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| 1 | /* | ||
| 2 | * Copyright (c) 1997, 2009, 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 | |||
| 27 | |||
| 28 | package javax.swing; | ||
| 29 | |||
| 30 | |||
| 31 | |||
| 32 | import java.util.*; | ||
| 33 | import java.util.concurrent.*; | ||
| 34 | import java.util.concurrent.locks.*; | ||
| 35 | import java.util.concurrent.atomic.AtomicLong; | ||
| 36 | import sun.awt.AppContext; | ||
| 37 | |||
| 38 | |||
| 39 | |||
| 40 | /** | ||
| 41 | * Internal class to manage all Timers using one thread. | ||
| 42 | * TimerQueue manages a queue of Timers. The Timers are chained | ||
| 43 | * together in a linked list sorted by the order in which they will expire. | ||
| 44 | * | ||
| 45 | * @author Dave Moore | ||
| 46 | * @author Igor Kushnirskiy | ||
| 47 | */ | ||
| 48 | class TimerQueue implements Runnable | ||
| 49 | { | ||
| 50 | private static final Object sharedInstanceKey = | ||
| 51 | new StringBuffer("TimerQueue.sharedInstanceKey"); | ||
| 52 | private static final Object expiredTimersKey = | ||
| 53 | new StringBuffer("TimerQueue.expiredTimersKey"); | ||
| 54 | |||
| 55 | private final DelayQueue<DelayedTimer> queue; | ||
| 56 | private volatile boolean running; | ||
| 57 | private final Lock runningLock; | ||
| 58 | |||
| 59 | /* Lock object used in place of class object for synchronization. | ||
| 60 | * (4187686) | ||
| 61 | */ | ||
| 62 | private static final Object classLock = new Object(); | ||
| 63 | |||
| 64 | /** Base of nanosecond timings, to avoid wrapping */ | ||
| 65 | private static final long NANO_ORIGIN = System.nanoTime(); | ||
| 66 | |||
| 67 | /** | ||
| 68 | * Constructor for TimerQueue. | ||
| 69 | */ | ||
| 70 | public TimerQueue() { | ||
| 71 | super(); | ||
| 72 | queue = new DelayQueue<DelayedTimer>(); | ||
| 73 | // Now start the TimerQueue thread. | ||
| 74 | runningLock = new ReentrantLock(); | ||
| 75 | startIfNeeded(); | ||
| 76 | } | ||
| 77 | |||
| 78 | |||
| 79 | public static TimerQueue sharedInstance() { | ||
| 80 | synchronized (classLock) { | ||
| 81 | TimerQueue sharedInst = (TimerQueue) | ||
| 82 | SwingUtilities.appContextGet( | ||
| 83 | sharedInstanceKey); | ||
| 84 | if (sharedInst == null) { | ||
| 85 | sharedInst = new TimerQueue(); | ||
| 86 | SwingUtilities.appContextPut(sharedInstanceKey, sharedInst); | ||
| 87 | } | ||
| 88 | return sharedInst; | ||
| 89 | } | ||
| 90 | } | ||
| 91 | |||
| 92 | |||
| 93 | void startIfNeeded() { | ||
| 94 | if (! running) { | ||
| 95 | runningLock.lock(); | ||
| 96 | try { | ||
| 97 | final ThreadGroup threadGroup = | ||
| 98 | AppContext.getAppContext().getThreadGroup(); | ||
| 99 | java.security.AccessController.doPrivileged( | ||
| 100 | new java.security.PrivilegedAction<Object>() { | ||
| 101 | public Object run() { | ||
| 102 | Thread timerThread = new Thread(threadGroup, TimerQueue.this, | ||
| 103 | "TimerQueue"); | ||
| 104 | timerThread.setDaemon(true); | ||
| 105 | timerThread.setPriority(Thread.NORM_PRIORITY); | ||
| 106 | timerThread.start(); | ||
| 107 | return null; | ||
| 108 | } | ||
