1a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson/* 229957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 329957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * 429957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * This code is free software; you can redistribute it and/or modify it 529957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * under the terms of the GNU General Public License version 2 only, as 629957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * published by the Free Software Foundation. Oracle designates this 729957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * particular file as subject to the "Classpath" exception as provided 829957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * by Oracle in the LICENSE file that accompanied this code. 929957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * 1029957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * This code is distributed in the hope that it will be useful, but WITHOUT 1129957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 1229957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 1329957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * version 2 for more details (a copy is included in the LICENSE file that 1429957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * accompanied this code). 1529957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * 1629957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * You should have received a copy of the GNU General Public License version 1729957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * 2 along with this work; if not, write to the Free Software Foundation, 1829957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 1929957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * 2029957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 2129957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * or visit www.oracle.com if you need additional information or have any 2229957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * questions. 2329957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer */ 2429957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer 2529957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer/* 2629957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * This file is available under and governed by the GNU General Public 2729957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * License version 2 only, as published by the Free Software Foundation. 2829957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * However, the following notice accompanied the original version of this 2929957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * file: 3029957558cf0db700bfaae360a80c42dc3871d0e5Tobias Thierer * 31a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Written by Doug Lea with assistance from members of JCP JSR-166 32a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Expert Group and released to the public domain, as explained at 33a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * http://creativecommons.org/publicdomain/zero/1.0/ 34a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 35a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 36a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilsonpackage java.util.concurrent; 37a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 38a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilsonimport java.io.Serializable; 39b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniakimport java.lang.ref.ReferenceQueue; 40b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniakimport java.lang.ref.WeakReference; 41b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniakimport java.lang.reflect.Constructor; 42a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilsonimport java.util.Collection; 43a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilsonimport java.util.List; 44a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilsonimport java.util.RandomAccess; 45a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilsonimport java.util.concurrent.locks.ReentrantLock; 46b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak 47b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak// BEGIN android-note 48b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak// removed java 9 code 49b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak// END android-note 50a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 51a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson/** 52a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Abstract base class for tasks that run within a {@link ForkJoinPool}. 53a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * A {@code ForkJoinTask} is a thread-like entity that is much 54a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * lighter weight than a normal thread. Huge numbers of tasks and 55a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * subtasks may be hosted by a small number of actual threads in a 56a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * ForkJoinPool, at the price of some usage limitations. 57a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 5891770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * <p>A "main" {@code ForkJoinTask} begins execution when it is 5991770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * explicitly submitted to a {@link ForkJoinPool}, or, if not already 60b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * engaged in a ForkJoin computation, commenced in the {@link 61b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * ForkJoinPool#commonPool()} via {@link #fork}, {@link #invoke}, or 6291770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * related methods. Once started, it will usually in turn start other 6391770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * subtasks. As indicated by the name of this class, many programs 6491770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * using {@code ForkJoinTask} employ only methods {@link #fork} and 6591770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * {@link #join}, or derivatives such as {@link 66a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * #invokeAll(ForkJoinTask...) invokeAll}. However, this class also 67a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * provides a number of other methods that can come into play in 6891770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * advanced usages, as well as extension mechanics that allow support 6991770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * of new forms of fork/join processing. 70a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 71a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * <p>A {@code ForkJoinTask} is a lightweight form of {@link Future}. 72a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * The efficiency of {@code ForkJoinTask}s stems from a set of 73a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * restrictions (that are only partially statically enforceable) 7491770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * reflecting their main use as computational tasks calculating pure 7591770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * functions or operating on purely isolated objects. The primary 7691770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * coordination mechanisms are {@link #fork}, that arranges 77a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * asynchronous execution, and {@link #join}, that doesn't proceed 78a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * until the task's result has been computed. Computations should 7991770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * ideally avoid {@code synchronized} methods or blocks, and should 8091770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * minimize other blocking synchronization apart from joining other 8191770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * tasks or using synchronizers such as Phasers that are advertised to 8291770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * cooperate with fork/join scheduling. Subdividable tasks should also 8391770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * not perform blocking I/O, and should ideally access variables that 8491770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * are completely independent of those accessed by other running 8591770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * tasks. These guidelines are loosely enforced by not permitting 8691770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * checked exceptions such as {@code IOExceptions} to be 8791770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * thrown. However, computations may still encounter unchecked 8891770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * exceptions, that are rethrown to callers attempting to join 8991770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * them. These exceptions may additionally include {@link 9091770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * RejectedExecutionException} stemming from internal resource 9191770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * exhaustion, such as failure to allocate internal task 9291770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * queues. Rethrown exceptions behave in the same way as regular 9391770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * exceptions, but, when possible, contain stack traces (as displayed 9491770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * for example using {@code ex.printStackTrace()}) of both the thread 9591770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * that initiated the computation as well as the thread actually 9691770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * encountering the exception; minimally only the latter. 9791770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * 9891770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * <p>It is possible to define and use ForkJoinTasks that may block, 9991770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * but doing do requires three further considerations: (1) Completion 10091770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * of few if any <em>other</em> tasks should be dependent on a task 10191770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * that blocks on external synchronization or I/O. Event-style async 102b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * tasks that are never joined (for example, those subclassing {@link 103b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * CountedCompleter}) often fall into this category. (2) To minimize 104b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * resource impact, tasks should be small; ideally performing only the 105b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * (possibly) blocking action. (3) Unless the {@link 10691770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * ForkJoinPool.ManagedBlocker} API is used, or the number of possibly 10791770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * blocked tasks is known to be less than the pool's {@link 10891770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * ForkJoinPool#getParallelism} level, the pool cannot guarantee that 10991770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * enough threads will be available to ensure progress or good 11091770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * performance. 111a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 112a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * <p>The primary method for awaiting completion and extracting 113a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * results of a task is {@link #join}, but there are several variants: 114a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * The {@link Future#get} methods support interruptible and/or timed 115a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * waits for completion and report results using {@code Future} 116a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * conventions. Method {@link #invoke} is semantically 117a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * equivalent to {@code fork(); join()} but always attempts to begin 118a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * execution in the current thread. The "<em>quiet</em>" forms of 119a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * these methods do not extract results or report exceptions. These 120a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * may be useful when a set of tasks are being executed, and you need 121a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * to delay processing of results or exceptions until all complete. 122a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Method {@code invokeAll} (available in multiple versions) 123a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * performs the most common form of parallel invocation: forking a set 124a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * of tasks and joining them all. 125a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 12691770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * <p>In the most typical usages, a fork-join pair act like a call 12791770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * (fork) and return (join) from a parallel recursive function. As is 12891770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * the case with other forms of recursive calls, returns (joins) 12991770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * should be performed innermost-first. For example, {@code a.fork(); 13091770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * b.fork(); b.join(); a.join();} is likely to be substantially more 13191770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * efficient than joining {@code a} before {@code b}. 13291770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * 133a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * <p>The execution status of tasks may be queried at several levels 134a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * of detail: {@link #isDone} is true if a task completed in any way 135a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * (including the case where a task was cancelled without executing); 136a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * {@link #isCompletedNormally} is true if a task completed without 137a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * cancellation or encountering an exception; {@link #isCancelled} is 138a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * true if the task was cancelled (in which case {@link #getException} 139a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * returns a {@link java.util.concurrent.CancellationException}); and 140a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * {@link #isCompletedAbnormally} is true if a task was either 141a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * cancelled or encountered an exception, in which case {@link 142a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * #getException} will return either the encountered exception or 143a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * {@link java.util.concurrent.CancellationException}. 144a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 145a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * <p>The ForkJoinTask class is not usually directly subclassed. 146a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Instead, you subclass one of the abstract classes that support a 147a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * particular style of fork/join processing, typically {@link 148b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * RecursiveAction} for most computations that do not return results, 149b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * {@link RecursiveTask} for those that do, and {@link 150b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * CountedCompleter} for those in which completed actions trigger 151b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * other actions. Normally, a concrete ForkJoinTask subclass declares 152b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * fields comprising its parameters, established in a constructor, and 153b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * then defines a {@code compute} method that somehow uses the control 154b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * methods supplied by this base class. 