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| 1 | +/* | |
| 2 | + * Copyright (c) 2010, 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.util.Timer; | |
| 29 | +import java.util.TimerTask; | |
| 30 | +import java.util.concurrent.atomic.AtomicBoolean; | |
| 31 | + | |
| 32 | +import java.security.PrivilegedAction; | |
| 33 | +import java.security.AccessController; | |
| 34 | + | |
| 35 | +import sun.awt.PeerEvent; | |
| 36 | + | |
| 37 | +import sun.util.logging.PlatformLogger; | |
| 38 | + | |
| 39 | +/** | |
| 40 | + * This utility class is used to suspend execution on a thread | |
| 41 | + * while still allowing {@code EventDispatchThread} to dispatch events. | |
| 42 | + * The API methods of the class are thread-safe. | |
| 43 | + * | |
| 44 | + * @author Anton Tarasov, Artem Ananiev | |
| 45 | + * | |
| 46 | + * @since 1.7 | |
| 47 | + */ | |
| 48 | +class WaitDispatchSupport implements SecondaryLoop { | |
| 49 | + | |
| 50 | + private final static PlatformLogger log = | |
| 51 | + PlatformLogger.getLogger("java.awt.event.WaitDispatchSupport"); | |
| 52 | + | |
| 53 | + private EventDispatchThread dispatchThread; | |
| 54 | + private EventFilter filter; | |
| 55 | + | |
| 56 | + private volatile Conditional extCondition; | |
| 57 | + private volatile Conditional condition; | |
| 58 | + | |
| 59 | + private long interval; | |
| 60 | + // Use a shared daemon timer to serve all the WaitDispatchSupports | |
| 61 | + private static Timer timer; | |
| 62 | + // When this WDS expires, we cancel the timer task leaving the | |
| 63 | + // shared timer up and running | |
| 64 | + private TimerTask timerTask; | |
| 65 | + | |
| 66 | + private AtomicBoolean keepBlockingEDT = new AtomicBoolean(false); | |
| 67 | + private AtomicBoolean keepBlockingCT = new AtomicBoolean(false); | |
| 68 | + | |
| 69 | + private static synchronized void initializeTimer() { | |
| 70 | + if (timer == null) { | |
| 71 | + timer = new Timer("AWT-WaitDispatchSupport-Timer", true); | |
| 72 | + } | |
| 73 | + } | |
| 74 | + | |
| 75 | + /** | |
| 76 | + * Creates a {@code WaitDispatchSupport} instance to | |
| 77 | + * serve the given event dispatch thread. | |
| 78 | + * | |
| 79 | + * @param dispatchThread An event dispatch thread that | |
| 80 | + * should not stop dispatching events while waiting | |
| 81 | + * | |
| 82 | + * @since 1.7 | |
| 83 | + */ | |
| 84 | + public WaitDispatchSupport(EventDispatchThread dispatchThread) { | |
| 85 | + this(dispatchThread, null); | |
| 86 | + } | |
| 87 | + | |
| 88 | + /** | |
| 89 | + * Creates a {@code WaitDispatchSupport} instance to | |
| 90 | + * serve the given event dispatch thread. | |
| 91 | + * | |
| 92 | + * @param dispatchThread An event dispatch thread that | |
| 93 | + * should not stop dispatching events while waiting | |
| 94 | + * @param extCondition A conditional object used to determine | |
| 95 | + * if the loop should be terminated | |
| 96 | + * | |
| 97 | + * @since 1.7 | |
| 98 | + */ | |
| 99 | + public WaitDispatchSupport(EventDispatchThread dispatchThread, | |
| 100 | + Conditional extCond) | |
| 101 | + { | |
| 102 | + if (dispatchThread == null) { | |
| 103 | + throw new IllegalArgumentException("The dispatchThread can not be null"); | |
| 104 | + } | |
| 105 | + | |
| 106 | + this.dispatchThread = dispatchThread; | |
| 107 | + this.extCondition = extCond; | |
| 108 | + this.condition = new Conditional() { | |
| 109 | + @Override | |
| 110 | + public boolean evaluate() { | |
| 111 | + if (log.isLoggable(PlatformLogger.FINEST)) { | |
| 112 | + log.finest("evaluate(): blockingEDT=" + keepBlockingEDT.get() + | |
| 113 | + ", blockingCT=" + keepBlockingCT.get()); | |
| 114 | + } | |