| 109 | }); | ||
| 110 | running = true; | ||
| 111 | } finally { | ||
| 112 | runningLock.unlock(); | ||
| 113 | } | ||
| 114 | } | ||
| 115 | } | ||
| 116 | |||
| 117 | void addTimer(Timer timer, long delayMillis) { | ||
| 118 | timer.getLock().lock(); | ||
| 119 | try { | ||
| 120 | // If the Timer is already in the queue, then ignore the add. | ||
| 121 | if (! containsTimer(timer)) { | ||
| 122 | addTimer(new DelayedTimer(timer, | ||
| 123 | TimeUnit.MILLISECONDS.toNanos(delayMillis) | ||
| 124 | + now())); | ||
| 125 | } | ||
| 126 | } finally { | ||
| 127 | timer.getLock().unlock(); | ||
| 128 | } | ||
| 129 | } | ||
| 130 | |||
| 131 | private void addTimer(DelayedTimer delayedTimer) { | ||
| 132 | assert delayedTimer != null && ! containsTimer(delayedTimer.getTimer()); | ||
| 133 | |||
| 134 | Timer timer = delayedTimer.getTimer(); | ||
| 135 | timer.getLock().lock(); | ||
| 136 | try { | ||
| 137 | timer.delayedTimer = delayedTimer; | ||
| 138 | queue.add(delayedTimer); | ||
| 139 | } finally { | ||
| 140 | timer.getLock().unlock(); | ||
| 141 | } | ||
| 142 | } | ||
| 143 | |||
| 144 | void removeTimer(Timer timer) { | ||
| 145 | timer.getLock().lock(); | ||
| 146 | try { | ||
| 147 | if (timer.delayedTimer != null) { | ||
| 148 | queue.remove(timer.delayedTimer); | ||
| 149 | timer.delayedTimer = null; | ||
| 150 | } | ||
| 151 | } finally { | ||
| 152 | timer.getLock().unlock(); | ||
| 153 | } | ||
| 154 | } | ||
| 155 | |||
| 156 | boolean containsTimer(Timer timer) { | ||
| 157 | timer.getLock().lock(); | ||
| 158 | try { | ||
| 159 | return timer.delayedTimer != null; | ||
| 160 | } finally { | ||
| 161 | timer.getLock().unlock(); | ||
| 162 | } | ||
| 163 | } | ||
| 164 | |||
| 165 | |||
| 166 | public void run() { | ||
| 167 | runningLock.lock(); | ||
| 168 | try { | ||
| 169 | while (running) { | ||
| 170 | try { | ||
| 171 | Timer timer = queue.take().getTimer(); | ||
| 172 | timer.getLock().lock(); | ||
| 173 | try { | ||
| 174 | DelayedTimer delayedTimer = timer.delayedTimer; | ||
| 175 | if (delayedTimer != null) { | ||
| 176 | /* | ||
| 177 | * Timer is not removed after we get it from | ||
| 178 | * the queue and before the lock on the timer is | ||
| 179 | * acquired | ||
| 180 | */ | ||
| 181 | timer.post(); // have timer post an event | ||
| 182 | timer.delayedTimer = null; | ||
| 183 | if (timer.isRepeats()) { | ||
| 184 | delayedTimer.setTime(now() | ||
| 185 | + TimeUnit.MILLISECONDS.toNanos( | ||
| 186 | timer.getDelay())); | ||
| 187 | addTimer(delayedTimer); | ||
| 188 | } | ||
| 189 | } | ||
| 190 | } catch (SecurityException ignore) { | ||
| 191 | } finally { | ||
| 192 | timer.getLock().unlock(); | ||
| 193 | } | ||
| 194 | } catch (InterruptedException ie) { | ||
| 195 | // Shouldn't ignore InterruptedExceptions here, so AppContext | ||
| 196 | // is disposed gracefully, see 6799345 for details | ||
| 197 | if (AppContext.getAppContext().isDisposed()) { | ||
| 198 | break; | ||
| 199 | } | ||
| 200 | } | ||
| 201 | } | ||
| 202 | } | ||
| 203 | catch (ThreadDeath td) { | ||
| 204 | // Mark all the timers we contain as not being queued. | ||
