1a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson/* 2a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Written by Doug Lea with assistance from members of JCP JSR-166 3a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Expert Group and released to the public domain, as explained at 4a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * http://creativecommons.org/publicdomain/zero/1.0/ 5a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 6a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 7a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilsonpackage java.util.concurrent; 8a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 9a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilsonimport java.io.Serializable; 10a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilsonimport java.util.Collection; 11a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilsonimport java.util.List; 12a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilsonimport java.util.RandomAccess; 13a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilsonimport java.lang.ref.WeakReference; 14a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilsonimport java.lang.ref.ReferenceQueue; 15a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilsonimport java.util.concurrent.Callable; 16a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilsonimport java.util.concurrent.CancellationException; 17a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilsonimport java.util.concurrent.ExecutionException; 18a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilsonimport java.util.concurrent.Future; 19a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilsonimport java.util.concurrent.RejectedExecutionException; 20a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilsonimport java.util.concurrent.RunnableFuture; 21a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilsonimport java.util.concurrent.TimeUnit; 22a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilsonimport java.util.concurrent.TimeoutException; 23a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilsonimport java.util.concurrent.locks.ReentrantLock; 24a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilsonimport java.lang.reflect.Constructor; 25a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilsonimport libcore.util.SneakyThrow; 26a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 27a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson/** 28a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Abstract base class for tasks that run within a {@link ForkJoinPool}. 29a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * A {@code ForkJoinTask} is a thread-like entity that is much 30a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * lighter weight than a normal thread. Huge numbers of tasks and 31a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * subtasks may be hosted by a small number of actual threads in a 32a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * ForkJoinPool, at the price of some usage limitations. 33a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 34a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * <p>A "main" {@code ForkJoinTask} begins execution when submitted 35a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * to a {@link ForkJoinPool}. Once started, it will usually in turn 36a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * start other subtasks. As indicated by the name of this class, 37a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * many programs using {@code ForkJoinTask} employ only methods 38a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * {@link #fork} and {@link #join}, or derivatives such as {@link 39a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * #invokeAll(ForkJoinTask...) invokeAll}. However, this class also 40a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * provides a number of other methods that can come into play in 41a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * advanced usages, as well as extension mechanics that allow 42a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * support of new forms of fork/join processing. 43a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 44a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * <p>A {@code ForkJoinTask} is a lightweight form of {@link Future}. 45a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * The efficiency of {@code ForkJoinTask}s stems from a set of 46a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * restrictions (that are only partially statically enforceable) 47a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * reflecting their intended use as computational tasks calculating 48a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * pure functions or operating on purely isolated objects. The 49a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * primary coordination mechanisms are {@link #fork}, that arranges 50a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * asynchronous execution, and {@link #join}, that doesn't proceed 51a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * until the task's result has been computed. Computations should 52a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * avoid {@code synchronized} methods or blocks, and should minimize 53a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * other blocking synchronization apart from joining other tasks or 54a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * using synchronizers such as Phasers that are advertised to 55a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * cooperate with fork/join scheduling. Tasks should also not perform 56a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * blocking IO, and should ideally access variables that are 57a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * completely independent of those accessed by other running 58a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * tasks. Minor breaches of these restrictions, for example using 59a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * shared output streams, may be tolerable in practice, but frequent 60a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * use may result in poor performance, and the potential to 61a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * indefinitely stall if the number of threads not waiting for IO or 62a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * other external synchronization becomes exhausted. This usage 63a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * restriction is in part enforced by not permitting checked 64a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * exceptions such as {@code IOExceptions} to be thrown. However, 65a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * computations may still encounter unchecked exceptions, that are 66a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * rethrown to callers attempting to join them. These exceptions may 67a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * additionally include {@link RejectedExecutionException} stemming 68a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * from internal resource exhaustion, such as failure to allocate 69a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * internal task queues. Rethrown exceptions behave in the same way as 70a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * regular exceptions, but, when possible, contain stack traces (as 71a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * displayed for example using {@code ex.printStackTrace()}) of both 72a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * the thread that initiated the computation as well as the thread 73a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * actually encountering the exception; minimally only the latter. 74a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 75a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * <p>The primary method for awaiting completion and extracting 76a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * results of a task is {@link #join}, but there are several variants: 77a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * The {@link Future#get} methods support interruptible and/or timed 78a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * waits for completion and report results using {@code Future} 79a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * conventions. Method {@link #invoke} is semantically 80a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * equivalent to {@code fork(); join()} but always attempts to begin 81a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * execution in the current thread. The "<em>quiet</em>" forms of 82a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * these methods do not extract results or report exceptions. These 83a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * may be useful when a set of tasks are being executed, and you need 84a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * to delay processing of results or exceptions until all complete. 