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dl |
1.1 |
/* |
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* Written by Doug Lea with assistance from members of JCP JSR-166 |
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* Expert Group and released to the public domain. Use, modify, and |
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* redistribute this code in any way without acknowledgement. |
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*/ |
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package java.util.concurrent; |
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import java.util.concurrent.atomic.*; |
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import java.util.*; |
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/** |
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* A {@link ThreadPoolExecutor} that can schedule commands to run |
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* after a given delay, or to execute periodically. This class is |
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* preferable to {@link java.util.Timer} when multiple worker threads |
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* are needed, or when the additional flexibility or capabilities of |
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* {@link ThreadPoolExecutor} (which this class extends) are required. |
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* |
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* <p> Delayed tasks execute no sooner than they are enabled, but |
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* without any real-time guarantees about when, after they are enabled, |
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* they will commence. Tasks tied for the same execution time are |
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* enabled in first-in-first-out (FIFO) order of submission. |
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* |
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* <p>While this class inherits from {@link ThreadPoolExecutor}, a few |
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* of the inherited tuning methods are not especially useful for |
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* it. In particular, because a <tt>ScheduledExecutor</tt> always acts |
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* as a fixed-sized pool using <tt>corePoolSize</tt> threads and an |
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* unbounded queue, adjustments to <tt>maximumPoolSize</tt> have no |
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* useful effect. |
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* |
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* @since 1.5 |
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* @author Doug Lea |
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*/ |
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tim |
1.3 |
public class ScheduledThreadPoolExecutor |
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extends ThreadPoolExecutor |
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implements ScheduledExecutorService { |
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dl |
1.1 |
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/** |
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* False if should cancel/suppress periodic tasks on shutdown. |
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*/ |
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private volatile boolean continueExistingPeriodicTasksAfterShutdown; |
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/** |
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* False if should cancel non-periodic tasks on shutdown. |
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*/ |
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private volatile boolean executeExistingDelayedTasksAfterShutdown = true; |
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/** |
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* Sequence number to break scheduling ties, and in turn to |
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* guarantee FIFO order among tied entries. |
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*/ |
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private static final AtomicLong sequencer = new AtomicLong(0); |
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private static class ScheduledFutureTask<V> |
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extends FutureTask<V> implements ScheduledFuture<V> { |
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/** Sequence number to break ties FIFO */ |
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private final long sequenceNumber; |
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/** The time the task is enabled to execute in nanoTime units */ |
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private long time; |
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/** The delay following next time, or <= 0 if non-periodic */ |
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private final long period; |
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/** true if at fixed rate; false if fixed delay */ |
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private final boolean rateBased; |
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/** |
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* Creates a one-shot action with given nanoTime-based trigger time |
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*/ |
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ScheduledFutureTask(Runnable r, V result, long ns) { |
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super(r, result); |
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this.time = ns; |
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this.period = 0; |
