1 |
dl |
1.1 |
/* |
2 |
|
|
* Written by Doug Lea with assistance from members of JCP JSR-166 |
3 |
|
|
* Expert Group and released to the public domain, as explained at |
4 |
|
|
* http://creativecommons.org/publicdomain/zero/1.0/ |
5 |
|
|
*/ |
6 |
|
|
|
7 |
|
|
package java.util.concurrent; |
8 |
|
|
import static java.util.concurrent.TimeUnit.NANOSECONDS; |
9 |
|
|
import java.util.concurrent.atomic.AtomicLong; |
10 |
|
|
import java.util.concurrent.locks.Condition; |
11 |
|
|
import java.util.concurrent.locks.ReentrantLock; |
12 |
|
|
import java.util.*; |
13 |
|
|
|
14 |
|
|
/** |
15 |
|
|
* A {@link ThreadPoolExecutor} that can additionally schedule |
16 |
|
|
* commands to run after a given delay, or to execute |
17 |
|
|
* periodically. This class is preferable to {@link java.util.Timer} |
18 |
|
|
* when multiple worker threads are needed, or when the additional |
19 |
|
|
* flexibility or capabilities of {@link ThreadPoolExecutor} (which |
20 |
|
|
* this class extends) are required. |
21 |
|
|
* |
22 |
|
|
* <p>Delayed tasks execute no sooner than they are enabled, but |
23 |
|
|
* without any real-time guarantees about when, after they are |
24 |
|
|
* enabled, they will commence. Tasks scheduled for exactly the same |
25 |
|
|
* execution time are enabled in first-in-first-out (FIFO) order of |
26 |
|
|
* submission. |
27 |
|
|
* |
28 |
|
|
* <p>When a submitted task is cancelled before it is run, execution |
29 |
|
|
* is suppressed. By default, such a cancelled task is not |
30 |
|
|
* automatically removed from the work queue until its delay |
31 |
|
|
* elapses. While this enables further inspection and monitoring, it |
32 |
|
|
* may also cause unbounded retention of cancelled tasks. To avoid |
33 |
|
|
* this, set {@link #setRemoveOnCancelPolicy} to {@code true}, which |
34 |
|
|
* causes tasks to be immediately removed from the work queue at |
35 |
|
|
* time of cancellation. |
36 |
|
|
* |
37 |
|
|
* <p>Successive executions of a task scheduled via |
38 |
|
|
* {@code scheduleAtFixedRate} or |
39 |
|
|
* {@code scheduleWithFixedDelay} do not overlap. While different |
40 |
|
|
* executions may be performed by different threads, the effects of |
41 |
|
|
* prior executions <a |
42 |
|
|
* href="package-summary.html#MemoryVisibility"><i>happen-before</i></a> |
43 |
|
|
* those of subsequent ones. |
44 |
|
|
* |
45 |
|
|
* <p>While this class inherits from {@link ThreadPoolExecutor}, a few |
46 |
|
|
* of the inherited tuning methods are not useful for it. In |
47 |
|
|
* particular, because it acts as a fixed-sized pool using |
48 |
|
|
* {@code corePoolSize} threads and an unbounded queue, adjustments |
49 |
|
|
* to {@code maximumPoolSize} have no useful effect. Additionally, it |
50 |
|
|
* is almost never a good idea to set {@code corePoolSize} to zero or |
51 |
|
|
* use {@code allowCoreThreadTimeOut} because this may leave the pool |
52 |
|
|
* without threads to handle tasks once they become eligible to run. |
53 |
|
|
* |
54 |
|
|
* <p><b>Extension notes:</b> This class overrides the |
55 |
jsr166 |
1.4 |
* {@link ThreadPoolExecutor#execute(Runnable) execute} and |
56 |
dl |
1.1 |
* {@link AbstractExecutorService#submit(Runnable) submit} |
57 |
|
|
* methods to generate internal {@link ScheduledFuture} objects to |
58 |
|
|
* control per-task delays and scheduling. To preserve |
59 |
|
|
* functionality, any further overrides of these methods in |
60 |
|
|
* subclasses must invoke superclass versions, which effectively |
61 |
|
|
* disables additional task customization. However, this class |
62 |
|
|
* provides alternative protected extension method |
63 |
|
|
* {@code decorateTask} (one version each for {@code Runnable} and |
64 |
|
|
* {@code Callable}) that can be used to customize the concrete task |
65 |
|
|
* types used to execute commands entered via {@code execute}, |
66 |
|
|
* {@code submit}, {@code schedule}, {@code scheduleAtFixedRate}, |
67 |
|
|
* and {@code scheduleWithFixedDelay}. By default, a |
68 |
|
|
* {@code ScheduledThreadPoolExecutor} uses a task type extending |
69 |
|
|
* {@link FutureTask}. However, this may be modified or replaced using |
70 |
|
|
* subclasses of the form: |
71 |
|
|
* |
72 |
|
|
* <pre> {@code |
73 |
|
|
* public class CustomScheduledExecutor extends ScheduledThreadPoolExecutor { |
74 |
|
|
* |
75 |
|
|
* static class CustomTask<V> implements RunnableScheduledFuture<V> { ... } |
76 |
|
|
* |
77 |
|
|
* protected <V> RunnableScheduledFuture<V> decorateTask( |
78 |
|
|
* Runnable r, RunnableScheduledFuture<V> task) { |
79 |
|
|
* return new CustomTask<V>(r, task); |
80 |
|
|
* } |
81 |
|
|
* |
82 |
|
|
* protected <V> RunnableScheduledFuture<V> decorateTask( |
83 |
|
|
* Callable<V> c, RunnableScheduledFuture<V> task) { |
84 |
|
|
* return new CustomTask<V>(c, task); |
85 |
|
|
* } |
86 |
|
|
* // ... add constructors, etc. |
87 |
|
|
* }}</pre> |
88 |
|
|
* |
89 |
|
|
* @since 1.5 |
90 |
|
|
* @author Doug Lea |
91 |
|
|
*/ |
92 |
|
|
public class ScheduledThreadPoolExecutor |
93 |
|
|
extends ThreadPoolExecutor |
94 |
|
|
implements ScheduledExecutorService { |
95 |
|
|
|
96 |
|
|
/* |
97 |
|
|
* This class specializes ThreadPoolExecutor implementation by |
98 |
|
|
* |
99 |
|
|
* 1. Using a custom task type, ScheduledFutureTask for |
100 |
|
|
* tasks, even those that don't require scheduling (i.e., |
101 |
|
|
* those submitted using ExecutorService execute, not |
102 |
|
|
* ScheduledExecutorService methods) which are treated as |
103 |
|
|
* delayed tasks with a delay of zero. |
104 |
|
|
* |
105 |
|
|
* 2. Using a custom queue (DelayedWorkQueue), a variant of |
106 |
|
|
* unbounded DelayQueue. The lack of capacity constraint and |
107 |
|
|
* the fact that corePoolSize and maximumPoolSize are |
108 |
|
|
* effectively identical simplifies some execution mechanics |
109 |
|
|
* (see delayedExecute) compared to ThreadPoolExecutor. |
110 |
|
|
* |
111 |
|
|
* 3. Supporting optional run-after-shutdown parameters, which |
112 |
|
|
* leads to overrides of shutdown methods to remove and cancel |
113 |
|
|
* tasks that should NOT be run after shutdown, as well as |
114 |
|
|
* different recheck logic when task (re)submission overlaps |
115 |
|
|
* with a shutdown. |
116 |
|
|
* |
117 |
|
|
* 4. Task decoration methods to allow interception and |
