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/* |
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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, as explained at |
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* http://creativecommons.org/publicdomain/zero/1.0/ |
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*/ |
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|
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package java.util.concurrent; |
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|
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import static java.lang.ref.Reference.reachabilityFence; |
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import java.security.AccessControlContext; |
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import java.security.AccessControlException; |
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import java.security.AccessController; |
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import java.security.PrivilegedAction; |
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import java.security.PrivilegedActionException; |
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import java.security.PrivilegedExceptionAction; |
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import java.util.Collection; |
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import java.util.List; |
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import java.util.concurrent.atomic.AtomicInteger; |
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import sun.security.util.SecurityConstants; |
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|
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/** |
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* Factory and utility methods for {@link Executor}, {@link |
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* ExecutorService}, {@link ScheduledExecutorService}, {@link |
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* ThreadFactory}, and {@link Callable} classes defined in this |
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* package. This class supports the following kinds of methods: |
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* |
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* <ul> |
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* <li>Methods that create and return an {@link ExecutorService} |
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* set up with commonly useful configuration settings. |
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* <li>Methods that create and return a {@link ScheduledExecutorService} |
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* set up with commonly useful configuration settings. |
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* <li>Methods that create and return a "wrapped" ExecutorService, that |
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* disables reconfiguration by making implementation-specific methods |
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* inaccessible. |
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* <li>Methods that create and return a {@link ThreadFactory} |
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* that sets newly created threads to a known state. |
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* <li>Methods that create and return a {@link Callable} |
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* out of other closure-like forms, so they can be used |
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* in execution methods requiring {@code Callable}. |
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* </ul> |
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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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public class Executors { |
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|
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/** |
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* Creates a thread pool that reuses a fixed number of threads |
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* operating off a shared unbounded queue. At any point, at most |
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* {@code nThreads} threads will be active processing tasks. |
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* If additional tasks are submitted when all threads are active, |
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* they will wait in the queue until a thread is available. |
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* If any thread terminates due to a failure during execution |
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* prior to shutdown, a new one will take its place if needed to |
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* execute subsequent tasks. The threads in the pool will exist |
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* until it is explicitly {@link ExecutorService#shutdown shutdown}. |
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* |
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* @param nThreads the number of threads in the pool |
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* @return the newly created thread pool |
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* @throws IllegalArgumentException if {@code nThreads <= 0} |
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*/ |
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public static ExecutorService newFixedThreadPool(int nThreads) { |
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return new ThreadPoolExecutor(nThreads, nThreads, |
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0L, TimeUnit.MILLISECONDS, |
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new LinkedBlockingQueue<Runnable>()); |
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} |
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|
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/** |
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* Creates a thread pool that maintains enough threads to support |
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* the given parallelism level, and may use multiple queues to |
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* reduce contention. The parallelism level corresponds to the |
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* maximum number of threads actively engaged in, or available to |
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* engage in, task processing. The actual number of threads may |
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* grow and shrink dynamically. A work-stealing pool makes no |
