyright (c) 1999, 2007, 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 sun.awt; | |
| 27 | + | |
| 28 | +import java.awt.*; | |
| 29 | +import java.awt.event.InputEvent; | |
| 30 | +import java.awt.event.InvocationEvent; | |
| 31 | + | |
| 32 | +/** | |
| 33 | + * A stateless class which responds to native mouse moves, Component resizes, | |
| 34 | + * Component moves, showing and hiding of Components, minimizing and | |
| 35 | + * maximizing of top level Windows, addition and removal of Components, | |
| 36 | + * and calls to setCursor(). | |
| 37 | + */ | |
| 38 | +public abstract class GlobalCursorManager { | |
| 39 | + | |
| 40 | + class NativeUpdater implements Runnable { | |
| 41 | + boolean pending = false; | |
| 42 | + | |
| 43 | + public void run() { | |
| 44 | + boolean shouldUpdate = false; | |
| 45 | + synchronized (this) { | |
| 46 | + if (pending) { | |
| 47 | + pending = false; | |
| 48 | + shouldUpdate = true; | |
| 49 | + } | |
| 50 | + } | |
| 51 | + if (shouldUpdate) { | |
| 52 | + _updateCursor(false); | |
| 53 | + } | |
| 54 | + } | |
| 55 | + | |
| 56 | + public void postIfNotPending(Component heavy, InvocationEvent in) { | |
| 57 | + boolean shouldPost = false; | |
| 58 | + synchronized (this) { | |
| 59 | + if (!pending) { | |
| 60 | + pending = shouldPost = true; | |
| 61 | + } | |
| 62 | + } | |
| 63 | + if (shouldPost) { | |
| 64 | + SunToolkit.postEvent(SunToolkit.targetToAppContext(heavy), in); | |
| 65 | + } | |
| 66 | + } | |
| 67 | + } | |
| 68 | + | |
| 69 | + /** | |
| 70 | + * Use a singleton NativeUpdater for better performance. We cannot use | |
| 71 | + * a singleton InvocationEvent because we want each event to have a fresh | |
| 72 | + * timestamp. | |
| 73 | + */ | |
| 74 | + private final NativeUpdater nativeUpdater = new NativeUpdater(); | |
| 75 | + | |
| 76 | + /** | |
| 77 | + * The last time the cursor was updated, in milliseconds. | |
| 78 | + */ | |
| 79 | + private long lastUpdateMillis; | |
| 80 | + | |
| 81 | + /** | |
| 82 | + * Locking object for synchronizing access to lastUpdateMillis. The VM | |
| 83 | + * does not guarantee atomicity of longs. | |
| 84 | + */ | |
| 85 | + private final Object lastUpdateLock = new Object(); | |
| 86 | + | |
| 87 | + /** | |
| 88 | + * Should be called for any activity at the Java level which may affect | |
| 89 | + * the global cursor, except for Java MOUSE_MOVED events. | |
| 90 | + */ | |
| 91 | + public void updateCursorImmediately() { | |
| 92 | + synchronized (nativeUpdater) { | |
| 93 | + nativeUpdater.pending = false; | |
| 94 | + } | |
| 95 | + _updateCursor(false); | |
| 96 | + } | |
| 97 | + | |
| 98 | + /** | |
| 99 | + * Should be called in response to Java MOUSE_MOVED events. The update | |
| 100 | + * will be discarded if the InputEvent is outdated. | |
| 101 | + * | |
| 102 | + * @param e the InputEvent which triggered the cursor update. | |
| 103 | + */ | |
| 104 | + public void updateCursorImmediately(InputEvent e) { | |
| 105 | + boolean shouldUpdate; | |
| 106 | + synchronized (lastUpdateLock) { | |
| 107 | + shouldUpdate = (e.getWhen() >= lastUpdateMillis); | |
| 108 | + } | |
| 109 | + if (shouldUpdate) { | |
| 110 | + _updateCursor(true); | |
| 111 | + } | |
| 112 | + } | |
| 113 | + | |
| 114 | + /** | |
| 115 | + * Should be called in response to a native mouse enter or native mouse | |
| 116 | + * button released message. Should not be called during a mouse drag. | |
| 117 | + */ | |
| 118 | + public void updateCursorLater(Component heavy) { | |
| 119 | + nativeUpdater.postIfNotPending(heavy, new InvocationEvent | |
| 120 | + (Toolkit.getDefaultToolkit(), nativeUpdater)); | |
| 121 | + } | |
| 122 | + | |
| 123 | + protected GlobalCursorManager() { } | |
| 124 | + | |
| 125 | + /** | |
| 126 | + * Set the global cursor to the specified cursor. The component over | |
| 127 | + * which the Cursor current resides is provided as a convenience. Not | |
