1 |
dl |
1.1 |
/* |
2 |
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* Written by Doug Lea with assistance from members of JCP JSR-166 |
3 |
dl |
1.11 |
* Expert Group and released to the public domain, as explained at |
4 |
jsr166 |
1.58 |
* http://creativecommons.org/publicdomain/zero/1.0/ |
5 |
dl |
1.1 |
*/ |
6 |
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package java.util.concurrent; |
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jsr166 |
1.62 |
import static java.util.concurrent.TimeUnit.NANOSECONDS; |
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import java.util.concurrent.atomic.AtomicLong; |
10 |
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import java.util.concurrent.locks.Condition; |
11 |
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import java.util.concurrent.locks.ReentrantLock; |
12 |
dl |
1.1 |
import java.util.*; |
13 |
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14 |
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/** |
15 |
dl |
1.7 |
* A {@link ThreadPoolExecutor} that can additionally schedule |
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jsr166 |
1.75 |
* commands to run after a given delay, or to execute periodically. |
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* This class is preferable to {@link java.util.Timer} when multiple |
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* worker threads are needed, or when the additional flexibility or |
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* capabilities of {@link ThreadPoolExecutor} (which this class |
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* extends) are required. |
21 |
dl |
1.1 |
* |
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jsr166 |
1.46 |
* <p>Delayed tasks execute no sooner than they are enabled, but |
23 |
dl |
1.18 |
* without any real-time guarantees about when, after they are |
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* enabled, they will commence. Tasks scheduled for exactly the same |
25 |
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* execution time are enabled in first-in-first-out (FIFO) order of |
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jsr166 |
1.46 |
* submission. |
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* |
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* <p>When a submitted task is cancelled before it is run, execution |
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jsr166 |
1.75 |
* is suppressed. By default, such a cancelled task is not |
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* automatically removed from the work queue until its delay elapses. |
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* While this enables further inspection and monitoring, it may also |
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* cause unbounded retention of cancelled tasks. To avoid this, use |
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* {@link #setRemoveOnCancelPolicy} to cause tasks to be immediately |
34 |
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* removed from the work queue at time of cancellation. |
35 |
dl |
1.1 |
* |
36 |
jsr166 |
1.75 |
* <p>Successive executions of a periodic task scheduled via |
37 |
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* {@link #scheduleAtFixedRate} or |
38 |
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* {@link #scheduleWithFixedDelay} do not overlap. While different |
39 |
dl |
1.51 |
* executions may be performed by different threads, the effects of |
40 |
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* prior executions <a |
41 |
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* href="package-summary.html#MemoryVisibility"><i>happen-before</i></a> |
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* those of subsequent ones. |
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* |
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dl |
1.1 |
* <p>While this class inherits from {@link ThreadPoolExecutor}, a few |
45 |
dl |
1.8 |
* of the inherited tuning methods are not useful for it. In |
46 |
jsr166 |
1.53 |
* particular, because it acts as a fixed-sized pool using |
47 |
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* {@code corePoolSize} threads and an unbounded queue, adjustments |
48 |
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* to {@code maximumPoolSize} have no useful effect. Additionally, it |
49 |
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* is almost never a good idea to set {@code corePoolSize} to zero or |
50 |
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* use {@code allowCoreThreadTimeOut} because this may leave the pool |
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* without threads to handle tasks once they become eligible to run. |
52 |
dl |
1.1 |
* |
53 |
jsr166 |
1.39 |
* <p><b>Extension notes:</b> This class overrides the |
54 |
jsr166 |
1.69 |
* {@link ThreadPoolExecutor#execute(Runnable) execute} and |
55 |
jsr166 |
1.39 |
* {@link AbstractExecutorService#submit(Runnable) submit} |
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* methods to generate internal {@link ScheduledFuture} objects to |
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* control per-task delays and scheduling. To preserve |
58 |
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* functionality, any further overrides of these methods in |
59 |
dl |
1.32 |
* subclasses must invoke superclass versions, which effectively |
60 |
jsr166 |
1.39 |
* disables additional task customization. However, this class |
61 |
dl |
1.32 |
* provides alternative protected extension method |
62 |
jsr166 |
1.39 |
* {@code decorateTask} (one version each for {@code Runnable} and |
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* {@code Callable}) that can be used to customize the concrete task |
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* types used to execute commands entered via {@code execute}, |
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* {@code submit}, {@code schedule}, {@code scheduleAtFixedRate}, |
66 |
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* and {@code scheduleWithFixedDelay}. By default, a |
67 |
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* {@code ScheduledThreadPoolExecutor} uses a task type extending |
68 |
dl |
1.32 |
* {@link FutureTask}. However, this may be modified or replaced using |
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* subclasses of the form: |
70 |
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* |
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jsr166 |
1.39 |
* <pre> {@code |
72 |
dl |
1.23 |
* public class CustomScheduledExecutor extends ScheduledThreadPoolExecutor { |
73 |
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* |
74 |
jsr166 |
1.39 |
* static class CustomTask<V> implements RunnableScheduledFuture<V> { ... } |
75 |
dl |
1.23 |
* |
76 |
jsr166 |
1.39 |
* protected <V> RunnableScheduledFuture<V> decorateTask( |
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* Runnable r, RunnableScheduledFuture<V> task) { |
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* return new CustomTask<V>(r, task); |
79 |
jsr166 |
1.29 |
* } |
80 |
dl |
1.23 |
* |
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jsr166 |
1.39 |
* protected <V> RunnableScheduledFuture<V> decorateTask( |
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* Callable<V> c, RunnableScheduledFuture<V> task) { |
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* return new CustomTask<V>(c, task); |
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jsr166 |
1.29 |
* } |
85 |
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* // ... add constructors, etc. |
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jsr166 |
1.39 |
* }}</pre> |
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* |
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dl |
1.1 |
* @since 1.5 |
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* @author Doug Lea |
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*/ |
91 |
jsr166 |
1.21 |
public class ScheduledThreadPoolExecutor |