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* guarantees about the order in which submitted tasks are |
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* executed. |
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* |
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* @param parallelism the targeted parallelism level |
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* @return the newly created thread pool |
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* @throws IllegalArgumentException if {@code parallelism <= 0} |
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* @since 1.8 |
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*/ |
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public static ExecutorService newWorkStealingPool(int parallelism) { |
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return new ForkJoinPool |
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(parallelism, |
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ForkJoinPool.defaultForkJoinWorkerThreadFactory, |
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null, true); |
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} |
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|
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/** |
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* Creates a work-stealing thread pool using the number of |
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* {@linkplain Runtime#availableProcessors available processors} |
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* as its target parallelism level. |
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* |
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* @return the newly created thread pool |
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* @see #newWorkStealingPool(int) |
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* @since 1.8 |
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*/ |
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public static ExecutorService newWorkStealingPool() { |
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return new ForkJoinPool |
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(Runtime.getRuntime().availableProcessors(), |
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ForkJoinPool.defaultForkJoinWorkerThreadFactory, |
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null, true); |
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} |
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|
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/** |
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* Creates a thread pool that reuses a fixed number of threads |
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* operating off a shared unbounded queue, using the provided |
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* ThreadFactory to create new threads when needed. At any point, |
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* at most {@code nThreads} threads will be active processing |
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* tasks. If additional tasks are submitted when all threads are |
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* active, they will wait in the queue until a thread is |
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* available. If any thread terminates due to a failure during |
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* execution prior to shutdown, a new one will take its place if |
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* needed to execute subsequent tasks. The threads in the pool will |
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* exist until it is explicitly {@link ExecutorService#shutdown |
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* shutdown}. |
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* |
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* @param nThreads the number of threads in the pool |
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* @param threadFactory the factory to use when creating new threads |
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* @return the newly created thread pool |
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* @throws NullPointerException if threadFactory is null |
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* @throws IllegalArgumentException if {@code nThreads <= 0} |
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*/ |
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public static ExecutorService newFixedThreadPool(int nThreads, ThreadFactory threadFactory) { |
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return new ThreadPoolExecutor(nThreads, nThreads, |
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0L, TimeUnit.MILLISECONDS, |
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new LinkedBlockingQueue<Runnable>(), |
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threadFactory); |
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} |
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|
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/** |
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* Creates an Executor that uses a single worker thread operating |
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* off an unbounded queue. (Note however that if this single |
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* thread terminates due to a failure during execution prior to |
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* shutdown, a new one will take its place if needed to execute |
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* subsequent tasks.) Tasks are guaranteed to execute |
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* sequentially, and no more than one task will be active at any |
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* given time. Unlike the otherwise equivalent |
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* {@code newFixedThreadPool(1)} the returned executor is |
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* guaranteed not to be reconfigurable to use additional threads. |
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* |
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* @return the newly created single-threaded Executor |
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*/ |
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public static ExecutorService newSingleThreadExecutor() { |
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return new FinalizableDelegatedExecutorService |