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rateBased = false; |
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this.sequenceNumber = sequencer.getAndIncrement(); |
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} |
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/** |
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* Creates a periodic action with given nano time and period |
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*/ |
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ScheduledFutureTask(Runnable r, V result, long ns, long period, boolean rateBased) { |
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super(r, result); |
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this.time = ns; |
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this.period = period; |
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this.rateBased = rateBased; |
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this.sequenceNumber = sequencer.getAndIncrement(); |
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} |
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/** |
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* Creates a one-shot action with given nanoTime-based trigger |
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*/ |
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ScheduledFutureTask(Callable<V> callable, long ns) { |
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super(callable); |
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this.time = ns; |
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this.period = 0; |
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rateBased = false; |
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this.sequenceNumber = sequencer.getAndIncrement(); |
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} |
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public long getDelay(TimeUnit unit) { |
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long d = unit.convert(time - System.nanoTime(), |
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TimeUnit.NANOSECONDS); |
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return d; |
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} |
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public int compareTo(Object other) { |
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if (other == this) // compare zero ONLY if same object |
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return 0; |
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ScheduledFutureTask<?> x = (ScheduledFutureTask<?>)other; |
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long diff = time - x.time; |
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if (diff < 0) |
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return -1; |
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else if (diff > 0) |
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return 1; |
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else if (sequenceNumber < x.sequenceNumber) |
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return -1; |
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else |
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return 1; |
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} |
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/** |
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* Return true if this is a periodic (not a one-shot) action. |
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* @return true if periodic |
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*/ |
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public boolean isPeriodic() { |
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return period > 0; |
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} |
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/** |
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* Returns the period, or zero if non-periodic. |
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* |
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* @return the period |
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*/ |
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public long getPeriod(TimeUnit unit) { |
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return unit.convert(period, TimeUnit.NANOSECONDS); |
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} |
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/** |
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dl |
1.2 |
* Overrides FutureTask version so as to reset if periodic. |
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dl |
1.1 |
*/ |
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public void run() { |
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dl |
1.2 |
if (isPeriodic()) |
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runAndReset(); |
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else |
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super.run(); |
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dl |
1.1 |
} |
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/** |
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* Return a task (which may be this task) that will trigger in |
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* the period subsequent to current task, or null if |
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* non-periodic or cancelled. |
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*/ |
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ScheduledFutureTask nextTask() { |
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if (period <= 0 || !reset()) |
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return null; |
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time = period + (rateBased ? time : System.nanoTime()); |
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return this; |
