提交 bb129db0 编写于 作者: O ohair

Merge

......@@ -286,11 +286,18 @@ JAVA_JAVA_java = \
java/util/concurrent/ExecutorService.java \
java/util/concurrent/ExecutorCompletionService.java \
java/util/concurrent/Executors.java \
java/util/concurrent/ForkJoinPool.java \
java/util/concurrent/ForkJoinTask.java \
java/util/concurrent/ForkJoinWorkerThread.java \
java/util/concurrent/Future.java \
java/util/concurrent/FutureTask.java \
java/util/concurrent/LinkedBlockingDeque.java \
java/util/concurrent/LinkedBlockingQueue.java \
java/util/concurrent/LinkedTransferQueue.java \
java/util/concurrent/Phaser.java \
java/util/concurrent/PriorityBlockingQueue.java \
java/util/concurrent/RecursiveAction.java \
java/util/concurrent/RecursiveTask.java \
java/util/concurrent/RejectedExecutionException.java \
java/util/concurrent/RejectedExecutionHandler.java \
java/util/concurrent/RunnableFuture.java \
......@@ -301,9 +308,11 @@ JAVA_JAVA_java = \
java/util/concurrent/Semaphore.java \
java/util/concurrent/SynchronousQueue.java \
java/util/concurrent/ThreadFactory.java \
java/util/concurrent/ThreadLocalRandom.java \
java/util/concurrent/ThreadPoolExecutor.java \
java/util/concurrent/TimeUnit.java \
java/util/concurrent/TimeoutException.java \
java/util/concurrent/TransferQueue.java \
java/util/concurrent/atomic/AtomicBoolean.java \
java/util/concurrent/atomic/AtomicInteger.java \
java/util/concurrent/atomic/AtomicIntegerArray.java \
......
......@@ -256,9 +256,8 @@ public abstract class AbstractList<E> extends AbstractCollection<E> implements L
public boolean addAll(int index, Collection<? extends E> c) {
rangeCheckForAdd(index);
boolean modified = false;
Iterator<? extends E> e = c.iterator();
while (e.hasNext()) {
add(index++, e.next());
for (E e : c) {
add(index++, e);
modified = true;
}
return modified;
......
......@@ -183,11 +183,9 @@ public abstract class AbstractQueue<E>
if (c == this)
throw new IllegalArgumentException();
boolean modified = false;
Iterator<? extends E> e = c.iterator();
while (e.hasNext()) {
if (add(e.next()))
for (E e : c)
if (add(e))
modified = true;
}
return modified;
}
......
......@@ -448,11 +448,9 @@ public class HashMap<K,V>
}
private void putAllForCreate(Map<? extends K, ? extends V> m) {
for (Iterator<? extends Map.Entry<? extends K, ? extends V>> i = m.entrySet().iterator(); i.hasNext(); ) {
Map.Entry<? extends K, ? extends V> e = i.next();
for (Map.Entry<? extends K, ? extends V> e : m.entrySet())
putForCreate(e.getKey(), e.getValue());
}
}
/**
* Rehashes the contents of this map into a new array with a
......@@ -536,11 +534,9 @@ public class HashMap<K,V>
resize(newCapacity);
}
for (Iterator<? extends Map.Entry<? extends K, ? extends V>> i = m.entrySet().iterator(); i.hasNext(); ) {
Map.Entry<? extends K, ? extends V> e = i.next();
for (Map.Entry<? extends K, ? extends V> e : m.entrySet())
put(e.getKey(), e.getValue());
}
}
/**
* Removes the mapping for the specified key from this map if present.
......
......@@ -280,8 +280,8 @@ public class HashSet<E>
s.writeInt(map.size());
// Write out all elements in the proper order.
for (Iterator i=map.keySet().iterator(); i.hasNext(); )
s.writeObject(i.next());
for (E e : map.keySet())
s.writeObject(e);
}
/**
......