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(new ThreadPoolExecutor(1, 1, |
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0L, TimeUnit.MILLISECONDS, |
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new LinkedBlockingQueue<Runnable>())); |
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} |
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|
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/** |
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* Creates an Executor that uses a single worker thread operating |
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* off an unbounded queue, and uses the provided ThreadFactory to |
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* create a new thread when needed. Unlike the otherwise |
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* equivalent {@code newFixedThreadPool(1, threadFactory)} the |
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* returned executor is guaranteed not to be reconfigurable to use |
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* additional threads. |
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* |
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* @param threadFactory the factory to use when creating new threads |
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* @return the newly created single-threaded Executor |
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* @throws NullPointerException if threadFactory is null |
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*/ |
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public static ExecutorService newSingleThreadExecutor(ThreadFactory threadFactory) { |
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return new FinalizableDelegatedExecutorService |
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(new ThreadPoolExecutor(1, 1, |
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0L, TimeUnit.MILLISECONDS, |
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new LinkedBlockingQueue<Runnable>(), |
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threadFactory)); |
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} |
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|
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/** |
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* Creates a thread pool that creates new threads as needed, but |
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* will reuse previously constructed threads when they are |
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* available. These pools will typically improve the performance |
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* of programs that execute many short-lived asynchronous tasks. |
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* Calls to {@code execute} will reuse previously constructed |
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* threads if available. If no existing thread is available, a new |
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* thread will be created and added to the pool. Threads that have |
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* not been used for sixty seconds are terminated and removed from |
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* the cache. Thus, a pool that remains idle for long enough will |
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* not consume any resources. Note that pools with similar |
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* properties but different details (for example, timeout parameters) |
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* may be created using {@link ThreadPoolExecutor} constructors. |
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* |
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* @return the newly created thread pool |
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*/ |
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public static ExecutorService newCachedThreadPool() { |
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return new ThreadPoolExecutor(0, Integer.MAX_VALUE, |
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60L, TimeUnit.SECONDS, |
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new SynchronousQueue<Runnable>()); |
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} |
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|
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/** |
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* Creates a thread pool that creates new threads as needed, but |
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* will reuse previously constructed threads when they are |
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* available, and uses the provided |
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* ThreadFactory to create new threads when needed. |
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* |
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* @param threadFactory the factory to use when creating new threads |
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* @return the newly created thread pool |
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* @throws NullPointerException if threadFactory is null |
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*/ |
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public static ExecutorService newCachedThreadPool(ThreadFactory threadFactory) { |
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return new ThreadPoolExecutor(0, Integer.MAX_VALUE, |
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60L, TimeUnit.SECONDS, |
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new SynchronousQueue<Runnable>(), |
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threadFactory); |
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} |
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|
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/** |
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* Creates a single-threaded executor that can schedule commands |
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* to run after a given delay, or to execute periodically. |
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* (Note however that if this single |
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* thread terminates due to a failure during execution prior to |
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* shutdown, a new one will take its place if needed to execute |
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* subsequent tasks.) Tasks are guaranteed to execute |
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* sequentially, and no more than one task will be active at any |
