diff -r 000000000000 -r 212417b74b72 rt/emul/compact/src/main/java/java/util/concurrent/ExecutorService.java --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/rt/emul/compact/src/main/java/java/util/concurrent/ExecutorService.java Sat Mar 19 10:46:31 2016 +0100 @@ -0,0 +1,370 @@ +/* + * 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. Oracle designates this + * particular file as subject to the "Classpath" exception as provided + * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA + * or visit www.oracle.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/publicdomain/zero/1.0/ + */ + +package java.util.concurrent; +import java.util.List; +import java.util.Collection; +import java.security.PrivilegedAction; +import java.security.PrivilegedExceptionAction; + +/** + * An {@link Executor} that provides methods to manage termination and + * methods that can produce a {@link Future} for tracking progress of + * one or more asynchronous tasks. + * + *

An ExecutorService can be shut down, which will cause + * it to reject new tasks. Two different methods are provided for + * shutting down an ExecutorService. The {@link #shutdown} + * method will allow previously submitted tasks to execute before + * terminating, while the {@link #shutdownNow} method prevents waiting + * tasks from starting and attempts to stop currently executing tasks. + * Upon termination, an executor has no tasks actively executing, no + * tasks awaiting execution, and no new tasks can be submitted. An + * unused ExecutorService should be shut down to allow + * reclamation of its resources. + * + *

Method submit extends base method {@link + * Executor#execute} by creating and returning a {@link Future} that + * can be used to cancel execution and/or wait for completion. + * Methods invokeAny and invokeAll perform the most + * commonly useful forms of bulk execution, executing a collection of + * tasks and then waiting for at least one, or all, to + * complete. (Class {@link ExecutorCompletionService} can be used to + * write customized variants of these methods.) + * + *

The {@link Executors} class provides factory methods for the + * executor services provided in this package. + * + *

Usage Examples

+ * + * Here is a sketch of a network service in which threads in a thread + * pool service incoming requests. It uses the preconfigured {@link + * Executors#newFixedThreadPool} factory method: + * + *
+ * class NetworkService implements Runnable {
+ *   private final ServerSocket serverSocket;
+ *   private final ExecutorService pool;
+ *
+ *   public NetworkService(int port, int poolSize)
+ *       throws IOException {
+ *     serverSocket = new ServerSocket(port);
+ *     pool = Executors.newFixedThreadPool(poolSize);
+ *   }
+ *
+ *   public void run() { // run the service
+ *     try {
+ *       for (;;) {
+ *         pool.execute(new Handler(serverSocket.accept()));
+ *       }
+ *     } catch (IOException ex) {
+ *       pool.shutdown();
+ *     }
+ *   }
+ * }
+ *
+ * class Handler implements Runnable {
+ *   private final Socket socket;
+ *   Handler(Socket socket) { this.socket = socket; }
+ *   public void run() {
+ *     // read and service request on socket
+ *   }
+ * }
+ * 
+ * + * The following method shuts down an ExecutorService in two phases, + * first by calling shutdown to reject incoming tasks, and then + * calling shutdownNow, if necessary, to cancel any lingering tasks: + * + *
+ * void shutdownAndAwaitTermination(ExecutorService pool) {
+ *   pool.shutdown(); // Disable new tasks from being submitted
+ *   try {
+ *     // Wait a while for existing tasks to terminate
+ *     if (!pool.awaitTermination(60, TimeUnit.SECONDS)) {
+ *       pool.shutdownNow(); // Cancel currently executing tasks
+ *       // Wait a while for tasks to respond to being cancelled
+ *       if (!pool.awaitTermination(60, TimeUnit.SECONDS))
+ *           System.err.println("Pool did not terminate");
+ *     }
+ *   } catch (InterruptedException ie) {
+ *     // (Re-)Cancel if current thread also interrupted
+ *     pool.shutdownNow();
+ *     // Preserve interrupt status
+ *     Thread.currentThread().interrupt();
+ *   }
+ * }
+ * 
+ * + *

Memory consistency effects: Actions in a thread prior to the + * submission of a {@code Runnable} or {@code Callable} task to an + * {@code ExecutorService} + * happen-before + * any actions taken by that task, which in turn happen-before the + * result is retrieved via {@code Future.get()}. + * + * @since 1.5 + * @author Doug Lea + */ +public interface ExecutorService extends Executor { + + /** + * Initiates an orderly shutdown in which previously submitted + * tasks are executed, but no new tasks will be accepted. + * Invocation has no additional effect if already shut down. + * + *

This method does not wait for previously submitted tasks to + * complete execution. Use {@link #awaitTermination awaitTermination} + * to do that. + * + * @throws SecurityException if a security manager exists and + * shutting down this ExecutorService may manipulate + * threads that the caller is not permitted to modify + * because it does not hold {@link + * java.lang.RuntimePermission}("modifyThread"), + * or the security manager's checkAccess method + * denies access. + */ + void shutdown(); + + /** + * Attempts to stop all actively executing tasks, halts the + * processing of waiting tasks, and returns a list of the tasks + * that were awaiting execution. + * + *

This method does not wait for actively executing tasks to + * terminate. Use {@link #awaitTermination awaitTermination} to + * do that. + * + *

