diff options
Diffstat (limited to 'luni/src/main/java/java/util/concurrent/DelayQueue.java')
| -rw-r--r-- | luni/src/main/java/java/util/concurrent/DelayQueue.java | 81 |
1 files changed, 48 insertions, 33 deletions
diff --git a/luni/src/main/java/java/util/concurrent/DelayQueue.java b/luni/src/main/java/java/util/concurrent/DelayQueue.java index 8c44e82..52028cb 100644 --- a/luni/src/main/java/java/util/concurrent/DelayQueue.java +++ b/luni/src/main/java/java/util/concurrent/DelayQueue.java @@ -1,12 +1,14 @@ /* * Written by Doug Lea with assistance from members of JCP JSR-166 * Expert Group and released to the public domain, as explained at - * http://creativecommons.org/licenses/publicdomain + * http://creativecommons.org/publicdomain/zero/1.0/ */ package java.util.concurrent; -import java.util.concurrent.locks.*; +import static java.util.concurrent.TimeUnit.NANOSECONDS; +import java.util.concurrent.locks.Condition; +import java.util.concurrent.locks.ReentrantLock; import java.util.*; // BEGIN android-note @@ -29,7 +31,9 @@ import java.util.*; * * <p>This class and its iterator implement all of the * <em>optional</em> methods of the {@link Collection} and {@link - * Iterator} interfaces. + * Iterator} interfaces. The Iterator provided in method {@link + * #iterator()} is <em>not</em> guaranteed to traverse the elements of + * the DelayQueue in any particular order. * * @since 1.5 * @author Doug Lea @@ -154,7 +158,7 @@ public class DelayQueue<E extends Delayed> extends AbstractQueue<E> lock.lock(); try { E first = q.peek(); - if (first == null || first.getDelay(TimeUnit.NANOSECONDS) > 0) + if (first == null || first.getDelay(NANOSECONDS) > 0) return null; else return q.poll(); @@ -179,7 +183,7 @@ public class DelayQueue<E extends Delayed> extends AbstractQueue<E> if (first == null) available.await(); else { - long delay = first.getDelay(TimeUnit.NANOSECONDS); + long delay = first.getDelay(NANOSECONDS); if (delay <= 0) return q.poll(); else if (leader != null) @@ -226,7 +230,7 @@ public class DelayQueue<E extends Delayed> extends AbstractQueue<E> else nanos = available.awaitNanos(nanos); } else { - long delay = first.getDelay(TimeUnit.NANOSECONDS); + long delay = first.getDelay(NANOSECONDS); if (delay <= 0) return q.poll(); if (nanos <= 0) @@ -284,6 +288,17 @@ public class DelayQueue<E extends Delayed> extends AbstractQueue<E> } /** + * Return first element only if it is expired. + * Used only by drainTo. Call only when holding lock. + */ + private E peekExpired() { + // assert lock.isHeldByCurrentThread(); + E first = q.peek(); + return (first == null || first.getDelay(NANOSECONDS) > 0) ? + null : first; + } + + /** * @throws UnsupportedOperationException {@inheritDoc} * @throws ClassCastException {@inheritDoc} * @throws NullPointerException {@inheritDoc} @@ -298,11 +313,9 @@ public class DelayQueue<E extends Delayed> extends AbstractQueue<E> lock.lock(); try { int n = 0; - for (;;) { - E first = q.peek(); - if (first == null || first.getDelay(TimeUnit.NANOSECONDS) > 0) - break; - c.add(q.poll()); + for (E e; (e = peekExpired()) != null;) { + c.add(e); // In this order, in case add() throws. + q.poll(); ++n; } return n; @@ -328,11 +341,9 @@ public class DelayQueue<E extends Delayed> extends AbstractQueue<E> lock.lock(); try { int n = 0; - while (n < maxElements) { - E first = q.peek(); - if (first == null || first.getDelay(TimeUnit.NANOSECONDS) > 0) - break; - c.add(q.poll()); + for (E e; n < maxElements && (e = peekExpired()) != null;) { + c.add(e); // In this order, in case add() throws. + q.poll(); ++n; } return n; @@ -411,8 +422,7 @@ public class DelayQueue<E extends Delayed> extends AbstractQueue<E> * <p>The following code can be used to dump a delay queue into a newly * allocated array of <tt>Delayed</tt>: * - * <pre> - * Delayed[] a = q.toArray(new Delayed[0]);</pre> + * <pre> {@code Delayed[] a = q.toArray(new Delayed[0]);}</pre> * * Note that <tt>toArray(new Object[0])</tt> is identical in function to * <tt>toArray()</tt>. @@ -451,6 +461,24 @@ public class DelayQueue<E extends Delayed> extends AbstractQueue<E> } /** + * Identity-based version for use in Itr.remove + */ + void removeEQ(Object o) { + final ReentrantLock lock = this.lock; + lock.lock(); + try { + for (Iterator<E> it = q.iterator(); it.hasNext(); ) { + if (o == it.next()) { + it.remove(); + break; + } + } + } finally { + lock.unlock(); + } + } + + /** * Returns an iterator over all the elements (both expired and * unexpired) in this queue. The iterator does not return the * elements in any particular order. @@ -473,7 +501,7 @@ public class DelayQueue<E extends Delayed> extends AbstractQueue<E> */ private class Itr implements Iterator<E> { final Object[] array; // Array of all elements - int cursor; // index of next element to return; + int cursor; // index of next element to return int lastRet; // index of last element, or -1 if no such Itr(Object[] array) { @@ -496,21 +524,8 @@ public class DelayQueue<E extends Delayed> extends AbstractQueue<E> public void remove() { if (lastRet < 0) throw new IllegalStateException(); - Object x = array[lastRet]; + removeEQ(array[lastRet]); lastRet = -1; - // Traverse underlying queue to find == element, - // not just a .equals element. - lock.lock(); - try { - for (Iterator it = q.iterator(); it.hasNext(); ) { - if (it.next() == x) { - it.remove(); - return; - } - } - } finally { - lock.unlock(); - } } } |