......@@ -50,6 +50,18 @@ import sun.misc.Unsafe;
* <p>
* Many applications will find the method {@link Math#random} simpler to use.
*
* <p>Instances of {@code java.util.Random} are threadsafe.
* However, the concurrent use of the same {@code java.util.Random}
* instance across threads may encounter contention and consequent
* poor performance. Consider instead using
* {@link java.util.concurrent.ThreadLocalRandom} in multithreaded
* designs.
*
* <p>Instances of {@code java.util.Random} are not cryptographically
* secure. Consider instead using {@link java.security.SecureRandom} to
* get a cryptographically secure pseudo-random number generator for use
* by security-sensitive applications.
*
* @author Frank Yellin
* @since 1.0
*/
......
......@@ -218,8 +218,8 @@ public class ArrayBlockingQueue<E> extends AbstractQueue<E>
if (capacity < c.size())
throw new IllegalArgumentException();
for (Iterator<? extends E> it = c.iterator(); it.hasNext();)
add(it.next());
for (E e : c)
add(e);
}
/**
......
......@@ -250,8 +250,8 @@ public class ConcurrentLinkedQueue<E> extends AbstractQueue<E>
* of its elements are null
*/
public ConcurrentLinkedQueue(Collection<? extends E> c) {
for (Iterator<? extends E> it = c.iterator(); it.hasNext();)
add(it.next());
for (E e : c)
add(e);
}
// Have to override just to update the javadoc
......
......@@ -895,7 +895,7 @@ public class ConcurrentSkipListMap<K,V> extends AbstractMap<K,V>
if (n != null) {
Node<K,V> f = n.next;
if (n != b.next) // inconsistent read
break;;
break;
Object v = n.value;
if (v == null) { // n is deleted
n.helpDelete(b, f);
......
......@@ -148,7 +148,8 @@ import java.util.concurrent.atomic.*;
*
* </pre>
*
* <p>Memory consistency effects: Actions in a thread prior to calling
* <p>Memory consistency effects: Until the count reaches
* zero, actions in a thread prior to calling
* {@code countDown()}
* <a href="package-summary.html#MemoryVisibility"><i>happen-before</i></a>
* actions following a successful return from a corresponding
......
......@@ -332,8 +332,8 @@ public interface ExecutorService extends Executor {
* @param tasks the collection of tasks
* @return the result returned by one of the tasks
* @throws InterruptedException if interrupted while waiting
* @throws NullPointerException if tasks or any of its elements
* are <tt>null</tt>
* @throws NullPointerException if tasks or any element task
* subject to execution is <tt>null</tt>
* @throws IllegalArgumentException if tasks is empty
* @throws ExecutionException if no task successfully completes
* @throws RejectedExecutionException if tasks cannot be scheduled
......@@ -356,8 +356,8 @@ public interface ExecutorService extends Executor {
* @param unit the time unit of the timeout argument
* @return the result returned by one of the tasks.
* @throws InterruptedException if interrupted while waiting
* @throws NullPointerException if tasks, any of its elements, or
* unit are <tt>null</tt>
* @throws NullPointerException if tasks, or unit, or any element
* task subject to execution is <tt>null</tt>
* @throws TimeoutException if the given timeout elapses before
* any task successfully completes
* @throws ExecutionException if no task successfully completes
......
此差异已折叠。
/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Sun designates this
* particular file as subject to the "Classpath" exception as provided
* by Sun in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
* CA 95054 USA or visit www.sun.com if you need additional information or
* have any questions.
*/
/*
* This file is available under and governed by the GNU General Public
* License version 2 only, as published by the Free Software Foundation.
* However, the following notice accompanied the original version of this
* file:
*
* 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
*/
package java.util.concurrent;
/**
* A recursive resultless {@link ForkJoinTask}. This class
* establishes conventions to parameterize resultless actions as
* {@code Void} {@code ForkJoinTask}s. Because {@code null} is the
* only valid value of type {@code Void}, methods such as join always
* return {@code null} upon completion.