There are no guarantees beyond best-effort attempts to stop + * processing actively executing tasks. For example, typical + * implementations will cancel via {@link Thread#interrupt}, so any + * task that fails to respond to interrupts may never terminate. + * + * @return list of tasks that never commenced execution + * @throws SecurityException if a security manager exists and + * shutting down this ExecutorService may manipulate + * threads that the caller is not permitted to modify + * because it does not hold {@link + * java.lang.RuntimePermission}("modifyThread"), + * or the security manager's checkAccess method + * denies access. + */ + List shutdownNow(); + + /** + * Returns true if this executor has been shut down. + * + * @return true if this executor has been shut down + */ + boolean isShutdown(); + + /** + * Returns true if all tasks have completed following shut down. + * Note that isTerminated is never true unless + * either shutdown or shutdownNow was called first. + * + * @return true if all tasks have completed following shut down + */ + boolean isTerminated(); + + /** + * Blocks until all tasks have completed execution after a shutdown + * request, or the timeout occurs, or the current thread is + * interrupted, whichever happens first. + * + * @param timeout the maximum time to wait + * @param unit the time unit of the timeout argument + * @return true if this executor terminated and + * false if the timeout elapsed before termination + * @throws InterruptedException if interrupted while waiting + */ + boolean awaitTermination(long timeout, TimeUnit unit) + throws InterruptedException; + + + /** + * Submits a value-returning task for execution and returns a + * Future representing the pending results of the task. The + * Future's get method will return the task's result upon + * successful completion. + * + *

+ * If you would like to immediately block waiting + * for a task, you can use constructions of the form + * result = exec.submit(aCallable).get(); + * + *

Note: The {@link Executors} class includes a set of methods + * that can convert some other common closure-like objects, + * for example, {@link java.security.PrivilegedAction} to + * {@link Callable} form so they can be submitted. + * + * @param task the task to submit + * @return a Future representing pending completion of the task + * @throws RejectedExecutionException if the task cannot be + * scheduled for execution + * @throws NullPointerException if the task is null + */ + Future submit(Callable task); + + /** + * Submits a Runnable task for execution and returns a Future + * representing that task. The Future's get method will + * return the given result upon successful completion. + * + * @param task the task to submit + * @param result the result to return + * @return a Future representing pending completion of the task + * @throws RejectedExecutionException if the task cannot be + * scheduled for execution + * @throws NullPointerException if the task is null + */ + Future submit(Runnable task, T result); + + /** + * Submits a Runnable task for execution and returns a Future + * representing that task. The Future's get method will + * return null upon successful completion. + * + * @param task the task to submit + * @return a Future representing pending completion of the task + * @throws RejectedExecutionException if the task cannot be + * scheduled for execution + * @throws NullPointerException if the task is null + */ + Future submit(Runnable task); + + /** + * Executes the given tasks, returning a list of Futures holding + * their status and results when all complete. + * {@link Future#isDone} is true for each + * element of the returned list. + * Note that a completed task could have + * terminated either normally or by throwing an exception. + * The results of this method are undefined if the given + * collection is modified while this operation is in progress. + * + * @param tasks the collection of tasks + * @return A list of Futures representing the tasks, in the same + * sequential order as produced by the iterator for the + * given task list, each of which has completed. + * @throws InterruptedException if interrupted while waiting, in + * which case unfinished tasks are cancelled. + * @throws NullPointerException if tasks or any of its elements are null + * @throws RejectedExecutionException if any task cannot be + * scheduled for execution + */ + + List> invokeAll(Collection> tasks) + throws InterruptedException; + + /** + * Executes the given tasks, returning a list of Futures holding + * their status and results + * when all complete or the timeout expires, whichever happens first. + * {@link Future#isDone} is true for each + * element of the returned list. + * Upon return, tasks that have not completed are cancelled. + * Note that a completed task could have + * terminated either normally or by throwing an exception. + * The results of this method are undefined if the given + * collection is modified while this operation is in progress. + * + * @param tasks the collection of tasks + * @param timeout the maximum time to wait + * @param unit the time unit of the timeout argument + * @return a list of Futures representing the tasks, in the same + * sequential order as produced by the iterator for the + * given task list. If the operation did not time out, + * each task will have completed. If it did time out, some + * of these tasks will not have completed. + * @throws InterruptedException if interrupted while waiting, in + * which case unfinished tasks are cancelled + * @throws NullPointerException if tasks, any of its elements, or + * unit are null + * @throws RejectedExecutionException if any task cannot be scheduled + * for execution + */ + List> invokeAll(Collection> tasks, + long timeout, TimeUnit unit) + throws InterruptedException; + + /** + * Executes the given tasks, returning the result + * of one that has completed successfully (i.e., without throwing + * an exception), if any do. Upon normal or exceptional return, + * tasks that have not completed are cancelled. + * The results of this method are undefined if the given + * collection is modified while this operation is in progress. + * + * @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 element task + * subject to execution is null + * @throws IllegalArgumentException if tasks is empty + * @throws ExecutionException if no task successfully completes + * @throws RejectedExecutionException if tasks cannot be scheduled + * for execution + */ + T invokeAny(Collection> tasks) + throws InterruptedException, ExecutionException; + + /** + * Executes the given tasks, returning the result + * of one that has completed successfully (i.e., without throwing + * an exception), if any do before the given timeout elapses. + * Upon normal or exceptional return, tasks that have not + * completed are cancelled. + * The results of this method are undefined if the given + * collection is modified while this operation is in progress. + * + * @param tasks the collection of tasks + * @param timeout the maximum time to wait + * @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, or unit, or any element + * task subject to execution is null + * @throws TimeoutException if the given timeout elapses before + * any task successfully completes + * @throws ExecutionException if no task successfully completes + * @throws RejectedExecutionException if tasks cannot be scheduled + * for execution + */ + T invokeAny(Collection> tasks, + long timeout, TimeUnit unit) + throws InterruptedException, ExecutionException, TimeoutException; +}