| 205 | for (DelayedTimer delayedTimer : queue) { | ||
| 206 | delayedTimer.getTimer().cancelEvent(); | ||
| 207 | } | ||
| 208 | throw td; | ||
| 209 | } finally { | ||
| 210 | running = false; | ||
| 211 | runningLock.unlock(); | ||
| 212 | } | ||
| 213 | } | ||
| 214 | |||
| 215 | |||
| 216 | public String toString() { | ||
| 217 | StringBuilder buf = new StringBuilder(); | ||
| 218 | buf.append("TimerQueue ("); | ||
| 219 | boolean isFirst = true; | ||
| 220 | for (DelayedTimer delayedTimer : queue) { | ||
| 221 | if (! isFirst) { | ||
| 222 | buf.append(", "); | ||
| 223 | } | ||
| 224 | buf.append(delayedTimer.getTimer().toString()); | ||
| 225 | isFirst = false; | ||
| 226 | } | ||
| 227 | buf.append(")"); | ||
| 228 | return buf.toString(); | ||
| 229 | } | ||
| 230 | |||
| 231 | /** | ||
| 232 | * Returns nanosecond time offset by origin | ||
| 233 | */ | ||
| 234 | private static long now() { | ||
| 235 | return System.nanoTime() - NANO_ORIGIN; | ||
| 236 | } | ||
| 237 | |||
| 238 | static class DelayedTimer implements Delayed { | ||
| 239 | // most of it copied from | ||
| 240 | // java.util.concurrent.ScheduledThreadPoolExecutor | ||
| 241 | |||
| 242 | /** | ||
| 243 | * Sequence number to break scheduling ties, and in turn to | ||
| 244 | * guarantee FIFO order among tied entries. | ||
| 245 | */ | ||
| 246 | private static final AtomicLong sequencer = new AtomicLong(0); | ||
| 247 | |||
| 248 | /** Sequence number to break ties FIFO */ | ||
| 249 | private final long sequenceNumber; | ||
| 250 | |||
| 251 | |||
| 252 | /** The time the task is enabled to execute in nanoTime units */ | ||
| 253 | private volatile long time; | ||
| 254 | |||
| 255 | private final Timer timer; | ||
| 256 | |||
| 257 | DelayedTimer(Timer timer, long nanos) { | ||
| 258 | this.timer = timer; | ||
| 259 | time = nanos; | ||
| 260 | sequenceNumber = sequencer.getAndIncrement(); | ||
| 261 | } | ||
| 262 | |||
| 263 | |||
| 264 | final public long getDelay(TimeUnit unit) { | ||
| 265 | return unit.convert(time - now(), TimeUnit.NANOSECONDS); | ||
| 266 | } | ||
| 267 | |||
| 268 | final void setTime(long nanos) { | ||
| 269 | time = nanos; | ||
| 270 | } | ||
| 271 | |||
| 272 | final Timer getTimer() { | ||
| 273 | return timer; | ||
| 274 | } | ||
| 275 | |||
| 276 | public int compareTo(Delayed other) { | ||
| 277 | if (other == this) { // compare zero ONLY if same object | ||
| 278 | return 0; | ||
| 279 | } | ||
| 280 | if (other instanceof DelayedTimer) { | ||
| 281 | DelayedTimer x = (DelayedTimer)other; | ||
| 282 | long diff = time - x.time; | ||
| 283 | if (diff < 0) { | ||
| 284 | return -1; | ||
| 285 | } else if (diff > 0) { | ||
| 286 | return 1; | ||
| 287 | } else if (sequenceNumber < x.sequenceNumber) { | ||
| 288 | return -1; | ||
| 289 | } else { | ||
| 290 | return 1; | ||
| 291 | } | ||
| 292 | } | ||
| 293 | long d = (getDelay(TimeUnit.NANOSECONDS) - | ||
| 294 | other.getDelay(TimeUnit.NANOSECONDS)); | ||
| 295 | return (d == 0) ? 0 : ((d < 0) ? -1 : 1); | ||
| 296 | } | ||
| 297 | } | ||
| 298 | } | ||