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} |
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} |
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/** |
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* An annoying wrapper class to convince generics compiler to |
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* use a DelayQueue<ScheduledFutureTask> as a BlockingQueue<Runnable> |
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*/ |
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private static class DelayedWorkQueue |
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extends AbstractCollection<Runnable> implements BlockingQueue<Runnable> { |
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private final DelayQueue<ScheduledFutureTask> dq = new DelayQueue<ScheduledFutureTask>(); |
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public Runnable poll() { return dq.poll(); } |
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public Runnable peek() { return dq.peek(); } |
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public Runnable take() throws InterruptedException { return dq.take(); } |
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public Runnable poll(long timeout, TimeUnit unit) throws InterruptedException { |
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return dq.poll(timeout, unit); |
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} |
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public boolean add(Runnable x) { return dq.add((ScheduledFutureTask)x); } |
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public boolean offer(Runnable x) { return dq.offer((ScheduledFutureTask)x); } |
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public void put(Runnable x) { |
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dq.put((ScheduledFutureTask)x); |
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} |
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public boolean offer(Runnable x, long timeout, TimeUnit unit) { |
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return dq.offer((ScheduledFutureTask)x, timeout, unit); |
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} |
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public Runnable remove() { return dq.remove(); } |
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public Runnable element() { return dq.element(); } |
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public void clear() { dq.clear(); } |
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public int drainTo(Collection<? super Runnable> c) { return dq.drainTo(c); } |
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public int drainTo(Collection<? super Runnable> c, int maxElements) { |
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return dq.drainTo(c, maxElements); |
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} |
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public int remainingCapacity() { return dq.remainingCapacity(); } |
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public boolean remove(Object x) { return dq.remove(x); } |
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public boolean contains(Object x) { return dq.contains(x); } |
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public int size() { return dq.size(); } |
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public boolean isEmpty() { return dq.isEmpty(); } |
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public Object[] toArray() { return dq.toArray(); } |
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public <T> T[] toArray(T[] array) { return dq.toArray(array); } |
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public Iterator<Runnable> iterator() { |
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return new Iterator<Runnable>() { |
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private Iterator<ScheduledFutureTask> it = dq.iterator(); |
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public boolean hasNext() { return it.hasNext(); } |
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public Runnable next() { return it.next(); } |
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public void remove() { it.remove(); } |
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}; |
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} |
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} |
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/** |
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* Creates a new ScheduledThreadPoolExecutor with the given core pool size. |
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* |
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* @param corePoolSize the number of threads to keep in the pool, |
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* even if they are idle. |
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* @throws IllegalArgumentException if corePoolSize less than or |
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* equal to zero |
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*/ |
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public ScheduledThreadPoolExecutor(int corePoolSize) { |
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super(corePoolSize, Integer.MAX_VALUE, 0, TimeUnit.NANOSECONDS, |
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new DelayedWorkQueue()); |
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} |
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/** |
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* Creates a new ScheduledThreadPoolExecutor with the given initial parameters. |
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* |
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* @param corePoolSize the number of threads to keep in the pool, |
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* even if they are idle. |