92 |
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extends ThreadPoolExecutor |
93 |
tim |
1.3 |
implements ScheduledExecutorService { |
94 |
dl |
1.1 |
|
95 |
dl |
1.37 |
/* |
96 |
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* This class specializes ThreadPoolExecutor implementation by |
97 |
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* |
98 |
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* 1. Using a custom task type, ScheduledFutureTask for |
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* tasks, even those that don't require scheduling (i.e., |
100 |
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* those submitted using ExecutorService execute, not |
101 |
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* ScheduledExecutorService methods) which are treated as |
102 |
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* delayed tasks with a delay of zero. |
103 |
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* |
104 |
jsr166 |
1.46 |
* 2. Using a custom queue (DelayedWorkQueue), a variant of |
105 |
dl |
1.37 |
* unbounded DelayQueue. The lack of capacity constraint and |
106 |
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* the fact that corePoolSize and maximumPoolSize are |
107 |
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* effectively identical simplifies some execution mechanics |
108 |
jsr166 |
1.46 |
* (see delayedExecute) compared to ThreadPoolExecutor. |
109 |
dl |
1.37 |
* |
110 |
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* 3. Supporting optional run-after-shutdown parameters, which |
111 |
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* leads to overrides of shutdown methods to remove and cancel |
112 |
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* tasks that should NOT be run after shutdown, as well as |
113 |
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* different recheck logic when task (re)submission overlaps |
114 |
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* with a shutdown. |
115 |
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* |
116 |
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* 4. Task decoration methods to allow interception and |
117 |
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* instrumentation, which are needed because subclasses cannot |
118 |
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* otherwise override submit methods to get this effect. These |
119 |
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* don't have any impact on pool control logic though. |
120 |
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*/ |
121 |
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122 |
dl |
1.1 |
/** |
123 |
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* False if should cancel/suppress periodic tasks on shutdown. |
124 |
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*/ |
125 |
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private volatile boolean continueExistingPeriodicTasksAfterShutdown; |
126 |
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127 |
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/** |
128 |
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* False if should cancel non-periodic tasks on shutdown. |
129 |
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*/ |
130 |
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private volatile boolean executeExistingDelayedTasksAfterShutdown = true; |
131 |
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132 |
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/** |
133 |
jsr166 |
1.75 |
* True if ScheduledFutureTask.cancel should remove from queue. |
134 |
dl |
1.41 |
*/ |
135 |
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private volatile boolean removeOnCancel = false; |
136 |
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137 |
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/** |
138 |
dl |
1.1 |
* Sequence number to break scheduling ties, and in turn to |
139 |
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* guarantee FIFO order among tied entries. |
140 |
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*/ |
141 |
jsr166 |
1.60 |
private static final AtomicLong sequencer = new AtomicLong(); |
142 |
dl |
1.14 |
|
143 |
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/** |
144 |
jsr166 |
1.39 |
* Returns current nanosecond time. |
145 |
dl |
1.14 |
*/ |
146 |
jsr166 |
1.54 |
final long now() { |
147 |
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return System.nanoTime(); |
148 |
dl |
1.14 |
} |
149 |
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150 |
jsr166 |
1.21 |
private class ScheduledFutureTask<V> |
151 |
peierls |
1.22 |
extends FutureTask<V> implements RunnableScheduledFuture<V> { |
152 |
jsr166 |
1.21 |
|
153 |
dl |
1.1 |
/** Sequence number to break ties FIFO */ |
154 |
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private final long sequenceNumber; |
155 |
jsr166 |
1.44 |
|
156 |
dl |
1.1 |
/** The time the task is enabled to execute in nanoTime units */ |
157 |
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private long time; |
158 |
jsr166 |
1.44 |
|
159 |
dl |
1.16 |
/** |
160 |
jsr166 |
1.75 |
* Period in nanoseconds for repeating tasks. |
161 |
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* A positive value indicates fixed-rate execution. |
162 |
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* A negative value indicates fixed-delay execution. |
163 |
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* A value of 0 indicates a non-repeating (one-shot) task. |
164 |
dl |
1.16 |
*/ |
165 |
dl |
1.1 |
private final long period; |
166 |
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167 |
jsr166 |
1.48 |
/** The actual task to be re-enqueued by reExecutePeriodic */ |
168 |
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RunnableScheduledFuture<V> outerTask = this; |
169 |
jsr166 |
1.44 |
|
170 |
dl |
1.1 |
/** |
171 |
dl |
1.40 |
* Index into delay queue, to support faster cancellation. |
172 |
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*/ |
173 |
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int heapIndex; |
174 |
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175 |
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/** |
176 |
jsr166 |
1.30 |
* Creates a one-shot action with given nanoTime-based trigger time. |
177 |
dl |
1.1 |
*/ |
178 |
jsr166 |
1.75 |
ScheduledFutureTask(Runnable r, V result, long triggerTime) { |
179 |
dl |
1.1 |
super(r, result); |
180 |
jsr166 |
1.75 |
this.time = triggerTime; |
181 |
dl |
1.1 |
this.period = 0; |
182 |
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this.sequenceNumber = sequencer.getAndIncrement(); |
183 |
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} |
184 |
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185 |
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/** |
186 |
jsr166 |
1.75 |
* Creates a periodic action with given nanoTime-based initial |
187 |
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* trigger time and period. |
188 |
dl |
1.1 |
*/ |
189 |
jsr166 |
1.75 |
ScheduledFutureTask(Runnable r, V result, long triggerTime, |
190 |
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long period) { |
191 |
dl |
1.1 |
super(r, result); |
192 |
jsr166 |
1.75 |
this.time = triggerTime; |
193 |
dl |
1.1 |
this.period = period; |
194 |
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this.sequenceNumber = sequencer.getAndIncrement(); |
195 |
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} |
196 |
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197 |
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/** |
198 |
jsr166 |
1.65 |
* Creates a one-shot action with given nanoTime-based trigger time. |
199 |
dl |
1.1 |
*/ |
200 |
jsr166 |
1.75 |
ScheduledFutureTask(Callable<V> callable, long triggerTime) { |
201 |
dl |
1.1 |
super(callable); |
202 |
jsr166 |
1.75 |
this.time = triggerTime; |
203 |
dl |
1.1 |
this.period = 0; |
204 |
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this.sequenceNumber = sequencer.getAndIncrement(); |