155a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 156a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * <p>Method {@link #join} and its variants are appropriate for use 157a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * only when completion dependencies are acyclic; that is, the 158a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * parallel computation can be described as a directed acyclic graph 159a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * (DAG). Otherwise, executions may encounter a form of deadlock as 160a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * tasks cyclically wait for each other. However, this framework 161a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * supports other methods and techniques (for example the use of 162a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * {@link Phaser}, {@link #helpQuiesce}, and {@link #complete}) that 163a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * may be of use in constructing custom subclasses for problems that 16475a06e56a4cc4599946e21422513e4bafa759509Calin Juravle * are not statically structured as DAGs. To support such usages, a 16591770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * ForkJoinTask may be atomically <em>tagged</em> with a {@code short} 166b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * value using {@link #setForkJoinTaskTag} or {@link 167b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * #compareAndSetForkJoinTaskTag} and checked using {@link 168b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * #getForkJoinTaskTag}. The ForkJoinTask implementation does not use 16991770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * these {@code protected} methods or tags for any purpose, but they 17091770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * may be of use in the construction of specialized subclasses. For 17191770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * example, parallel graph traversals can use the supplied methods to 17291770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * avoid revisiting nodes/tasks that have already been processed. 17391770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * (Method names for tagging are bulky in part to encourage definition 17491770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * of methods that reflect their usage patterns.) 175a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 176a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * <p>Most base support methods are {@code final}, to prevent 177a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * overriding of implementations that are intrinsically tied to the 178a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * underlying lightweight task scheduling framework. Developers 179a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * creating new basic styles of fork/join processing should minimally 180a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * implement {@code protected} methods {@link #exec}, {@link 181a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * #setRawResult}, and {@link #getRawResult}, while also introducing 182a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * an abstract computational method that can be implemented in its 183a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * subclasses, possibly relying on other {@code protected} methods 184a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * provided by this class. 185a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 186a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * <p>ForkJoinTasks should perform relatively small amounts of 187a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * computation. Large tasks should be split into smaller subtasks, 188a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * usually via recursive decomposition. As a very rough rule of thumb, 189a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * a task should perform more than 100 and less than 10000 basic 190a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * computational steps, and should avoid indefinite looping. If tasks 191a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * are too big, then parallelism cannot improve throughput. If too 192a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * small, then memory and internal task maintenance overhead may 193a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * overwhelm processing. 194a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 195a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * <p>This class provides {@code adapt} methods for {@link Runnable} 196a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * and {@link Callable}, that may be of use when mixing execution of 197a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * {@code ForkJoinTasks} with other kinds of tasks. When all tasks are 198a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * of this form, consider using a pool constructed in <em>asyncMode</em>. 199a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 200a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * <p>ForkJoinTasks are {@code Serializable}, which enables them to be 201a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * used in extensions such as remote execution frameworks. It is 202a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * sensible to serialize tasks only before or after, but not during, 203a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * execution. Serialization is not relied on during execution itself. 204a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 205a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @since 1.7 206a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @author Doug Lea 207a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 208a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilsonpublic abstract class ForkJoinTask<V> implements Future<V>, Serializable { 209a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 210a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /* 211a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * See the internal documentation of class ForkJoinPool for a 212a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * general implementation overview. ForkJoinTasks are mainly 213a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * responsible for maintaining their "status" field amidst relays 214a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * to methods in ForkJoinWorkerThread and ForkJoinPool. 215a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 216a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * The methods of this class are more-or-less layered into 217a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * (1) basic status maintenance 218a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * (2) execution and awaiting completion 219a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * (3) user-level methods that additionally report results. 220a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * This is sometimes hard to see because this file orders exported 221a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * methods in a way that flows well in javadocs. 222a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 223a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 224a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /* 225a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * The status field holds run control status bits packed into a 226a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * single int to minimize footprint and to ensure atomicity (via 227a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * CAS). Status is initially zero, and takes on nonnegative 22891770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * values until completed, upon which status (anded with 22991770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * DONE_MASK) holds value NORMAL, CANCELLED, or EXCEPTIONAL. Tasks 23091770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * undergoing blocking waits by other threads have the SIGNAL bit 23191770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * set. Completion of a stolen task with SIGNAL set awakens any 23291770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * waiters via notifyAll. Even though suboptimal for some 23391770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * purposes, we use basic builtin wait/notify to take advantage of 23491770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * "monitor inflation" in JVMs that we would otherwise need to 23591770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * emulate to avoid adding further per-task bookkeeping overhead. 23691770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * We want these monitors to be "fat", i.e., not use biasing or 23791770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * thin-lock techniques, so use some odd coding idioms that tend 23891770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * to avoid them, mainly by arranging that every synchronized 23991770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * block performs a wait, notifyAll or both. 24091770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * 24191770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * These control bits occupy only (some of) the upper half (16 24291770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * bits) of status field. The lower bits are used for user-defined 24391770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * tags. 244a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 245a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 246a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** The run status of this task */ 247a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson volatile int status; // accessed directly by pool and workers 24891770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle static final int DONE_MASK = 0xf0000000; // mask out non-completion bits 24991770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle static final int NORMAL = 0xf0000000; // must be negative 25091770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle static final int CANCELLED = 0xc0000000; // must be < NORMAL 25191770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle static final int EXCEPTIONAL = 0x80000000; // must be < CANCELLED 25291770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle static final int SIGNAL = 0x00010000; // must be >= 1 << 16 25391770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle static final int SMASK = 0x0000ffff; // short bits for tags 254a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 255a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 25691770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * Marks completion and wakes up threads waiting to join this 25791770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * task. 258a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 259a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @param completion one of NORMAL, CANCELLED, EXCEPTIONAL 260a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return completion status on exit 261a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 262a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson private int setCompletion(int completion) { 263a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson for (int s;;) { 264a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if ((s = status) < 0) 265a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return s; 26691770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle if (U.compareAndSwapInt(this, STATUS, s, s | completion)) { 26791770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle if ((s >>> 16) != 0) 268a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson synchronized (this) { notifyAll(); } 269a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return completion; 270a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 271a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 272a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 273a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 274a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 27591770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * Primary execution method for stolen tasks. Unless done, calls 27691770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * exec and records status if completed, but doesn't wait for 27791770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * completion otherwise. 278a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 27991770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * @return status on exit from this method 280a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 28191770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle final int doExec() { 28291770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle int s; boolean completed; 28391770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle if ((s = status) >= 0) { 28491770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle try { 28591770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle completed = exec(); 28691770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle } catch (Throwable rex) { 28791770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle return setExceptionalCompletion(rex); 288a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 28991770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle if (completed) 29091770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle s = setCompletion(NORMAL); 291a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 29291770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle return s; 29391770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle } 29491770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle 29591770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle /** 296b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * If not done, sets SIGNAL status and performs Object.wait(timeout). 297b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * This task may or may not be done on exit. Ignores interrupts. 29891770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * 299b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * @param timeout using Object.wait conventions. 30091770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle */ 301b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak final void internalWait(long timeout) { 302b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak int s; 303b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak if ((s = status) >= 0 && // force completer to issue notify 304b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak U.compareAndSwapInt(this, STATUS, s, s | SIGNAL)) { 305b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak synchronized (this) { 306b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak if (status >= 0) 307b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak try { wait(timeout); } catch (InterruptedException ie) { } 308b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak else 309b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak notifyAll(); 310b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak } 311b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak } 312a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 313a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 314a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 315a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Blocks a non-worker-thread until completion. 316a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return status upon completion 317a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 318a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson private int externalAwaitDone() { 319b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak int s = ((this instanceof CountedCompleter) ? // try helping 320b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak ForkJoinPool.common.externalHelpComplete( 321b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak (CountedCompleter<?>)this, 0) : 322b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak ForkJoinPool.common.tryExternalUnpush(this) ? doExec() : 0); 323b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak if (s >= 0 && (s = status) >= 0) { 324b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak boolean interrupted = false; 325b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak do { 326b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak if (U.compareAndSwapInt(this, STATUS, s, s | SIGNAL)) { 327b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak synchronized (this) { 328b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak if (status >= 0) { 329b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak try { 330b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak wait(0L); 331b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak } catch (InterruptedException ie) { 332b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak interrupted = true; 33375a06e56a4cc4599946e21422513e4bafa759509Calin Juravle } 334a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 335b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak else 336b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak notifyAll(); 337a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 338b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak } 339b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak } while ((s = status) >= 0); 340b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak if (interrupted) 341b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak Thread.currentThread().interrupt(); 342a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 343a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return s; 344a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 345a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 346a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 34791770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * Blocks a non-worker-thread until completion or interruption. 