85a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Method {@code invokeAll} (available in multiple versions) 86a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * performs the most common form of parallel invocation: forking a set 87a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * of tasks and joining them all. 88a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 89a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * <p>The execution status of tasks may be queried at several levels 90a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * of detail: {@link #isDone} is true if a task completed in any way 91a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * (including the case where a task was cancelled without executing); 92a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * {@link #isCompletedNormally} is true if a task completed without 93a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * cancellation or encountering an exception; {@link #isCancelled} is 94a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * true if the task was cancelled (in which case {@link #getException} 95a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * returns a {@link java.util.concurrent.CancellationException}); and 96a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * {@link #isCompletedAbnormally} is true if a task was either 97a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * cancelled or encountered an exception, in which case {@link 98a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * #getException} will return either the encountered exception or 99a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * {@link java.util.concurrent.CancellationException}. 100a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 101a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * <p>The ForkJoinTask class is not usually directly subclassed. 102a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Instead, you subclass one of the abstract classes that support a 103a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * particular style of fork/join processing, typically {@link 104a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * RecursiveAction} for computations that do not return results, or 105a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * {@link RecursiveTask} for those that do. Normally, a concrete 106a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * ForkJoinTask subclass declares fields comprising its parameters, 107a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * established in a constructor, and then defines a {@code compute} 108a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * method that somehow uses the control methods supplied by this base 109a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * class. While these methods have {@code public} access (to allow 110a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * instances of different task subclasses to call each other's 111a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * methods), some of them may only be called from within other 112a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * ForkJoinTasks (as may be determined using method {@link 113a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * #inForkJoinPool}). Attempts to invoke them in other contexts 114a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * result in exceptions or errors, possibly including 115a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * {@code ClassCastException}. 116a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 117a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * <p>Method {@link #join} and its variants are appropriate for use 118a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * only when completion dependencies are acyclic; that is, the 119a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * parallel computation can be described as a directed acyclic graph 120a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * (DAG). Otherwise, executions may encounter a form of deadlock as 121a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * tasks cyclically wait for each other. However, this framework 122a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * supports other methods and techniques (for example the use of 123a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * {@link Phaser}, {@link #helpQuiesce}, and {@link #complete}) that 124a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * may be of use in constructing custom subclasses for problems that 125a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * are not statically structured as DAGs. 126a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 127a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * <p>Most base support methods are {@code final}, to prevent 128a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * overriding of implementations that are intrinsically tied to the 129a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * underlying lightweight task scheduling framework. Developers 130a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * creating new basic styles of fork/join processing should minimally 131a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * implement {@code protected} methods {@link #exec}, {@link 132a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * #setRawResult}, and {@link #getRawResult}, while also introducing 133a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * an abstract computational method that can be implemented in its 134a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * subclasses, possibly relying on other {@code protected} methods 135a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * provided by this class. 136a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 137a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * <p>ForkJoinTasks should perform relatively small amounts of 138a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * computation. Large tasks should be split into smaller subtasks, 139a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * usually via recursive decomposition. As a very rough rule of thumb, 140a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * a task should perform more than 100 and less than 10000 basic 141a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * computational steps, and should avoid indefinite looping. If tasks 142a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * are too big, then parallelism cannot improve throughput. If too 143a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * small, then memory and internal task maintenance overhead may 144a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * overwhelm processing. 145a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 146a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * <p>This class provides {@code adapt} methods for {@link Runnable} 147a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * and {@link Callable}, that may be of use when mixing execution of 148a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * {@code ForkJoinTasks} with other kinds of tasks. When all tasks are 149a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * of this form, consider using a pool constructed in <em>asyncMode</em>. 150a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 151a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * <p>ForkJoinTasks are {@code Serializable}, which enables them to be 152a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * used in extensions such as remote execution frameworks. It is 153a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * sensible to serialize tasks only before or after, but not during, 154a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * execution. Serialization is not relied on during execution itself. 155a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 156a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @since 1.7 157a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @hide 158a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @author Doug Lea 159a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 160a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilsonpublic abstract class ForkJoinTask<V> implements Future<V>, Serializable { 161a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 162a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /* 163a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * See the internal documentation of class ForkJoinPool for a 164a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * general implementation overview. ForkJoinTasks are mainly 165a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * responsible for maintaining their "status" field amidst relays 166a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * to methods in ForkJoinWorkerThread and ForkJoinPool. 