205 |
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} |
206 |
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207 |
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public long getDelay(TimeUnit unit) { |
208 |
jsr166 |
1.62 |
return unit.convert(time - now(), NANOSECONDS); |
209 |
dl |
1.1 |
} |
210 |
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|
211 |
dl |
1.20 |
public int compareTo(Delayed other) { |
212 |
dl |
1.59 |
if (other == this) // compare zero if same object |
213 |
dl |
1.1 |
return 0; |
214 |
dl |
1.34 |
if (other instanceof ScheduledFutureTask) { |
215 |
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ScheduledFutureTask<?> x = (ScheduledFutureTask<?>)other; |
216 |
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long diff = time - x.time; |
217 |
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if (diff < 0) |
218 |
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return -1; |
219 |
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else if (diff > 0) |
220 |
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return 1; |
221 |
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else if (sequenceNumber < x.sequenceNumber) |
222 |
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return -1; |
223 |
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else |
224 |
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return 1; |
225 |
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} |
226 |
jsr166 |
1.64 |
long diff = getDelay(NANOSECONDS) - other.getDelay(NANOSECONDS); |
227 |
jsr166 |
1.61 |
return (diff < 0) ? -1 : (diff > 0) ? 1 : 0; |
228 |
dl |
1.1 |
} |
229 |
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230 |
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/** |
231 |
jsr166 |
1.70 |
* Returns {@code true} if this is a periodic (not a one-shot) action. |
232 |
jsr166 |
1.30 |
* |
233 |
jsr166 |
1.70 |
* @return {@code true} if periodic |
234 |
dl |
1.1 |
*/ |
235 |
dl |
1.23 |
public boolean isPeriodic() { |
236 |
dl |
1.16 |
return period != 0; |
237 |
dl |
1.1 |
} |
238 |
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239 |
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/** |
240 |
jsr166 |
1.39 |
* Sets the next time to run for a periodic task. |
241 |
dl |
1.13 |
*/ |
242 |
dl |
1.37 |
private void setNextRunTime() { |
243 |
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long p = period; |
244 |
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if (p > 0) |
245 |
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time += p; |
246 |
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else |
247 |
jsr166 |
1.54 |
time = triggerTime(-p); |
248 |
dl |
1.13 |
} |
249 |
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|
250 |
dl |
1.40 |
public boolean cancel(boolean mayInterruptIfRunning) { |
251 |
dl |
1.41 |
boolean cancelled = super.cancel(mayInterruptIfRunning); |
252 |
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if (cancelled && removeOnCancel && heapIndex >= 0) |
253 |
jsr166 |
1.42 |
remove(this); |
254 |
dl |
1.41 |
return cancelled; |
255 |
dl |
1.40 |
} |
256 |
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|
257 |
dl |
1.13 |
/** |
258 |
dl |
1.5 |
* Overrides FutureTask version so as to reset/requeue if periodic. |
259 |
jsr166 |
1.21 |
*/ |
260 |
dl |
1.1 |
public void run() { |
261 |
dl |
1.37 |
boolean periodic = isPeriodic(); |
262 |
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if (!canRunInCurrentRunState(periodic)) |
263 |
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cancel(false); |
264 |
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else if (!periodic) |
265 |
dl |
1.5 |
ScheduledFutureTask.super.run(); |
266 |
dl |
1.37 |
else if (ScheduledFutureTask.super.runAndReset()) { |
267 |
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setNextRunTime(); |
268 |
jsr166 |
1.44 |
reExecutePeriodic(outerTask); |
269 |
dl |
1.37 |
} |
270 |
dl |
1.1 |
} |
271 |
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} |
272 |
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|
273 |
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/** |
274 |
dl |
1.37 |
* Returns true if can run a task given current run state |
275 |
jsr166 |
1.39 |
* and run-after-shutdown parameters. |
276 |
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* |
277 |
dl |
1.37 |
* @param periodic true if this task periodic, false if delayed |
278 |
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*/ |
279 |
|
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boolean canRunInCurrentRunState(boolean periodic) { |
280 |
jsr166 |
1.38 |
return isRunningOrShutdown(periodic ? |
281 |
dl |
1.37 |
continueExistingPeriodicTasksAfterShutdown : |
282 |
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executeExistingDelayedTasksAfterShutdown); |
283 |
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} |
284 |
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|
285 |
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/** |
286 |
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* Main execution method for delayed or periodic tasks. If pool |
287 |
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* is shut down, rejects the task. Otherwise adds task to queue |
288 |
|
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* and starts a thread, if necessary, to run it. (We cannot |
289 |
|
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* prestart the thread to run the task because the task (probably) |
290 |
jsr166 |
1.67 |
* shouldn't be run yet.) If the pool is shut down while the task |
291 |
dl |
1.37 |
* is being added, cancel and remove it if required by state and |
292 |
jsr166 |
1.39 |
* run-after-shutdown parameters. |
293 |
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* |
294 |
dl |
1.37 |
* @param task the task |
295 |
|
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*/ |
296 |
|
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private void delayedExecute(RunnableScheduledFuture<?> task) { |
297 |
|
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if (isShutdown()) |
298 |
|
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reject(task); |
299 |
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else { |
300 |
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super.getQueue().add(task); |
301 |
|
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if (isShutdown() && |
302 |
|
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!canRunInCurrentRunState(task.isPeriodic()) && |
303 |
|
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remove(task)) |
304 |
|
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task.cancel(false); |
305 |
jsr166 |
1.48 |
else |
306 |
dl |
1.63 |
ensurePrestart(); |
307 |
dl |
1.37 |
} |
308 |
|
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} |
309 |
jsr166 |
1.21 |
|
310 |
dl |
1.37 |
/** |
311 |
jsr166 |
1.39 |
* Requeues a periodic task unless current run state precludes it. |
312 |
|
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* Same idea as delayedExecute except drops task rather than rejecting. |
313 |
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* |
314 |
dl |
1.37 |
* @param task the task |
315 |
|
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*/ |
316 |
|
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void reExecutePeriodic(RunnableScheduledFuture<?> task) { |
317 |
|
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if (canRunInCurrentRunState(true)) { |
318 |
|
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super.getQueue().add(task); |
319 |
|
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if (!canRunInCurrentRunState(true) && remove(task)) |
320 |
|
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task.cancel(false); |
321 |
jsr166 |
1.48 |
else |
322 |
dl |
1.63 |
ensurePrestart(); |
323 |
dl |
1.37 |
} |
324 |
dl |
1.13 |
} |
325 |
dl |
1.1 |
|
326 |
dl |
1.13 |
/** |
327 |
jsr166 |
1.21 |
* Cancels and clears the queue of all tasks that should not be run |
328 |
jsr166 |
1.39 |
* due to shutdown policy. Invoked within super.shutdown. |