348a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 34991770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle private int externalInterruptibleAwaitDone() throws InterruptedException { 350a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson int s; 351a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (Thread.interrupted()) 352a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson throw new InterruptedException(); 353b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak if ((s = status) >= 0 && 354b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak (s = ((this instanceof CountedCompleter) ? 355b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak ForkJoinPool.common.externalHelpComplete( 356b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak (CountedCompleter<?>)this, 0) : 357b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak ForkJoinPool.common.tryExternalUnpush(this) ? doExec() : 358b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak 0)) >= 0) { 359b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak while ((s = status) >= 0) { 360b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak if (U.compareAndSwapInt(this, STATUS, s, s | SIGNAL)) { 361b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak synchronized (this) { 362b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak if (status >= 0) 363b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak wait(0L); 364b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak else 365b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak notifyAll(); 366b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak } 367a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 368a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 369a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 370a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return s; 371a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 372a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 373a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 37491770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * Implementation for join, get, quietlyJoin. Directly handles 37591770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * only cases of already-completed, external wait, and 37691770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * unfork+exec. Others are relayed to ForkJoinPool.awaitJoin. 37791770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * 378a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return status upon completion 379a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 380a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson private int doJoin() { 38191770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle int s; Thread t; ForkJoinWorkerThread wt; ForkJoinPool.WorkQueue w; 38291770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle return (s = status) < 0 ? s : 38391770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle ((t = Thread.currentThread()) instanceof ForkJoinWorkerThread) ? 38491770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle (w = (wt = (ForkJoinWorkerThread)t).workQueue). 38591770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle tryUnpush(this) && (s = doExec()) < 0 ? s : 386b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak wt.pool.awaitJoin(w, this, 0L) : 38791770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle externalAwaitDone(); 388a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 389a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 390a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 39191770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * Implementation for invoke, quietlyInvoke. 39291770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * 393a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return status upon completion 394a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 395a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson private int doInvoke() { 39691770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle int s; Thread t; ForkJoinWorkerThread wt; 39791770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle return (s = doExec()) < 0 ? s : 39891770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle ((t = Thread.currentThread()) instanceof ForkJoinWorkerThread) ? 399b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak (wt = (ForkJoinWorkerThread)t).pool. 400b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak awaitJoin(wt.workQueue, this, 0L) : 40191770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle externalAwaitDone(); 402a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 403a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 404a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson // Exception table support 405a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 406a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 407a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Table of exceptions thrown by tasks, to enable reporting by 408a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * callers. Because exceptions are rare, we don't directly keep 409a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * them with task objects, but instead use a weak ref table. Note 410a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * that cancellation exceptions don't appear in the table, but are 411a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * instead recorded as status values. 412a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 413a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Note: These statics are initialized below in static block. 414a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 415a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson private static final ExceptionNode[] exceptionTable; 416a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson private static final ReentrantLock exceptionTableLock; 417a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson private static final ReferenceQueue<Object> exceptionTableRefQueue; 418a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 419a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 420a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Fixed capacity for exceptionTable. 421a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 422a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson private static final int EXCEPTION_MAP_CAPACITY = 32; 423a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 424a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 425a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Key-value nodes for exception table. The chained hash table 426a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * uses identity comparisons, full locking, and weak references 427a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * for keys. The table has a fixed capacity because it only 428a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * maintains task exceptions long enough for joiners to access 429a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * them, so should never become very large for sustained 430a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * periods. However, since we do not know when the last joiner 431a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * completes, we must use weak references and expunge them. We do 432a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * so on each operation (hence full locking). Also, some thread in 433a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * any ForkJoinPool will call helpExpungeStaleExceptions when its 434a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * pool becomes isQuiescent. 435a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 43691770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle static final class ExceptionNode extends WeakReference<ForkJoinTask<?>> { 437a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson final Throwable ex; 438a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson ExceptionNode next; 439a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson final long thrower; // use id not ref to avoid weak cycles 440edf43d27e240d82106f39ae91404963c23987234Narayan Kamath final int hashCode; // store task hashCode before weak ref disappears 441b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak ExceptionNode(ForkJoinTask<?> task, Throwable ex, ExceptionNode next, 442b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak ReferenceQueue<Object> exceptionTableRefQueue) { 443a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson super(task, exceptionTableRefQueue); 444a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson this.ex = ex; 445a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson this.next = next; 446a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson this.thrower = Thread.currentThread().getId(); 447edf43d27e240d82106f39ae91404963c23987234Narayan Kamath this.hashCode = System.identityHashCode(task); 448a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 449a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 450a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 451a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 45291770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * Records exception and sets status. 453a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 454a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return status on exit 455a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 45691770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle final int recordExceptionalCompletion(Throwable ex) { 45791770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle int s; 45891770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle if ((s = status) >= 0) { 45991770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle int h = System.identityHashCode(this); 46091770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle final ReentrantLock lock = exceptionTableLock; 46191770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle lock.lock(); 46291770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle try { 46391770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle expungeStaleExceptions(); 46491770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle ExceptionNode[] t = exceptionTable; 46591770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle int i = h & (t.length - 1); 46691770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle for (ExceptionNode e = t[i]; ; e = e.next) { 46791770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle if (e == null) { 468b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak t[i] = new ExceptionNode(this, ex, t[i], 469b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak exceptionTableRefQueue); 47091770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle break; 47191770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle } 47291770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle if (e.get() == this) // already present 47391770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle break; 474a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 47591770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle } finally { 47691770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle lock.unlock(); 47791770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle } 47891770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle s = setCompletion(EXCEPTIONAL); 47991770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle } 48091770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle return s; 48191770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle } 48291770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle 48391770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle /** 48491770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * Records exception and possibly propagates. 48591770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * 48691770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * @return status on exit 48791770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle */ 48891770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle private int setExceptionalCompletion(Throwable ex) { 48991770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle int s = recordExceptionalCompletion(ex); 49091770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle if ((s & DONE_MASK) == EXCEPTIONAL) 49191770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle internalPropagateException(ex); 49291770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle return s; 49391770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle } 49491770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle 49591770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle /** 49691770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * Hook for exception propagation support for tasks with completers. 49791770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle */ 49891770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle void internalPropagateException(Throwable ex) { 49991770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle } 50091770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle 50191770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle /** 50291770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * Cancels, ignoring any exceptions thrown by cancel. Used during 50391770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * worker and pool shutdown. Cancel is spec'ed not to throw any 50491770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * exceptions, but if it does anyway, we have no recourse during 50591770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * shutdown, so guard against this case. 50691770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle */ 50791770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle static final void cancelIgnoringExceptions(ForkJoinTask<?> t) { 50891770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle if (t != null && t.status >= 0) { 50991770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle try { 51091770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle t.cancel(false); 51191770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle } catch (Throwable ignore) { 512a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 513a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 514a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 515a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 516a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 51791770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * Removes exception node and clears status. 518a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 519a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson private void clearExceptionalCompletion() { 520a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson int h = System.identityHashCode(this); 521a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson final ReentrantLock lock = exceptionTableLock; 522a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson lock.lock(); 523a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson try { 524a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson ExceptionNode[] t = exceptionTable; 525a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson int i = h & (t.length - 1); 526a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson ExceptionNode e = t[i]; 527a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson ExceptionNode pred = null; 528a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson while (e != null) { 529a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson ExceptionNode next = e.next; 530a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (e.get() == this) { 531a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (pred == null) 532a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson t[i] = next; 533a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson else 534a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson pred.next = next; 535a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson break; 536a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 537a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson pred = e; 538a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson e = next; 539a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 540a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson expungeStaleExceptions(); 541a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson status = 0; 542a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } finally { 543a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson lock.unlock(); 544a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 545a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 546a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 547a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 548b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * Returns a rethrowable exception for this task, if available. 549b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * To provide accurate stack traces, if the exception was not 550b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * thrown by the current thread, we try to create a new exception 551b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * of the same type as the one thrown, but with the recorded 552b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * exception as its cause. If there is no such constructor, we 553b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * instead try to use a no-arg constructor, followed by initCause, 554b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * to the same effect. If none of these apply, or any fail due to 555b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * other exceptions, we return the recorded exception, which is 556b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * still correct, although it may contain a misleading stack 557b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * trace. 