*
* <p><b>Sample Usages.</b> Here is a sketch of a ForkJoin sort that
* sorts a given {@code long[]} array:
*
* <pre> {@code
* class SortTask extends RecursiveAction {
* final long[] array; final int lo; final int hi;
* SortTask(long[] array, int lo, int hi) {
* this.array = array; this.lo = lo; this.hi = hi;
* }
* protected void compute() {
* if (hi - lo < THRESHOLD)
* sequentiallySort(array, lo, hi);
* else {
* int mid = (lo + hi) >>> 1;
* invokeAll(new SortTask(array, lo, mid),
* new SortTask(array, mid, hi));
* merge(array, lo, hi);
* }
* }
* }}</pre>
*
* You could then sort {@code anArray} by creating {@code new
* SortTask(anArray, 0, anArray.length-1) } and invoking it in a
* ForkJoinPool. As a more concrete simple example, the following
* task increments each element of an array:
* <pre> {@code
* class IncrementTask extends RecursiveAction {
* final long[] array; final int lo; final int hi;
* IncrementTask(long[] array, int lo, int hi) {
* this.array = array; this.lo = lo; this.hi = hi;
* }
* protected void compute() {
* if (hi - lo < THRESHOLD) {
* for (int i = lo; i < hi; ++i)
* array[i]++;
* }
* else {
* int mid = (lo + hi) >>> 1;
* invokeAll(new IncrementTask(array, lo, mid),
* new IncrementTask(array, mid, hi));
* }
* }
* }}</pre>
*
* <p>The following example illustrates some refinements and idioms
* that may lead to better performance: RecursiveActions need not be
* fully recursive, so long as they maintain the basic
* divide-and-conquer approach. Here is a class that sums the squares
* of each element of a double array, by subdividing out only the
* right-hand-sides of repeated divisions by two, and keeping track of
* them with a chain of {@code next} references. It uses a dynamic
* threshold based on method {@code getSurplusQueuedTaskCount}, but
* counterbalances potential excess partitioning by directly
* performing leaf actions on unstolen tasks rather than further
* subdividing.
*
* <pre> {@code
* double sumOfSquares(ForkJoinPool pool, double[] array) {
* int n = array.length;
* Applyer a = new Applyer(array, 0, n, null);
* pool.invoke(a);
* return a.result;
* }
*
* class Applyer extends RecursiveAction {
* final double[] array;
* final int lo, hi;
* double result;
* Applyer next; // keeps track of right-hand-side tasks
* Applyer(double[] array, int lo, int hi, Applyer next) {
* this.array = array; this.lo = lo; this.hi = hi;
* this.next = next;
* }
*
* double atLeaf(int l, int h) {
* double sum = 0;
* for (int i = l; i < h; ++i) // perform leftmost base step
* sum += array[i] * array[i];
* return sum;
* }
*
* protected void compute() {
* int l = lo;
* int h = hi;
* Applyer right = null;
* while (h - l > 1 && getSurplusQueuedTaskCount() <= 3) {
* int mid = (l + h) >>> 1;
* right = new Applyer(array, mid, h, right);
* right.fork();
* h = mid;
* }
* double sum = atLeaf(l, h);
* while (right != null) {
* if (right.tryUnfork()) // directly calculate if not stolen
* sum += right.atLeaf(right.lo, right.hi);
* else {
* right.helpJoin();
* sum += right.result;
* }
* right = right.next;
* }
* result = sum;
* }
* }}</pre>
*
* @since 1.7
* @author Doug Lea
*/
public abstract class RecursiveAction extends ForkJoinTask<Void> {
private static final long serialVersionUID = 5232453952276485070L;
/**
* The main computation performed by this task.
*/
protected abstract void compute();
/**
* Always returns null.
*/
public final Void getRawResult() { return null; }
/**
* Requires null completion value.
*/
protected final void setRawResult(Void mustBeNull) { }
/**
* Implements execution conventions for RecursiveActions.