329 |
dl |
1.13 |
*/ |
330 |
dl |
1.37 |
@Override void onShutdown() { |
331 |
|
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BlockingQueue<Runnable> q = super.getQueue(); |
332 |
|
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boolean keepDelayed = |
333 |
|
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getExecuteExistingDelayedTasksAfterShutdownPolicy(); |
334 |
|
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boolean keepPeriodic = |
335 |
|
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getContinueExistingPeriodicTasksAfterShutdownPolicy(); |
336 |
jsr166 |
1.57 |
if (!keepDelayed && !keepPeriodic) { |
337 |
|
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for (Object e : q.toArray()) |
338 |
|
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if (e instanceof RunnableScheduledFuture<?>) |
339 |
|
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((RunnableScheduledFuture<?>) e).cancel(false); |
340 |
dl |
1.37 |
q.clear(); |
341 |
jsr166 |
1.57 |
} |
342 |
dl |
1.37 |
else { |
343 |
|
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// Traverse snapshot to avoid iterator exceptions |
344 |
jsr166 |
1.39 |
for (Object e : q.toArray()) { |
345 |
dl |
1.23 |
if (e instanceof RunnableScheduledFuture) { |
346 |
dl |
1.37 |
RunnableScheduledFuture<?> t = |
347 |
|
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(RunnableScheduledFuture<?>)e; |
348 |
dl |
1.41 |
if ((t.isPeriodic() ? !keepPeriodic : !keepDelayed) || |
349 |
|
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t.isCancelled()) { // also remove if already cancelled |
350 |
|
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if (q.remove(t)) |
351 |
|
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t.cancel(false); |
352 |
|
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} |
353 |
dl |
1.13 |
} |
354 |
|
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} |
355 |
dl |
1.1 |
} |
356 |
jsr166 |
1.48 |
tryTerminate(); |
357 |
dl |
1.1 |
} |
358 |
|
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|
359 |
dl |
1.23 |
/** |
360 |
jsr166 |
1.30 |
* Modifies or replaces the task used to execute a runnable. |
361 |
jsr166 |
1.28 |
* This method can be used to override the concrete |
362 |
dl |
1.23 |
* class used for managing internal tasks. |
363 |
jsr166 |
1.30 |
* The default implementation simply returns the given task. |
364 |
jsr166 |
1.28 |
* |
365 |
dl |
1.23 |
* @param runnable the submitted Runnable |
366 |
|
|
* @param task the task created to execute the runnable |
367 |
jsr166 |
1.72 |
* @param <V> the type of the task's result |
368 |
dl |
1.23 |
* @return a task that can execute the runnable |
369 |
|
|
* @since 1.6 |
370 |
|
|
*/ |
371 |
peierls |
1.22 |
protected <V> RunnableScheduledFuture<V> decorateTask( |
372 |
dl |
1.23 |
Runnable runnable, RunnableScheduledFuture<V> task) { |
373 |
|
|
return task; |
374 |
peierls |
1.22 |
} |
375 |
|
|
|
376 |
dl |
1.23 |
/** |
377 |
jsr166 |
1.30 |
* Modifies or replaces the task used to execute a callable. |
378 |
jsr166 |
1.28 |
* This method can be used to override the concrete |
379 |
dl |
1.23 |
* class used for managing internal tasks. |
380 |
jsr166 |
1.30 |
* The default implementation simply returns the given task. |
381 |
jsr166 |
1.28 |
* |
382 |
dl |
1.23 |
* @param callable the submitted Callable |
383 |
|
|
* @param task the task created to execute the callable |
384 |
jsr166 |
1.72 |
* @param <V> the type of the task's result |
385 |
dl |
1.23 |
* @return a task that can execute the callable |
386 |
|
|
* @since 1.6 |
387 |
|
|
*/ |
388 |
peierls |
1.22 |
protected <V> RunnableScheduledFuture<V> decorateTask( |
389 |
dl |
1.23 |
Callable<V> callable, RunnableScheduledFuture<V> task) { |
390 |
|
|
return task; |
391 |
dl |
1.19 |
} |
392 |
|
|
|
393 |
dl |
1.1 |
/** |
394 |
jsr166 |
1.39 |
* Creates a new {@code ScheduledThreadPoolExecutor} with the |
395 |
|
|
* given core pool size. |
396 |
jsr166 |
1.21 |
* |
397 |
jsr166 |
1.39 |
* @param corePoolSize the number of threads to keep in the pool, even |
398 |
|
|
* if they are idle, unless {@code allowCoreThreadTimeOut} is set |
399 |
|
|
* @throws IllegalArgumentException if {@code corePoolSize < 0} |
400 |
dl |
1.1 |
*/ |
401 |
|
|
public ScheduledThreadPoolExecutor(int corePoolSize) { |
402 |
jsr166 |
1.62 |
super(corePoolSize, Integer.MAX_VALUE, 0, NANOSECONDS, |
403 |
dl |
1.1 |
new DelayedWorkQueue()); |
404 |
|
|
} |
405 |
|
|
|
406 |
|
|
/** |
407 |
jsr166 |
1.39 |
* Creates a new {@code ScheduledThreadPoolExecutor} with the |
408 |
|
|
* given initial parameters. |
409 |
jsr166 |
1.21 |
* |
410 |
jsr166 |
1.39 |
* @param corePoolSize the number of threads to keep in the pool, even |
411 |
|
|
* if they are idle, unless {@code allowCoreThreadTimeOut} is set |
412 |
dl |
1.1 |
* @param threadFactory the factory to use when the executor |
413 |
jsr166 |
1.39 |
* creates a new thread |
414 |
|
|
* @throws IllegalArgumentException if {@code corePoolSize < 0} |
415 |
|
|
* @throws NullPointerException if {@code threadFactory} is null |
416 |
dl |
1.1 |
*/ |
417 |
|
|
public ScheduledThreadPoolExecutor(int corePoolSize, |
418 |
jsr166 |
1.56 |
ThreadFactory threadFactory) { |
419 |
jsr166 |
1.62 |
super(corePoolSize, Integer.MAX_VALUE, 0, NANOSECONDS, |
420 |
dl |
1.1 |
new DelayedWorkQueue(), threadFactory); |
421 |
|
|
} |
422 |
|
|
|
423 |
|
|
/** |
424 |
dl |
1.13 |
* Creates a new ScheduledThreadPoolExecutor with the given |
425 |
|
|
* initial parameters. |
426 |
jsr166 |
1.21 |
* |
427 |
jsr166 |
1.39 |
* @param corePoolSize the number of threads to keep in the pool, even |
428 |
|
|
* if they are idle, unless {@code allowCoreThreadTimeOut} is set |
429 |
dl |
1.1 |
* @param handler the handler to use when execution is blocked |
430 |
jsr166 |
1.39 |
* because the thread bounds and queue capacities are reached |
431 |
|
|
* @throws IllegalArgumentException if {@code corePoolSize < 0} |
432 |
|
|
* @throws NullPointerException if {@code handler} is null |
433 |
dl |
1.1 |
*/ |
434 |
|
|
public ScheduledThreadPoolExecutor(int corePoolSize, |
435 |
jsr166 |
1.56 |
RejectedExecutionHandler handler) { |
436 |
jsr166 |
1.62 |
super(corePoolSize, Integer.MAX_VALUE, 0, NANOSECONDS, |
437 |
dl |
1.1 |
new DelayedWorkQueue(), handler); |
438 |
|
|
} |
439 |
|
|
|
440 |
|
|
/** |
441 |
dl |
1.13 |
* Creates a new ScheduledThreadPoolExecutor with the given |
442 |
|
|
* initial parameters. |
443 |
jsr166 |
1.21 |
* |
444 |
jsr166 |
1.39 |
* @param corePoolSize the number of threads to keep in the pool, even |
445 |
|
|
* if they are idle, unless {@code allowCoreThreadTimeOut} is set |
446 |
dl |
1.1 |
* @param threadFactory the factory to use when the executor |
447 |
jsr166 |
1.39 |
* creates a new thread |
448 |
dl |
1.1 |
* @param handler the handler to use when execution is blocked |
449 |
jsr166 |
1.39 |
* because the thread bounds and queue capacities are reached |
450 |
|
|
* @throws IllegalArgumentException if {@code corePoolSize < 0} |
451 |
|
|
* @throws NullPointerException if {@code threadFactory} or |
452 |
|
|
* {@code handler} is null |
453 |
dl |
1.1 |
*/ |
454 |
|
|
public ScheduledThreadPoolExecutor(int corePoolSize, |
455 |
jsr166 |
1.56 |
ThreadFactory threadFactory, |
456 |
|
|
RejectedExecutionHandler handler) { |
457 |
jsr166 |
1.62 |
super(corePoolSize, Integer.MAX_VALUE, 0, NANOSECONDS, |
458 |
dl |
1.1 |
new DelayedWorkQueue(), threadFactory, handler); |
459 |
|
|
} |
460 |
|
|
|
461 |
dl |
1.37 |
/** |
462 |
jsr166 |
1.73 |
* Returns the nanoTime-based trigger time of a delayed action. |
463 |
jsr166 |
1.54 |
*/ |
464 |
|
|
private long triggerTime(long delay, TimeUnit unit) { |
465 |
|
|
return triggerTime(unit.toNanos((delay < 0) ? 0 : delay)); |
466 |
|
|
} |
467 |
|
|
|
468 |
|
|
/** |
469 |
jsr166 |
1.73 |
* Returns the nanoTime-based trigger time of a delayed action. |
470 |
dl |
1.50 |
*/ |
471 |
jsr166 |
1.54 |
long triggerTime(long delay) { |
472 |
|
|
return now() + |
473 |
|
|
((delay < (Long.MAX_VALUE >> 1)) ? delay : overflowFree(delay)); |
474 |
|
|
} |
475 |
|
|
|
476 |
|
|
/** |
477 |
|
|
* Constrains the values of all delays in the queue to be within |