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* @param threadFactory the factory to use when the executor |
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* creates a new thread. |
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* @throws NullPointerException if threadFactory is null |
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*/ |
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public ScheduledThreadPoolExecutor(int corePoolSize, |
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ThreadFactory threadFactory) { |
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super(corePoolSize, Integer.MAX_VALUE, 0, TimeUnit.NANOSECONDS, |
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new DelayedWorkQueue(), threadFactory); |
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} |
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/** |
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* Creates a new ScheduledThreadPoolExecutor with the given initial parameters. |
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* |
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* @param corePoolSize the number of threads to keep in the pool, |
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* even if they are idle. |
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* @param handler the handler to use when execution is blocked |
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* because the thread bounds and queue capacities are reached. |
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* @throws NullPointerException if handler is null |
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*/ |
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public ScheduledThreadPoolExecutor(int corePoolSize, |
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RejectedExecutionHandler handler) { |
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super(corePoolSize, Integer.MAX_VALUE, 0, TimeUnit.NANOSECONDS, |
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new DelayedWorkQueue(), handler); |
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} |
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/** |
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* Creates a new ScheduledThreadPoolExecutor with the given initial parameters. |
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* |
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* @param corePoolSize the number of threads to keep in the pool, |
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* even if they are idle. |
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* @param threadFactory the factory to use when the executor |
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* creates a new thread. |
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* @param handler the handler to use when execution is blocked |
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* because the thread bounds and queue capacities are reached. |
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* @throws NullPointerException if threadFactory or handler is null |
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*/ |
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public ScheduledThreadPoolExecutor(int corePoolSize, |
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ThreadFactory threadFactory, |
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RejectedExecutionHandler handler) { |
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super(corePoolSize, Integer.MAX_VALUE, 0, TimeUnit.NANOSECONDS, |
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new DelayedWorkQueue(), threadFactory, handler); |
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} |
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/** |
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* Specialized variant of ThreadPoolExecutor.execute for delayed tasks. |
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*/ |
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private void delayedExecute(Runnable command) { |
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if (isShutdown()) { |
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reject(command); |
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return; |
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} |
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// Prestart a thread if necessary. We cannot prestart it |
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// running the task because the task (probably) shouldn't be |
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// run yet, so thread will just idle until delay elapses. |
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if (getPoolSize() < getCorePoolSize()) |
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prestartCoreThread(); |
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super.getQueue().add(command); |
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} |
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/** |
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* Creates and executes a one-shot action that becomes enabled after |
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* the given delay. |
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* @param command the task to execute. |
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* @param delay the time from now to delay execution. |
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* @param unit the time unit of the delay parameter. |
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* @return a Future representing pending completion of the task, |
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* and whose <tt>get()</tt> method will return <tt>Boolean.TRUE</tt> |
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* upon completion. |
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* @throws RejectedExecutionException if task cannot be scheduled |