558a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 559a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return the exception, or null if none 560a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 561a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson private Throwable getThrowableException() { 562a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson int h = System.identityHashCode(this); 563a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson ExceptionNode e; 564a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson final ReentrantLock lock = exceptionTableLock; 565a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson lock.lock(); 566a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson try { 567a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson expungeStaleExceptions(); 568a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson ExceptionNode[] t = exceptionTable; 569a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson e = t[h & (t.length - 1)]; 570a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson while (e != null && e.get() != this) 571a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson e = e.next; 572a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } finally { 573a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson lock.unlock(); 574a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 575a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson Throwable ex; 576a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (e == null || (ex = e.ex) == null) 577a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return null; 578b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak if (e.thrower != Thread.currentThread().getId()) { 579a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson try { 580a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson Constructor<?> noArgCtor = null; 581b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak // public ctors only 582b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak for (Constructor<?> c : ex.getClass().getConstructors()) { 583a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson Class<?>[] ps = c.getParameterTypes(); 584a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (ps.length == 0) 585a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson noArgCtor = c; 586a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson else if (ps.length == 1 && ps[0] == Throwable.class) 587b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak return (Throwable)c.newInstance(ex); 588a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 589a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (noArgCtor != null) { 590b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak Throwable wx = (Throwable)noArgCtor.newInstance(); 591a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson wx.initCause(ex); 592a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return wx; 593a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 594a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } catch (Exception ignore) { 595a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 596a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 597a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return ex; 598a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 599a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 600a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 601b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * Polls stale refs and removes them. Call only while holding lock. 602a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 603a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson private static void expungeStaleExceptions() { 604a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson for (Object x; (x = exceptionTableRefQueue.poll()) != null;) { 605a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (x instanceof ExceptionNode) { 606edf43d27e240d82106f39ae91404963c23987234Narayan Kamath int hashCode = ((ExceptionNode)x).hashCode; 607a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson ExceptionNode[] t = exceptionTable; 608edf43d27e240d82106f39ae91404963c23987234Narayan Kamath int i = hashCode & (t.length - 1); 609a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson ExceptionNode e = t[i]; 610a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson ExceptionNode pred = null; 611a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson while (e != null) { 612a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson ExceptionNode next = e.next; 613a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (e == x) { 614a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (pred == null) 615a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson t[i] = next; 616a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson else 617a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson pred.next = next; 618a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson break; 619a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 620a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson pred = e; 621a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson e = next; 622a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 623a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 624a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 625a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 626a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 627a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 628b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * If lock is available, polls stale refs and removes them. 629a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Called from ForkJoinPool when pools become quiescent. 630a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 631a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson static final void helpExpungeStaleExceptions() { 632a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson final ReentrantLock lock = exceptionTableLock; 633a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (lock.tryLock()) { 634a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson try { 635a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson expungeStaleExceptions(); 636a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } finally { 637a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson lock.unlock(); 638a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 639a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 640a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 641a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 642a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 643b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * A version of "sneaky throw" to relay exceptions. 64491770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle */ 64575a06e56a4cc4599946e21422513e4bafa759509Calin Juravle static void rethrow(Throwable ex) { 646b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak ForkJoinTask.<RuntimeException>uncheckedThrow(ex); 64791770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle } 64891770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle 64991770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle /** 65091770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * The sneaky part of sneaky throw, relying on generics 65191770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * limitations to evade compiler complaints about rethrowing 652b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * unchecked exceptions. 653a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 65491770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle @SuppressWarnings("unchecked") static <T extends Throwable> 655b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak void uncheckedThrow(Throwable t) throws T { 656b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak if (t != null) 657b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak throw (T)t; // rely on vacuous cast 658b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak else 659b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak throw new Error("Unknown Exception"); 66091770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle } 66191770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle 66291770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle /** 66391770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * Throws exception, if any, associated with the given status. 66491770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle */ 66591770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle private void reportException(int s) { 66691770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle if (s == CANCELLED) 667a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson throw new CancellationException(); 66891770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle if (s == EXCEPTIONAL) 66991770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle rethrow(getThrowableException()); 670a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 671a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 672a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson // public methods 673a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 674a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 67591770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * Arranges to asynchronously execute this task in the pool the 676b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * current task is running in, if applicable, or using the {@link 677b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * ForkJoinPool#commonPool()} if not {@link #inForkJoinPool}. While 67891770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * it is not necessarily enforced, it is a usage error to fork a 67991770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * task more than once unless it has completed and been 68091770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * reinitialized. Subsequent modifications to the state of this 68191770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * task or any data it operates on are not necessarily 68291770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * consistently observable by any thread other than the one 68391770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * executing it unless preceded by a call to {@link #join} or 68491770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * related methods, or a call to {@link #isDone} returning {@code 68591770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * true}. 686a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 687a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return {@code this}, to simplify usage 688a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 689a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public final ForkJoinTask<V> fork() { 69091770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle Thread t; 69191770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle if ((t = Thread.currentThread()) instanceof ForkJoinWorkerThread) 69291770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle ((ForkJoinWorkerThread)t).workQueue.push(this); 69391770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle else 69475a06e56a4cc4599946e21422513e4bafa759509Calin Juravle ForkJoinPool.common.externalPush(this); 695a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return this; 696a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 697a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 698a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 699a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Returns the result of the computation when it {@link #isDone is 700a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * done}. This method differs from {@link #get()} in that 701a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * abnormal completion results in {@code RuntimeException} or 702a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * {@code Error}, not {@code ExecutionException}, and that 703a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * interrupts of the calling thread do <em>not</em> cause the 704a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * method to abruptly return by throwing {@code 705a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * InterruptedException}. 706a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 707a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return the computed result 708a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 709a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public final V join() { 71091770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle int s; 71191770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle if ((s = doJoin() & DONE_MASK) != NORMAL) 71291770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle reportException(s); 71391770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle return getRawResult(); 714a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 715a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 716a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 717a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Commences performing this task, awaits its completion if 718a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * necessary, and returns its result, or throws an (unchecked) 719a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * {@code RuntimeException} or {@code Error} if the underlying 720a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * computation did so. 721a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 722a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return the computed result 723a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 724a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public final V invoke() { 72591770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle int s; 72691770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle if ((s = doInvoke() & DONE_MASK) != NORMAL) 72791770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle reportException(s); 72891770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle return getRawResult(); 729a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 730a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 731a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 732a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Forks the given tasks, returning when {@code isDone} holds for 733a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * each task or an (unchecked) exception is encountered, in which 734a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * case the exception is rethrown. If more than one task 735a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * encounters an exception, then this method throws any one of 736a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * these exceptions. If any task encounters an exception, the 737a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * other may be cancelled. However, the execution status of 738a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * individual tasks is not guaranteed upon exceptional return. The 739a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * status of each task may be obtained using {@link 740a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * #getException()} and related methods to check if they have been 741a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * cancelled, completed normally or exceptionally, or left 742a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * unprocessed. 743a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 744a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @param t1 the first task 745a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @param t2 the second task 746a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @throws NullPointerException if any task is null 747a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 748a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public static void invokeAll(ForkJoinTask<?> t1, ForkJoinTask<?> t2) { 74991770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle int s1, s2; 750a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson t2.fork(); 75191770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle if ((s1 = t1.doInvoke() & DONE_MASK) != NORMAL) 75291770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle t1.reportException(s1); 75391770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle if ((s2 = t2.doJoin() & DONE_MASK) != NORMAL) 75491770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle t2.reportException(s2); 755a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 756a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 757a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 758a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Forks the given tasks, returning when {@code isDone} holds for 759a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * each task or an (unchecked) exception is encountered, in which 760a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * case the exception is rethrown. If more than one task 761a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * encounters an exception, then this method throws any one of 762a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * these exceptions. If any task encounters an exception, others 763a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * may be cancelled. However, the execution status of individual 764a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * tasks is not guaranteed upon exceptional return. The status of 765a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * each task may be obtained using {@link #getException()} and 766a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * related methods to check if they have been cancelled, completed 767a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * normally or exceptionally, or left unprocessed. 