| 115 | + boolean extEvaluate = | |
| 116 | + (extCondition != null) ? extCondition.evaluate() : true; | |
| 117 | + if (!keepBlockingEDT.get() || !extEvaluate) { | |
| 118 | + if (timerTask != null) { | |
| 119 | + timerTask.cancel(); | |
| 120 | + timerTask = null; | |
| 121 | + } | |
| 122 | + return false; | |
| 123 | + } | |
| 124 | + return true; | |
| 125 | + } | |
| 126 | + }; | |
| 127 | + } | |
| 128 | + | |
| 129 | + /** | |
| 130 | + * Creates a {@code WaitDispatchSupport} instance to | |
| 131 | + * serve the given event dispatch thread. | |
| 132 | + * <p> | |
| 133 | + * The {@link EventFilter} is set on the {@code dispatchThread} | |
| 134 | + * while waiting. The filter is removed on completion of the | |
| 135 | + * waiting process. | |
| 136 | + * <p> | |
| 137 | + * | |
| 138 | + * | |
| 139 | + * @param dispatchThread An event dispatch thread that | |
| 140 | + * should not stop dispatching events while waiting | |
| 141 | + * @param filter {@code EventFilter} to be set | |
| 142 | + * @param interval A time interval to wait for. Note that | |
| 143 | + * when the waiting process takes place on EDT | |
| 144 | + * there is no guarantee to stop it in the given time | |
| 145 | + * | |
| 146 | + * @since 1.7 | |
| 147 | + */ | |
| 148 | + public WaitDispatchSupport(EventDispatchThread dispatchThread, | |
| 149 | + Conditional extCondition, | |
| 150 | + EventFilter filter, long interval) | |
| 151 | + { | |
| 152 | + this(dispatchThread, extCondition); | |
| 153 | + this.filter = filter; | |
| 154 | + if (interval < 0) { | |
| 155 | + throw new IllegalArgumentException("The interval value must be >= 0"); | |
| 156 | + } | |
| 157 | + this.interval = interval; | |
| 158 | + if (interval != 0) { | |
| 159 | + initializeTimer(); | |
| 160 | + } | |
| 161 | + } | |
| 162 | + | |
| 163 | + /** | |
| 164 | + * @inheritDoc | |
| 165 | + */ | |
| 166 | + @Override | |
| 167 | + public boolean enter() { | |
| 168 | + log.fine("enter(): blockingEDT=" + keepBlockingEDT.get() + | |
| 169 | + ", blockingCT=" + keepBlockingCT.get()); | |
| 170 | + | |
| 171 | + if (!keepBlockingEDT.compareAndSet(false, true)) { | |
| 172 | + log.fine("The secondary loop is already running, aborting"); | |
| 173 | + return false; | |
| 174 | + } | |
| 175 | + | |
| 176 | + final Runnable run = new Runnable() { | |
| 177 | + public void run() { | |
| 178 | + log.fine("Starting a new event pump"); | |
| 179 | + if (filter == null) { | |
| 180 | + dispatchThread.pumpEvents(condition); | |
| 181 | + } else { | |
| 182 | + dispatchThread.pumpEventsForFilter(condition, filter); | |
| 183 | + } | |
| 184 | + } | |
| 185 | + }; | |
| 186 | + | |
| 187 | + // We have two mechanisms for blocking: if we're on the | |
| 188 | + // dispatch thread, start a new event pump; if we're | |
| 189 | + // on any other thread, call wait() on the treelock | |
| 190 | + | |
| 191 | + Thread currentThread = Thread.currentThread(); | |
| 192 | + if (currentThread == dispatchThread) { | |
| 193 | + log.finest("On dispatch thread: " + dispatchThread); | |
| 194 | + if (interval != 0) { | |
| 195 | + log.finest("scheduling the timer for " + interval + " ms"); | |
| 196 | + timer.schedule(timerTask = new TimerTask() { | |
| 197 | + @Override | |
| 198 | + public void run() { | |
| 199 | + if (keepBlockingEDT.compareAndSet(true, false)) { | |
| 200 | + wakeupEDT(); | |
| 201 | + } | |
| 202 | + } | |
| 203 | + }, interval); | |
| 204 | + } | |
| 205 | + // Dispose SequencedEvent we are dispatching on the the current | |
| 206 | + // AppContext, to prevent us from hang - see 4531693 for details | |
| 207 | + SequencedEvent currentSE = KeyboardFocusManager. | |