*/
protected final boolean exec() {
compute();
return true;
}
}
/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Sun designates this
* particular file as subject to the "Classpath" exception as provided
* by Sun in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
* CA 95054 USA or visit www.sun.com if you need additional information or
* have any questions.
*/
/*
* This file is available under and governed by the GNU General Public
* License version 2 only, as published by the Free Software Foundation.
* However, the following notice accompanied the original version of this
* file:
*
* 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
*/
package java.util.concurrent;
/**
* A recursive result-bearing {@link ForkJoinTask}.
*
* <p>For a classic example, here is a task computing Fibonacci numbers:
*
* <pre> {@code
* class Fibonacci extends RecursiveTask<Integer> {
* final int n;
* Fibonacci(int n) { this.n = n; }
* Integer compute() {
* if (n <= 1)
* return n;
* Fibonacci f1 = new Fibonacci(n - 1);
* f1.fork();
* Fibonacci f2 = new Fibonacci(n - 2);
* return f2.compute() + f1.join();
* }
* }}</pre>
*
* However, besides being a dumb way to compute Fibonacci functions
* (there is a simple fast linear algorithm that you'd use in
* practice), this is likely to perform poorly because the smallest
* subtasks are too small to be worthwhile splitting up. Instead, as
* is the case for nearly all fork/join applications, you'd pick some
* minimum granularity size (for example 10 here) for which you always
* sequentially solve rather than subdividing.
*
* @since 1.7
* @author Doug Lea
*/
public abstract class RecursiveTask<V> extends ForkJoinTask<V> {
private static final long serialVersionUID = 5232453952276485270L;
/**
* The result of the computation.
*/
V result;
/**
* The main computation performed by this task.
*/
protected abstract V compute();
public final V getRawResult() {
return result;
}
protected final void setRawResult(V value) {
result = value;
}
/**
* Implements execution conventions for RecursiveTask.
*/
protected final boolean exec() {
result = compute();
return true;
}
}
......@@ -61,6 +61,14 @@ import java.util.*;
* causes tasks to be immediately removed from the work queue at
* time of cancellation.
*
* <p>Successive executions of a task scheduled via
* <code>scheduleAtFixedRate</code> or
* <code>scheduleWithFixedDelay</code> do not overlap. While different
* executions may be performed by different threads, the effects of
* prior executions <a
* href="package-summary.html#MemoryVisibility"><i>happen-before</i></a>
* those of subsequent ones.
*
* <p>While this class inherits from {@link ThreadPoolExecutor}, a few
* of the inherited tuning methods are not useful for it. In
* particular, because it acts as a fixed-sized pool using
......
/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Sun designates this
* particular file as subject to the "Classpath" exception as provided
* by Sun in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
* CA 95054 USA or visit www.sun.com if you need additional information or
* have any questions.
*/
/*
* This file is available under and governed by the GNU General Public
* License version 2 only, as published by the Free Software Foundation.
* However, the following notice accompanied the original version of this
* file:
*
* 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
*/
package java.util.concurrent;
import java.util.Random;
/**
* A random number generator isolated to the current thread. Like the
* global {@link java.util.Random} generator used by the {@link
* java.lang.Math} class, a {@code ThreadLocalRandom} is initialized
* with an internally generated seed that may not otherwise be
* modified. When applicable, use of {@code ThreadLocalRandom} rather
* than shared {@code Random} objects in concurrent programs will
* typically encounter much less overhead and contention. Use of
* {@code ThreadLocalRandom} is particularly appropriate when multiple
* tasks (for example, each a {@link ForkJoinTask}) use random numbers
* in parallel in thread pools.
*
* <p>Usages of this class should typically be of the form:
* {@code ThreadLocalRandom.current().nextX(...)} (where
* {@code X} is {@code Int}, {@code Long}, etc).
* When all usages are of this form, it is never possible to
* accidently share a {@code ThreadLocalRandom} across multiple threads.
*
* <p>This class also provides additional commonly used bounded random
* generation methods.