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* given time. Unlike the otherwise equivalent |
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* {@code newScheduledThreadPool(1)} the returned executor is |
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* guaranteed not to be reconfigurable to use additional threads. |
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* |
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* @return the newly created scheduled executor |
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*/ |
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public static ScheduledExecutorService newSingleThreadScheduledExecutor() { |
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return new DelegatedScheduledExecutorService |
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(new ScheduledThreadPoolExecutor(1)); |
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} |
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|
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/** |
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* Creates a single-threaded executor that can schedule commands |
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* to run after a given delay, or to execute periodically. (Note |
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* however that if this single thread terminates due to a failure |
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* during execution prior to shutdown, a new one will take its |
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* place if needed to execute subsequent tasks.) Tasks are |
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* guaranteed to execute sequentially, and no more than one task |
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* will be active at any given time. Unlike the otherwise |
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* equivalent {@code newScheduledThreadPool(1, threadFactory)} |
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* the returned executor is guaranteed not to be reconfigurable to |
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* use additional threads. |
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* |
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* @param threadFactory the factory to use when creating new threads |
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* @return the newly created scheduled executor |
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* @throws NullPointerException if threadFactory is null |
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*/ |
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public static ScheduledExecutorService newSingleThreadScheduledExecutor(ThreadFactory threadFactory) { |
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return new DelegatedScheduledExecutorService |
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(new ScheduledThreadPoolExecutor(1, threadFactory)); |
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} |
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|
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/** |
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* Creates a thread pool that can schedule commands to run after a |
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* given delay, or to execute periodically. |
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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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* @return the newly created scheduled thread pool |
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* @throws IllegalArgumentException if {@code corePoolSize < 0} |
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*/ |
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public static ScheduledExecutorService newScheduledThreadPool(int corePoolSize) { |
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return new ScheduledThreadPoolExecutor(corePoolSize); |
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} |
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|
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/** |
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* Creates a thread pool that can schedule commands to run after a |
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* given delay, or to execute periodically. |
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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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* @return the newly created scheduled thread pool |
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* @throws IllegalArgumentException if {@code corePoolSize < 0} |
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* @throws NullPointerException if threadFactory is null |
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*/ |
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public static ScheduledExecutorService newScheduledThreadPool( |
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int corePoolSize, ThreadFactory threadFactory) { |
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return new ScheduledThreadPoolExecutor(corePoolSize, threadFactory); |
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} |
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|
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/** |
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* Returns an object that delegates all defined {@link |
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* ExecutorService} methods to the given executor, but not any |
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* other methods that might otherwise be accessible using |
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* casts. This provides a way to safely "freeze" configuration and |
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* disallow tuning of a given concrete implementation. |
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* @param executor the underlying implementation |
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* @return an {@code ExecutorService} instance |
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* @throws NullPointerException if executor null |
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*/ |
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public static ExecutorService unconfigurableExecutorService(ExecutorService executor) { |
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if (executor == null) |
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throw new NullPointerException(); |
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return new DelegatedExecutorService(executor); |