478 |
|
|
* Long.MAX_VALUE of each other, to avoid overflow in compareTo. |
479 |
|
|
* This may occur if a task is eligible to be dequeued, but has |
480 |
|
|
* not yet been, while some other task is added with a delay of |
481 |
|
|
* Long.MAX_VALUE. |
482 |
|
|
*/ |
483 |
|
|
private long overflowFree(long delay) { |
484 |
|
|
Delayed head = (Delayed) super.getQueue().peek(); |
485 |
|
|
if (head != null) { |
486 |
jsr166 |
1.62 |
long headDelay = head.getDelay(NANOSECONDS); |
487 |
jsr166 |
1.54 |
if (headDelay < 0 && (delay - headDelay < 0)) |
488 |
|
|
delay = Long.MAX_VALUE + headDelay; |
489 |
|
|
} |
490 |
|
|
return delay; |
491 |
dl |
1.50 |
} |
492 |
|
|
|
493 |
|
|
/** |
494 |
dl |
1.37 |
* @throws RejectedExecutionException {@inheritDoc} |
495 |
|
|
* @throws NullPointerException {@inheritDoc} |
496 |
|
|
*/ |
497 |
jsr166 |
1.21 |
public ScheduledFuture<?> schedule(Runnable command, |
498 |
|
|
long delay, |
499 |
dl |
1.13 |
TimeUnit unit) { |
500 |
dl |
1.9 |
if (command == null || unit == null) |
501 |
dl |
1.1 |
throw new NullPointerException(); |
502 |
peierls |
1.22 |
RunnableScheduledFuture<?> t = decorateTask(command, |
503 |
jsr166 |
1.54 |
new ScheduledFutureTask<Void>(command, null, |
504 |
|
|
triggerTime(delay, unit))); |
505 |
dl |
1.1 |
delayedExecute(t); |
506 |
|
|
return t; |
507 |
|
|
} |
508 |
jsr166 |
1.52 |
|
509 |
dl |
1.37 |
/** |
510 |
|
|
* @throws RejectedExecutionException {@inheritDoc} |
511 |
|
|
* @throws NullPointerException {@inheritDoc} |
512 |
|
|
*/ |
513 |
jsr166 |
1.21 |
public <V> ScheduledFuture<V> schedule(Callable<V> callable, |
514 |
|
|
long delay, |
515 |
dl |
1.13 |
TimeUnit unit) { |
516 |
dl |
1.9 |
if (callable == null || unit == null) |
517 |
dl |
1.1 |
throw new NullPointerException(); |
518 |
peierls |
1.22 |
RunnableScheduledFuture<V> t = decorateTask(callable, |
519 |
jsr166 |
1.54 |
new ScheduledFutureTask<V>(callable, |
520 |
|
|
triggerTime(delay, unit))); |
521 |
dl |
1.1 |
delayedExecute(t); |
522 |
|
|
return t; |
523 |
|
|
} |
524 |
|
|
|
525 |
dl |
1.37 |
/** |
526 |
|
|
* @throws RejectedExecutionException {@inheritDoc} |
527 |
|
|
* @throws NullPointerException {@inheritDoc} |
528 |
|
|
* @throws IllegalArgumentException {@inheritDoc} |
529 |
|
|
*/ |
530 |
jsr166 |
1.21 |
public ScheduledFuture<?> scheduleAtFixedRate(Runnable command, |
531 |
|
|
long initialDelay, |
532 |
|
|
long period, |
533 |
dl |
1.13 |
TimeUnit unit) { |
534 |
dl |
1.9 |
if (command == null || unit == null) |
535 |
dl |
1.1 |
throw new NullPointerException(); |
536 |
|
|
if (period <= 0) |
537 |
|
|
throw new IllegalArgumentException(); |
538 |
jsr166 |
1.48 |
ScheduledFutureTask<Void> sft = |
539 |
|
|
new ScheduledFutureTask<Void>(command, |
540 |
|
|
null, |
541 |
jsr166 |
1.54 |
triggerTime(initialDelay, unit), |
542 |
jsr166 |
1.48 |
unit.toNanos(period)); |
543 |
jsr166 |
1.44 |
RunnableScheduledFuture<Void> t = decorateTask(command, sft); |
544 |
jsr166 |
1.48 |
sft.outerTask = t; |
545 |
dl |
1.1 |
delayedExecute(t); |
546 |
|
|
return t; |
547 |
|
|
} |
548 |
jsr166 |
1.21 |
|
549 |
dl |
1.37 |
/** |
550 |
|
|
* @throws RejectedExecutionException {@inheritDoc} |
551 |
|
|
* @throws NullPointerException {@inheritDoc} |
552 |
|
|
* @throws IllegalArgumentException {@inheritDoc} |
553 |
|
|
*/ |
554 |
jsr166 |
1.21 |
public ScheduledFuture<?> scheduleWithFixedDelay(Runnable command, |
555 |
|
|
long initialDelay, |
556 |
|
|
long delay, |
557 |
dl |
1.13 |
TimeUnit unit) { |
558 |
dl |
1.9 |
if (command == null || unit == null) |
559 |
dl |
1.1 |
throw new NullPointerException(); |
560 |
|
|
if (delay <= 0) |
561 |
|
|
throw new IllegalArgumentException(); |
562 |
jsr166 |
1.48 |
ScheduledFutureTask<Void> sft = |
563 |
|
|
new ScheduledFutureTask<Void>(command, |
564 |
|
|
null, |
565 |
jsr166 |
1.54 |
triggerTime(initialDelay, unit), |
566 |
jsr166 |
1.48 |
unit.toNanos(-delay)); |
567 |
jsr166 |
1.44 |
RunnableScheduledFuture<Void> t = decorateTask(command, sft); |
568 |
jsr166 |
1.48 |
sft.outerTask = t; |
569 |
dl |
1.1 |
delayedExecute(t); |
570 |
|
|
return t; |
571 |
|
|
} |
572 |
jsr166 |
1.21 |
|
573 |
dl |
1.1 |
/** |
574 |
jsr166 |
1.39 |
* Executes {@code command} with zero required delay. |
575 |
|
|
* This has effect equivalent to |
576 |
|
|
* {@link #schedule(Runnable,long,TimeUnit) schedule(command, 0, anyUnit)}. |
577 |
|
|
* Note that inspections of the queue and of the list returned by |
578 |
|
|
* {@code shutdownNow} will access the zero-delayed |
579 |
|
|
* {@link ScheduledFuture}, not the {@code command} itself. |
580 |
|
|
* |
581 |
|
|
* <p>A consequence of the use of {@code ScheduledFuture} objects is |
582 |
|
|
* that {@link ThreadPoolExecutor#afterExecute afterExecute} is always |
583 |
|
|
* called with a null second {@code Throwable} argument, even if the |
584 |
|
|
* {@code command} terminated abruptly. Instead, the {@code Throwable} |
585 |
|
|
* thrown by such a task can be obtained via {@link Future#get}. |
586 |
dl |
1.1 |
* |
587 |
|
|
* @throws RejectedExecutionException at discretion of |
588 |
jsr166 |
1.39 |
* {@code RejectedExecutionHandler}, if the task |
589 |
|
|
* cannot be accepted for execution because the |
590 |
|
|
* executor has been shut down |
591 |
|
|
* @throws NullPointerException {@inheritDoc} |
592 |
dl |
1.1 |
*/ |
593 |
|
|
public void execute(Runnable command) { |
594 |
jsr166 |
1.62 |
schedule(command, 0, NANOSECONDS); |
595 |
dl |
1.1 |
} |
596 |
|
|
|
597 |
dl |
1.13 |
// Override AbstractExecutorService methods |
598 |
|
|
|
599 |
dl |
1.37 |
/** |
600 |
|
|
* @throws RejectedExecutionException {@inheritDoc} |
601 |
|
|
* @throws NullPointerException {@inheritDoc} |
602 |
|
|
*/ |
603 |
dl |
1.7 |
public Future<?> submit(Runnable task) { |
604 |
jsr166 |
1.62 |
return schedule(task, 0, NANOSECONDS); |
605 |
dl |
1.7 |
} |
606 |
|
|
|
607 |
dl |
1.37 |
/** |
608 |
|
|
* @throws RejectedExecutionException {@inheritDoc} |
609 |
|
|
* @throws NullPointerException {@inheritDoc} |
610 |
|
|
*/ |
611 |
dl |
1.7 |
public <T> Future<T> submit(Runnable task, T result) { |
612 |
jsr166 |
1.62 |
return schedule(Executors.callable(task, result), 0, NANOSECONDS); |
613 |
dl |
1.7 |
} |
614 |
|
|
|
615 |
dl |
1.37 |
/** |
616 |
|
|
* @throws RejectedExecutionException {@inheritDoc} |
617 |
|
|
* @throws NullPointerException {@inheritDoc} |
618 |
|
|
*/ |
619 |
dl |
1.7 |
public <T> Future<T> submit(Callable<T> task) { |
620 |
jsr166 |
1.62 |
return schedule(task, 0, NANOSECONDS); |
621 |
dl |
1.7 |
} |
622 |
dl |
1.1 |
|
623 |
|
|
/** |
624 |
dl |
1.37 |
* Sets the policy on whether to continue executing existing |
625 |
jsr166 |
1.39 |
* periodic tasks even when this executor has been {@code shutdown}. |
626 |
|
|
* In this case, these tasks will only terminate upon |
627 |
|
|
* {@code shutdownNow} or after setting the policy to |
628 |
|
|
* {@code false} when already shutdown. |
629 |
|
|
* This value is by default {@code false}. |
630 |
jsr166 |
1.30 |
* |
631 |
jsr166 |
1.68 |
* @param value if {@code true}, continue after shutdown, else don't |
632 |
jsr166 |
1.25 |
* @see #getContinueExistingPeriodicTasksAfterShutdownPolicy |
633 |
dl |
1.1 |
*/ |
634 |
|
|
public void setContinueExistingPeriodicTasksAfterShutdownPolicy(boolean value) { |
635 |
|
|
continueExistingPeriodicTasksAfterShutdown = value; |
636 |
jsr166 |
1.39 |
if (!value && isShutdown()) |
637 |
dl |
1.37 |
onShutdown(); |
638 |
dl |
1.1 |
} |
639 |
|
|
|
640 |
|
|
/** |
641 |
jsr166 |
1.21 |
* Gets the policy on whether to continue executing existing |
642 |
jsr166 |
1.39 |
* periodic tasks even when this executor has been {@code shutdown}. |
643 |
|
|
* In this case, these tasks will only terminate upon |
644 |
|
|
* {@code shutdownNow} or after setting the policy to |
645 |
|
|
* {@code false} when already shutdown. |
646 |
|
|
* This value is by default {@code false}. |
647 |
jsr166 |
1.30 |
* |
648 |
jsr166 |
1.39 |
* @return {@code true} if will continue after shutdown |
649 |
dl |
1.16 |
* @see #setContinueExistingPeriodicTasksAfterShutdownPolicy |
650 |
dl |
1.1 |
*/ |
651 |
|
|
public boolean getContinueExistingPeriodicTasksAfterShutdownPolicy() { |