118 |
|
|
* instrumentation, which are needed because subclasses cannot |
119 |
|
|
* otherwise override submit methods to get this effect. These |
120 |
|
|
* don't have any impact on pool control logic though. |
121 |
|
|
*/ |
122 |
|
|
|
123 |
|
|
/** |
124 |
|
|
* False if should cancel/suppress periodic tasks on shutdown. |
125 |
|
|
*/ |
126 |
|
|
private volatile boolean continueExistingPeriodicTasksAfterShutdown; |
127 |
|
|
|
128 |
|
|
/** |
129 |
|
|
* False if should cancel non-periodic tasks on shutdown. |
130 |
|
|
*/ |
131 |
|
|
private volatile boolean executeExistingDelayedTasksAfterShutdown = true; |
132 |
|
|
|
133 |
|
|
/** |
134 |
|
|
* True if ScheduledFutureTask.cancel should remove from queue |
135 |
|
|
*/ |
136 |
|
|
private volatile boolean removeOnCancel = false; |
137 |
|
|
|
138 |
|
|
/** |
139 |
|
|
* Sequence number to break scheduling ties, and in turn to |
140 |
|
|
* guarantee FIFO order among tied entries. |
141 |
|
|
*/ |
142 |
|
|
private static final AtomicLong sequencer = new AtomicLong(); |
143 |
|
|
|
144 |
|
|
/** |
145 |
|
|
* Returns current nanosecond time. |
146 |
|
|
*/ |
147 |
|
|
final long now() { |
148 |
|
|
return System.nanoTime(); |
149 |
|
|
} |
150 |
|
|
|
151 |
|
|
private class ScheduledFutureTask<V> |
152 |
|
|
extends FutureTask<V> implements RunnableScheduledFuture<V> { |
153 |
|
|
|
154 |
|
|
/** Sequence number to break ties FIFO */ |
155 |
|
|
private final long sequenceNumber; |
156 |
|
|
|
157 |
|
|
/** The time the task is enabled to execute in nanoTime units */ |
158 |
|
|
private long time; |
159 |
|
|
|
160 |
|
|
/** |
161 |
|
|
* Period in nanoseconds for repeating tasks. A positive |
162 |
|
|
* value indicates fixed-rate execution. A negative value |
163 |
|
|
* indicates fixed-delay execution. A value of 0 indicates a |
164 |
|
|
* non-repeating task. |
165 |
|
|
*/ |
166 |
|
|
private final long period; |
167 |
|
|
|
168 |
|
|
/** The actual task to be re-enqueued by reExecutePeriodic */ |
169 |
|
|
RunnableScheduledFuture<V> outerTask = this; |
170 |
|
|
|
171 |
|
|
/** |
172 |
|
|
* Index into delay queue, to support faster cancellation. |
173 |
|
|
*/ |
174 |
|
|
int heapIndex; |
175 |
|
|
|
176 |
|
|
/** |
177 |
|
|
* Creates a one-shot action with given nanoTime-based trigger time. |
178 |
|
|
*/ |
179 |
|
|
ScheduledFutureTask(Runnable r, V result, long ns) { |
180 |
|
|
super(r, result); |
181 |
|
|
this.time = ns; |
182 |
|
|
this.period = 0; |
183 |
|
|
this.sequenceNumber = sequencer.getAndIncrement(); |
184 |
|
|
} |
185 |
|
|
|
186 |
|
|
/** |
187 |
|
|
* Creates a periodic action with given nano time and period. |
188 |
|
|
*/ |
189 |
|
|
ScheduledFutureTask(Runnable r, V result, long ns, long period) { |
190 |
|
|
super(r, result); |
191 |
|
|
this.time = ns; |
192 |
|
|
this.period = period; |
193 |
|
|
this.sequenceNumber = sequencer.getAndIncrement(); |
194 |
|
|
} |
195 |
|
|
|
196 |
|
|
/** |
197 |
|
|
* Creates a one-shot action with given nanoTime-based trigger time. |
198 |
|
|
*/ |
199 |
|
|
ScheduledFutureTask(Callable<V> callable, long ns) { |
200 |
|
|
super(callable); |
201 |
|
|
this.time = ns; |
202 |
|
|
this.period = 0; |
203 |
|
|
this.sequenceNumber = sequencer.getAndIncrement(); |
204 |
|
|
} |
205 |
|
|
|
206 |
|
|
public long getDelay(TimeUnit unit) { |
207 |
|
|
return unit.convert(time - now(), NANOSECONDS); |
208 |
|
|
} |
209 |
|
|
|
210 |
|
|
public int compareTo(Delayed other) { |
211 |
|
|
if (other == this) // compare zero if same object |
212 |
|
|
return 0; |
213 |
|
|
if (other instanceof ScheduledFutureTask) { |
214 |
|
|
ScheduledFutureTask<?> x = (ScheduledFutureTask<?>)other; |
215 |
|
|
long diff = time - x.time; |
216 |
|
|
if (diff < 0) |
217 |
|
|
return -1; |
218 |
|
|
else if (diff > 0) |
219 |
|
|
return 1; |
220 |
|
|
else if (sequenceNumber < x.sequenceNumber) |
221 |
|
|
return -1; |
222 |
|
|
else |
223 |
|
|
return 1; |
224 |
|
|
} |
225 |
|
|
long diff = getDelay(NANOSECONDS) - other.getDelay(NANOSECONDS); |
226 |
|
|
return (diff < 0) ? -1 : (diff > 0) ? 1 : 0; |
227 |
|
|
} |
228 |
|
|
|
229 |
|
|
/** |
230 |
jsr166 |
1.4 |
* Returns {@code true} if this is a periodic (not a one-shot) action. |
231 |
dl |
1.1 |
* |
232 |
jsr166 |
1.4 |
* @return {@code true} if periodic |
233 |
dl |
1.1 |
*/ |
234 |
|
|
public boolean isPeriodic() { |
235 |
|
|
return period != 0; |
236 |
|
|
} |
237 |
|
|
|
238 |
|
|
/** |
239 |
|
|
* Sets the next time to run for a periodic task. |
240 |
|
|
*/ |
241 |
|
|
private void setNextRunTime() { |
242 |
|
|
long p = period; |
243 |
|
|
if (p > 0) |
244 |
|
|
time += p; |
245 |
|
|
else |
246 |
|
|
time = triggerTime(-p); |
247 |
|
|
} |
248 |
|
|
|
249 |
|
|
public boolean cancel(boolean mayInterruptIfRunning) { |
250 |
|
|
boolean cancelled = super.cancel(mayInterruptIfRunning); |
251 |
|
|
if (cancelled && removeOnCancel && heapIndex >= 0) |
252 |
|
|
remove(this); |
253 |
|
|
return cancelled; |
254 |
|
|
} |
255 |
|
|
|
256 |
|
|
/** |
257 |
|
|
* Overrides FutureTask version so as to reset/requeue if periodic. |
258 |
|
|
*/ |
259 |
|
|
public void run() { |
260 |
|
|
boolean periodic = isPeriodic(); |
261 |
|
|
if (!canRunInCurrentRunState(periodic)) |
262 |
|
|
cancel(false); |
263 |
|
|
else if (!periodic) |
264 |
|
|
ScheduledFutureTask.super.run(); |
265 |
|
|
else if (ScheduledFutureTask.super.runAndReset()) { |
266 |
|
|
setNextRunTime(); |
267 |
|
|
reExecutePeriodic(outerTask); |
268 |
|
|
} |
269 |
|
|
} |
270 |
|
|
} |
271 |
|
|
|
272 |
|
|
/** |
273 |
|
|
* Returns true if can run a task given current run state |
274 |
|
|
* and run-after-shutdown parameters. |
275 |
|
|
* |
276 |
|
|
* @param periodic true if this task periodic, false if delayed |
277 |
|
|
*/ |
278 |
|
|
boolean canRunInCurrentRunState(boolean periodic) { |
279 |
|
|
return isRunningOrShutdown(periodic ? |
280 |
|
|
continueExistingPeriodicTasksAfterShutdown : |
281 |
|
|
executeExistingDelayedTasksAfterShutdown); |
282 |
|
|
} |
283 |
|
|
|
284 |
|
|
/** |
285 |
|
|
* Main execution method for delayed or periodic tasks. If pool |
286 |
|
|
* is shut down, rejects the task. Otherwise adds task to queue |
287 |
|
|
* and starts a thread, if necessary, to run it. (We cannot |
288 |
|
|
* prestart the thread to run the task because the task (probably) |
289 |