768a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 769a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @param tasks the tasks 770a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @throws NullPointerException if any task is null 771a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 772a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public static void invokeAll(ForkJoinTask<?>... tasks) { 773a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson Throwable ex = null; 774a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson int last = tasks.length - 1; 775a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson for (int i = last; i >= 0; --i) { 776a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson ForkJoinTask<?> t = tasks[i]; 777a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (t == null) { 778a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (ex == null) 779a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson ex = new NullPointerException(); 780a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 781a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson else if (i != 0) 782a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson t.fork(); 783a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson else if (t.doInvoke() < NORMAL && ex == null) 784a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson ex = t.getException(); 785a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 786a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson for (int i = 1; i <= last; ++i) { 787a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson ForkJoinTask<?> t = tasks[i]; 788a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (t != null) { 789a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (ex != null) 790a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson t.cancel(false); 791a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson else if (t.doJoin() < NORMAL) 792a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson ex = t.getException(); 793a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 794a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 795a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (ex != null) 79691770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle rethrow(ex); 797a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 798a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 799a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 800a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Forks all tasks in the specified collection, returning when 801a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * {@code isDone} holds for each task or an (unchecked) exception 802a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * is encountered, in which case the exception is rethrown. If 803a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * more than one task encounters an exception, then this method 804a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * throws any one of these exceptions. If any task encounters an 805a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * exception, others may be cancelled. However, the execution 806a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * status of individual tasks is not guaranteed upon exceptional 807a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * return. The status of each task may be obtained using {@link 808a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * #getException()} and related methods to check if they have been 809a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * cancelled, completed normally or exceptionally, or left 810a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * unprocessed. 811a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 812a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @param tasks the collection of tasks 813fd81a99407d318ea3d8b5782294a0644e580d126Neil Fuller * @param <T> the type of the values returned from the tasks 814a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return the tasks argument, to simplify usage 815a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @throws NullPointerException if tasks or any element are null 816a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 817a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public static <T extends ForkJoinTask<?>> Collection<T> invokeAll(Collection<T> tasks) { 818a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (!(tasks instanceof RandomAccess) || !(tasks instanceof List<?>)) { 819a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson invokeAll(tasks.toArray(new ForkJoinTask<?>[tasks.size()])); 820a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return tasks; 821a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 822a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson @SuppressWarnings("unchecked") 823a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson List<? extends ForkJoinTask<?>> ts = 824a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson (List<? extends ForkJoinTask<?>>) tasks; 825a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson Throwable ex = null; 826a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson int last = ts.size() - 1; 827a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson for (int i = last; i >= 0; --i) { 828a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson ForkJoinTask<?> t = ts.get(i); 829a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (t == null) { 830a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (ex == null) 831a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson ex = new NullPointerException(); 832a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 833a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson else if (i != 0) 834a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson t.fork(); 835a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson else if (t.doInvoke() < NORMAL && ex == null) 836a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson ex = t.getException(); 837a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 838a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson for (int i = 1; i <= last; ++i) { 839a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson ForkJoinTask<?> t = ts.get(i); 840a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (t != null) { 841a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (ex != null) 842a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson t.cancel(false); 843a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson else if (t.doJoin() < NORMAL) 844a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson ex = t.getException(); 845a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 846a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 847a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (ex != null) 84891770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle rethrow(ex); 849a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return tasks; 850a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 851a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 852a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 853a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Attempts to cancel execution of this task. This attempt will 854a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * fail if the task has already completed or could not be 855a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * cancelled for some other reason. If successful, and this task 856a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * has not started when {@code cancel} is called, execution of 857a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * this task is suppressed. After this method returns 858a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * successfully, unless there is an intervening call to {@link 859a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * #reinitialize}, subsequent calls to {@link #isCancelled}, 860a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * {@link #isDone}, and {@code cancel} will return {@code true} 861a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * and calls to {@link #join} and related methods will result in 862a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * {@code CancellationException}. 863a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 864a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * <p>This method may be overridden in subclasses, but if so, must 865a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * still ensure that these properties hold. In particular, the 866a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * {@code cancel} method itself must not throw exceptions. 867a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 868a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * <p>This method is designed to be invoked by <em>other</em> 869a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * tasks. To terminate the current task, you can just return or 870a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * throw an unchecked exception from its computation method, or 87175a06e56a4cc4599946e21422513e4bafa759509Calin Juravle * invoke {@link #completeExceptionally(Throwable)}. 872a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 873a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @param mayInterruptIfRunning this value has no effect in the 874a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * default implementation because interrupts are not used to 875a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * control cancellation. 876a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 877a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return {@code true} if this task is now cancelled 878a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 879a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public boolean cancel(boolean mayInterruptIfRunning) { 88091770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle return (setCompletion(CANCELLED) & DONE_MASK) == CANCELLED; 881a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 882a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 883a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public final boolean isDone() { 884a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return status < 0; 885a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 886a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 887a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public final boolean isCancelled() { 88891770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle return (status & DONE_MASK) == CANCELLED; 889a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 890a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 891a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 892a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Returns {@code true} if this task threw an exception or was cancelled. 893a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 894a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return {@code true} if this task threw an exception or was cancelled 895a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 896a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public final boolean isCompletedAbnormally() { 897a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return status < NORMAL; 898a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 899a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 900a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 901a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Returns {@code true} if this task completed without throwing an 902a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * exception and was not cancelled. 903a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 904a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return {@code true} if this task completed without throwing an 905a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * exception and was not cancelled 906a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 907a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public final boolean isCompletedNormally() { 90891770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle return (status & DONE_MASK) == NORMAL; 909a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 910a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 911a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 912a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Returns the exception thrown by the base computation, or a 913a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * {@code CancellationException} if cancelled, or {@code null} if 914a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * none or if the method has not yet completed. 915a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 916a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return the exception, or {@code null} if none 917a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 918a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public final Throwable getException() { 91991770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle int s = status & DONE_MASK; 920a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return ((s >= NORMAL) ? null : 921a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson (s == CANCELLED) ? new CancellationException() : 922a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson getThrowableException()); 923a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 924a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 925a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 926a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Completes this task abnormally, and if not already aborted or 927a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * cancelled, causes it to throw the given exception upon 928a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * {@code join} and related operations. This method may be used 929a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * to induce exceptions in asynchronous tasks, or to force 930a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * completion of tasks that would not otherwise complete. Its use 931a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * in other situations is discouraged. This method is 932a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * overridable, but overridden versions must invoke {@code super} 933a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * implementation to maintain guarantees. 934a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 935a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @param ex the exception to throw. If this exception is not a 936a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * {@code RuntimeException} or {@code Error}, the actual exception 937a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * thrown will be a {@code RuntimeException} with cause {@code ex}. 938a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 939a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public void completeExceptionally(Throwable ex) { 940a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson setExceptionalCompletion((ex instanceof RuntimeException) || 941a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson (ex instanceof Error) ? ex : 942a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson new RuntimeException(ex)); 943a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 944a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 945a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 946a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Completes this task, and if not already aborted or cancelled, 947a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * returning the given value as the result of subsequent 948a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * invocations of {@code join} and related operations. This method 949a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * may be used to provide results for asynchronous tasks, or to 950a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * provide alternative handling for tasks that would not otherwise 951a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * complete normally. Its use in other situations is 952a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * discouraged. This method is overridable, but overridden 953a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * versions must invoke {@code super} implementation to maintain 954a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * guarantees. 