167a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 168a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * The methods of this class are more-or-less layered into 169a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * (1) basic status maintenance 170a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * (2) execution and awaiting completion 171a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * (3) user-level methods that additionally report results. 172a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * This is sometimes hard to see because this file orders exported 173a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * methods in a way that flows well in javadocs. 174a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 175a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 176a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /* 177a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * The status field holds run control status bits packed into a 178a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * single int to minimize footprint and to ensure atomicity (via 179a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * CAS). Status is initially zero, and takes on nonnegative 180a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * values until completed, upon which status holds value 181a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * NORMAL, CANCELLED, or EXCEPTIONAL. Tasks undergoing blocking 182a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * waits by other threads have the SIGNAL bit set. Completion of 183a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * a stolen task with SIGNAL set awakens any waiters via 184a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * notifyAll. Even though suboptimal for some purposes, we use 185a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * basic builtin wait/notify to take advantage of "monitor 186a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * inflation" in JVMs that we would otherwise need to emulate to 187a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * avoid adding further per-task bookkeeping overhead. We want 188a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * these monitors to be "fat", i.e., not use biasing or thin-lock 189a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * techniques, so use some odd coding idioms that tend to avoid 190a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * them. 191a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 192a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 193a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** The run status of this task */ 194a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson volatile int status; // accessed directly by pool and workers 195a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson private static final int NORMAL = -1; 196a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson private static final int CANCELLED = -2; 197a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson private static final int EXCEPTIONAL = -3; 198a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson private static final int SIGNAL = 1; 199a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 200a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 201a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Marks completion and wakes up threads waiting to join this task, 202a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * also clearing signal request bits. 203a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 204a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @param completion one of NORMAL, CANCELLED, EXCEPTIONAL 205a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return completion status on exit 206a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 207a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson private int setCompletion(int completion) { 208a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson for (int s;;) { 209a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if ((s = status) < 0) 210a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return s; 211a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (UNSAFE.compareAndSwapInt(this, statusOffset, s, completion)) { 212a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (s != 0) 213a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson synchronized (this) { notifyAll(); } 214a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return completion; 215a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 216a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 217a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 218a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 219a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 220a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Tries to block a worker thread until completed or timed out. 221a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Uses Object.wait time argument conventions. 222a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * May fail on contention or interrupt. 223a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 224a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @param millis if > 0, wait time. 225a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 226a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson final void tryAwaitDone(long millis) { 227a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson int s; 228a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson try { 229a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (((s = status) > 0 || 230a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson (s == 0 && 231a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson UNSAFE.compareAndSwapInt(this, statusOffset, 0, SIGNAL))) && 232a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson status > 0) { 233a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson synchronized (this) { 234a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (status > 0) 235a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson wait(millis); 236a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 237a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 238a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } catch (InterruptedException ie) { 239a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson // caller must check termination 240a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 241a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 242a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 243a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 244a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Blocks a non-worker-thread until completion. 245a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return status upon completion 246a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 247a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson private int externalAwaitDone() { 248a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson int s; 249a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if ((s = status) >= 0) { 250a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson boolean interrupted = false; 251a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson synchronized (this) { 252a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson while ((s = status) >= 0) { 253a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (s == 0) 254a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson UNSAFE.compareAndSwapInt(this, statusOffset, 255a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 0, SIGNAL); 256a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson else { 257a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson try { 258a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson wait(); 259a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } catch (InterruptedException ie) { 260a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson interrupted = true; 261a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 262a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 263a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 264a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 265a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (interrupted) 266a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson Thread.currentThread().interrupt(); 267a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 268a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return s; 269a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 270a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 271a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 272a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Blocks a non-worker-thread until completion or interruption or timeout. 