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* for execution because the executor has been shut down. |
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* @throws NullPointerException if command is null |
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*/ |
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public ScheduledFuture<Boolean> schedule(Runnable command, long delay, TimeUnit unit) { |
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if (command == null) |
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throw new NullPointerException(); |
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long triggerTime = System.nanoTime() + unit.toNanos(delay); |
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ScheduledFutureTask<Boolean> t = new ScheduledFutureTask<Boolean>(command, Boolean.TRUE, triggerTime); |
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delayedExecute(t); |
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return t; |
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} |
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/** |
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* Creates and executes a ScheduledFuture that becomes enabled after the |
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* given delay. |
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* @param callable the function to execute. |
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* @param delay the time from now to delay execution. |
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* @param unit the time unit of the delay parameter. |
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* @return a ScheduledFuture that can be used to extract result or cancel. |
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* @throws RejectedExecutionException if task cannot be scheduled |
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* for execution because the executor has been shut down. |
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* @throws NullPointerException if callable is null |
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*/ |
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public <V> ScheduledFuture<V> schedule(Callable<V> callable, long delay, TimeUnit unit) { |
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if (callable == null) |
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throw new NullPointerException(); |
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long triggerTime = System.nanoTime() + unit.toNanos(delay); |
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ScheduledFutureTask<V> t = new ScheduledFutureTask<V>(callable, triggerTime); |
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delayedExecute(t); |
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return t; |
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} |
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/** |
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* Creates and executes a periodic action that becomes enabled first |
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* after the given initial delay, and subsequently with the given |
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* period; that is executions will commence after |
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* <tt>initialDelay</tt> then <tt>initialDelay+period</tt>, then |
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* <tt>initialDelay + 2 * period</tt>, and so on. The |
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* task will only terminate via cancellation. |
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* @param command the task to execute. |
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* @param initialDelay the time to delay first execution. |
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* @param period the period between successive executions. |
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* @param unit the time unit of the delay and period parameters |
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* @return a Future representing pending completion of the task, |
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* and whose <tt>get()</tt> method will throw an exception upon |
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* cancellation. |
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* @throws RejectedExecutionException if task cannot be scheduled |
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* for execution because the executor has been shut down. |
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* @throws NullPointerException if command is null |
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* @throws IllegalArgumentException if period less than or equal to zero. |
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*/ |
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public ScheduledFuture<Boolean> scheduleAtFixedRate(Runnable command, long initialDelay, long period, TimeUnit unit) { |
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if (command == null) |
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throw new NullPointerException(); |
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if (period <= 0) |
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throw new IllegalArgumentException(); |
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long triggerTime = System.nanoTime() + unit.toNanos(initialDelay); |
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ScheduledFutureTask<Boolean> t = new ScheduledFutureTask<Boolean> |
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(command, Boolean.TRUE, |
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triggerTime, |
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unit.toNanos(period), |
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true); |
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delayedExecute(t); |