652 |
|
|
return continueExistingPeriodicTasksAfterShutdown; |
653 |
|
|
} |
654 |
|
|
|
655 |
|
|
/** |
656 |
jsr166 |
1.21 |
* Sets the policy on whether to execute existing delayed |
657 |
jsr166 |
1.39 |
* tasks even when this executor has been {@code shutdown}. |
658 |
|
|
* In this case, these tasks will only terminate upon |
659 |
|
|
* {@code shutdownNow}, or after setting the policy to |
660 |
|
|
* {@code false} when already shutdown. |
661 |
|
|
* This value is by default {@code true}. |
662 |
jsr166 |
1.30 |
* |
663 |
jsr166 |
1.68 |
* @param value if {@code true}, execute after shutdown, else don't |
664 |
dl |
1.16 |
* @see #getExecuteExistingDelayedTasksAfterShutdownPolicy |
665 |
dl |
1.1 |
*/ |
666 |
|
|
public void setExecuteExistingDelayedTasksAfterShutdownPolicy(boolean value) { |
667 |
|
|
executeExistingDelayedTasksAfterShutdown = value; |
668 |
jsr166 |
1.39 |
if (!value && isShutdown()) |
669 |
dl |
1.37 |
onShutdown(); |
670 |
dl |
1.1 |
} |
671 |
|
|
|
672 |
|
|
/** |
673 |
jsr166 |
1.21 |
* Gets the policy on whether to execute existing delayed |
674 |
jsr166 |
1.39 |
* tasks even when this executor has been {@code shutdown}. |
675 |
|
|
* In this case, these tasks will only terminate upon |
676 |
|
|
* {@code shutdownNow}, or after setting the policy to |
677 |
|
|
* {@code false} when already shutdown. |
678 |
|
|
* This value is by default {@code true}. |
679 |
jsr166 |
1.30 |
* |
680 |
jsr166 |
1.39 |
* @return {@code true} if will execute after shutdown |
681 |
dl |
1.16 |
* @see #setExecuteExistingDelayedTasksAfterShutdownPolicy |
682 |
dl |
1.1 |
*/ |
683 |
|
|
public boolean getExecuteExistingDelayedTasksAfterShutdownPolicy() { |
684 |
|
|
return executeExistingDelayedTasksAfterShutdown; |
685 |
|
|
} |
686 |
|
|
|
687 |
|
|
/** |
688 |
jsr166 |
1.46 |
* Sets the policy on whether cancelled tasks should be immediately |
689 |
|
|
* removed from the work queue at time of cancellation. This value is |
690 |
|
|
* by default {@code false}. |
691 |
dl |
1.41 |
* |
692 |
jsr166 |
1.42 |
* @param value if {@code true}, remove on cancellation, else don't |
693 |
dl |
1.41 |
* @see #getRemoveOnCancelPolicy |
694 |
jsr166 |
1.43 |
* @since 1.7 |
695 |
dl |
1.41 |
*/ |
696 |
|
|
public void setRemoveOnCancelPolicy(boolean value) { |
697 |
|
|
removeOnCancel = value; |
698 |
|
|
} |
699 |
|
|
|
700 |
|
|
/** |
701 |
jsr166 |
1.46 |
* Gets the policy on whether cancelled tasks should be immediately |
702 |
|
|
* removed from the work queue at time of cancellation. This value is |
703 |
|
|
* by default {@code false}. |
704 |
dl |
1.41 |
* |
705 |
jsr166 |
1.46 |
* @return {@code true} if cancelled tasks are immediately removed |
706 |
|
|
* from the queue |
707 |
dl |
1.41 |
* @see #setRemoveOnCancelPolicy |
708 |
jsr166 |
1.43 |
* @since 1.7 |
709 |
dl |
1.41 |
*/ |
710 |
|
|
public boolean getRemoveOnCancelPolicy() { |
711 |
|
|
return removeOnCancel; |
712 |
|
|
} |
713 |
|
|
|
714 |
|
|
/** |
715 |
dl |
1.1 |
* Initiates an orderly shutdown in which previously submitted |
716 |
jsr166 |
1.49 |
* tasks are executed, but no new tasks will be accepted. |
717 |
|
|
* Invocation has no additional effect if already shut down. |
718 |
|
|
* |
719 |
|
|
* <p>This method does not wait for previously submitted tasks to |
720 |
|
|
* complete execution. Use {@link #awaitTermination awaitTermination} |
721 |
|
|
* to do that. |
722 |
|
|
* |
723 |
|
|
* <p>If the {@code ExecuteExistingDelayedTasksAfterShutdownPolicy} |
724 |
|
|
* has been set {@code false}, existing delayed tasks whose delays |
725 |
|
|
* have not yet elapsed are cancelled. And unless the {@code |
726 |
|
|
* ContinueExistingPeriodicTasksAfterShutdownPolicy} has been set |
727 |
|
|
* {@code true}, future executions of existing periodic tasks will |
728 |
|
|
* be cancelled. |
729 |
jsr166 |
1.39 |
* |
730 |
|
|
* @throws SecurityException {@inheritDoc} |
731 |
dl |
1.1 |
*/ |
732 |
|
|
public void shutdown() { |
733 |
|
|
super.shutdown(); |
734 |
|
|
} |
735 |
|
|
|
736 |
|
|
/** |
737 |
|
|
* Attempts to stop all actively executing tasks, halts the |
738 |
jsr166 |
1.30 |
* processing of waiting tasks, and returns a list of the tasks |
739 |
|
|
* that were awaiting execution. |
740 |
jsr166 |
1.21 |
* |
741 |
jsr166 |
1.49 |
* <p>This method does not wait for actively executing tasks to |
742 |
|
|
* terminate. Use {@link #awaitTermination awaitTermination} to |
743 |
|
|
* do that. |
744 |
|
|
* |
745 |
dl |
1.1 |
* <p>There are no guarantees beyond best-effort attempts to stop |
746 |
dl |
1.18 |
* processing actively executing tasks. This implementation |
747 |
jsr166 |
1.31 |
* cancels tasks via {@link Thread#interrupt}, so any task that |
748 |
|
|
* fails to respond to interrupts may never terminate. |
749 |
dl |
1.1 |
* |
750 |
jsr166 |
1.39 |
* @return list of tasks that never commenced execution. |
751 |
|
|
* Each element of this list is a {@link ScheduledFuture}, |
752 |
|
|
* including those tasks submitted using {@code execute}, |
753 |
|
|
* which are for scheduling purposes used as the basis of a |
754 |
|
|
* zero-delay {@code ScheduledFuture}. |
755 |
jsr166 |
1.31 |
* @throws SecurityException {@inheritDoc} |
756 |
dl |
1.1 |
*/ |
757 |
tim |
1.4 |
public List<Runnable> shutdownNow() { |
758 |
dl |
1.1 |
return super.shutdownNow(); |
759 |
|
|
} |
760 |
|
|
|
761 |
|
|
/** |
762 |
|
|
* Returns the task queue used by this executor. Each element of |
763 |
|
|
* this queue is a {@link ScheduledFuture}, including those |
764 |
jsr166 |
1.39 |
* tasks submitted using {@code execute} which are for scheduling |
765 |
dl |
1.1 |
* purposes used as the basis of a zero-delay |
766 |
jsr166 |
1.39 |
* {@code ScheduledFuture}. Iteration over this queue is |
767 |
dl |
1.15 |
* <em>not</em> guaranteed to traverse tasks in the order in |
768 |
dl |
1.1 |
* which they will execute. |
769 |
|
|
* |
770 |
|
|
* @return the task queue |
771 |
|
|
*/ |
772 |
|
|
public BlockingQueue<Runnable> getQueue() { |
773 |
|
|
return super.getQueue(); |
774 |
|
|
} |
775 |
|
|
|
776 |
dl |
1.13 |
/** |
777 |
dl |
1.40 |
* Specialized delay queue. To mesh with TPE declarations, this |
778 |
|
|
* class must be declared as a BlockingQueue<Runnable> even though |
779 |
jsr166 |
1.42 |
* it can only hold RunnableScheduledFutures. |
780 |
jsr166 |
1.21 |
*/ |
781 |
dl |
1.40 |
static class DelayedWorkQueue extends AbstractQueue<Runnable> |
782 |
dl |
1.13 |
implements BlockingQueue<Runnable> { |
783 |
jsr166 |
1.21 |
|
784 |
dl |
1.40 |
/* |
785 |
|
|
* A DelayedWorkQueue is based on a heap-based data structure |
786 |
|
|
* like those in DelayQueue and PriorityQueue, except that |
787 |
|
|
* every ScheduledFutureTask also records its index into the |
788 |
|
|
* heap array. This eliminates the need to find a task upon |
789 |
|
|
* cancellation, greatly speeding up removal (down from O(n) |
790 |
|
|
* to O(log n)), and reducing garbage retention that would |
791 |
|
|
* otherwise occur by waiting for the element to rise to top |
792 |
|
|
* before clearing. But because the queue may also hold |
793 |
|
|
* RunnableScheduledFutures that are not ScheduledFutureTasks, |
794 |
|
|
* we are not guaranteed to have such indices available, in |
795 |
|
|
* which case we fall back to linear search. (We expect that |
796 |
|
|
* most tasks will not be decorated, and that the faster cases |
797 |
|
|
* will be much more common.) |
798 |
|
|
* |
799 |
|
|
* All heap operations must record index changes -- mainly |
800 |
|
|
* within siftUp and siftDown. Upon removal, a task's |
801 |
|
|
* heapIndex is set to -1. Note that ScheduledFutureTasks can |
802 |
|
|
* appear at most once in the queue (this need not be true for |
803 |
|
|
* other kinds of tasks or work queues), so are uniquely |
804 |
|
|
* identified by heapIndex. |
805 |
|
|
*/ |
806 |
|
|
|
807 |
jsr166 |
1.46 |
private static final int INITIAL_CAPACITY = 16; |
808 |
jsr166 |
1.61 |
private RunnableScheduledFuture<?>[] queue = |
809 |
|
|
new RunnableScheduledFuture<?>[INITIAL_CAPACITY]; |
810 |
jsr166 |
1.46 |
private final ReentrantLock lock = new ReentrantLock(); |
811 |
dl |
1.40 |
private int size = 0; |