jsr166 |
1.2 |
* shouldn't be run yet.) If the pool is shut down while the task |
290 |
dl |
1.1 |
* is being added, cancel and remove it if required by state and |
291 |
|
|
* run-after-shutdown parameters. |
292 |
|
|
* |
293 |
|
|
* @param task the task |
294 |
|
|
*/ |
295 |
|
|
private void delayedExecute(RunnableScheduledFuture<?> task) { |
296 |
|
|
if (isShutdown()) |
297 |
|
|
reject(task); |
298 |
|
|
else { |
299 |
|
|
super.getQueue().add(task); |
300 |
|
|
if (isShutdown() && |
301 |
|
|
!canRunInCurrentRunState(task.isPeriodic()) && |
302 |
|
|
remove(task)) |
303 |
|
|
task.cancel(false); |
304 |
|
|
else |
305 |
|
|
ensurePrestart(); |
306 |
|
|
} |
307 |
|
|
} |
308 |
|
|
|
309 |
|
|
/** |
310 |
|
|
* Requeues a periodic task unless current run state precludes it. |
311 |
|
|
* Same idea as delayedExecute except drops task rather than rejecting. |
312 |
|
|
* |
313 |
|
|
* @param task the task |
314 |
|
|
*/ |
315 |
|
|
void reExecutePeriodic(RunnableScheduledFuture<?> task) { |
316 |
|
|
if (canRunInCurrentRunState(true)) { |
317 |
|
|
super.getQueue().add(task); |
318 |
|
|
if (!canRunInCurrentRunState(true) && remove(task)) |
319 |
|
|
task.cancel(false); |
320 |
|
|
else |
321 |
|
|
ensurePrestart(); |
322 |
|
|
} |
323 |
|
|
} |
324 |
|
|
|
325 |
|
|
/** |
326 |
|
|
* Cancels and clears the queue of all tasks that should not be run |
327 |
|
|
* due to shutdown policy. Invoked within super.shutdown. |
328 |
|
|
*/ |
329 |
|
|
@Override void onShutdown() { |
330 |
|
|
BlockingQueue<Runnable> q = super.getQueue(); |
331 |
|
|
boolean keepDelayed = |
332 |
|
|
getExecuteExistingDelayedTasksAfterShutdownPolicy(); |
333 |
|
|
boolean keepPeriodic = |
334 |
|
|
getContinueExistingPeriodicTasksAfterShutdownPolicy(); |
335 |
|
|
if (!keepDelayed && !keepPeriodic) { |
336 |
|
|
for (Object e : q.toArray()) |
337 |
|
|
if (e instanceof RunnableScheduledFuture<?>) |
338 |
|
|
((RunnableScheduledFuture<?>) e).cancel(false); |
339 |
|
|
q.clear(); |
340 |
|
|
} |
341 |
|
|
else { |
342 |
|
|
// Traverse snapshot to avoid iterator exceptions |
343 |
|
|
for (Object e : q.toArray()) { |
344 |
|
|
if (e instanceof RunnableScheduledFuture) { |
345 |
|
|
RunnableScheduledFuture<?> t = |
346 |
|
|
(RunnableScheduledFuture<?>)e; |
347 |
|
|
if ((t.isPeriodic() ? !keepPeriodic : !keepDelayed) || |
348 |
|
|
t.isCancelled()) { // also remove if already cancelled |
349 |
|
|
if (q.remove(t)) |
350 |
|
|
t.cancel(false); |
351 |
|
|
} |
352 |
|
|
} |
353 |
|
|
} |
354 |
|
|
} |
355 |
|
|
tryTerminate(); |
356 |
|
|
} |
357 |
|
|
|
358 |
|
|
/** |
359 |
|
|
* Modifies or replaces the task used to execute a runnable. |
360 |
|
|
* This method can be used to override the concrete |
361 |
|
|
* class used for managing internal tasks. |
362 |
|
|
* The default implementation simply returns the given task. |
363 |
|
|
* |
364 |
|
|
* @param runnable the submitted Runnable |
365 |
|
|
* @param task the task created to execute the runnable |
366 |
jsr166 |
1.5 |
* @param <V> the type of the task's result |
367 |
dl |
1.1 |
* @return a task that can execute the runnable |
368 |
|
|
* @since 1.6 |
369 |
|
|
*/ |
370 |
|
|
protected <V> RunnableScheduledFuture<V> decorateTask( |
371 |
|
|
Runnable runnable, RunnableScheduledFuture<V> task) { |
372 |
|
|
return task; |
373 |
|
|
} |
374 |
|
|
|
375 |
|
|
/** |
376 |
|
|
* Modifies or replaces the task used to execute a callable. |
377 |
|
|
* This method can be used to override the concrete |
378 |
|
|
* class used for managing internal tasks. |
379 |
|
|
* The default implementation simply returns the given task. |
380 |
|
|
* |
381 |
|
|
* @param callable the submitted Callable |
382 |
|
|
* @param task the task created to execute the callable |
383 |
jsr166 |
1.5 |
* @param <V> the type of the task's result |
384 |
dl |
1.1 |
* @return a task that can execute the callable |
385 |
|
|
* @since 1.6 |
386 |
|
|
*/ |
387 |
|
|
protected <V> RunnableScheduledFuture<V> decorateTask( |
388 |
|
|
Callable<V> callable, RunnableScheduledFuture<V> task) { |
389 |
|
|
return task; |
390 |
|
|
} |
391 |
|
|
|
392 |
|
|
/** |
393 |
|
|
* Creates a new {@code ScheduledThreadPoolExecutor} with the |
394 |
|
|
* given core pool size. |
395 |
|
|
* |
396 |
|
|
* @param corePoolSize the number of threads to keep in the pool, even |
397 |
|
|
* if they are idle, unless {@code allowCoreThreadTimeOut} is set |
398 |
|
|
* @throws IllegalArgumentException if {@code corePoolSize < 0} |
399 |
|
|
*/ |
400 |
|
|
public ScheduledThreadPoolExecutor(int corePoolSize) { |
401 |
|
|
super(corePoolSize, Integer.MAX_VALUE, 0, NANOSECONDS, |
402 |
|
|
new DelayedWorkQueue()); |
403 |
|
|
} |
404 |
|
|
|
405 |
|
|
/** |
406 |
|
|
* Creates a new {@code ScheduledThreadPoolExecutor} with the |
407 |
|
|
* given initial parameters. |
408 |
|
|
* |
409 |
|
|
* @param corePoolSize the number of threads to keep in the pool, even |
410 |
|
|
* if they are idle, unless {@code allowCoreThreadTimeOut} is set |
411 |
|
|
* @param threadFactory the factory to use when the executor |
412 |
|
|
* creates a new thread |
413 |
|
|
* @throws IllegalArgumentException if {@code corePoolSize < 0} |
414 |
|
|
* @throws NullPointerException if {@code threadFactory} is null |
415 |
|
|
*/ |
416 |
|
|
public ScheduledThreadPoolExecutor(int corePoolSize, |
417 |
|
|
ThreadFactory threadFactory) { |
418 |
|
|
super(corePoolSize, Integer.MAX_VALUE, 0, NANOSECONDS, |
419 |
|
|
new DelayedWorkQueue(), threadFactory); |
420 |
|
|
} |
421 |
|
|
|
422 |
|
|
/** |
423 |
|
|
* Creates a new ScheduledThreadPoolExecutor with the given |
424 |
|
|
* initial parameters. |
425 |
|
|
* |
426 |
|
|
* @param corePoolSize the number of threads to keep in the pool, even |
427 |
|
|
* if they are idle, unless {@code allowCoreThreadTimeOut} is set |
428 |
|
|
* @param handler the handler to use when execution is blocked |
429 |
|
|
* because the thread bounds and queue capacities are reached |
430 |
|
|
* @throws IllegalArgumentException if {@code corePoolSize < 0} |
431 |
|
|
* @throws NullPointerException if {@code handler} is null |
432 |
|
|
*/ |
433 |
|
|
public ScheduledThreadPoolExecutor(int corePoolSize, |
434 |
|
|
RejectedExecutionHandler handler) { |
435 |
|
|
super(corePoolSize, Integer.MAX_VALUE, 0, NANOSECONDS, |
436 |
|
|
new DelayedWorkQueue(), handler); |