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} |
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|
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/** |
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* Returns an object that delegates all defined {@link |
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* ScheduledExecutorService} methods to the given executor, but |
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* not any other methods that might otherwise be accessible using |
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* casts. This provides a way to safely "freeze" configuration and |
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* disallow tuning of a given concrete implementation. |
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* @param executor the underlying implementation |
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* @return a {@code ScheduledExecutorService} instance |
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* @throws NullPointerException if executor null |
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*/ |
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public static ScheduledExecutorService unconfigurableScheduledExecutorService(ScheduledExecutorService executor) { |
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if (executor == null) |
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throw new NullPointerException(); |
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return new DelegatedScheduledExecutorService(executor); |
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} |
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|
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/** |
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* Returns a default thread factory used to create new threads. |
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* This factory creates all new threads used by an Executor in the |
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* same {@link ThreadGroup}. If there is a {@link |
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* java.lang.SecurityManager}, it uses the group of {@link |
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* System#getSecurityManager}, else the group of the thread |
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* invoking this {@code defaultThreadFactory} method. Each new |
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* thread is created as a non-daemon thread with priority set to |
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* the smaller of {@code Thread.NORM_PRIORITY} and the maximum |
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* priority permitted in the thread group. New threads have names |
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* accessible via {@link Thread#getName} of |
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* <em>pool-N-thread-M</em>, where <em>N</em> is the sequence |
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* number of this factory, and <em>M</em> is the sequence number |
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* of the thread created by this factory. |
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* @return a thread factory |
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*/ |
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public static ThreadFactory defaultThreadFactory() { |
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return new DefaultThreadFactory(); |
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} |
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|
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/** |
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* Returns a thread factory used to create new threads that |
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* have the same permissions as the current thread. |
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* This factory creates threads with the same settings as {@link |
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* Executors#defaultThreadFactory}, additionally setting the |
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* AccessControlContext and contextClassLoader of new threads to |
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* be the same as the thread invoking this |
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* {@code privilegedThreadFactory} method. A new |
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* {@code privilegedThreadFactory} can be created within an |
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* {@link AccessController#doPrivileged AccessController.doPrivileged} |
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* action setting the current thread's access control context to |
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* create threads with the selected permission settings holding |
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* within that action. |
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* |
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* <p>Note that while tasks running within such threads will have |
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* the same access control and class loader settings as the |
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* current thread, they need not have the same {@link |
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* java.lang.ThreadLocal} or {@link |
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* java.lang.InheritableThreadLocal} values. If necessary, |
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* particular values of thread locals can be set or reset before |
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* any task runs in {@link ThreadPoolExecutor} subclasses using |
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* {@link ThreadPoolExecutor#beforeExecute(Thread, Runnable)}. |
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* Also, if it is necessary to initialize worker threads to have |
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* the same InheritableThreadLocal settings as some other |
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* designated thread, you can create a custom ThreadFactory in |
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* which that thread waits for and services requests to create |
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* others that will inherit its values. |
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* |
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* @return a thread factory |