812 |
|
|
|
813 |
jsr166 |
1.48 |
/** |
814 |
|
|
* Thread designated to wait for the task at the head of the |
815 |
|
|
* queue. This variant of the Leader-Follower pattern |
816 |
|
|
* (http://www.cs.wustl.edu/~schmidt/POSA/POSA2/) serves to |
817 |
|
|
* minimize unnecessary timed waiting. When a thread becomes |
818 |
|
|
* the leader, it waits only for the next delay to elapse, but |
819 |
|
|
* other threads await indefinitely. The leader thread must |
820 |
|
|
* signal some other thread before returning from take() or |
821 |
|
|
* poll(...), unless some other thread becomes leader in the |
822 |
|
|
* interim. Whenever the head of the queue is replaced with a |
823 |
|
|
* task with an earlier expiration time, the leader field is |
824 |
|
|
* invalidated by being reset to null, and some waiting |
825 |
|
|
* thread, but not necessarily the current leader, is |
826 |
|
|
* signalled. So waiting threads must be prepared to acquire |
827 |
|
|
* and lose leadership while waiting. |
828 |
|
|
*/ |
829 |
|
|
private Thread leader = null; |
830 |
|
|
|
831 |
|
|
/** |
832 |
|
|
* Condition signalled when a newer task becomes available at the |
833 |
|
|
* head of the queue or a new thread may need to become leader. |
834 |
|
|
*/ |
835 |
|
|
private final Condition available = lock.newCondition(); |
836 |
dl |
1.40 |
|
837 |
|
|
/** |
838 |
jsr166 |
1.66 |
* Sets f's heapIndex if it is a ScheduledFutureTask. |
839 |
dl |
1.40 |
*/ |
840 |
jsr166 |
1.61 |
private void setIndex(RunnableScheduledFuture<?> f, int idx) { |
841 |
dl |
1.40 |
if (f instanceof ScheduledFutureTask) |
842 |
|
|
((ScheduledFutureTask)f).heapIndex = idx; |
843 |
|
|
} |
844 |
|
|
|
845 |
|
|
/** |
846 |
jsr166 |
1.66 |
* Sifts element added at bottom up to its heap-ordered spot. |
847 |
dl |
1.40 |
* Call only when holding lock. |
848 |
|
|
*/ |
849 |
jsr166 |
1.61 |
private void siftUp(int k, RunnableScheduledFuture<?> key) { |
850 |
dl |
1.40 |
while (k > 0) { |
851 |
|
|
int parent = (k - 1) >>> 1; |
852 |
jsr166 |
1.61 |
RunnableScheduledFuture<?> e = queue[parent]; |
853 |
dl |
1.40 |
if (key.compareTo(e) >= 0) |
854 |
|
|
break; |
855 |
|
|
queue[k] = e; |
856 |
|
|
setIndex(e, k); |
857 |
|
|
k = parent; |
858 |
|
|
} |
859 |
|
|
queue[k] = key; |
860 |
|
|
setIndex(key, k); |
861 |
|
|
} |
862 |
|
|
|
863 |
|
|
/** |
864 |
jsr166 |
1.66 |
* Sifts element added at top down to its heap-ordered spot. |
865 |
dl |
1.40 |
* Call only when holding lock. |
866 |
|
|
*/ |
867 |
jsr166 |
1.61 |
private void siftDown(int k, RunnableScheduledFuture<?> key) { |
868 |
jsr166 |
1.42 |
int half = size >>> 1; |
869 |
dl |
1.40 |
while (k < half) { |
870 |
jsr166 |
1.42 |
int child = (k << 1) + 1; |
871 |
jsr166 |
1.61 |
RunnableScheduledFuture<?> c = queue[child]; |
872 |
dl |
1.40 |
int right = child + 1; |
873 |
|
|
if (right < size && c.compareTo(queue[right]) > 0) |
874 |
|
|
c = queue[child = right]; |
875 |
|
|
if (key.compareTo(c) <= 0) |
876 |
|
|
break; |
877 |
|
|
queue[k] = c; |
878 |
|
|
setIndex(c, k); |
879 |
|
|
k = child; |
880 |
|
|
} |
881 |
|
|
queue[k] = key; |
882 |
|
|
setIndex(key, k); |
883 |
|
|
} |
884 |
|
|
|
885 |
|
|
/** |
886 |
jsr166 |
1.66 |
* Resizes the heap array. Call only when holding lock. |
887 |
dl |
1.40 |
*/ |
888 |
|
|
private void grow() { |
889 |
|
|
int oldCapacity = queue.length; |
890 |
|
|
int newCapacity = oldCapacity + (oldCapacity >> 1); // grow 50% |
891 |
|
|
if (newCapacity < 0) // overflow |
892 |
|
|
newCapacity = Integer.MAX_VALUE; |
893 |
|
|
queue = Arrays.copyOf(queue, newCapacity); |
894 |
|
|
} |
895 |
|
|
|
896 |
|
|
/** |
897 |
jsr166 |
1.66 |
* Finds index of given object, or -1 if absent. |
898 |
dl |
1.40 |
*/ |
899 |
|
|
private int indexOf(Object x) { |
900 |
|
|
if (x != null) { |
901 |
jsr166 |
1.48 |
if (x instanceof ScheduledFutureTask) { |
902 |
|
|
int i = ((ScheduledFutureTask) x).heapIndex; |
903 |
|
|
// Sanity check; x could conceivably be a |
904 |
|
|
// ScheduledFutureTask from some other pool. |
905 |
|
|
if (i >= 0 && i < size && queue[i] == x) |
906 |
|
|
return i; |
907 |
|
|
} else { |
908 |
|
|
for (int i = 0; i < size; i++) |
909 |
|
|
if (x.equals(queue[i])) |
910 |
|
|
return i; |
911 |
|
|
} |
912 |
dl |
1.40 |
} |
913 |
|
|
return -1; |
914 |
|
|
} |
915 |
|
|
|
916 |
jsr166 |
1.48 |
public boolean contains(Object x) { |
917 |
|
|
final ReentrantLock lock = this.lock; |
918 |
jsr166 |
1.45 |
lock.lock(); |
919 |
|
|
try { |
920 |
jsr166 |
1.48 |
return indexOf(x) != -1; |
921 |
jsr166 |
1.45 |
} finally { |
922 |
|
|
lock.unlock(); |
923 |
|
|
} |
924 |
jsr166 |
1.48 |
} |
925 |
jsr166 |
1.45 |
|
926 |
dl |
1.40 |
public boolean remove(Object x) { |
927 |
|
|
final ReentrantLock lock = this.lock; |
928 |
|
|
lock.lock(); |
929 |
|
|
try { |
930 |
jsr166 |
1.45 |
int i = indexOf(x); |
931 |
jsr166 |
1.48 |
if (i < 0) |
932 |
|
|
return false; |
933 |
jsr166 |
1.45 |
|
934 |
jsr166 |
1.48 |
setIndex(queue[i], -1); |
935 |
|
|
int s = --size; |
936 |
jsr166 |
1.61 |
RunnableScheduledFuture<?> replacement = queue[s]; |
937 |
jsr166 |
1.48 |
queue[s] = null; |
938 |
|
|
if (s != i) { |
939 |
|
|
siftDown(i, replacement); |
940 |
|
|
if (queue[i] == replacement) |
941 |
|
|
siftUp(i, replacement); |
942 |
|
|
} |
943 |
|
|
return true; |
944 |
dl |
1.40 |
} finally { |
945 |
|
|
lock.unlock(); |
946 |
|
|
} |
947 |
|
|
} |
948 |
|
|
|
949 |
|
|
public int size() { |
950 |
|
|
final ReentrantLock lock = this.lock; |
951 |
|
|
lock.lock(); |
952 |
|
|
try { |
953 |
jsr166 |
1.45 |
return size; |
954 |
dl |
1.40 |
} finally { |
955 |
|
|
lock.unlock(); |
956 |
|
|
} |
957 |
|
|
} |
958 |
|
|
|
959 |
jsr166 |
1.42 |
public boolean isEmpty() { |
960 |
|
|
return size() == 0; |
961 |
dl |
1.40 |
} |
962 |
|
|
|
963 |
|
|
public int remainingCapacity() { |
964 |
|
|
return Integer.MAX_VALUE; |
965 |
|
|
} |
966 |
|
|
|
967 |
jsr166 |
1.61 |
public RunnableScheduledFuture<?> peek() { |
968 |
dl |
1.40 |
final ReentrantLock lock = this.lock; |
969 |
|
|
lock.lock(); |
970 |
|
|
try { |
971 |
|
|
return queue[0]; |
972 |
|
|
} finally { |
973 |
|
|
lock.unlock(); |
974 |
|
|
} |
975 |
dl |
1.13 |
} |
976 |
|
|
|
977 |
dl |
1.40 |
public boolean offer(Runnable x) { |
978 |
|
|
if (x == null) |
979 |
|
|
throw new NullPointerException(); |
980 |
jsr166 |
1.61 |
RunnableScheduledFuture<?> e = (RunnableScheduledFuture<?>)x; |
981 |
dl |
1.40 |
final ReentrantLock lock = this.lock; |
982 |
|
|
lock.lock(); |
983 |
|
|
try { |
984 |
|
|
int i = size; |
985 |
|
|
if (i >= queue.length) |
986 |
|
|
grow(); |
987 |
|
|
size = i + 1; |
988 |
|
|
if (i == 0) { |
989 |
|
|
queue[0] = e; |
990 |
|
|
setIndex(e, 0); |
991 |
jsr166 |
1.45 |
} else { |
992 |
dl |
1.40 |
siftUp(i, e); |
993 |
|
|
} |
994 |
jsr166 |
1.46 |
if (queue[0] == e) { |
995 |
jsr166 |
1.48 |
leader = null; |
996 |
jsr166 |
1.46 |
available.signal(); |
997 |
jsr166 |
1.48 |
} |
998 |
dl |
1.40 |
} finally { |
999 |
|
|
lock.unlock(); |
1000 |
|
|
} |
1001 |
|
|
return true; |
1002 |
jsr166 |
1.48 |
} |
1003 |
dl |
1.40 |
|
1004 |
|
|
public void put(Runnable e) { |
1005 |
|
|
offer(e); |
1006 |
|
|
} |
1007 |
|
|
|
1008 |
|
|
public boolean add(Runnable e) { |
1009 |
jsr166 |
1.48 |
return offer(e); |
1010 |
|
|
} |
1011 |
dl |
1.40 |
|
1012 |
|
|
public boolean offer(Runnable e, long timeout, TimeUnit unit) { |
1013 |
|
|
return offer(e); |
1014 |
|
|
} |
1015 |
jsr166 |
1.42 |
|
1016 |
jsr166 |
1.46 |
/** |
1017 |
|
|
* Performs common bookkeeping for poll and take: Replaces |
1018 |
jsr166 |
1.47 |
* first element with last and sifts it down. Call only when |
1019 |
|
|
* holding lock. |
1020 |
jsr166 |
1.46 |
* @param f the task to remove and return |
1021 |
|
|
*/ |
1022 |
jsr166 |
1.61 |
private RunnableScheduledFuture<?> finishPoll(RunnableScheduledFuture<?> f) { |
1023 |
jsr166 |
1.46 |
int s = --size; |
1024 |
jsr166 |
1.61 |
RunnableScheduledFuture<?> x = queue[s]; |
1025 |
jsr166 |
1.46 |
queue[s] = null; |
1026 |
|
|
if (s != 0) |
1027 |
|
|
siftDown(0, x); |
1028 |
|
|
setIndex(f, -1); |
1029 |
|
|
return f; |
1030 |
|
|
} |
1031 |
|
|
|
1032 |
jsr166 |
1.61 |
public RunnableScheduledFuture<?> poll() { |
1033 |
dl |
1.40 |