955a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 956a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @param value the result value for this task 957a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 958a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public void complete(V value) { 959a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson try { 960a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson setRawResult(value); 961a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } catch (Throwable rex) { 962a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson setExceptionalCompletion(rex); 963a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return; 964a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 965a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson setCompletion(NORMAL); 966a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 967a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 968a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 96991770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * Completes this task normally without setting a value. The most 97091770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * recent value established by {@link #setRawResult} (or {@code 97191770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * null} by default) will be returned as the result of subsequent 97291770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * invocations of {@code join} and related operations. 97391770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * 97491770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * @since 1.8 97591770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle */ 97691770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle public final void quietlyComplete() { 97791770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle setCompletion(NORMAL); 97891770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle } 97991770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle 98091770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle /** 981a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Waits if necessary for the computation to complete, and then 982a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * retrieves its result. 983a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 984a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return the computed result 985a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @throws CancellationException if the computation was cancelled 986a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @throws ExecutionException if the computation threw an 987a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * exception 988a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @throws InterruptedException if the current thread is not a 989a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * member of a ForkJoinPool and was interrupted while waiting 990a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 991a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public final V get() throws InterruptedException, ExecutionException { 992a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson int s = (Thread.currentThread() instanceof ForkJoinWorkerThread) ? 99391770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle doJoin() : externalInterruptibleAwaitDone(); 99491770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle if ((s &= DONE_MASK) == CANCELLED) 995a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson throw new CancellationException(); 996b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak if (s == EXCEPTIONAL) 997b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak throw new ExecutionException(getThrowableException()); 998a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return getRawResult(); 999a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1000a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1001a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 1002a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Waits if necessary for at most the given time for the computation 1003a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * to complete, and then retrieves its result, if available. 1004a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 1005a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @param timeout the maximum time to wait 1006a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @param unit the time unit of the timeout argument 1007a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return the computed result 1008a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @throws CancellationException if the computation was cancelled 1009a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @throws ExecutionException if the computation threw an 1010a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * exception 1011a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @throws InterruptedException if the current thread is not a 1012a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * member of a ForkJoinPool and was interrupted while waiting 1013a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @throws TimeoutException if the wait timed out 1014a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 1015a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public final V get(long timeout, TimeUnit unit) 1016a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson throws InterruptedException, ExecutionException, TimeoutException { 1017b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak int s; 1018b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak long nanos = unit.toNanos(timeout); 101991770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle if (Thread.interrupted()) 102091770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle throw new InterruptedException(); 1021b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak if ((s = status) >= 0 && nanos > 0L) { 1022b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak long d = System.nanoTime() + nanos; 1023b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak long deadline = (d == 0L) ? 1L : d; // avoid 0 102491770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle Thread t = Thread.currentThread(); 102591770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle if (t instanceof ForkJoinWorkerThread) { 102691770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle ForkJoinWorkerThread wt = (ForkJoinWorkerThread)t; 1027b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak s = wt.pool.awaitJoin(wt.workQueue, this, deadline); 1028ed4f365789d43b1961657195df223a19bf4ef20fPrzemyslaw Szczepaniak } 1029b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak else if ((s = ((this instanceof CountedCompleter) ? 1030b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak ForkJoinPool.common.externalHelpComplete( 1031b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak (CountedCompleter<?>)this, 0) : 1032b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak ForkJoinPool.common.tryExternalUnpush(this) ? 1033b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak doExec() : 0)) >= 0) { 1034b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak long ns, ms; // measure in nanosecs, but wait in millisecs 1035b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak while ((s = status) >= 0 && 1036b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak (ns = deadline - System.nanoTime()) > 0L) { 1037b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak if ((ms = TimeUnit.NANOSECONDS.toMillis(ns)) > 0L && 1038b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak U.compareAndSwapInt(this, STATUS, s, s | SIGNAL)) { 1039b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak synchronized (this) { 1040b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak if (status >= 0) 1041b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak wait(ms); // OK to throw InterruptedException 1042b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak else 1043b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak notifyAll(); 104491770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle } 1045a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1046a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1047a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1048a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1049b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak if (s >= 0) 1050b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak s = status; 105191770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle if ((s &= DONE_MASK) != NORMAL) { 1052a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (s == CANCELLED) 1053a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson throw new CancellationException(); 1054a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (s != EXCEPTIONAL) 1055a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson throw new TimeoutException(); 1056b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak throw new ExecutionException(getThrowableException()); 1057a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1058a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return getRawResult(); 1059a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1060a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1061a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 1062a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Joins this task, without returning its result or throwing its 1063a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * exception. This method may be useful when processing 1064a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * collections of tasks when some have been cancelled or otherwise 1065a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * known to have aborted. 1066a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 1067a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public final void quietlyJoin() { 1068a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson doJoin(); 1069a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1070a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1071a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 1072a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Commences performing this task and awaits its completion if 1073a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * necessary, without returning its result or throwing its 1074a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * exception. 1075a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 1076a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public final void quietlyInvoke() { 1077a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson doInvoke(); 1078a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1079a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1080a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 1081a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Possibly executes tasks until the pool hosting the current task 1082b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * {@linkplain ForkJoinPool#isQuiescent is quiescent}. This 1083b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * method may be of use in designs in which many tasks are forked, 1084b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * but none are explicitly joined, instead executing them until 1085b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * all are processed. 1086a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 1087a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public static void helpQuiesce() { 108891770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle Thread t; 108991770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle if ((t = Thread.currentThread()) instanceof ForkJoinWorkerThread) { 109091770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle ForkJoinWorkerThread wt = (ForkJoinWorkerThread)t; 109191770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle wt.pool.helpQuiescePool(wt.workQueue); 109291770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle } 109391770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle else 109475a06e56a4cc4599946e21422513e4bafa759509Calin Juravle ForkJoinPool.quiesceCommonPool(); 1095a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1096a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1097a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 1098a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Resets the internal bookkeeping state of this task, allowing a 1099a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * subsequent {@code fork}. This method allows repeated reuse of 1100a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * this task, but only if reuse occurs when this task has either 1101a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * never been forked, or has been forked, then completed and all 1102a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * outstanding joins of this task have also completed. Effects 1103a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * under any other usage conditions are not guaranteed. 1104a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * This method may be useful when executing 1105a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * pre-constructed trees of subtasks in loops. 1106a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 1107a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * <p>Upon completion of this method, {@code isDone()} reports 1108a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * {@code false}, and {@code getException()} reports {@code 1109a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * null}. However, the value returned by {@code getRawResult} is 1110a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * unaffected. To clear this value, you can invoke {@code 1111a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * setRawResult(null)}. 1112a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 1113a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public void reinitialize() { 111491770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle if ((status & DONE_MASK) == EXCEPTIONAL) 1115a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson clearExceptionalCompletion(); 1116a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson else 1117a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson status = 0; 1118a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1119a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1120a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 1121b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * Returns the pool hosting the current thread, or {@code null} 1122b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * if the current thread is executing outside of any ForkJoinPool. 1123b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * 1124b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * <p>This method returns {@code null} if and only if {@link 1125b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * #inForkJoinPool} returns {@code false}. 1126a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 1127a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return the pool, or {@code null} if none 1128a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 1129a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public static ForkJoinPool getPool() { 1130a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson Thread t = Thread.currentThread(); 1131a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return (t instanceof ForkJoinWorkerThread) ? 1132a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson ((ForkJoinWorkerThread) t).pool : null; 1133a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1134a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1135a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 1136a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Returns {@code true} if the current thread is a {@link 1137a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * ForkJoinWorkerThread} executing as a ForkJoinPool computation. 1138a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 1139a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return {@code true} if the current thread is a {@link 1140a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * ForkJoinWorkerThread} executing as a ForkJoinPool computation, 1141a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * or {@code false} otherwise 1142a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 1143a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public static boolean inForkJoinPool() { 1144a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return Thread.currentThread() instanceof ForkJoinWorkerThread; 1145a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1146a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1147a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 1148a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Tries to unschedule this task for execution. This method will 114991770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * typically (but is not guaranteed to) succeed if this task is 115091770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * the most recently forked task by the current thread, and has 115191770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * not commenced executing in another thread. This method may be 115291770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * useful when arranging alternative local processing of tasks 115391770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * that could have been, but were not, stolen. 