273a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 274a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson private int externalInterruptibleAwaitDone(long millis) 275a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson throws InterruptedException { 276a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson int s; 277a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (Thread.interrupted()) 278a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson throw new InterruptedException(); 279a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if ((s = status) >= 0) { 280a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson synchronized (this) { 281a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson while ((s = status) >= 0) { 282a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (s == 0) 283a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson UNSAFE.compareAndSwapInt(this, statusOffset, 284a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 0, SIGNAL); 285a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson else { 286a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson wait(millis); 287a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (millis > 0L) 288a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson break; 289a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 290a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 291a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 292a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 293a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return s; 294a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 295a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 296a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 297a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Primary execution method for stolen tasks. Unless done, calls 298a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * exec and records status if completed, but doesn't wait for 299a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * completion otherwise. 300a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 301a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson final void doExec() { 302a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (status >= 0) { 303a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson boolean completed; 304a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson try { 305a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson completed = exec(); 306a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } catch (Throwable rex) { 307a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson setExceptionalCompletion(rex); 308a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return; 309a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 310a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (completed) 311a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson setCompletion(NORMAL); // must be outside try block 312a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 313a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 314a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 315a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 316a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Primary mechanics for join, get, quietlyJoin. 317a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return status upon completion 318a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 319a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson private int doJoin() { 320a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson Thread t; ForkJoinWorkerThread w; int s; boolean completed; 321a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if ((t = Thread.currentThread()) instanceof ForkJoinWorkerThread) { 322a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if ((s = status) < 0) 323a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return s; 324a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if ((w = (ForkJoinWorkerThread)t).unpushTask(this)) { 325a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson try { 326a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson completed = exec(); 327a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } catch (Throwable rex) { 328a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return setExceptionalCompletion(rex); 329a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 330a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (completed) 331a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return setCompletion(NORMAL); 332a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 333a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return w.joinTask(this); 334a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 335a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson else 336a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return externalAwaitDone(); 337a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 338a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 339a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 340a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Primary mechanics for invoke, quietlyInvoke. 341a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return status upon completion 342a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 343a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson private int doInvoke() { 344a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson int s; boolean completed; 345a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if ((s = status) < 0) 346a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return s; 347a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson try { 348a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson completed = exec(); 349a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } catch (Throwable rex) { 350a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return setExceptionalCompletion(rex); 351a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 352a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (completed) 353a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return setCompletion(NORMAL); 354a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson else 355a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return doJoin(); 356a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 357a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 358a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson // Exception table support 359a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 360a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 361a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Table of exceptions thrown by tasks, to enable reporting by 362a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * callers. Because exceptions are rare, we don't directly keep 363a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * them with task objects, but instead use a weak ref table. Note 364a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * that cancellation exceptions don't appear in the table, but are 365a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * instead recorded as status values. 366a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 367a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Note: These statics are initialized below in static block. 368a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 369a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson private static final ExceptionNode[] exceptionTable; 370a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson private static final ReentrantLock exceptionTableLock; 371a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson private static final ReferenceQueue<Object> exceptionTableRefQueue; 372a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 373a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 374a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Fixed capacity for exceptionTable. 375a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 376a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson private static final int EXCEPTION_MAP_CAPACITY = 32; 377a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 378a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 379a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Key-value nodes for exception table. The chained hash table 380a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * uses identity comparisons, full locking, and weak references 381a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * for keys. The table has a fixed capacity because it only 382a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * maintains task exceptions long enough for joiners to access 383a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * them, so should never become very large for sustained 384a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * periods. However, since we do not know when the last joiner 385a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * completes, we must use weak references and expunge them. We do 386a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * so on each operation (hence full locking). Also, some thread in 387a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * any ForkJoinPool will call helpExpungeStaleExceptions when its 388a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * pool becomes isQuiescent. 