437 |
|
|
} |
438 |
|
|
|
439 |
|
|
/** |
440 |
|
|
* Creates a new ScheduledThreadPoolExecutor with the given |
441 |
|
|
* initial parameters. |
442 |
|
|
* |
443 |
|
|
* @param corePoolSize the number of threads to keep in the pool, even |
444 |
|
|
* if they are idle, unless {@code allowCoreThreadTimeOut} is set |
445 |
|
|
* @param threadFactory the factory to use when the executor |
446 |
|
|
* creates a new thread |
447 |
|
|
* @param handler the handler to use when execution is blocked |
448 |
|
|
* because the thread bounds and queue capacities are reached |
449 |
|
|
* @throws IllegalArgumentException if {@code corePoolSize < 0} |
450 |
|
|
* @throws NullPointerException if {@code threadFactory} or |
451 |
|
|
* {@code handler} is null |
452 |
|
|
*/ |
453 |
|
|
public ScheduledThreadPoolExecutor(int corePoolSize, |
454 |
|
|
ThreadFactory threadFactory, |
455 |
|
|
RejectedExecutionHandler handler) { |
456 |
|
|
super(corePoolSize, Integer.MAX_VALUE, 0, NANOSECONDS, |
457 |
|
|
new DelayedWorkQueue(), threadFactory, handler); |
458 |
|
|
} |
459 |
|
|
|
460 |
|
|
/** |
461 |
|
|
* Returns the trigger time of a delayed action. |
462 |
|
|
*/ |
463 |
|
|
private long triggerTime(long delay, TimeUnit unit) { |
464 |
|
|
return triggerTime(unit.toNanos((delay < 0) ? 0 : delay)); |
465 |
|
|
} |
466 |
|
|
|
467 |
|
|
/** |
468 |
|
|
* Returns the trigger time of a delayed action. |
469 |
|
|
*/ |
470 |
|
|
long triggerTime(long delay) { |
471 |
|
|
return now() + |
472 |
|
|
((delay < (Long.MAX_VALUE >> 1)) ? delay : overflowFree(delay)); |
473 |
|
|
} |
474 |
|
|
|
475 |
|
|
/** |
476 |
|
|
* Constrains the values of all delays in the queue to be within |
477 |
|
|
* Long.MAX_VALUE of each other, to avoid overflow in compareTo. |
478 |
|
|
* This may occur if a task is eligible to be dequeued, but has |
479 |
|
|
* not yet been, while some other task is added with a delay of |
480 |
|
|
* Long.MAX_VALUE. |
481 |
|
|
*/ |
482 |
|
|
private long overflowFree(long delay) { |
483 |
|
|
Delayed head = (Delayed) super.getQueue().peek(); |
484 |
|
|
if (head != null) { |
485 |
|
|
long headDelay = head.getDelay(NANOSECONDS); |
486 |
|
|
if (headDelay < 0 && (delay - headDelay < 0)) |
487 |
|
|
delay = Long.MAX_VALUE + headDelay; |
488 |
|
|
} |
489 |
|
|
return delay; |
490 |
|
|
} |
491 |
|
|
|
492 |
|
|
/** |
493 |
|
|
* @throws RejectedExecutionException {@inheritDoc} |
494 |
|
|
* @throws NullPointerException {@inheritDoc} |
495 |
|
|
*/ |
496 |
|
|
public ScheduledFuture<?> schedule(Runnable command, |
497 |
|
|
long delay, |
498 |
|
|
TimeUnit unit) { |
499 |
|
|
if (command == null || unit == null) |
500 |
|
|
throw new NullPointerException(); |
501 |
|
|
RunnableScheduledFuture<?> t = decorateTask(command, |
502 |
|
|
new ScheduledFutureTask<Void>(command, null, |
503 |
|
|
triggerTime(delay, unit))); |
504 |
|
|
delayedExecute(t); |
505 |
|
|
return t; |
506 |
|
|
} |
507 |
|
|
|
508 |
|
|
/** |
509 |
|
|
* @throws RejectedExecutionException {@inheritDoc} |
510 |
|
|
* @throws NullPointerException {@inheritDoc} |
511 |
|
|
*/ |
512 |
|
|
public <V> ScheduledFuture<V> schedule(Callable<V> callable, |
513 |
|
|
long delay, |
514 |
|
|
TimeUnit unit) { |
515 |
|
|
if (callable == null || unit == null) |
516 |
|
|
throw new NullPointerException(); |
517 |
|
|
RunnableScheduledFuture<V> t = decorateTask(callable, |
518 |
|
|
new ScheduledFutureTask<V>(callable, |
519 |
|
|
triggerTime(delay, unit))); |
520 |
|
|
delayedExecute(t); |
521 |
|
|
return t; |
522 |
|
|
} |
523 |
|
|
|
524 |
|
|
/** |
525 |
|
|
* @throws RejectedExecutionException {@inheritDoc} |
526 |
|
|
* @throws NullPointerException {@inheritDoc} |
527 |
|
|
* @throws IllegalArgumentException {@inheritDoc} |
528 |
|
|
*/ |
529 |
|
|
public ScheduledFuture<?> scheduleAtFixedRate(Runnable command, |
530 |
|
|
long initialDelay, |
531 |
|
|
long period, |
532 |
|
|
TimeUnit unit) { |
533 |
|
|
if (command == null || unit == null) |
534 |
|
|
throw new NullPointerException(); |
535 |
|
|
if (period <= 0) |
536 |
|
|
throw new IllegalArgumentException(); |
537 |
|
|
ScheduledFutureTask<Void> sft = |
538 |
|
|
new ScheduledFutureTask<Void>(command, |
539 |
|
|
null, |
540 |
|
|
triggerTime(initialDelay, unit), |
541 |
|
|
unit.toNanos(period)); |
542 |
|
|
RunnableScheduledFuture<Void> t = decorateTask(command, sft); |
543 |
|
|
sft.outerTask = t; |
544 |
|
|
delayedExecute(t); |
545 |
|
|
return t; |
546 |
|
|
} |
547 |
|
|
|
548 |
|
|
/** |
549 |
|
|
* @throws RejectedExecutionException {@inheritDoc} |
550 |
|
|
* @throws NullPointerException {@inheritDoc} |
551 |
|
|
* @throws IllegalArgumentException {@inheritDoc} |
552 |
|
|
*/ |
553 |
|
|
public ScheduledFuture<?> scheduleWithFixedDelay(Runnable command, |
554 |
|
|
long initialDelay, |
555 |
|
|
long delay, |
556 |
|
|
TimeUnit unit) { |
557 |
|
|
if (command == null || unit == null) |
558 |
|
|
throw new NullPointerException(); |
559 |
|
|
if (delay <= 0) |
560 |
|
|
throw new IllegalArgumentException(); |
561 |
|
|
ScheduledFutureTask<Void> sft = |
562 |
|
|
new ScheduledFutureTask<Void>(command, |
563 |
|
|
null, |
564 |
|
|
triggerTime(initialDelay, unit), |
565 |
|
|
unit.toNanos(-delay)); |
566 |
|
|
RunnableScheduledFuture<Void> t = decorateTask(command, sft); |
567 |
|
|
sft.outerTask = t; |
568 |
|
|
delayedExecute(t); |
569 |
|
|
return t; |
570 |
|
|
} |
571 |
|
|
|
572 |
|
|
/** |
573 |
|
|
* Executes {@code command} with zero required delay. |
574 |
|
|
* This has effect equivalent to |
575 |
|
|
* {@link #schedule(Runnable,long,TimeUnit) schedule(command, 0, anyUnit)}. |
576 |
|
|
* Note that inspections of the queue and of the list returned by |
577 |
|
|
* {@code shutdownNow} will access the zero-delayed |
578 |
|
|
* {@link ScheduledFuture}, not the {@code command} itself. |
579 |
|
|
* |
580 |
|
|
* <p>A consequence of the use of {@code ScheduledFuture} objects is |
581 |
|
|
* that {@link ThreadPoolExecutor#afterExecute afterExecute} is always |
582 |
|
|
* called with a null second {@code Throwable} argument, even if the |
583 |
|
|
* {@code command} terminated abruptly. Instead, the {@code Throwable} |
584 |
|
|
* thrown by such a task can be obtained via {@link Future#get}. |
585 |
|
|
* |
586 |
|
|
* @throws RejectedExecutionException at discretion of |
587 |