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return t; |
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} |
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366 |
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/** |
367 |
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* Creates and executes a periodic action that becomes enabled first |
368 |
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* after the given initial delay, and subsequently with the |
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* given delay between the termination of one execution and the |
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* commencement of the next. |
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* The task will only terminate via cancellation. |
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* @param command the task to execute. |
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* @param initialDelay the time to delay first execution. |
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* @param delay the delay between the termination of one |
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* execution and the commencement of the next. |
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* @param unit the time unit of the delay and delay parameters |
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* @return a Future representing pending completion of the task, |
378 |
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* and whose <tt>get()</tt> method will throw an exception upon |
379 |
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* cancellation. |
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* @throws RejectedExecutionException if task cannot be scheduled |
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* for execution because the executor has been shut down. |
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* @throws NullPointerException if command is null |
383 |
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* @throws IllegalArgumentException if delay less than or equal to zero. |
384 |
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*/ |
385 |
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public ScheduledFuture<Boolean> scheduleWithFixedDelay(Runnable command, long initialDelay, long delay, TimeUnit unit) { |
386 |
|
|
if (command == null) |
387 |
|
|
throw new NullPointerException(); |
388 |
|
|
if (delay <= 0) |
389 |
|
|
throw new IllegalArgumentException(); |
390 |
|
|
long triggerTime = System.nanoTime() + unit.toNanos(initialDelay); |
391 |
|
|
ScheduledFutureTask<Boolean> t = new ScheduledFutureTask<Boolean> |
392 |
|
|
(command, |
393 |
|
|
Boolean.TRUE, |
394 |
|
|
triggerTime, |
395 |
|
|
unit.toNanos(delay), |
396 |
|
|
false); |
397 |
|
|
delayedExecute(t); |
398 |
|
|
return t; |
399 |
|
|
} |
400 |
|
|
|
401 |
|
|
|
402 |
|
|
/** |
403 |
|
|
* Execute command with zero required delay. This has effect |
404 |
|
|
* equivalent to <tt>schedule(command, 0, anyUnit)</tt>. Note |
405 |
|
|
* that inspections of the queue and of the list returned by |
406 |
|
|
* <tt>shutdownNow</tt> will access the zero-delayed |
407 |
|
|
* {@link ScheduledFuture}, not the <tt>command</tt> itself. |
408 |
|
|
* |
409 |
|
|
* @param command the task to execute |
410 |
|
|
* @throws RejectedExecutionException at discretion of |
411 |
|
|
* <tt>RejectedExecutionHandler</tt>, if task cannot be accepted |
412 |
|
|
* for execution because the executor has been shut down. |
413 |
|
|
* @throws NullPointerException if command is null |
414 |
|
|
*/ |
415 |
|
|
public void execute(Runnable command) { |
416 |
|
|
if (command == null) |
417 |
|
|
throw new NullPointerException(); |
418 |
|
|
schedule(command, 0, TimeUnit.NANOSECONDS); |
419 |
|
|
} |
420 |
|
|
|
421 |
|
|
|
422 |
|
|
/** |
423 |
|
|
* Set policy on whether to continue executing existing periodic |
424 |
|
|
* tasks even when this executor has been <tt>shutdown</tt>. In |
425 |
|
|
* this case, these tasks will only terminate upon |
426 |
|
|
* <tt>shutdownNow</tt>, or after setting the policy to |
427 |
|
|
* <tt>false</tt> when already shutdown. This value is by default |
428 |
|
|
* false. |
429 |
|
|
* @param value if true, continue after shutdown, else don't. |
430 |
|
|
*/ |
431 |
|
|
public void setContinueExistingPeriodicTasksAfterShutdownPolicy(boolean value) { |
432 |
|
|
continueExistingPeriodicTasksAfterShutdown = value; |
433 |
|
|
if (!value && isShutdown()) |
434 |
|
|
cancelUnwantedTasks(); |
435 |
|
|
} |
436 |
|
|
|
437 |
|
|
/** |
438 |
|
|
* Get the policy on whether to continue executing existing |
439 |
|
|
* periodic tasks even when this executor has been |
440 |
|
|
* <tt>shutdown</tt>. In this case, these tasks will only |
441 |
|
|
* terminate upon <tt>shutdownNow</tt> or after setting the policy |
442 |
|
|
* to <tt>false</tt> when already shutdown. This value is by |
443 |
|
|
* default false. |
444 |
|
|
* @return true if will continue after shutdown. |
445 |
|
|
*/ |
446 |
|
|
public boolean getContinueExistingPeriodicTasksAfterShutdownPolicy() { |
447 |
|
|
return continueExistingPeriodicTasksAfterShutdown; |
448 |
|
|
} |
449 |
|
|
|
450 |
|
|
/** |
451 |
|
|
* Set policy on whether to execute existing delayed |
452 |
|
|
* tasks even when this executor has been <tt>shutdown</tt>. In |
453 |
|
|
* this case, these tasks will only terminate upon |
454 |
|
|
* <tt>shutdownNow</tt>, or after setting the policy to |
455 |
|
|
* <tt>false</tt> when already shutdown. This value is by default |
456 |
|
|
* true. |
457 |
|
|
* @param value if true, execute after shutdown, else don't. |
458 |
|
|
*/ |
459 |
|
|
public void setExecuteExistingDelayedTasksAfterShutdownPolicy(boolean value) { |
460 |
|
|
executeExistingDelayedTasksAfterShutdown = value; |
461 |
|
|
if (!value && isShutdown()) |
462 |
|
|
cancelUnwantedTasks(); |
463 |
|
|
} |
464 |
|
|
|
465 |
|
|
/** |
466 |
|
|
* Get policy on whether to execute existing delayed |