389a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 390a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson static final class ExceptionNode extends WeakReference<ForkJoinTask<?>>{ 391a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson final Throwable ex; 392a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson ExceptionNode next; 393a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson final long thrower; // use id not ref to avoid weak cycles 394a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson ExceptionNode(ForkJoinTask<?> task, Throwable ex, ExceptionNode next) { 395a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson super(task, exceptionTableRefQueue); 396a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson this.ex = ex; 397a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson this.next = next; 398a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson this.thrower = Thread.currentThread().getId(); 399a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 400a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 401a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 402a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 403a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Records exception and sets exceptional completion. 404a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 405a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return status on exit 406a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 407a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson private int setExceptionalCompletion(Throwable ex) { 408a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson int h = System.identityHashCode(this); 409a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson final ReentrantLock lock = exceptionTableLock; 410a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson lock.lock(); 411a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson try { 412a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson expungeStaleExceptions(); 413a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson ExceptionNode[] t = exceptionTable; 414a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson int i = h & (t.length - 1); 415a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson for (ExceptionNode e = t[i]; ; e = e.next) { 416a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (e == null) { 417a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson t[i] = new ExceptionNode(this, ex, t[i]); 418a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson break; 419a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 420a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (e.get() == this) // already present 421a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson break; 422a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 423a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } finally { 424a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson lock.unlock(); 425a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 426a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return setCompletion(EXCEPTIONAL); 427a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 428a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 429a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 430a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Removes exception node and clears status 431a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 432a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson private void clearExceptionalCompletion() { 433a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson int h = System.identityHashCode(this); 434a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson final ReentrantLock lock = exceptionTableLock; 435a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson lock.lock(); 436a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson try { 437a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson ExceptionNode[] t = exceptionTable; 438a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson int i = h & (t.length - 1); 439a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson ExceptionNode e = t[i]; 440a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson ExceptionNode pred = null; 441a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson while (e != null) { 442a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson ExceptionNode next = e.next; 443a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (e.get() == this) { 444a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (pred == null) 445a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson t[i] = next; 446a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson else 447a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson pred.next = next; 448a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson break; 449a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 450a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson pred = e; 451a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson e = next; 452a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 453a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson expungeStaleExceptions(); 454a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson status = 0; 455a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } finally { 456a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson lock.unlock(); 457a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 458a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 459a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 460a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 461a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Returns a rethrowable exception for the given task, if 462a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * available. To provide accurate stack traces, if the exception 463a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * was not thrown by the current thread, we try to create a new 464a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * exception of the same type as the one thrown, but with the 465a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * recorded exception as its cause. If there is no such 466a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * constructor, we instead try to use a no-arg constructor, 467a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * followed by initCause, to the same effect. If none of these 468a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * apply, or any fail due to other exceptions, we return the 469a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * recorded exception, which is still correct, although it may 470a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * contain a misleading stack trace. 471a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 472a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return the exception, or null if none 473a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 474a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson private Throwable getThrowableException() { 475a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (status != EXCEPTIONAL) 476a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return null; 477a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson int h = System.identityHashCode(this); 478a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson ExceptionNode e; 479a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson final ReentrantLock lock = exceptionTableLock; 480a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson lock.lock(); 481a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson try { 482a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson expungeStaleExceptions(); 483a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson ExceptionNode[] t = exceptionTable; 484a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson e = t[h & (t.length - 1)]; 485a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson while (e != null && e.get() != this) 486a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson e = e.next; 487a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } finally { 488a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson lock.unlock(); 489a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 490a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson Throwable ex; 491a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (e == null || (ex = e.ex) == null) 492a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return null; 493a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (e.thrower != Thread.currentThread().getId()) { 494a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson Class<? extends Throwable> ec = ex.getClass(); 495a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson try { 496a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson Constructor<?