|
|
* {@code RejectedExecutionHandler}, if the task |
588 |
|
|
* cannot be accepted for execution because the |
589 |
|
|
* executor has been shut down |
590 |
|
|
* @throws NullPointerException {@inheritDoc} |
591 |
|
|
*/ |
592 |
|
|
public void execute(Runnable command) { |
593 |
|
|
schedule(command, 0, NANOSECONDS); |
594 |
|
|
} |
595 |
|
|
|
596 |
|
|
// Override AbstractExecutorService methods |
597 |
|
|
|
598 |
|
|
/** |
599 |
|
|
* @throws RejectedExecutionException {@inheritDoc} |
600 |
|
|
* @throws NullPointerException {@inheritDoc} |
601 |
|
|
*/ |
602 |
|
|
public Future<?> submit(Runnable task) { |
603 |
|
|
return schedule(task, 0, NANOSECONDS); |
604 |
|
|
} |
605 |
|
|
|
606 |
|
|
/** |
607 |
|
|
* @throws RejectedExecutionException {@inheritDoc} |
608 |
|
|
* @throws NullPointerException {@inheritDoc} |
609 |
|
|
*/ |
610 |
|
|
public <T> Future<T> submit(Runnable task, T result) { |
611 |
|
|
return schedule(Executors.callable(task, result), 0, NANOSECONDS); |
612 |
|
|
} |
613 |
|
|
|
614 |
|
|
/** |
615 |
|
|
* @throws RejectedExecutionException {@inheritDoc} |
616 |
|
|
* @throws NullPointerException {@inheritDoc} |
617 |
|
|
*/ |
618 |
|
|
public <T> Future<T> submit(Callable<T> task) { |
619 |
|
|
return schedule(task, 0, NANOSECONDS); |
620 |
|
|
} |
621 |
|
|
|
622 |
|
|
/** |
623 |
|
|
* Sets the policy on whether to continue executing existing |
624 |
|
|
* periodic tasks even when this executor has been {@code shutdown}. |
625 |
|
|
* In this case, these tasks will only terminate upon |
626 |
|
|
* {@code shutdownNow} or after setting the policy to |
627 |
|
|
* {@code false} when already shutdown. |
628 |
|
|
* This value is by default {@code false}. |
629 |
|
|
* |
630 |
jsr166 |
1.3 |
* @param value if {@code true}, continue after shutdown, else don't |
631 |
dl |
1.1 |
* @see #getContinueExistingPeriodicTasksAfterShutdownPolicy |
632 |
|
|
*/ |
633 |
|
|
public void setContinueExistingPeriodicTasksAfterShutdownPolicy(boolean value) { |
634 |
|
|
continueExistingPeriodicTasksAfterShutdown = value; |
635 |
|
|
if (!value && isShutdown()) |
636 |
|
|
onShutdown(); |
637 |
|
|
} |
638 |
|
|
|
639 |
|
|
/** |
640 |
|
|
* Gets the policy on whether to continue executing existing |
641 |
|
|
* periodic tasks even when this executor has been {@code shutdown}. |
642 |
|
|
* In this case, these tasks will only terminate upon |
643 |
|
|
* {@code shutdownNow} or after setting the policy to |
644 |
|
|
* {@code false} when already shutdown. |
645 |
|
|
* This value is by default {@code false}. |
646 |
|
|
* |
647 |
|
|
* @return {@code true} if will continue after shutdown |
648 |
|
|
* @see #setContinueExistingPeriodicTasksAfterShutdownPolicy |
649 |
|
|
*/ |
650 |
|
|
public boolean getContinueExistingPeriodicTasksAfterShutdownPolicy() { |
651 |
|
|
return continueExistingPeriodicTasksAfterShutdown; |
652 |
|
|
} |
653 |
|
|
|
654 |
|
|
/** |
655 |
|
|
* Sets the policy on whether to execute existing delayed |
656 |
|
|
* tasks even when this executor has been {@code shutdown}. |
657 |
|
|
* In this case, these tasks will only terminate upon |
658 |
|
|
* {@code shutdownNow}, or after setting the policy to |
659 |
|
|
* {@code false} when already shutdown. |
660 |
|
|
* This value is by default {@code true}. |
661 |
|
|
* |
662 |
jsr166 |
1.3 |
* @param value if {@code true}, execute after shutdown, else don't |
663 |
dl |
1.1 |
* @see #getExecuteExistingDelayedTasksAfterShutdownPolicy |
664 |
|
|
*/ |
665 |
|
|
public void setExecuteExistingDelayedTasksAfterShutdownPolicy(boolean value) { |
666 |
|
|
executeExistingDelayedTasksAfterShutdown = value; |
667 |
|
|
if (!value && isShutdown()) |
668 |
|
|
onShutdown(); |
669 |
|
|
} |
670 |
|
|
|
671 |
|
|
/** |
672 |
|
|
* Gets the policy on whether to execute existing delayed |
673 |
|
|
* tasks even when this executor has been {@code shutdown}. |
674 |
|
|
* In this case, these tasks will only terminate upon |
675 |
|
|
* {@code shutdownNow}, or after setting the policy to |
676 |
|
|
* {@code false} when already shutdown. |
677 |
|
|
* This value is by default {@code true}. |
678 |
|
|
* |
679 |
|
|
* @return {@code true} if will execute after shutdown |
680 |
|
|
* @see #setExecuteExistingDelayedTasksAfterShutdownPolicy |
681 |
|
|
*/ |
682 |
|
|
public boolean getExecuteExistingDelayedTasksAfterShutdownPolicy() { |
683 |
|
|
return executeExistingDelayedTasksAfterShutdown; |
684 |
|
|
} |
685 |
|
|
|
686 |
|
|
/** |
687 |
|
|
* Sets the policy on whether cancelled tasks should be immediately |
688 |
|
|
* removed from the work queue at time of cancellation. This value is |
689 |
|
|
* by default {@code false}. |
690 |
|
|
* |
691 |
|
|
* @param value if {@code true}, remove on cancellation, else don't |
692 |
|
|
* @see #getRemoveOnCancelPolicy |
693 |
|
|
* @since 1.7 |
694 |
|
|
*/ |
695 |
|
|
public void setRemoveOnCancelPolicy(boolean value) { |
696 |
|
|
removeOnCancel = value; |
697 |
|
|
} |
698 |
|
|
|
699 |
|
|
/** |
700 |
|
|
* Gets the policy on whether cancelled tasks should be immediately |
701 |
|
|
* removed from the work queue at time of cancellation. This value is |
702 |
|
|
* by default {@code false}. |
703 |
|
|
* |
704 |
|
|
* @return {@code true} if cancelled tasks are immediately removed |
705 |
|
|
* from the queue |
706 |
|
|
* @see #setRemoveOnCancelPolicy |
707 |
|
|
* @since 1.7 |
708 |
|
|
*/ |
709 |
|
|
public boolean getRemoveOnCancelPolicy() { |
710 |
|
|
return removeOnCancel; |
711 |
|
|
} |
712 |
|
|
|
713 |
|
|
/** |
714 |
|
|
* Initiates an orderly shutdown in which previously submitted |
715 |
|
|
* tasks are executed, but no new tasks will be accepted. |
716 |
|
|
* Invocation has no additional effect if already shut down. |
717 |
|
|
* |
718 |
|
|
* <p>This method does not wait for previously submitted tasks to |
719 |
|
|
* complete execution. Use {@link #awaitTermination awaitTermination} |
720 |
|
|
* to do that. |
721 |
|
|
* |
722 |
|
|
* <p>If the {@code ExecuteExistingDelayedTasksAfterShutdownPolicy} |
723 |
|
|
* has been set {@code false}, existing delayed tasks whose delays |
724 |
|
|
* have not yet elapsed are cancelled. And unless the {@code |
725 |
|
|
* ContinueExistingPeriodicTasksAfterShutdownPolicy} has been set |
726 |
|
|
* {@code true}, future executions of existing periodic tasks will |