1154a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 1155a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return {@code true} if unforked 1156a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 1157a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public boolean tryUnfork() { 115891770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle Thread t; 115991770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle return (((t = Thread.currentThread()) instanceof ForkJoinWorkerThread) ? 116091770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle ((ForkJoinWorkerThread)t).workQueue.tryUnpush(this) : 116175a06e56a4cc4599946e21422513e4bafa759509Calin Juravle ForkJoinPool.common.tryExternalUnpush(this)); 1162a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1163a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1164a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 1165a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Returns an estimate of the number of tasks that have been 1166a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * forked by the current worker thread but not yet executed. This 1167a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * value may be useful for heuristic decisions about whether to 1168a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * fork other tasks. 1169a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 1170a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return the number of tasks 1171a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 1172a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public static int getQueuedTaskCount() { 117391770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle Thread t; ForkJoinPool.WorkQueue q; 117491770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle if ((t = Thread.currentThread()) instanceof ForkJoinWorkerThread) 117591770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle q = ((ForkJoinWorkerThread)t).workQueue; 117691770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle else 117791770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle q = ForkJoinPool.commonSubmitterQueue(); 117891770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle return (q == null) ? 0 : q.queueSize(); 1179a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1180a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1181a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 1182a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Returns an estimate of how many more locally queued tasks are 1183a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * held by the current worker thread than there are other worker 118491770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * threads that might steal them, or zero if this thread is not 118591770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * operating in a ForkJoinPool. This value may be useful for 1186a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * heuristic decisions about whether to fork other tasks. In many 1187a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * usages of ForkJoinTasks, at steady state, each worker should 1188a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * aim to maintain a small constant surplus (for example, 3) of 1189a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * tasks, and to process computations locally if this threshold is 1190a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * exceeded. 1191a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 1192a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return the surplus number of tasks, which may be negative 1193a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 1194a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public static int getSurplusQueuedTaskCount() { 119591770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle return ForkJoinPool.getSurplusQueuedTaskCount(); 1196a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1197a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1198a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson // Extension methods 1199a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1200a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 1201a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Returns the result that would be returned by {@link #join}, even 1202a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * if this task completed abnormally, or {@code null} if this task 1203a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * is not known to have been completed. This method is designed 1204a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * to aid debugging, as well as to support extensions. Its use in 1205a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * any other context is discouraged. 1206a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 1207a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return the result, or {@code null} if not completed 1208a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 1209a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public abstract V getRawResult(); 1210a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1211a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 1212a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Forces the given value to be returned as a result. This method 1213a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * is designed to support extensions, and should not in general be 1214a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * called otherwise. 1215a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 1216a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @param value the value 1217a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 1218a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson protected abstract void setRawResult(V value); 1219a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1220a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 122191770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * Immediately performs the base action of this task and returns 122291770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * true if, upon return from this method, this task is guaranteed 122391770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * to have completed normally. This method may return false 122491770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * otherwise, to indicate that this task is not necessarily 122591770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * complete (or is not known to be complete), for example in 1226a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * asynchronous actions that require explicit invocations of 122791770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * completion methods. This method may also throw an (unchecked) 122891770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * exception to indicate abnormal exit. This method is designed to 122991770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * support extensions, and should not in general be called 123091770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * otherwise. 1231a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 123291770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * @return {@code true} if this task is known to have completed normally 1233a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 1234a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson protected abstract boolean exec(); 1235a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1236a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 1237a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Returns, but does not unschedule or execute, a task queued by 1238a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * the current thread but not yet executed, if one is immediately 1239a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * available. There is no guarantee that this task will actually 1240a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * be polled or executed next. Conversely, this method may return 1241a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * null even if a task exists but cannot be accessed without 1242a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * contention with other threads. This method is designed 1243a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * primarily to support extensions, and is unlikely to be useful 1244a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * otherwise. 1245a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 1246a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return the next task, or {@code null} if none are available 1247a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 1248a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson protected static ForkJoinTask<?> peekNextLocalTask() { 124991770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle Thread t; ForkJoinPool.WorkQueue q; 125091770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle if ((t = Thread.currentThread()) instanceof ForkJoinWorkerThread) 125191770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle q = ((ForkJoinWorkerThread)t).workQueue; 125291770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle else 125391770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle q = ForkJoinPool.commonSubmitterQueue(); 125491770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle return (q == null) ? null : q.peek(); 1255a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1256a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1257a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 1258a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Unschedules and returns, without executing, the next task 125991770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * queued by the current thread but not yet executed, if the 126091770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * current thread is operating in a ForkJoinPool. This method is 126191770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * designed primarily to support extensions, and is unlikely to be 126291770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * useful otherwise. 1263a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 1264a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return the next task, or {@code null} if none are available 1265a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 1266a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson protected static ForkJoinTask<?> pollNextLocalTask() { 126791770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle Thread t; 126891770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle return ((t = Thread.currentThread()) instanceof ForkJoinWorkerThread) ? 126991770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle ((ForkJoinWorkerThread)t).workQueue.nextLocalTask() : 127091770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle null; 1271a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1272a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1273a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 127491770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * If the current thread is operating in a ForkJoinPool, 127591770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * unschedules and returns, without executing, the next task 1276a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * queued by the current thread but not yet executed, if one is 1277a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * available, or if not available, a task that was forked by some 1278a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * other thread, if available. Availability may be transient, so a 127991770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * {@code null} result does not necessarily imply quiescence of 128091770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * the pool this task is operating in. This method is designed 1281a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * primarily to support extensions, and is unlikely to be useful 1282a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * otherwise. 1283a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 1284a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return a task, or {@code null} if none are available 1285a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 1286a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson protected static ForkJoinTask<?> pollTask() { 128791770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle Thread t; ForkJoinWorkerThread wt; 128891770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle return ((t = Thread.currentThread()) instanceof ForkJoinWorkerThread) ? 128991770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle (wt = (ForkJoinWorkerThread)t).pool.nextTaskFor(wt.workQueue) : 129091770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle null; 129191770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle } 129291770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle 1293b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak /** 1294b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * If the current thread is operating in a ForkJoinPool, 1295b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * unschedules and returns, without executing, a task externally 1296b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * submitted to the pool, if one is available. Availability may be 1297b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * transient, so a {@code null} result does not necessarily imply 1298b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * quiescence of the pool. This method is designed primarily to 1299b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * support extensions, and is unlikely to be useful otherwise. 1300b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * 1301b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * @return a task, or {@code null} if none are available 1302b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * @since 9 1303b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * @hide 1304b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak */ 13056975f84c2ed72e1e26d20190b6f318718c849008Tobias Thierer // Android-changed: hidden 1306b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak protected static ForkJoinTask<?> pollSubmission() { 1307b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak Thread t; 1308b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak return ((t = Thread.currentThread()) instanceof ForkJoinWorkerThread) ? 1309b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak ((ForkJoinWorkerThread)t).pool.pollSubmission() : null; 1310b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak } 1311b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak 131291770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle // tag operations 131391770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle 131491770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle /** 131591770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * Returns the tag for this task. 131691770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * 131791770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * @return the tag for this task 131891770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * @since 1.8 131991770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle */ 132091770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle public final short getForkJoinTaskTag() { 132191770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle return (short)status; 132291770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle } 132391770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle 132491770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle /** 1325b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * Atomically sets the tag value for this task and returns the old value. 132691770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * 1327b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * @param newValue the new tag value 132891770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * @return the previous value of the tag 132991770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * @since 1.8 133091770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle */ 1331b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak public final short setForkJoinTaskTag(short newValue) { 133291770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle for (int s;;) { 133391770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle if (U.compareAndSwapInt(this, STATUS, s = status, 1334b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak (s & ~SMASK) | (newValue & SMASK))) 133591770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle return (short)s; 133691770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle } 133791770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle } 133891770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle 133991770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle /** 134091770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * Atomically conditionally sets the tag value for this task. 134191770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * Among other applications, tags can be used as visit markers 134291770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * in tasks operating on graphs, as in methods that check: {@code 134391770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * if (task.compareAndSetForkJoinTaskTag((short)0, (short)1))} 134491770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * before processing, otherwise exiting because the node has 134591770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * already been visited. 