> noArgCtor = null; 497a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson Constructor<?>[] cs = ec.getConstructors();// public ctors only 498a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson for (int i = 0; i < cs.length; ++i) { 499a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson Constructor<?> c = cs[i]; 500a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson Class<?>[] ps = c.getParameterTypes(); 501a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (ps.length == 0) 502a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson noArgCtor = c; 503a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson else if (ps.length == 1 && ps[0] == Throwable.class) 504a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return (Throwable)(c.newInstance(ex)); 505a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 506a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (noArgCtor != null) { 507a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson Throwable wx = (Throwable)(noArgCtor.newInstance()); 508a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson wx.initCause(ex); 509a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return wx; 510a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 511a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } catch (Exception ignore) { 512a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 513a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 514a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return ex; 515a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 516a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 517a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 518a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Poll stale refs and remove them. Call only while holding lock. 519a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 520a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson private static void expungeStaleExceptions() { 521a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson for (Object x; (x = exceptionTableRefQueue.poll()) != null;) { 522a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (x instanceof ExceptionNode) { 523a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson ForkJoinTask<?> key = ((ExceptionNode)x).get(); 524a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson ExceptionNode[] t = exceptionTable; 525a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson int i = System.identityHashCode(key) & (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 == x) { 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 } 541a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 542a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 543a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 544a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 545a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * If lock is available, poll stale refs and remove them. 546a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Called from ForkJoinPool when pools become quiescent. 547a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 548a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson static final void helpExpungeStaleExceptions() { 549a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson final ReentrantLock lock = exceptionTableLock; 550a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (lock.tryLock()) { 551a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson try { 552a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson expungeStaleExceptions(); 553a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } finally { 554a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson lock.unlock(); 555a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 556a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 557a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 558a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 559a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 560a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Report the result of invoke or join; called only upon 561a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * non-normal return of internal versions. 562a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 563a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson private V reportResult() { 564a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson int s; Throwable ex; 565a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if ((s = status) == CANCELLED) 566a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson throw new CancellationException(); 567a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (s == EXCEPTIONAL && (ex = getThrowableException()) != null) 568a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson SneakyThrow.sneakyThrow(ex); // android-changed 569a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return getRawResult(); 570a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 571a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 572a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson // public methods 573a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 574a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 575a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Arranges to asynchronously execute this task. While it is not 576a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * necessarily enforced, it is a usage error to fork a task more 577a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * than once unless it has completed and been reinitialized. 578a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Subsequent modifications to the state of this task or any data 579a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * it operates on are not necessarily consistently observable by 580a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * any thread other than the one executing it unless preceded by a 581a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * call to {@link #join} or related methods, or a call to {@link 582a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * #isDone} returning {@code true}. 583a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 584a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * <p>This method may be invoked only from within {@code 585a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * ForkJoinPool} computations (as may be determined using method 586a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * {@link #inForkJoinPool}). Attempts to invoke in other contexts 587a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * result in exceptions or errors, possibly including {@code 588a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * ClassCastException}. 589a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 590a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return {@code this}, to simplify usage 591a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 592a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public final ForkJoinTask<V> fork() { 593a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson ((ForkJoinWorkerThread) Thread.currentThread()) 594a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson .pushTask(this); 595a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return this; 596a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 597a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 598a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 599a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Returns the result of the computation when it {@link #isDone is 600a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * done}. This method differs from {@link #get()} in that 601a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * abnormal completion results in {@code RuntimeException} or 602a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * {@code Error}, not {@code ExecutionException}, and that 603a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * interrupts of the calling thread do <em>not</em> cause the 604a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * method to abruptly return by throwing {@code 605a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * InterruptedException}. 