| 128 | + * all platforms may require the Component. | |
| 129 | + */ | |
| 130 | + protected abstract void setCursor(Component comp, Cursor cursor, | |
| 131 | + boolean useCache); | |
| 132 | + /** | |
| 133 | + * Returns the global cursor position, in screen coordinates. | |
| 134 | + */ | |
| 135 | + protected abstract void getCursorPos(Point p); | |
| 136 | + | |
| 137 | + protected abstract Component findComponentAt(Container con, int x, int y); | |
| 138 | + protected abstract Point getLocationOnScreen(Component com); | |
| 139 | + | |
| 140 | + /** | |
| 141 | + * Returns the most specific, visible, heavyweight Component | |
| 142 | + * under the cursor. This method should return null iff the cursor is | |
| 143 | + * not over any Java Window. | |
| 144 | + * | |
| 145 | + * @param useCache If true, the implementation is free to use caching | |
| 146 | + * mechanisms because the Z-order, visibility, and enabled state of the | |
| 147 | + * Components has not changed. If false, the implementation should not | |
| 148 | + * make these assumptions. | |
| 149 | + */ | |
| 150 | + protected abstract Component findHeavyweightUnderCursor(boolean useCache); | |
| 151 | + | |
| 152 | + /** | |
| 153 | + * Updates the global cursor. We apply a three-step scheme to cursor | |
| 154 | + * updates:<p> | |
| 155 | + * | |
| 156 | + * (1) InputEvent updates which are outdated are discarded by | |
| 157 | + * <code>updateCursorImmediately(InputEvent)</code>.<p> | |
| 158 | + * | |
| 159 | + * (2) If 'useCache' is true, the native code is free to use a cached | |
| 160 | + * value to determine the most specific, visible, enabled heavyweight | |
| 161 | + * because this update is occuring in response to a mouse move. If | |
| 162 | + * 'useCache' is false, the native code must perform a new search given | |
| 163 | + * the current mouse coordinates. | |
| 164 | + * | |
| 165 | + * (3) Once we have determined the most specific, visible, enabled | |
| 166 | + * heavyweight, we use findComponentAt to find the most specific, visible, | |
| 167 | + * enabled Component. | |
| 168 | + */ | |
| 169 | + private void _updateCursor(boolean useCache) { | |
| 170 | + | |
| 171 | + synchronized (lastUpdateLock) { | |
| 172 | + lastUpdateMillis = System.currentTimeMillis(); | |
| 173 | + } | |
| 174 | + | |
| 175 | + Point queryPos = null, p = null; | |
| 176 | + Component comp; | |
| 177 | + | |
| 178 | + try { | |
| 179 | + comp = findHeavyweightUnderCursor(useCache); | |
| 180 | + if (comp == null) { | |
| 181 | + updateCursorOutOfJava(); | |
| 182 | + return; | |
| 183 | + } | |
| 184 | + | |
| 185 | + if (comp instanceof Window) { | |
| 186 | + p = AWTAccessor.getComponentAccessor().getLocation(comp); | |
| 187 | + } else if (comp instanceof Container) { | |
| 188 | + p = getLocationOnScreen(comp); | |
| 189 | + } | |
| 190 | + if (p != null) { | |
| 191 | + queryPos = new Point(); | |
| 192 | + getCursorPos(queryPos); | |
| 193 | + Component c = findComponentAt((Container)comp, | |
| 194 | + queryPos.x - p.x, | |
| 195 | + queryPos.y - p.y); | |
| 196 | + // If findComponentAt returns null, then something bad has | |
| 197 | + // happened. For example, the heavyweight Component may | |
| 198 | + // have been hidden or disabled by another thread. In that | |
| 199 | + // case, we'll just use the originial heavyweight. | |
| 200 | + if (c != null) { | |
| 201 | + comp = c; | |
| 202 | + } | |
| 203 | + } | |
| 204 | + | |
| 205 | + setCursor(comp, AWTAccessor.getComponentAccessor().getCursor(comp), useCache); | |
| 206 | + | |
| 207 | + } catch (IllegalComponentStateException e) { | |
| 208 | + // Shouldn't happen, but if it does, abort. | |
| 209 | + } | |
| 210 | + } | |
| 211 | + | |
| 212 | + protected void updateCursorOutOfJava() { | |
| 213 | + // Cursor is not over a Java Window. Do nothing...usually | |
| 214 | + // But we need to update it in case of grab on X. | |
| 215 | + } | |
| 216 | +} | |