727 |
|
|
* be cancelled. |
728 |
|
|
* |
729 |
|
|
* @throws SecurityException {@inheritDoc} |
730 |
|
|
*/ |
731 |
|
|
public void shutdown() { |
732 |
|
|
super.shutdown(); |
733 |
|
|
} |
734 |
|
|
|
735 |
|
|
/** |
736 |
|
|
* Attempts to stop all actively executing tasks, halts the |
737 |
|
|
* processing of waiting tasks, and returns a list of the tasks |
738 |
|
|
* that were awaiting execution. |
739 |
|
|
* |
740 |
|
|
* <p>This method does not wait for actively executing tasks to |
741 |
|
|
* terminate. Use {@link #awaitTermination awaitTermination} to |
742 |
|
|
* do that. |
743 |
|
|
* |
744 |
|
|
* <p>There are no guarantees beyond best-effort attempts to stop |
745 |
|
|
* processing actively executing tasks. This implementation |
746 |
|
|
* cancels tasks via {@link Thread#interrupt}, so any task that |
747 |
|
|
* fails to respond to interrupts may never terminate. |
748 |
|
|
* |
749 |
|
|
* @return list of tasks that never commenced execution. |
750 |
|
|
* Each element of this list is a {@link ScheduledFuture}, |
751 |
|
|
* including those tasks submitted using {@code execute}, |
752 |
|
|
* which are for scheduling purposes used as the basis of a |
753 |
|
|
* zero-delay {@code ScheduledFuture}. |
754 |
|
|
* @throws SecurityException {@inheritDoc} |
755 |
|
|
*/ |
756 |
|
|
public List<Runnable> shutdownNow() { |
757 |
|
|
return super.shutdownNow(); |
758 |
|
|
} |
759 |
|
|
|
760 |
|
|
/** |
761 |
|
|
* Returns the task queue used by this executor. Each element of |
762 |
|
|
* this queue is a {@link ScheduledFuture}, including those |
763 |
|
|
* tasks submitted using {@code execute} which are for scheduling |
764 |
|
|
* purposes used as the basis of a zero-delay |
765 |
|
|
* {@code ScheduledFuture}. Iteration over this queue is |
766 |
|
|
* <em>not</em> guaranteed to traverse tasks in the order in |
767 |
|
|
* which they will execute. |
768 |
|
|
* |
769 |
|
|
* @return the task queue |
770 |
|
|
*/ |
771 |
|
|
public BlockingQueue<Runnable> getQueue() { |
772 |
|
|
return super.getQueue(); |
773 |
|
|
} |
774 |
|
|
|
775 |
|
|
/** |
776 |
|
|
* Specialized delay queue. To mesh with TPE declarations, this |
777 |
|
|
* class must be declared as a BlockingQueue<Runnable> even though |
778 |
|
|
* it can only hold RunnableScheduledFutures. |
779 |
|
|
*/ |
780 |
|
|
static class DelayedWorkQueue extends AbstractQueue<Runnable> |
781 |
|
|
implements BlockingQueue<Runnable> { |
782 |
|
|
|
783 |
|
|
/* |
784 |
|
|
* A DelayedWorkQueue is based on a heap-based data structure |
785 |
|
|
* like those in DelayQueue and PriorityQueue, except that |
786 |
|
|
* every ScheduledFutureTask also records its index into the |
787 |
|
|
* heap array. This eliminates the need to find a task upon |
788 |
|
|
* cancellation, greatly speeding up removal (down from O(n) |
789 |
|
|
* to O(log n)), and reducing garbage retention that would |
790 |
|
|
* otherwise occur by waiting for the element to rise to top |
791 |
|
|
* before clearing. But because the queue may also hold |
792 |
|
|
* RunnableScheduledFutures that are not ScheduledFutureTasks, |
793 |
|
|
* we are not guaranteed to have such indices available, in |
794 |
|
|
* which case we fall back to linear search. (We expect that |
795 |
|
|
* most tasks will not be decorated, and that the faster cases |
796 |
|
|
* will be much more common.) |
797 |
|
|
* |
798 |
|
|
* All heap operations must record index changes -- mainly |
799 |
|
|
* within siftUp and siftDown. Upon removal, a task's |
800 |
|
|
* heapIndex is set to -1. Note that ScheduledFutureTasks can |
801 |
|
|
* appear at most once in the queue (this need not be true for |
802 |
|
|
* other kinds of tasks or work queues), so are uniquely |
803 |
|
|
* identified by heapIndex. |
804 |
|
|
*/ |
805 |
|
|
|
806 |
|
|
private static final int INITIAL_CAPACITY = 16; |
807 |
|
|
private RunnableScheduledFuture<?>[] queue = |
808 |
|
|
new RunnableScheduledFuture<?>[INITIAL_CAPACITY]; |
809 |
|
|
private final ReentrantLock lock = new ReentrantLock(); |
810 |
jsr166 |
1.6 |
private int size; |
811 |
dl |
1.1 |
|
812 |
|
|
/** |
813 |
|
|
* Thread designated to wait for the task at the head of the |
814 |
|
|
* queue. This variant of the Leader-Follower pattern |
815 |
|
|
* (http://www.cs.wustl.edu/~schmidt/POSA/POSA2/) serves to |
816 |
|
|
* minimize unnecessary timed waiting. When a thread becomes |
817 |
|
|
* the leader, it waits only for the next delay to elapse, but |
818 |
|
|
* other threads await indefinitely. The leader thread must |
819 |
|
|
* signal some other thread before returning from take() or |
820 |
|
|
* poll(...), unless some other thread becomes leader in the |
821 |
|
|
* interim. Whenever the head of the queue is replaced with a |
822 |
|
|
* task with an earlier expiration time, the leader field is |
823 |
|
|
* invalidated by being reset to null, and some waiting |
824 |
|
|
* thread, but not necessarily the current leader, is |
825 |
|
|
* signalled. So waiting threads must be prepared to acquire |
826 |
|
|
* and lose leadership while waiting. |
827 |
|
|
*/ |
828 |
jsr166 |
1.6 |
private Thread leader; |
829 |
dl |
1.1 |
|
830 |
|
|
/** |
831 |
|
|
* Condition signalled when a newer task becomes available at the |
832 |
|
|
* head of the queue or a new thread may need to become leader. |
833 |
|
|
*/ |
834 |
|
|
private final Condition available = lock.newCondition(); |
835 |
|
|
|
836 |
|
|
/** |
837 |
|
|
* Sets f's heapIndex if it is a ScheduledFutureTask. |
838 |
|
|
*/ |
839 |
|
|
private void setIndex(RunnableScheduledFuture<?> f, int idx) { |
840 |
|
|
if (f instanceof ScheduledFutureTask) |
841 |
|
|
((ScheduledFutureTask)f).heapIndex = idx; |
842 |
|
|
} |
843 |
|
|
|
844 |
|
|
/** |
845 |
|
|
* Sifts element added at bottom up to its heap-ordered spot. |
846 |
|
|
* Call only when holding lock. |
847 |
|
|
*/ |
848 |
|
|
private void siftUp(int k, RunnableScheduledFuture<?> key) { |
849 |
|
|
while (k > 0) { |
850 |
|
|
int parent = (k - 1) >>> 1; |
851 |
|
|
RunnableScheduledFuture<?> e = queue[parent]; |
852 |
|
|
if (key.compareTo(e) >= 0) |
853 |
|
|
break; |
854 |
|
|
queue[k] = e; |
855 |
|
|
setIndex(e, k); |
856 |
|
|
k = parent; |
857 |
|
|
} |
858 |
|
|
queue[k] = key; |
859 |
|
|
setIndex(key, k); |
860 |
|
|
} |
861 |
|
|