134691770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * 1347b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * @param expect the expected tag value 1348b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * @param update the new tag value 134975a06e56a4cc4599946e21422513e4bafa759509Calin Juravle * @return {@code true} if successful; i.e., the current value was 1350b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * equal to {@code expect} and was changed to {@code update}. 135191770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * @since 1.8 135291770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle */ 1353b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak public final boolean compareAndSetForkJoinTaskTag(short expect, short update) { 135491770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle for (int s;;) { 1355b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak if ((short)(s = status) != expect) 135691770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle return false; 135791770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle if (U.compareAndSwapInt(this, STATUS, s, 1358b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak (s & ~SMASK) | (update & SMASK))) 135991770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle return true; 136091770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle } 1361a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1362a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1363a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 1364b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * Adapter for Runnables. This implements RunnableFuture 1365a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * to be compliant with AbstractExecutorService constraints 1366a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * when used in ForkJoinPool. 1367a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 1368a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson static final class AdaptedRunnable<T> extends ForkJoinTask<T> 1369a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson implements RunnableFuture<T> { 1370a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson final Runnable runnable; 1371a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson T result; 1372a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson AdaptedRunnable(Runnable runnable, T result) { 1373a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (runnable == null) throw new NullPointerException(); 1374a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson this.runnable = runnable; 137591770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle this.result = result; // OK to set this even before completion 1376a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 137791770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle public final T getRawResult() { return result; } 137891770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle public final void setRawResult(T v) { result = v; } 137991770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle public final boolean exec() { runnable.run(); return true; } 138091770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle public final void run() { invoke(); } 138191770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle private static final long serialVersionUID = 5232453952276885070L; 138291770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle } 138391770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle 138491770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle /** 1385b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * Adapter for Runnables without results. 138691770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle */ 138791770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle static final class AdaptedRunnableAction extends ForkJoinTask<Void> 138891770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle implements RunnableFuture<Void> { 138991770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle final Runnable runnable; 139091770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle AdaptedRunnableAction(Runnable runnable) { 139191770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle if (runnable == null) throw new NullPointerException(); 139291770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle this.runnable = runnable; 1393a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 139491770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle public final Void getRawResult() { return null; } 139591770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle public final void setRawResult(Void v) { } 139691770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle public final boolean exec() { runnable.run(); return true; } 139791770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle public final void run() { invoke(); } 1398a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson private static final long serialVersionUID = 5232453952276885070L; 1399a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1400a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1401a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 1402b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * Adapter for Runnables in which failure forces worker exception. 140375a06e56a4cc4599946e21422513e4bafa759509Calin Juravle */ 140475a06e56a4cc4599946e21422513e4bafa759509Calin Juravle static final class RunnableExecuteAction extends ForkJoinTask<Void> { 140575a06e56a4cc4599946e21422513e4bafa759509Calin Juravle final Runnable runnable; 140675a06e56a4cc4599946e21422513e4bafa759509Calin Juravle RunnableExecuteAction(Runnable runnable) { 140775a06e56a4cc4599946e21422513e4bafa759509Calin Juravle if (runnable == null) throw new NullPointerException(); 140875a06e56a4cc4599946e21422513e4bafa759509Calin Juravle this.runnable = runnable; 140975a06e56a4cc4599946e21422513e4bafa759509Calin Juravle } 141075a06e56a4cc4599946e21422513e4bafa759509Calin Juravle public final Void getRawResult() { return null; } 141175a06e56a4cc4599946e21422513e4bafa759509Calin Juravle public final void setRawResult(Void v) { } 141275a06e56a4cc4599946e21422513e4bafa759509Calin Juravle public final boolean exec() { runnable.run(); return true; } 141375a06e56a4cc4599946e21422513e4bafa759509Calin Juravle void internalPropagateException(Throwable ex) { 141475a06e56a4cc4599946e21422513e4bafa759509Calin Juravle rethrow(ex); // rethrow outside exec() catches. 141575a06e56a4cc4599946e21422513e4bafa759509Calin Juravle } 141675a06e56a4cc4599946e21422513e4bafa759509Calin Juravle private static final long serialVersionUID = 5232453952276885070L; 141775a06e56a4cc4599946e21422513e4bafa759509Calin Juravle } 141875a06e56a4cc4599946e21422513e4bafa759509Calin Juravle 141975a06e56a4cc4599946e21422513e4bafa759509Calin Juravle /** 1420b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * Adapter for Callables. 1421a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 1422a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson static final class AdaptedCallable<T> extends ForkJoinTask<T> 1423a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson implements RunnableFuture<T> { 1424a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson final Callable<? extends T> callable; 1425a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson T result; 1426a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson AdaptedCallable(Callable<? extends T> callable) { 1427a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (callable == null) throw new NullPointerException(); 1428a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson this.callable = callable; 1429a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 143091770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle public final T getRawResult() { return result; } 143191770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle public final void setRawResult(T v) { result = v; } 143291770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle public final boolean exec() { 1433a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson try { 1434a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson result = callable.call(); 1435a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return true; 1436a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } catch (RuntimeException rex) { 1437a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson throw rex; 1438a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } catch (Exception ex) { 1439a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson throw new RuntimeException(ex); 1440a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1441a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 144291770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle public final void run() { invoke(); } 1443a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson private static final long serialVersionUID = 2838392045355241008L; 1444a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1445a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1446a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 1447a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Returns a new {@code ForkJoinTask} that performs the {@code run} 1448a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * method of the given {@code Runnable} as its action, and returns 1449a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * a null result upon {@link #join}. 1450a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 1451a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @param runnable the runnable action 1452a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return the task 1453a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 1454a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public static ForkJoinTask<?> adapt(Runnable runnable) { 145591770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle return new AdaptedRunnableAction(runnable); 1456a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1457a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1458a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 1459a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Returns a new {@code ForkJoinTask} that performs the {@code run} 1460a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * method of the given {@code Runnable} as its action, and returns 1461a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * the given result upon {@link #join}. 1462a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 1463a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @param runnable the runnable action 1464a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @param result the result upon completion 1465fd81a99407d318ea3d8b5782294a0644e580d126Neil Fuller * @param <T> the type of the result 1466a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return the task 1467a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 1468a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public static <T> ForkJoinTask<T> adapt(Runnable runnable, T result) { 1469a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return new AdaptedRunnable<T>(runnable, result); 1470a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1471a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1472a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 1473a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Returns a new {@code ForkJoinTask} that performs the {@code call} 1474a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * method of the given {@code Callable} as its action, and returns 1475a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * its result upon {@link #join}, translating any checked exceptions 1476a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * encountered into {@code RuntimeException}. 1477a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 1478a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @param callable the callable action 1479fd81a99407d318ea3d8b5782294a0644e580d126Neil Fuller * @param <T> the type of the callable's result 1480a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return the task 1481a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 1482a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public static <T> ForkJoinTask<T> adapt(Callable<? extends T> callable) { 1483a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return new AdaptedCallable<T>(callable); 1484a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1485a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1486a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson // Serialization support 1487a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1488a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson private static final long serialVersionUID = -7721805057305804111L; 1489a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1490a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 149191770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * Saves this task to a stream (that is, serializes it). 1492a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 1493b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * @param s the stream 1494b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * @throws java.io.IOException if an I/O error occurs 1495a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @serialData the current run status and the exception thrown 1496a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * during execution, or {@code null} if none 1497a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 1498a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson private void writeObject(java.io.ObjectOutputStream s) 1499a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson throws java.io.IOException { 1500a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson s.defaultWriteObject(); 1501a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson s.writeObject(getException()); 1502a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1503a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1504a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 150591770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle * Reconstitutes this task from a stream (that is, deserializes it). 1506b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * @param s the stream 1507b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * @throws ClassNotFoundException if the class of a serialized object 1508b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * could not be found 1509b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak * @throws java.io.IOException if an I/O error occurs 1510a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 1511a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson private void readObject(java.io.ObjectInputStream s) 1512a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson throws java.io.IOException, ClassNotFoundException { 1513a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson s.defaultReadObject(); 1514a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson Object ex = s.readObject(); 1515a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (ex != null) 1516a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson setExceptionalCompletion((Throwable)ex); 1517a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1518a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1519a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson // Unsafe mechanics 1520b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak private static final sun.misc.Unsafe U = sun.misc.Unsafe.getUnsafe(); 152191770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle private static final long STATUS; 152291770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle 1523a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson static { 1524a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson exceptionTableLock = new ReentrantLock(); 1525a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson exceptionTableRefQueue = new ReferenceQueue<Object>(); 1526a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson exceptionTable = new ExceptionNode[EXCEPTION_MAP_CAPACITY]; 1527a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson try { 152891770798d8b9280d48d30df2ed7f63b3ed9b036fCalin Juravle STATUS = U.objectFieldOffset 1529b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak (ForkJoinTask.class.getDeclaredField("status")); 1530b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak } catch (ReflectiveOperationException e) { 1531a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson throw new Error(e); 1532a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1533a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1534b8b75116273ecfdb8ffdd1869b1c0dd04570a95ePrzemyslaw Szczepaniak 1535a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson} 1536