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* @throws AccessControlException if the current access control |
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* context does not have permission to both get and set context |
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* class loader |
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* |
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* @deprecated This method is only useful in conjunction with |
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* {@linkplain SecurityManager the Security Manager}, which is |
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* deprecated and subject to removal in a future release. |
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* Consequently, this method is also deprecated and subject to |
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* removal. There is no replacement for the Security Manager or this |
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* method. |
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*/ |
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@Deprecated(since="17", forRemoval=true) |
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public static ThreadFactory privilegedThreadFactory() { |
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return new PrivilegedThreadFactory(); |
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} |
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|
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/** |
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* Returns a {@link Callable} object that, when |
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* called, runs the given task and returns the given result. This |
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* can be useful when applying methods requiring a |
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* {@code Callable} to an otherwise resultless action. |
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* @param task the task to run |
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* @param result the result to return |
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* @param <T> the type of the result |
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* @return a callable object |
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* @throws NullPointerException if task null |
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*/ |
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public static <T> Callable<T> callable(Runnable task, T result) { |
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if (task == null) |
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throw new NullPointerException(); |
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return new RunnableAdapter<T>(task, result); |
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} |
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|
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/** |
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* Returns a {@link Callable} object that, when |
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* called, runs the given task and returns {@code null}. |
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* @param task the task to run |
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* @return a callable object |
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* @throws NullPointerException if task null |
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*/ |
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public static Callable<Object> callable(Runnable task) { |
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if (task == null) |
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throw new NullPointerException(); |
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return new RunnableAdapter<Object>(task, null); |
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} |
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|
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/** |
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* Returns a {@link Callable} object that, when |
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* called, runs the given privileged action and returns its result. |
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* @param action the privileged action to run |
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* @return a callable object |
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* @throws NullPointerException if action null |
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*/ |
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public static Callable<Object> callable(final PrivilegedAction<?> action) { |
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if (action == null) |
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throw new NullPointerException(); |
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return new Callable<Object>() { |
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public Object call() { return action.run(); }}; |
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} |
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|
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/** |
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* Returns a {@link Callable} object that, when |
422 |
* called, runs the given privileged exception action and returns |
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* its result. |
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* @param action the privileged exception action to run |
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* @return a callable object |
426 |
* @throws NullPointerException if action null |
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*/ |
428 |
public static Callable<Object> callable(final PrivilegedExceptionAction<?> action) { |
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if (action == null) |
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throw new NullPointerException(); |
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return new Callable<Object>() { |
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public Object call() throws Exception { return action.run(); }}; |
433 |
} |
434 |
|
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/** |
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* Returns a {@link Callable} object that will, when called, |
437 |
* execute the given {@code callable} under the current access |
438 |
* control context. This method should normally be invoked within |
439 |
