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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 | } | ||