*
* @since 1.7
* @author Doug Lea
*/
public class ThreadLocalRandom extends Random {
// same constants as Random, but must be redeclared because private
private final static long multiplier = 0x5DEECE66DL;
private final static long addend = 0xBL;
private final static long mask = (1L << 48) - 1;
/**
* The random seed. We can't use super.seed.
*/
private long rnd;
/**
* Initialization flag to permit the first and only allowed call
* to setSeed (inside Random constructor) to succeed. We can't
* allow others since it would cause setting seed in one part of a
* program to unintentionally impact other usages by the thread.
*/
boolean initialized;
// Padding to help avoid memory contention among seed updates in
// different TLRs in the common case that they are located near
// each other.
private long pad0, pad1, pad2, pad3, pad4, pad5, pad6, pad7;
/**
* The actual ThreadLocal
*/
private static final ThreadLocal<ThreadLocalRandom> localRandom =
new ThreadLocal<ThreadLocalRandom>() {
protected ThreadLocalRandom initialValue() {
return new ThreadLocalRandom();
}
};
/**
* Constructor called only by localRandom.initialValue.
* We rely on the fact that the superclass no-arg constructor
* invokes setSeed exactly once to initialize.
*/
ThreadLocalRandom() {
super();
}
/**
* Returns the current thread's {@code ThreadLocalRandom}.
*
* @return the current thread's {@code ThreadLocalRandom}
*/
public static ThreadLocalRandom current() {
return localRandom.get();
}
/**
* Throws {@code UnsupportedOperationException}. Setting seeds in
* this generator is not supported.
*
* @throws UnsupportedOperationException always
*/
public void setSeed(long seed) {
if (initialized)
throw new UnsupportedOperationException();
initialized = true;
rnd = (seed ^ multiplier) & mask;
}
protected int next(int bits) {
rnd = (rnd * multiplier + addend) & mask;
return (int) (rnd >>> (48-bits));
}
/**
* Returns a pseudorandom, uniformly distributed value between the
* given least value (inclusive) and bound (exclusive).
*
* @param least the least value returned
* @param bound the upper bound (exclusive)
* @throws IllegalArgumentException if least greater than or equal
* to bound
* @return the next value
*/
public int nextInt(int least, int bound) {
if (least >= bound)
throw new IllegalArgumentException();
return nextInt(bound - least) + least;
}
/**
* Returns a pseudorandom, uniformly distributed value
* between 0 (inclusive) and the specified value (exclusive).
*
* @param n the bound on the random number to be returned. Must be
* positive.
* @return the next value
* @throws IllegalArgumentException if n is not positive
*/
public long nextLong(long n) {
if (n <= 0)
throw new IllegalArgumentException("n must be positive");
// Divide n by two until small enough for nextInt. On each
// iteration (at most 31 of them but usually much less),
// randomly choose both whether to include high bit in result
// (offset) and whether to continue with the lower vs upper
// half (which makes a difference only if odd).
long offset = 0;
while (n >= Integer.MAX_VALUE) {
int bits = next(2);
long half = n >>> 1;
long nextn = ((bits & 2) == 0) ? half : n - half;
if ((bits & 1) == 0)
offset += n - nextn;
n = nextn;
}
return offset + nextInt((int) n);
}
/**
* Returns a pseudorandom, uniformly distributed value between the
* given least value (inclusive) and bound (exclusive).
*
* @param least the least value returned
* @param bound the upper bound (exclusive)
* @return the next value
* @throws IllegalArgumentException if least greater than or equal
* to bound
*/
public long nextLong(long least, long bound) {
if (least >= bound)
throw new IllegalArgumentException();
return nextLong(bound - least) + least;
}
/**
* Returns a pseudorandom, uniformly distributed {@code double} value
* between 0 (inclusive) and the specified value (exclusive).
*
* @param n the bound on the random number to be returned. Must be
* positive.