|
862 |
|
|
/** |
863 |
|
|
* Sifts element added at top down to its heap-ordered spot. |
864 |
|
|
* Call only when holding lock. |
865 |
|
|
*/ |
866 |
|
|
private void siftDown(int k, RunnableScheduledFuture<?> key) { |
867 |
|
|
int half = size >>> 1; |
868 |
|
|
while (k < half) { |
869 |
|
|
int child = (k << 1) + 1; |
870 |
|
|
RunnableScheduledFuture<?> c = queue[child]; |
871 |
|
|
int right = child + 1; |
872 |
|
|
if (right < size && c.compareTo(queue[right]) > 0) |
873 |
|
|
c = queue[child = right]; |
874 |
|
|
if (key.compareTo(c) <= 0) |
875 |
|
|
break; |
876 |
|
|
queue[k] = c; |
877 |
|
|
setIndex(c, k); |
878 |
|
|
k = child; |
879 |
|
|
} |
880 |
|
|
queue[k] = key; |
881 |
|
|
setIndex(key, k); |
882 |
|
|
} |
883 |
|
|
|
884 |
|
|
/** |
885 |
|
|
* Resizes the heap array. Call only when holding lock. |
886 |
|
|
*/ |
887 |
|
|
private void grow() { |
888 |
|
|
int oldCapacity = queue.length; |
889 |
|
|
int newCapacity = oldCapacity + (oldCapacity >> 1); // grow 50% |
890 |
|
|
if (newCapacity < 0) // overflow |
891 |
|
|
newCapacity = Integer.MAX_VALUE; |
892 |
|
|
queue = Arrays.copyOf(queue, newCapacity); |
893 |
|
|
} |
894 |
|
|
|
895 |
|
|
/** |
896 |
|
|
* Finds index of given object, or -1 if absent. |
897 |
|
|
*/ |
898 |
|
|
private int indexOf(Object x) { |
899 |
|
|
if (x != null) { |
900 |
|
|
if (x instanceof ScheduledFutureTask) { |
901 |
|
|
int i = ((ScheduledFutureTask) x).heapIndex; |
902 |
|
|
// Sanity check; x could conceivably be a |
903 |
|
|
// ScheduledFutureTask from some other pool. |
904 |
|
|
if (i >= 0 && i < size && queue[i] == x) |
905 |
|
|
return i; |
906 |
|
|
} else { |
907 |
|
|
for (int i = 0; i < size; i++) |
908 |
|
|
if (x.equals(queue[i])) |
909 |
|
|
return i; |
910 |
|
|
} |
911 |
|
|
} |
912 |
|
|
return -1; |
913 |
|
|
} |
914 |
|
|
|
915 |
|
|
public boolean contains(Object x) { |
916 |
|
|
final ReentrantLock lock = this.lock; |
917 |
|
|
lock.lock(); |
918 |
|
|
try { |
919 |
|
|
return indexOf(x) != -1; |
920 |
|
|
} finally { |
921 |
|
|
lock.unlock(); |
922 |
|
|
} |
923 |
|
|
} |
924 |
|
|
|
925 |
|
|
public boolean remove(Object x) { |
926 |
|
|
final ReentrantLock lock = this.lock; |
927 |
|
|
lock.lock(); |
928 |
|
|
try { |
929 |
|
|
int i = indexOf(x); |
930 |
|
|
if (i < 0) |
931 |
|
|
return false; |
932 |
|
|
|
933 |
|
|
setIndex(queue[i], -1); |
934 |
|
|
int s = --size; |
935 |
|
|
RunnableScheduledFuture<?> replacement = queue[s]; |
936 |
|
|
queue[s] = null; |
937 |
|
|
if (s != i) { |
938 |
|
|
siftDown(i, replacement); |
939 |
|
|
if (queue[i] == replacement) |
940 |
|
|
siftUp(i, replacement); |
941 |
|
|
} |
942 |
|
|
return true; |
943 |
|
|
} finally { |
944 |
|
|
lock.unlock(); |
945 |
|
|
} |
946 |
|
|
} |
947 |
|
|
|
948 |
|
|
public int size() { |
949 |
|
|
final ReentrantLock lock = this.lock; |
950 |
|
|
lock.lock(); |
951 |
|
|
try { |
952 |
|
|
return size; |
953 |
|
|
} finally { |
954 |
|
|
lock.unlock(); |
955 |
|
|
} |
956 |
|
|
} |
957 |
|
|
|
958 |
|
|
public boolean isEmpty() { |
959 |
|
|
return size() == 0; |
960 |
|
|
} |
961 |
|
|
|
962 |
|
|
public int remainingCapacity() { |
963 |
|
|
return Integer.MAX_VALUE; |
964 |
|
|
} |
965 |
|
|
|
966 |
|
|
public RunnableScheduledFuture<?> peek() { |
967 |
|
|
final ReentrantLock lock = this.lock; |
968 |
|
|
lock.lock(); |
969 |
|
|
try { |
970 |
|
|
return queue[0]; |
971 |
|
|
} finally { |
972 |
|
|
lock.unlock(); |
973 |
|
|
} |
974 |
|
|
} |
975 |
|
|
|
976 |
|
|
public boolean offer(Runnable x) { |
977 |
|
|
if (x == null) |
978 |
|
|
throw new NullPointerException(); |
979 |
|
|
RunnableScheduledFuture<?> e = (RunnableScheduledFuture<?>)x; |
980 |
|
|
final ReentrantLock lock = this.lock; |
981 |
|
|
lock.lock(); |
982 |
|
|
try { |
983 |
|
|
int i = size; |
984 |
|
|
if (i >= queue.length) |
985 |
|
|
grow(); |
986 |
|
|
size = i + 1; |
987 |
|
|
if (i == 0) { |
988 |
|
|
queue[0] = e; |
989 |
|
|
setIndex(e, 0); |
990 |
|
|
} else { |
991 |
|
|
siftUp(i, e); |
992 |
|
|
} |
993 |
|
|
if (queue[0] == e) { |
994 |
|
|
leader = null; |
995 |
|
|
available.signal(); |
996 |
|
|
} |
997 |
|
|
} finally { |
998 |
|
|
lock.unlock(); |
999 |
|
|
} |
1000 |
|
|
return true; |
1001 |
|
|
} |
1002 |
|
|
|
1003 |
|
|
public void put(Runnable e) { |
1004 |
|
|
offer(e); |
1005 |
|
|
} |
1006 |
|
|
|
1007 |
|
|
public boolean add(Runnable e) { |
1008 |
|
|
return offer(e); |
1009 |
|
|
} |
1010 |
|
|
|
1011 |
|
|
public boolean offer(Runnable e, long timeout, TimeUnit unit) { |
1012 |
|
|
return offer(e); |
1013 |
|
|
} |
1014 |
|
|
|
1015 |
|
|
/** |
1016 |
|
|
* Performs common bookkeeping for poll and take: Replaces |
1017 |
|
|
* first element with last and sifts it down. Call only when |
1018 |
|
|
* holding lock. |
1019 |
|
|
* @param f the task to remove and return |
1020 |
|
|
*/ |
1021 |
|
|
private RunnableScheduledFuture<?> finishPoll(RunnableScheduledFuture<?> f) { |
1022 |
|
|
int s = --size; |
1023 |
|
|
RunnableScheduledFuture<?> x = queue[s]; |
1024 |
|
|
queue[s] = null; |
1025 |
|
|
if (s != 0) |
1026 |
|
|
siftDown(0, x); |
1027 |
|
|
setIndex(f, -1); |
1028 |
|
|
return f; |
1029 |
|
|
} |
1030 |
|
|
|
1031 |
|
|
public RunnableScheduledFuture<?> poll() { |
1032 |
|
|
final ReentrantLock lock = this.lock; |
1033 |
|
|
lock.lock(); |
1034 |
|
|
try { |
1035 |
|
|
RunnableScheduledFuture<?> first = queue[0]; |
1036 |
|
|
if (first == null || first.getDelay(NANOSECONDS) > 0) |
1037 |
|
|
return null; |
1038 |
|
|
else |
1039 |
|
|
return finishPoll(first); |
1040 |
|
|
} finally { |
1041 |
|
|
lock.unlock(); |
1042 |
|
|
} |
1043 |
|
|
} |
1044 |
|
|
|
1045 |
|
|
public RunnableScheduledFuture<?> take() throws InterruptedException { |
1046 |
|
|
final ReentrantLock lock = this.lock; |
1047 |
|
|
lock.lockInterruptibly(); |
1048 |
|
|
try { |
1049 |
|
|
for (;;) { |
1050 |
|
|
RunnableScheduledFuture<?> first = queue[0]; |
1051 |
|
|
if (first == null) |
1052 |
|
|
available.await(); |
1053 |
|
|
else { |
1054 |
|
|
long delay = first.getDelay(NANOSECONDS); |
1055 |
|
|
if (delay <= 0) |
1056 |
|
|
return finishPoll(first); |
1057 |
jsr166 |
1.4 |
first = null; // don't retain ref while waiting |
1058 |
|
|
if (leader != null) |
1059 |
dl |
1.1 |
available.await(); |
1060 |
|
|
else { |
1061 |
|
|
Thread thisThread = Thread.currentThread(); |
1062 |