* an {@link AccessController#doPrivileged AccessController.doPrivileged} |
440 |
* action to create callables that will, if possible, execute |
441 |
* under the selected permission settings holding within that |
442 |
* action; or if not possible, throw an associated {@link |
443 |
* AccessControlException}. |
444 |
* @param callable the underlying task |
445 |
* @param <T> the type of the callable's result |
446 |
* @return a callable object |
447 |
* @throws NullPointerException if callable null |
448 |
* |
449 |
* @deprecated This method is only useful in conjunction with |
450 |
* {@linkplain SecurityManager the Security Manager}, which is |
451 |
* deprecated and subject to removal in a future release. |
452 |
* Consequently, this method is also deprecated and subject to |
453 |
* removal. There is no replacement for the Security Manager or this |
454 |
* method. |
455 |
*/ |
456 |
@Deprecated(since="17", forRemoval=true) |
457 |
public static <T> Callable<T> privilegedCallable(Callable<T> callable) { |
458 |
if (callable == null) |
459 |
throw new NullPointerException(); |
460 |
return new PrivilegedCallable<T>(callable); |
461 |
} |
462 |
|
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/** |
464 |
* Returns a {@link Callable} object that will, when called, |
465 |
* execute the given {@code callable} under the current access |
466 |
* control context, with the current context class loader as the |
467 |
* context class loader. This method should normally be invoked |
468 |
* within an |
469 |
* {@link AccessController#doPrivileged AccessController.doPrivileged} |
470 |
* action to create callables that will, if possible, execute |
471 |
* under the selected permission settings holding within that |
472 |
* action; or if not possible, throw an associated {@link |
473 |
* AccessControlException}. |
474 |
* |
475 |
* @param callable the underlying task |
476 |
* @param <T> the type of the callable's result |
477 |
* @return a callable object |
478 |
* @throws NullPointerException if callable null |
479 |
* @throws AccessControlException if the current access control |
480 |
* context does not have permission to both set and get context |
481 |
* class loader |
482 |
* |
483 |
* @deprecated This method is only useful in conjunction with |
484 |
* {@linkplain SecurityManager the Security Manager}, which is |
485 |
* deprecated and subject to removal in a future release. |
486 |
* Consequently, this method is also deprecated and subject to |
487 |
* removal. There is no replacement for the Security Manager or this |
488 |
* method. |
489 |
*/ |
490 |
@Deprecated(since="17", forRemoval=true) |
491 |
public static <T> Callable<T> privilegedCallableUsingCurrentClassLoader(Callable<T> callable) { |
492 |
if (callable == null) |
493 |
throw new NullPointerException(); |
494 |
return new PrivilegedCallableUsingCurrentClassLoader<T>(callable); |
495 |
} |
496 |
|
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// Non-public classes supporting the public methods |
498 |
|
499 |
/** |
500 |
* A callable that runs given task and returns given result. |
501 |
*/ |
502 |
private static final class RunnableAdapter<T> implements Callable<T> { |
503 |
private final Runnable task; |
504 |
private final T result; |
505 |
RunnableAdapter(Runnable task, T result) { |
506 |
this.task = task; |
507 |
this.result = result; |
508 |
} |
509 |
public T call() { |
510 |
task.run(); |
511 |
return result; |
512 |
} |
513 |
public String toString() { |
514 |
return super.toString() + "[Wrapped task = " + task + "]"; |
515 |
} |
516 |
} |
517 |
|
518 |
/** |
519 |
* A callable that runs under established access control settings. |
520 |
*/ |
521 |
private static final class PrivilegedCallable<T> implements Callable<T> { |
522 |
final Callable<T> task; |
523 |
@SuppressWarnings("removal") |
524 |
final AccessControlContext acc; |
525 |
|
526 |
@SuppressWarnings("removal") |
527 |
PrivilegedCallable(Callable<T> task) { |
528 |
this.task = task; |
529 |
this.acc = AccessController.getContext(); |
530 |
} |
531 |
|
532 |
@SuppressWarnings("removal") |
533 |
public T call() throws Exception { |
534 |
try { |
535 |
return AccessController.doPrivileged( |
536 |
new PrivilegedExceptionAction<T>() { |
537 |
public T run() throws Exception { |
538 |
return task.call(); |
539 |
} |
540 |
}, acc); |
541 |
} catch (PrivilegedActionException e) { |
542 |
throw e.getException(); |
543 |
} |
544 |
} |
545 |
|
546 |
public String toString() { |
547 |
return super.toString() + "[Wrapped task = " + task + "]"; |
548 |
} |
549 |
} |
550 |
|
551 |
/** |
552 |
* A callable that runs under established access control settings and |
553 |
* current ClassLoader. |
554 |
*/ |
555 |
private static final class PrivilegedCallableUsingCurrentClassLoader<T> |
556 |
implements Callable<T> { |
557 |
final Callable<T> task; |
558 |
@SuppressWarnings("removal") |
559 |
final AccessControlContext acc; |
560 |
final ClassLoader ccl; |
561 |
|
562 |
@SuppressWarnings("removal") |
563 |
PrivilegedCallableUsingCurrentClassLoader(Callable<T> task) { |
564 |
SecurityManager sm = System.getSecurityManager(); |
565 |
if (sm != null) { |
566 |
// Calls to getContextClassLoader from this class |
567 |
// never trigger a security check, but we check |
568 |
// whether our callers have this permission anyways. |
569 |
sm.checkPermission(SecurityConstants.GET_CLASSLOADER_PERMISSION); |
570 |
|
571 |
// Whether setContextClassLoader turns out to be necessary |
572 |
// or not, we fail fast if permission is not available. |
573 |
sm.checkPermission(new RuntimePermission("setContextClassLoader")); |
574 |
} |
575 |
this.task = task; |
576 |
this.acc = AccessController.getContext(); |
577 |
this.ccl = Thread.currentThread().getContextClassLoader(); |
578 |
} |
579 |
|
580 |
@SuppressWarnings("removal") |
581 |
public T call() throws Exception { |
582 |
try { |
583 |
return AccessController.doPrivileged( |
584 |
new PrivilegedExceptionAction<T>() { |
585 |
public T run() throws Exception { |
586 |
Thread t = Thread.currentThread(); |
587 |
ClassLoader cl = t.getContextClassLoader(); |
588 |
if (ccl == cl) { |
589 |
return task.call(); |
590 |
} else { |
591 |
t.setContextClassLoader(ccl); |
592 |
try { |
593 |
return task.call(); |
594 |
} finally { |
595 |
t.setContextClassLoader(cl); |
596 |
} |
597 |
} |
598 |
} |
599 |
}, acc); |
600 |
} catch (PrivilegedActionException e) { |
601 |
throw e.getException(); |
602 |
} |
603 |
} |
604 |
|
605 |
public String toString() { |
606 |
return super.toString() + "[Wrapped task = " + task + "]"; |
607 |
} |
608 |
} |
609 |
|
610 |
/** |
611 |
* The default thread factory. |
612 |
*/ |
613 |
private static class DefaultThreadFactory implements ThreadFactory { |
614 |