* @return the next value
* @throws IllegalArgumentException if n is not positive
*/
public double nextDouble(double n) {
if (n <= 0)
throw new IllegalArgumentException("n must be positive");
return nextDouble() * n;
}
/**
* Returns a pseudorandom, uniformly distributed value between the
* given least value (inclusive) and bound (exclusive).
*
* @param least the least value returned
* @param bound the upper bound (exclusive)
* @return the next value
* @throws IllegalArgumentException if least greater than or equal
* to bound
*/
public double nextDouble(double least, double bound) {
if (least >= bound)
throw new IllegalArgumentException();
return nextDouble() * (bound - least) + least;
}
private static final long serialVersionUID = -5851777807851030925L;
}
/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Sun designates this
* particular file as subject to the "Classpath" exception as provided
* by Sun in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
* CA 95054 USA or visit www.sun.com if you need additional information or
* have any questions.
*/
/*
* This file is available under and governed by the GNU General Public
* License version 2 only, as published by the Free Software Foundation.
* However, the following notice accompanied the original version of this
* file:
*
* 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
*/
package java.util.concurrent;
/**
* A {@link BlockingQueue} in which producers may wait for consumers
* to receive elements. A {@code TransferQueue} may be useful for
* example in message passing applications in which producers
* sometimes (using method {@link #transfer}) await receipt of
* elements by consumers invoking {@code take} or {@code poll}, while
* at other times enqueue elements (via method {@code put}) without
* waiting for receipt.
* {@linkplain #tryTransfer(Object) Non-blocking} and
* {@linkplain #tryTransfer(Object,long,TimeUnit) time-out} versions of
* {@code tryTransfer} are also available.
* A {@code TransferQueue} may also be queried, via {@link
* #hasWaitingConsumer}, whether there are any threads waiting for
* items, which is a converse analogy to a {@code peek} operation.
*
* <p>Like other blocking queues, a {@code TransferQueue} may be
* capacity bounded. If so, an attempted transfer operation may
* initially block waiting for available space, and/or subsequently
* block waiting for reception by a consumer. Note that in a queue
* with zero capacity, such as {@link SynchronousQueue}, {@code put}
* and {@code transfer} are effectively synonymous.
*
* <p>This interface is a member of the
* <a href="{@docRoot}/../technotes/guides/collections/index.html">
* Java Collections Framework</a>.
*
* @since 1.7
* @author Doug Lea
* @param <E> the type of elements held in this collection
*/
public interface TransferQueue<E> extends BlockingQueue<E> {
/**
* Transfers the element to a waiting consumer immediately, if possible.
*
* <p>More precisely, transfers the specified element immediately
* if there exists a consumer already waiting to receive it (in
* {@link #take} or timed {@link #poll(long,TimeUnit) poll}),
* otherwise returning {@code false} without enqueuing the element.
*
* @param e the element to transfer
* @return {@code true} if the element was transferred, else
* {@code false}
* @throws ClassCastException if the class of the specified element
* prevents it from being added to this queue
* @throws NullPointerException if the specified element is null
* @throws IllegalArgumentException if some property of the specified
* element prevents it from being added to this queue
*/
boolean tryTransfer(E e);
/**
* Transfers the element to a consumer, waiting if necessary to do so.
*
* <p>More precisely, transfers the specified element immediately
* if there exists a consumer already waiting to receive it (in
* {@link #take} or timed {@link #poll(long,TimeUnit) poll}),
* else waits until the element is received by a consumer.
*
* @param e the element to transfer
* @throws InterruptedException if interrupted while waiting,
* in which case the element is not left enqueued
* @throws ClassCastException if the class of the specified element
* prevents it from being added to this queue
* @throws NullPointerException if the specified element is null
* @throws IllegalArgumentException if some property of the specified
* element prevents it from being added to this queue
*/
void transfer(E e) throws InterruptedException;
/**
* Transfers the element to a consumer if it is possible to do so
* before the timeout elapses.