| 208 | + getCurrentKeyboardFocusManager().getCurrentSequencedEvent(); | |
| 209 | + if (currentSE != null) { | |
| 210 | + log.fine("Dispose current SequencedEvent: " + currentSE); | |
| 211 | + currentSE.dispose(); | |
| 212 | + } | |
| 213 | + // In case the exit() method is called before starting | |
| 214 | + // new event pump it will post the waking event to EDT. | |
| 215 | + // The event will be handled after the the new event pump | |
| 216 | + // starts. Thus, the enter() method will not hang. | |
| 217 | + // | |
| 218 | + // Event pump should be privileged. See 6300270. | |
| 219 | + AccessController.doPrivileged(new PrivilegedAction() { | |
| 220 | + public Object run() { | |
| 221 | + run.run(); | |
| 222 | + return null; | |
| 223 | + } | |
| 224 | + }); | |
| 225 | + } else { | |
| 226 | + log.finest("On non-dispatch thread: " + currentThread); | |
| 227 | + synchronized (getTreeLock()) { | |
| 228 | + if (filter != null) { | |
| 229 | + dispatchThread.addEventFilter(filter); | |
| 230 | + } | |
| 231 | + try { | |
| 232 | + EventQueue eq = dispatchThread.getEventQueue(); | |
| 233 | + eq.postEvent(new PeerEvent(this, run, PeerEvent.PRIORITY_EVENT)); | |
| 234 | + keepBlockingCT.set(true); | |
| 235 | + if (interval > 0) { | |
| 236 | + long currTime = System.currentTimeMillis(); | |
| 237 | + while (keepBlockingCT.get() && | |
| 238 | + ((extCondition != null) ? extCondition.evaluate() : true) && | |
| 239 | + (currTime + interval > System.currentTimeMillis())) | |
| 240 | + { | |
| 241 | + getTreeLock().wait(interval); | |
| 242 | + } | |
| 243 | + } else { | |
| 244 | + while (keepBlockingCT.get() && | |
| 245 | + ((extCondition != null) ? extCondition.evaluate() : true)) | |
| 246 | + { | |
| 247 | + getTreeLock().wait(); | |
| 248 | + } | |
| 249 | + } | |
| 250 | + log.fine("waitDone " + keepBlockingEDT.get() + " " + keepBlockingCT.get()); | |
| 251 | + } catch (InterruptedException e) { | |
| 252 | + log.fine("Exception caught while waiting: " + e); | |
| 253 | + } finally { | |
| 254 | + if (filter != null) { | |
| 255 | + dispatchThread.removeEventFilter(filter); | |
| 256 | + } | |
| 257 | + } | |
| 258 | + // If the waiting process has been stopped because of the | |
| 259 | + // time interval passed or an exception occurred, the state | |
| 260 | + // should be changed | |
| 261 | + keepBlockingEDT.set(false); | |
| 262 | + keepBlockingCT.set(false); | |
| 263 | + } | |
| 264 | + } | |
| 265 | + | |
| 266 | + return true; | |
| 267 | + } | |
| 268 | + | |
| 269 | + /** | |
| 270 | + * @inheritDoc | |
| 271 | + */ | |
| 272 | + public boolean exit() { | |
| 273 | + log.fine("exit(): blockingEDT=" + keepBlockingEDT.get() + | |
| 274 | + ", blockingCT=" + keepBlockingCT.get()); | |
| 275 | + if (keepBlockingEDT.compareAndSet(true, false)) { | |
| 276 | + wakeupEDT(); | |
| 277 | + return true; | |
| 278 | + } | |
| 279 | + return false; | |
| 280 | + } | |
| 281 | + | |
| 282 | + private final static Object getTreeLock() { | |
| 283 | + return Component.LOCK; | |
| 284 | + } | |
| 285 | + | |
| 286 | + private final Runnable wakingRunnable = new Runnable() { | |
| 287 | + public void run() { | |
| 288 | + log.fine("Wake up EDT"); | |
| 289 | + synchronized (getTreeLock()) { | |
| 290 | + keepBlockingCT.set(false); | |
| 291 | + getTreeLock().notifyAll(); | |
| 292 | + } | |
| 293 | + log.fine("Wake up EDT done"); | |
| 294 | + } | |
| 295 | + }; | |
| 296 | + | |
| 297 | + private void wakeupEDT() { | |
| 298 | + log.finest("wakeupEDT(): EDT == " + dispatchThread); | |
| 299 | + EventQueue eq = dispatchThread.getEventQueue(); | |
| 300 | + eq.postEvent(new PeerEvent(this, wakingRunnable, PeerEvent.PRIORITY_EVENT)); | |
| 301 | + } | |
| 302 | +} | |