|
|
leader = thisThread; |
1063 |
|
|
try { |
1064 |
|
|
available.awaitNanos(delay); |
1065 |
|
|
} finally { |
1066 |
|
|
if (leader == thisThread) |
1067 |
|
|
leader = null; |
1068 |
|
|
} |
1069 |
|
|
} |
1070 |
|
|
} |
1071 |
|
|
} |
1072 |
|
|
} finally { |
1073 |
|
|
if (leader == null && queue[0] != null) |
1074 |
|
|
available.signal(); |
1075 |
|
|
lock.unlock(); |
1076 |
|
|
} |
1077 |
|
|
} |
1078 |
|
|
|
1079 |
|
|
public RunnableScheduledFuture<?> poll(long timeout, TimeUnit unit) |
1080 |
|
|
throws InterruptedException { |
1081 |
|
|
long nanos = unit.toNanos(timeout); |
1082 |
|
|
final ReentrantLock lock = this.lock; |
1083 |
|
|
lock.lockInterruptibly(); |
1084 |
|
|
try { |
1085 |
|
|
for (;;) { |
1086 |
|
|
RunnableScheduledFuture<?> first = queue[0]; |
1087 |
|
|
if (first == null) { |
1088 |
|
|
if (nanos <= 0) |
1089 |
|
|
return null; |
1090 |
|
|
else |
1091 |
|
|
nanos = available.awaitNanos(nanos); |
1092 |
|
|
} else { |
1093 |
|
|
long delay = first.getDelay(NANOSECONDS); |
1094 |
|
|
if (delay <= 0) |
1095 |
|
|
return finishPoll(first); |
1096 |
|
|
if (nanos <= 0) |
1097 |
|
|
return null; |
1098 |
jsr166 |
1.4 |
first = null; // don't retain ref while waiting |
1099 |
dl |
1.1 |
if (nanos < delay || leader != null) |
1100 |
|
|
nanos = available.awaitNanos(nanos); |
1101 |
|
|
else { |
1102 |
|
|
Thread thisThread = Thread.currentThread(); |
1103 |
|
|
leader = thisThread; |
1104 |
|
|
try { |
1105 |
|
|
long timeLeft = available.awaitNanos(delay); |
1106 |
|
|
nanos -= delay - timeLeft; |
1107 |
|
|
} finally { |
1108 |
|
|
if (leader == thisThread) |
1109 |
|
|
leader = null; |
1110 |
|
|
} |
1111 |
|
|
} |
1112 |
|
|
} |
1113 |
|
|
} |
1114 |
|
|
} finally { |
1115 |
|
|
if (leader == null && queue[0] != null) |
1116 |
|
|
available.signal(); |
1117 |
|
|
lock.unlock(); |
1118 |
|
|
} |
1119 |
|
|
} |
1120 |
|
|
|
1121 |
|
|
public void clear() { |
1122 |
|
|
final ReentrantLock lock = this.lock; |
1123 |
|
|
lock.lock(); |
1124 |
|
|
try { |
1125 |
|
|
for (int i = 0; i < size; i++) { |
1126 |
|
|
RunnableScheduledFuture<?> t = queue[i]; |
1127 |
|
|
if (t != null) { |
1128 |
|
|
queue[i] = null; |
1129 |
|
|
setIndex(t, -1); |
1130 |
|
|
} |
1131 |
|
|
} |
1132 |
|
|
size = 0; |
1133 |
|
|
} finally { |
1134 |
|
|
lock.unlock(); |
1135 |
|
|
} |
1136 |
|
|
} |
1137 |
|
|
|
1138 |
|
|
/** |
1139 |
|
|
* Returns first element only if it is expired. |
1140 |
|
|
* Used only by drainTo. Call only when holding lock. |
1141 |
|
|
*/ |
1142 |
|
|
private RunnableScheduledFuture<?> peekExpired() { |
1143 |
|
|
// assert lock.isHeldByCurrentThread(); |
1144 |
|
|
RunnableScheduledFuture<?> first = queue[0]; |
1145 |
|
|
return (first == null || first.getDelay(NANOSECONDS) > 0) ? |
1146 |
|
|
null : first; |
1147 |
|
|
} |
1148 |
|
|
|
1149 |
|
|
public int drainTo(Collection<? super Runnable> c) { |
1150 |
|
|
if (c == null) |
1151 |
|
|
throw new NullPointerException(); |
1152 |
|
|
if (c == this) |
1153 |
|
|
throw new IllegalArgumentException(); |
1154 |
|
|
final ReentrantLock lock = this.lock; |
1155 |
|
|
lock.lock(); |
1156 |
|
|
try { |
1157 |
|
|
RunnableScheduledFuture<?> first; |
1158 |
|
|
int n = 0; |
1159 |
|
|
while ((first = peekExpired()) != null) { |
1160 |
|
|
c.add(first); // In this order, in case add() throws. |
1161 |
|
|
finishPoll(first); |
1162 |
|
|
++n; |
1163 |
|
|
} |
1164 |
|
|
return n; |
1165 |
|
|
} finally { |
1166 |
|
|
lock.unlock(); |
1167 |
|
|
} |
1168 |
|
|
} |
1169 |
|
|
|
1170 |
|
|
public int drainTo(Collection<? super Runnable> c, int maxElements) { |
1171 |
|
|
if (c == null) |
1172 |
|
|
throw new NullPointerException(); |
1173 |
|
|
if (c == this) |
1174 |
|
|
throw new IllegalArgumentException(); |
1175 |
|
|
if (maxElements <= 0) |
1176 |
|
|
return 0; |
1177 |
|
|
final ReentrantLock lock = this.lock; |
1178 |
|
|
lock.lock(); |
1179 |
|
|
try { |
1180 |
|
|
RunnableScheduledFuture<?> first; |
1181 |
|
|
int n = 0; |
1182 |
|
|
while (n < maxElements && (first = peekExpired()) != null) { |
1183 |
|
|
c.add(first); // In this order, in case add() throws. |
1184 |
|
|
finishPoll(first); |
1185 |
|
|
++n; |
1186 |
|
|
} |
1187 |
|
|
return n; |
1188 |
|
|
} finally { |
1189 |
|
|
lock.unlock(); |
1190 |
|
|
} |
1191 |
|
|
} |
1192 |
|
|
|
1193 |
|
|
public Object[] toArray() { |
1194 |
|
|
final ReentrantLock lock = this.lock; |
1195 |
|
|
lock.lock(); |
1196 |
|
|
try { |
1197 |
|
|
return Arrays.copyOf(queue, size, Object[].class); |
1198 |
|
|
} finally { |
1199 |
|
|
lock.unlock(); |
1200 |
|
|
} |
1201 |
|
|
} |
1202 |
|
|
|
1203 |
|
|
@SuppressWarnings("unchecked") |
1204 |
|
|
public <T> T[] toArray(T[] a) { |
1205 |
|
|
final ReentrantLock lock = this.lock; |
1206 |
|
|
lock.lock(); |
1207 |
|
|
try { |
1208 |
|
|
if (a.length < size) |
1209 |
|
|
return (T[]) Arrays.copyOf(queue, size, a.getClass()); |
1210 |
|
|
System.arraycopy(queue, 0, a, 0, size); |
1211 |
|
|
if (a.length > size) |
1212 |
|
|
a[size] = null; |
1213 |
|
|
return a; |
1214 |
|
|
} finally { |
1215 |
|
|
lock.unlock(); |
1216 |
|
|
} |
1217 |
|
|
} |
1218 |
|
|
|
1219 |
|
|
public Iterator<Runnable> iterator() { |
1220 |
|
|
return new Itr(Arrays.copyOf(queue, size)); |
1221 |
|
|
} |
1222 |
|
|
|
1223 |
|
|
/** |
1224 |
|
|
* Snapshot iterator that works off copy of underlying q array. |
1225 |
|
|
*/ |
1226 |
|
|
private class Itr implements Iterator<Runnable> { |
1227 |
|
|
final RunnableScheduledFuture[] array; |
1228 |
|
|
int cursor = 0; // index of next element to return |
1229 |
|
|
int lastRet = -1; // index of last element, or -1 if no such |
1230 |
|
|
|
1231 |
|
|
Itr(RunnableScheduledFuture[] array) { |
1232 |
|
|
this.array = array; |
1233 |
|
|
} |
1234 |
|
|
|
1235 |
|
|
public boolean hasNext() { |
1236 |
|
|
return cursor < array.length; |
1237 |
|
|
} |
1238 |
|
|
|
1239 |
|
|
public Runnable next() { |
1240 |
|
|
if (cursor >= array.length) |
1241 |
|
|
throw new NoSuchElementException(); |
1242 |
|
|
lastRet = cursor; |
1243 |
|
|
return array[cursor++]; |
1244 |
|
|
} |
1245 |
|
|
|
1246 |
|
|
public void remove() { |
1247 |
|
|
if (lastRet < 0) |
1248 |
|
|
throw new IllegalStateException(); |
1249 |
|
|
DelayedWorkQueue.this.remove(array[lastRet]); |
1250 |
|
|
lastRet = -1; |
1251 |
|
|
} |
1252 |
|
|
} |
1253 |
|
|
} |
1254 |
|
|
} |