private static final AtomicInteger poolNumber = new AtomicInteger(1); |
615 |
private final ThreadGroup group; |
616 |
private final AtomicInteger threadNumber = new AtomicInteger(1); |
617 |
private final String namePrefix; |
618 |
|
619 |
DefaultThreadFactory() { |
620 |
@SuppressWarnings("removal") |
621 |
SecurityManager s = System.getSecurityManager(); |
622 |
group = (s != null) ? s.getThreadGroup() : |
623 |
Thread.currentThread().getThreadGroup(); |
624 |
namePrefix = "pool-" + |
625 |
poolNumber.getAndIncrement() + |
626 |
"-thread-"; |
627 |
} |
628 |
|
629 |
public Thread newThread(Runnable r) { |
630 |
Thread t = new Thread(group, r, |
631 |
namePrefix + threadNumber.getAndIncrement(), |
632 |
0); |
633 |
if (t.isDaemon()) |
634 |
t.setDaemon(false); |
635 |
if (t.getPriority() != Thread.NORM_PRIORITY) |
636 |
t.setPriority(Thread.NORM_PRIORITY); |
637 |
return t; |
638 |
} |
639 |
} |
640 |
|
641 |
/** |
642 |
* Thread factory capturing access control context and class loader. |
643 |
*/ |
644 |
private static class PrivilegedThreadFactory extends DefaultThreadFactory { |
645 |
@SuppressWarnings("removal") |
646 |
final AccessControlContext acc; |
647 |
final ClassLoader ccl; |
648 |
|
649 |
@SuppressWarnings("removal") |
650 |
PrivilegedThreadFactory() { |
651 |
super(); |
652 |
SecurityManager sm = System.getSecurityManager(); |
653 |
if (sm != null) { |
654 |
// Calls to getContextClassLoader from this class |
655 |
// never trigger a security check, but we check |
656 |
// whether our callers have this permission anyways. |
657 |
sm.checkPermission(SecurityConstants.GET_CLASSLOADER_PERMISSION); |
658 |
|
659 |
// Fail fast |
660 |
sm.checkPermission(new RuntimePermission("setContextClassLoader")); |
661 |
} |
662 |
this.acc = AccessController.getContext(); |
663 |
this.ccl = Thread.currentThread().getContextClassLoader(); |
664 |
} |
665 |
|
666 |
public Thread newThread(final Runnable r) { |
667 |
return super.newThread(new Runnable() { |
668 |
@SuppressWarnings("removal") |
669 |
public void run() { |
670 |
AccessController.doPrivileged(new PrivilegedAction<>() { |
671 |
public Void run() { |
672 |
Thread.currentThread().setContextClassLoader(ccl); |
673 |
r.run(); |
674 |
return null; |
675 |
} |
676 |
}, acc); |
677 |
} |
678 |
}); |
679 |
} |
680 |
} |
681 |
|
682 |
/** |
683 |
* A wrapper class that exposes only the ExecutorService methods |
684 |
* of an ExecutorService implementation. |
685 |
*/ |
686 |
private static class DelegatedExecutorService |
687 |
implements ExecutorService { |
688 |
private final ExecutorService e; |
689 |
DelegatedExecutorService(ExecutorService executor) { e = executor; } |
690 |
public void execute(Runnable command) { |
691 |
try { |
692 |
e.execute(command); |
693 |
} finally { reachabilityFence(this); } |
694 |
} |
695 |
public void shutdown() { e.shutdown(); } |
696 |
public List<Runnable> shutdownNow() { |
697 |
try { |
698 |
return e.shutdownNow(); |
699 |
} finally { reachabilityFence(this); } |
700 |
} |
701 |
public boolean isShutdown() { |
702 |
try { |
703 |
return e.isShutdown(); |
704 |
} finally { reachabilityFence(this); } |
705 |
} |
706 |
public boolean isTerminated() { |
707 |
try { |
708 |
return e.isTerminated(); |
709 |
} finally { reachabilityFence(this); } |
710 |
} |
711 |
public boolean awaitTermination(long timeout, TimeUnit unit) |
712 |
throws InterruptedException { |
713 |
try { |
714 |
return e.awaitTermination(timeout, unit); |
715 |
} finally { reachabilityFence(this); } |
716 |
} |
717 |
public Future<?> submit(Runnable task) { |
718 |
try { |
719 |
return e.submit(task); |
720 |
} finally { reachabilityFence(this); } |
721 |
} |
722 |
public <T> Future<T> submit(Callable<T> task) { |
723 |
try { |
724 |
return e.submit(task); |
725 |
} finally { reachabilityFence(this); } |
726 |
} |
727 |
public <T> Future<T> submit(Runnable task, T result) { |
728 |
try { |
729 |
return e.submit(task, result); |
730 |
} finally { reachabilityFence(this); } |
731 |
} |
732 |
public <T> List<Future<T>> invokeAll(Collection<? extends Callable<T>> tasks) |
733 |
throws InterruptedException { |
734 |
try { |
735 |
return e.invokeAll(tasks); |
736 |
} finally { reachabilityFence(this); } |
737 |
} |
738 |
public <T> List<Future<T>> invokeAll(Collection<? extends Callable<T>> tasks, |
739 |
long timeout, TimeUnit unit) |
740 |
throws InterruptedException { |
741 |
try { |
742 |
return e.invokeAll(tasks, timeout, unit); |
743 |
} finally { reachabilityFence(this); } |
744 |
} |
745 |
public <T> T invokeAny(Collection<? extends Callable<T>> tasks) |
746 |
throws InterruptedException, ExecutionException { |
747 |
try { |
748 |
return e.invokeAny(tasks); |
749 |
} finally { reachabilityFence(this); } |
750 |
} |
751 |
public <T> T invokeAny(Collection<? extends Callable<T>> tasks, |
752 |
long timeout, TimeUnit unit) |
753 |
throws InterruptedException, ExecutionException, TimeoutException { |
754 |
try { |
755 |
return e.invokeAny(tasks, timeout, unit); |
756 |
} finally { reachabilityFence(this); } |
757 |
} |
758 |
} |
759 |
|
760 |
private static class FinalizableDelegatedExecutorService |
761 |
extends DelegatedExecutorService { |
762 |
FinalizableDelegatedExecutorService(ExecutorService executor) { |
763 |
super(executor); |
764 |
} |
765 |
@SuppressWarnings({"deprecation", "removal"}) |
766 |
protected void finalize() { |
767 |
super.shutdown(); |
768 |
} |
769 |
} |
770 |
|
771 |
/** |
772 |
* A wrapper class that exposes only the ScheduledExecutorService |
773 |
* methods of a ScheduledExecutorService implementation. |
774 |
*/ |
775 |
private static class DelegatedScheduledExecutorService |
776 |
extends DelegatedExecutorService |
777 |
implements ScheduledExecutorService { |
778 |
private final ScheduledExecutorService e; |
779 |
DelegatedScheduledExecutorService(ScheduledExecutorService executor) { |
780 |
super(executor); |
781 |
e = executor; |
782 |
} |
783 |
public ScheduledFuture<?> schedule(Runnable command, long delay, TimeUnit unit) { |
784 |
return e.schedule(command, delay, unit); |
785 |
} |
786 |
public <V> ScheduledFuture<V> schedule(Callable<V> callable, long delay, TimeUnit unit) { |
787 |
return e.schedule(callable, delay, unit); |
788 |
} |
789 |
public ScheduledFuture<?> scheduleAtFixedRate(Runnable command, long initialDelay, long period, TimeUnit unit) { |
790 |
return e.scheduleAtFixedRate(command, initialDelay, period, unit); |
791 |
} |
792 |
public ScheduledFuture<?> scheduleWithFixedDelay(Runnable command, long initialDelay, long delay, TimeUnit unit) { |
793 |
return e.scheduleWithFixedDelay(command, initialDelay, delay, unit); |
794 |
} |
795 |
} |
796 |
|
797 |
/** Cannot instantiate. */ |
798 |
private Executors() {} |
799 |
} |