467 |
|
|
* tasks even when this executor has been <tt>shutdown</tt>. In |
468 |
|
|
* this case, these tasks will only terminate upon |
469 |
|
|
* <tt>shutdownNow</tt>, or after setting the policy to |
470 |
|
|
* <tt>false</tt> when already shutdown. This value is by default |
471 |
|
|
* true. |
472 |
|
|
* @return true if will execute after shutdown. |
473 |
|
|
*/ |
474 |
|
|
public boolean getExecuteExistingDelayedTasksAfterShutdownPolicy() { |
475 |
|
|
return executeExistingDelayedTasksAfterShutdown; |
476 |
|
|
} |
477 |
|
|
|
478 |
|
|
/** |
479 |
|
|
* Cancel and clear the queue of all tasks that should not be run |
480 |
|
|
* due to shutdown policy. |
481 |
|
|
*/ |
482 |
|
|
private void cancelUnwantedTasks() { |
483 |
|
|
boolean keepDelayed = getExecuteExistingDelayedTasksAfterShutdownPolicy(); |
484 |
|
|
boolean keepPeriodic = getContinueExistingPeriodicTasksAfterShutdownPolicy(); |
485 |
|
|
if (!keepDelayed && !keepPeriodic) |
486 |
|
|
super.getQueue().clear(); |
487 |
|
|
else if (keepDelayed || keepPeriodic) { |
488 |
|
|
Object[] entries = super.getQueue().toArray(); |
489 |
|
|
for (int i = 0; i < entries.length; ++i) { |
490 |
|
|
ScheduledFutureTask<?> t = (ScheduledFutureTask<?>)entries[i]; |
491 |
|
|
if (t.isPeriodic()? !keepPeriodic : !keepDelayed) |
492 |
|
|
t.cancel(false); |
493 |
|
|
} |
494 |
|
|
entries = null; |
495 |
|
|
purge(); |
496 |
|
|
} |
497 |
|
|
} |
498 |
|
|
|
499 |
|
|
/** |
500 |
|
|
* Initiates an orderly shutdown in which previously submitted |
501 |
|
|
* tasks are executed, but no new tasks will be accepted. If the |
502 |
|
|
* <tt>ExecuteExistingDelayedTasksAfterShutdownPolicy</tt> has |
503 |
|
|
* been set <tt>false</tt>, existing delayed tasks whose delays |
504 |
|
|
* have not yet elapsed are cancelled. And unless the |
505 |
|
|
* <tt>ContinueExistingPeriodicTasksAfterShutdownPolicy</tt> has |
506 |
|
|
* been set <tt>true</tt>, future executions of existing periodic |
507 |
|
|
* tasks will be cancelled. |
508 |
|
|
*/ |
509 |
|
|
public void shutdown() { |
510 |
|
|
cancelUnwantedTasks(); |
511 |
|
|
super.shutdown(); |
512 |
|
|
} |
513 |
|
|
|
514 |
|
|
/** |
515 |
|
|
* Attempts to stop all actively executing tasks, halts the |
516 |
|
|
* processing of waiting tasks, and returns a list of the tasks that were |
517 |
|
|
* awaiting execution. |
518 |
|
|
* |
519 |
|
|
* <p>There are no guarantees beyond best-effort attempts to stop |
520 |
|
|
* processing actively executing tasks. This implementations |
521 |
|
|
* cancels via {@link Thread#interrupt}, so if any tasks mask or |
522 |
|
|
* fail to respond to interrupts, they may never terminate. |
523 |
|
|
* |
524 |
|
|
* @return list of tasks that never commenced execution. Each |
525 |
|
|
* element of this list is a {@link ScheduledFuture}, |
526 |
|
|
* including those tasks submitted using <tt>execute</tt> which |
527 |
|
|
* are for scheduling purposes used as the basis of a zero-delay |
528 |
|
|
* <tt>ScheduledFuture</tt>. |
529 |
|
|
*/ |
530 |
tim |
1.4 |
public List<Runnable> shutdownNow() { |
531 |
dl |
1.1 |
return super.shutdownNow(); |
532 |
|
|
} |
533 |
|
|
|
534 |
|
|
/** |
535 |
|
|
* Removes this task from internal queue if it is present, thus |
536 |
|
|
* causing it not to be run if it has not already started. This |
537 |
|
|
* method may be useful as one part of a cancellation scheme. |
538 |
|
|
* |
539 |
|
|
* @param task the task to remove |
540 |
|
|
* @return true if the task was removed |
541 |
|
|
*/ |
542 |
|
|
public boolean remove(Runnable task) { |
543 |
|
|
if (task instanceof ScheduledFuture) |
544 |
|
|
return super.remove(task); |
545 |
|
|
|
546 |
|
|
// The task might actually have been wrapped as a ScheduledFuture |
547 |
|
|
// in execute(), in which case we need to manually traverse |
548 |
|
|
// looking for it. |
549 |
|
|
|
550 |
|
|
ScheduledFuture wrap = null; |
551 |
|
|
Object[] entries = super.getQueue().toArray(); |
552 |
|
|
for (int i = 0; i < entries.length; ++i) { |
553 |
|
|
ScheduledFutureTask<?> t = (ScheduledFutureTask<?>)entries[i]; |
554 |
dl |
1.2 |
Object r = t.getTask(); |
555 |
dl |
1.1 |
if (task.equals(r)) { |
556 |
|
|
wrap = t; |
557 |
|
|
break; |
558 |
|
|
} |
559 |
|
|
} |
560 |
|
|
entries = null; |
561 |
|
|
return wrap != null && super.getQueue().remove(wrap); |
562 |
|
|
} |
563 |
|
|
|
564 |
|
|
|
565 |
|
|
/** |
566 |
|
|
* Returns the task queue used by this executor. Each element of |
567 |
|
|
* this queue is a {@link ScheduledFuture}, including those |
568 |
|
|
* tasks submitted using <tt>execute</tt> which are for scheduling |
569 |
|
|
* purposes used as the basis of a zero-delay |
570 |
|
|
* <tt>ScheduledFuture</tt>. Iteration over this queue is |
571 |
|
|
* </em>not</em> guaranteed to traverse tasks in the order in |
572 |
|
|
* which they will execute. |
573 |
|
|
* |
574 |
|
|
* @return the task queue |
575 |
|
|
*/ |
576 |
|
|
public BlockingQueue<Runnable> getQueue() { |
577 |
|
|
return super.getQueue(); |
578 |
|
|
} |
579 |
|
|
|
580 |
|
|
/** |
581 |
|
|
* Override of <tt>Executor</tt> hook method to support periodic |
582 |
|
|
* tasks. If the executed task was periodic, causes the task for |
583 |
|
|
* the next period to execute. |
584 |
|
|
* @param r the task (assumed to be a ScheduledFuture) |
585 |
|
|
* @param t the exception |
586 |
|
|
*/ |
587 |
|
|
protected void afterExecute(Runnable r, Throwable t) { |
588 |
|
|
super.afterExecute(r, t); |
589 |
|
|
ScheduledFutureTask<?> next = ((ScheduledFutureTask<?>)r).nextTask(); |
590 |
|
|
if (next != null && |
591 |
|
|
(!isShutdown() || |
592 |
|
|
(getContinueExistingPeriodicTasksAfterShutdownPolicy() && |
593 |
|
|
!isTerminating()))) |
594 |
|
|
super.getQueue().add(next); |
595 |
|
|
|
596 |
|
|
// This might have been the final executed delayed task. Wake |
597 |
|
|
// up threads to check. |
598 |
|
|
else if (isShutdown()) |
599 |
|
|
interruptIdleWorkers(); |
600 |
|
|
} |
601 |
|
|
} |