final ReentrantLock lock = this.lock; |
1034 |
|
|
lock.lock(); |
1035 |
|
|
try { |
1036 |
jsr166 |
1.61 |
RunnableScheduledFuture<?> first = queue[0]; |
1037 |
jsr166 |
1.62 |
if (first == null || first.getDelay(NANOSECONDS) > 0) |
1038 |
dl |
1.40 |
return null; |
1039 |
jsr166 |
1.42 |
else |
1040 |
dl |
1.40 |
return finishPoll(first); |
1041 |
|
|
} finally { |
1042 |
|
|
lock.unlock(); |
1043 |
|
|
} |
1044 |
|
|
} |
1045 |
|
|
|
1046 |
jsr166 |
1.61 |
public RunnableScheduledFuture<?> take() throws InterruptedException { |
1047 |
dl |
1.40 |
final ReentrantLock lock = this.lock; |
1048 |
|
|
lock.lockInterruptibly(); |
1049 |
|
|
try { |
1050 |
|
|
for (;;) { |
1051 |
jsr166 |
1.61 |
RunnableScheduledFuture<?> first = queue[0]; |
1052 |
jsr166 |
1.42 |
if (first == null) |
1053 |
dl |
1.40 |
available.await(); |
1054 |
|
|
else { |
1055 |
jsr166 |
1.62 |
long delay = first.getDelay(NANOSECONDS); |
1056 |
jsr166 |
1.48 |
if (delay <= 0) |
1057 |
|
|
return finishPoll(first); |
1058 |
jsr166 |
1.71 |
first = null; // don't retain ref while waiting |
1059 |
|
|
if (leader != null) |
1060 |
jsr166 |
1.48 |
available.await(); |
1061 |
|
|
else { |
1062 |
|
|
Thread thisThread = Thread.currentThread(); |
1063 |
|
|
leader = thisThread; |
1064 |
|
|
try { |
1065 |
|
|
available.awaitNanos(delay); |
1066 |
|
|
} finally { |
1067 |
|
|
if (leader == thisThread) |
1068 |
|
|
leader = null; |
1069 |
|
|
} |
1070 |
|
|
} |
1071 |
dl |
1.40 |
} |
1072 |
|
|
} |
1073 |
|
|
} finally { |
1074 |
jsr166 |
1.48 |
if (leader == null && queue[0] != null) |
1075 |
|
|
available.signal(); |
1076 |
dl |
1.40 |
lock.unlock(); |
1077 |
|
|
} |
1078 |
|
|
} |
1079 |
|
|
|
1080 |
jsr166 |
1.61 |
public RunnableScheduledFuture<?> poll(long timeout, TimeUnit unit) |
1081 |
dl |
1.40 |
throws InterruptedException { |
1082 |
|
|
long nanos = unit.toNanos(timeout); |
1083 |
|
|
final ReentrantLock lock = this.lock; |
1084 |
|
|
lock.lockInterruptibly(); |
1085 |
|
|
try { |
1086 |
|
|
for (;;) { |
1087 |
jsr166 |
1.61 |
RunnableScheduledFuture<?> first = queue[0]; |
1088 |
dl |
1.40 |
if (first == null) { |
1089 |
|
|
if (nanos <= 0) |
1090 |
|
|
return null; |
1091 |
|
|
else |
1092 |
|
|
nanos = available.awaitNanos(nanos); |
1093 |
|
|
} else { |
1094 |
jsr166 |
1.62 |
long delay = first.getDelay(NANOSECONDS); |
1095 |
jsr166 |
1.48 |
if (delay <= 0) |
1096 |
dl |
1.40 |
return finishPoll(first); |
1097 |
jsr166 |
1.48 |
if (nanos <= 0) |
1098 |
|
|
return null; |
1099 |
jsr166 |
1.71 |
first = null; // don't retain ref while waiting |
1100 |
jsr166 |
1.48 |
if (nanos < delay || leader != null) |
1101 |
|
|
nanos = available.awaitNanos(nanos); |
1102 |
|
|
else { |
1103 |
|
|
Thread thisThread = Thread.currentThread(); |
1104 |
|
|
leader = thisThread; |
1105 |
|
|
try { |
1106 |
|
|
long timeLeft = available.awaitNanos(delay); |
1107 |
|
|
nanos -= delay - timeLeft; |
1108 |
|
|
} finally { |
1109 |
|
|
if (leader == thisThread) |
1110 |
|
|
leader = null; |
1111 |
|
|
} |
1112 |
|
|
} |
1113 |
|
|
} |
1114 |
|
|
} |
1115 |
dl |
1.40 |
} finally { |
1116 |
jsr166 |
1.48 |
if (leader == null && queue[0] != null) |
1117 |
|
|
available.signal(); |
1118 |
dl |
1.40 |
lock.unlock(); |
1119 |
|
|
} |
1120 |
|
|
} |
1121 |
|
|
|
1122 |
|
|
public void clear() { |
1123 |
|
|
final ReentrantLock lock = this.lock; |
1124 |
|
|
lock.lock(); |
1125 |
|
|
try { |
1126 |
|
|
for (int i = 0; i < size; i++) { |
1127 |
jsr166 |
1.61 |
RunnableScheduledFuture<?> t = queue[i]; |
1128 |
dl |
1.40 |
if (t != null) { |
1129 |
|
|
queue[i] = null; |
1130 |
|
|
setIndex(t, -1); |
1131 |
|
|
} |
1132 |
|
|
} |
1133 |
|
|
size = 0; |
1134 |
|
|
} finally { |
1135 |
|
|
lock.unlock(); |
1136 |
|
|
} |
1137 |
dl |
1.13 |
} |
1138 |
dl |
1.40 |
|
1139 |
|
|
/** |
1140 |
jsr166 |
1.66 |
* Returns first element only if it is expired. |
1141 |
dl |
1.40 |
* Used only by drainTo. Call only when holding lock. |
1142 |
|
|
*/ |
1143 |
jsr166 |
1.62 |
private RunnableScheduledFuture<?> peekExpired() { |
1144 |
|
|
// assert lock.isHeldByCurrentThread(); |
1145 |
jsr166 |
1.61 |
RunnableScheduledFuture<?> first = queue[0]; |
1146 |
jsr166 |
1.62 |
return (first == null || first.getDelay(NANOSECONDS) > 0) ? |
1147 |
|
|
null : first; |
1148 |
dl |
1.40 |
} |
1149 |
|
|
|
1150 |
|
|
public int drainTo(Collection<? super Runnable> c) { |
1151 |
|
|
if (c == null) |
1152 |
|
|
throw new NullPointerException(); |
1153 |
|
|
if (c == this) |
1154 |
|
|
throw new IllegalArgumentException(); |
1155 |
|
|
final ReentrantLock lock = this.lock; |
1156 |
|
|
lock.lock(); |
1157 |
|
|
try { |
1158 |
jsr166 |
1.61 |
RunnableScheduledFuture<?> first; |
1159 |
dl |
1.40 |
int n = 0; |
1160 |
jsr166 |
1.62 |
while ((first = peekExpired()) != null) { |
1161 |
|
|
c.add(first); // In this order, in case add() throws. |
1162 |
|
|
finishPoll(first); |
1163 |
jsr166 |
1.48 |
++n; |
1164 |
|
|
} |
1165 |
dl |
1.40 |
return n; |
1166 |
|
|
} finally { |
1167 |
|
|
lock.unlock(); |
1168 |
|
|
} |
1169 |
dl |
1.13 |
} |
1170 |
|
|
|
1171 |
jsr166 |
1.21 |
public int drainTo(Collection<? super Runnable> c, int maxElements) { |
1172 |
dl |
1.40 |
if (c == null) |
1173 |
|
|
throw new NullPointerException(); |
1174 |
|
|
if (c == this) |
1175 |
|
|
throw new IllegalArgumentException(); |
1176 |
|
|
if (maxElements <= 0) |
1177 |
|
|
return 0; |
1178 |
|
|
final ReentrantLock lock = this.lock; |
1179 |
|
|
lock.lock(); |
1180 |
|
|
try { |
1181 |
jsr166 |
1.61 |
RunnableScheduledFuture<?> first; |
1182 |
dl |
1.40 |
int n = 0; |
1183 |
jsr166 |
1.62 |
while (n < maxElements && (first = peekExpired()) != null) { |
1184 |
|
|
c.add(first); // In this order, in case add() throws. |
1185 |
|
|
finishPoll(first); |
1186 |
jsr166 |
1.48 |
++n; |
1187 |
|
|
} |
1188 |
dl |
1.40 |
return n; |
1189 |
|
|
} finally { |
1190 |
|
|
lock.unlock(); |
1191 |
|
|
} |
1192 |
|
|
} |
1193 |
|
|
|
1194 |
|
|
public Object[] toArray() { |
1195 |
|
|
final ReentrantLock lock = this.lock; |
1196 |
|
|
lock.lock(); |
1197 |
|
|
try { |
1198 |
jsr166 |
1.45 |
return Arrays.copyOf(queue, size, Object[].class); |
1199 |
dl |
1.40 |
} finally { |
1200 |
|
|
lock.unlock(); |
1201 |
|
|
} |
1202 |
|
|
} |
1203 |
|
|
|
1204 |
jsr166 |
1.48 |
@SuppressWarnings("unchecked") |
1205 |
dl |
1.40 |
public <T> T[] toArray(T[] a) { |
1206 |
|
|
final ReentrantLock lock = this.lock; |
1207 |
|
|
lock.lock(); |
1208 |
|
|
try { |
1209 |
|
|
if (a.length < size) |
1210 |
|
|
return (T[]) Arrays.copyOf(queue, size, a.getClass()); |
1211 |
|
|
System.arraycopy(queue, 0, a, 0, size); |
1212 |
|
|
if (a.length > size) |
1213 |
|
|
a[size] = null; |
1214 |
|
|
return a; |
1215 |
|
|
} finally { |
1216 |
|
|
lock.unlock(); |
1217 |
|
|
} |
1218 |
dl |
1.13 |
} |
1219 |
|
|
|
1220 |
jsr166 |
1.21 |
public Iterator<Runnable> iterator() { |
1221 |
jsr166 |
1.45 |
return new Itr(Arrays.copyOf(queue, size)); |
1222 |
dl |
1.40 |
} |
1223 |
jsr166 |
1.42 |
|
1224 |
dl |
1.40 |
/** |
1225 |
|
|
* Snapshot iterator that works off copy of underlying q array. |
1226 |
|
|
*/ |
1227 |
|
|
private class Itr implements Iterator<Runnable> { |
1228 |
jsr166 |
1.74 |
final RunnableScheduledFuture<?>[] array; |
1229 |
jsr166 |
1.48 |
int cursor = 0; // index of next element to return |
1230 |
|
|
int lastRet = -1; // index of last element, or -1 if no such |
1231 |
jsr166 |
1.42 |
|
1232 |
jsr166 |
1.74 |
Itr(RunnableScheduledFuture<?>[] array) { |
1233 |
dl |
1.40 |
this.array = array; |
1234 |
|
|
} |
1235 |
jsr166 |
1.42 |
|
1236 |
dl |
1.40 |
public boolean hasNext() { |
1237 |
|
|
return cursor < array.length; |
1238 |
|
|
} |
1239 |
jsr166 |
1.42 |
|
1240 |
dl |
1.40 |
public Runnable next() { |
1241 |
|
|
if (cursor >= array.length) |
1242 |
|
|
throw new NoSuchElementException(); |
1243 |
|
|
lastRet = cursor; |
1244 |
jsr166 |
1.45 |
return array[cursor++]; |
1245 |
dl |
1.40 |
} |
1246 |
jsr166 |
1.42 |
|
1247 |
dl |
1.40 |
public void remove() { |
1248 |
|
|
if (lastRet < 0) |
1249 |
|
|
throw new IllegalStateException(); |
1250 |
|
|
DelayedWorkQueue.this.remove(array[lastRet]); |
1251 |
|
|
lastRet = -1; |
1252 |
|
|
} |
1253 |
dl |
1.13 |
} |
1254 |
|
|
} |
1255 |
dl |
1.1 |
} |