*
* <p>More precisely, transfers the specified element immediately
* if there exists a consumer already waiting to receive it (in
* {@link #take} or timed {@link #poll(long,TimeUnit) poll}),
* else waits until the element is received by a consumer,
* returning {@code false} if the specified wait time elapses
* before the element can be transferred.
*
* @param e the element to transfer
* @param timeout how long to wait before giving up, in units of
* {@code unit}
* @param unit a {@code TimeUnit} determining how to interpret the
* {@code timeout} parameter
* @return {@code true} if successful, or {@code false} if
* the specified waiting time elapses before completion,
* in which case the element is not left enqueued
* @throws InterruptedException if interrupted while waiting,
* in which case the element is not left enqueued
* @throws ClassCastException if the class of the specified element
* prevents it from being added to this queue
* @throws NullPointerException if the specified element is null
* @throws IllegalArgumentException if some property of the specified
* element prevents it from being added to this queue
*/
boolean tryTransfer(E e, long timeout, TimeUnit unit)
throws InterruptedException;
/**
* Returns {@code true} if there is at least one consumer waiting
* to receive an element via {@link #take} or
* timed {@link #poll(long,TimeUnit) poll}.
* The return value represents a momentary state of affairs.
*
* @return {@code true} if there is at least one waiting consumer
*/
boolean hasWaitingConsumer();
/**
* Returns an estimate of the number of consumers waiting to
* receive elements via {@link #take} or timed
* {@link #poll(long,TimeUnit) poll}. The return value is an
* approximation of a momentary state of affairs, that may be
* inaccurate if consumers have completed or given up waiting.
* The value may be useful for monitoring and heuristics, but
* not for synchronization control. Implementations of this
* method are likely to be noticeably slower than those for
* {@link #hasWaitingConsumer}.
*
* @return the number of consumers waiting to receive elements
*/
int getWaitingConsumerCount();
}
......@@ -170,8 +170,8 @@ import java.util.Date;
* <p>As interruption generally implies cancellation, and checks for
* interruption are often infrequent, an implementation can favor responding
* to an interrupt over normal method return. This is true even if it can be
* shown that the interrupt occurred after another action may have unblocked
* the thread. An implementation should document this behavior.
* shown that the interrupt occurred after another action that may have
* unblocked the thread. An implementation should document this behavior.
*
* @since 1.5
* @author Doug Lea
......
......@@ -178,10 +178,10 @@ public class BiggernYours {
new ConcurrentLinkedQueue() {
public int size() {return randomize(super.size());}});
// testCollections(
// new LinkedTransferQueue(),
// new LinkedTransferQueue() {
// public int size() {return randomize(super.size());}});
testCollections(
new LinkedTransferQueue(),
new LinkedTransferQueue() {
public int size() {return randomize(super.size());}});
testCollections(
new LinkedBlockingQueue(),
......
......@@ -49,7 +49,7 @@ public class IteratorAtEnd {
testCollection(new LinkedBlockingQueue());
testCollection(new ArrayBlockingQueue(100));
testCollection(new ConcurrentLinkedQueue());
// testCollection(new LinkedTransferQueue());
testCollection(new LinkedTransferQueue());
testMap(new HashMap());
testMap(new Hashtable());
......
......@@ -76,7 +76,7 @@ public class MOAT {
testCollection(new LinkedBlockingQueue<Integer>(20));
testCollection(new LinkedBlockingDeque<Integer>(20));
testCollection(new ConcurrentLinkedQueue<Integer>());
// testCollection(new LinkedTransferQueue<Integer>());
testCollection(new LinkedTransferQueue<Integer>());
testCollection(new ConcurrentSkipListSet<Integer>());
testCollection(Arrays.asList(new Integer(42)));
testCollection(Arrays.asList(1,2,3));
......
......@@ -52,7 +52,7 @@ public class CheckedNull {
testMap(Collections.checkedMap(
new HashMap<String, String>(),
String.class, String.class));;
String.class, String.class));
}
ClassCastException cce(F f) {
......
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