606a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 607a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return the computed result 608a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 609a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public final V join() { 610a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (doJoin() != NORMAL) 611a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return reportResult(); 612a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson else 613a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return getRawResult(); 614a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 615a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 616a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 617a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Commences performing this task, awaits its completion if 618a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * necessary, and returns its result, or throws an (unchecked) 619a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * {@code RuntimeException} or {@code Error} if the underlying 620a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * computation did so. 621a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 622a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return the computed result 623a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 624a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public final V invoke() { 625a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (doInvoke() != NORMAL) 626a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return reportResult(); 627a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson else 628a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return getRawResult(); 629a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 630a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 631a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 632a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Forks the given tasks, returning when {@code isDone} holds for 633a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * each task or an (unchecked) exception is encountered, in which 634a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * case the exception is rethrown. If more than one task 635a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * encounters an exception, then this method throws any one of 636a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * these exceptions. If any task encounters an exception, the 637a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * other may be cancelled. However, the execution status of 638a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * individual tasks is not guaranteed upon exceptional return. The 639a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * status of each task may be obtained using {@link 640a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * #getException()} and related methods to check if they have been 641a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * cancelled, completed normally or exceptionally, or left 642a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * unprocessed. 643a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 644a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * <p>This method may be invoked only from within {@code 645a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * ForkJoinPool} computations (as may be determined using method 646a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * {@link #inForkJoinPool}). Attempts to invoke in other contexts 647a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * result in exceptions or errors, possibly including {@code 648a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * ClassCastException}. 649a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 650a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @param t1 the first task 651a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @param t2 the second task 652a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @throws NullPointerException if any task is null 653a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 654a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public static void invokeAll(ForkJoinTask<?> t1, ForkJoinTask<?> t2) { 655a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson t2.fork(); 656a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson t1.invoke(); 657a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson t2.join(); 658a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 659a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 660a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 661a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Forks the given tasks, returning when {@code isDone} holds for 662a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * each task or an (unchecked) exception is encountered, in which 663a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * case the exception is rethrown. If more than one task 664a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * encounters an exception, then this method throws any one of 665a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * these exceptions. If any task encounters an exception, others 666a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * may be cancelled. However, the execution status of individual 667a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * tasks is not guaranteed upon exceptional return. The status of 668a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * each task may be obtained using {@link #getException()} and 669a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * related methods to check if they have been cancelled, completed 670a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * normally or exceptionally, or left unprocessed. 671a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 672a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * <p>This method may be invoked only from within {@code 673a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * ForkJoinPool} computations (as may be determined using method 674a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * {@link #inForkJoinPool}). Attempts to invoke in other contexts 675a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * result in exceptions or errors, possibly including {@code 676a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * ClassCastException}. 677a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 678a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @param tasks the tasks 679a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @throws NullPointerException if any task is null 680a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 681a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public static void invokeAll(ForkJoinTask<?>... tasks) { 682a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson Throwable ex = null; 683a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson int last = tasks.length - 1; 684a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson for (int i = last; i >= 0; --i) { 685a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson ForkJoinTask<?> t = tasks[i]; 686a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (t == null) { 687a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (ex == null) 688a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson ex = new NullPointerException(); 689a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 690a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson else if (i != 0) 691a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson t.fork(); 692a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson else if (t.doInvoke() < NORMAL && ex == null) 693a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson ex = t.getException(); 694a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 695a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson for (int i = 1; i <= last; ++i) { 696a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson ForkJoinTask<?> t = tasks[i]; 697a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (t != null) { 698a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (ex != null) 699a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson t.cancel(false); 700a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson else if (t.doJoin() < NORMAL) 701a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson ex = t.getException(); 702a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 703a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 704a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (ex != null) 705a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson SneakyThrow.sneakyThrow(ex); // android-changed 706a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 707a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 708a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 709a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Forks all tasks in the specified collection, returning when 710a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * {@code isDone} holds for each task or an (unchecked) exception 711a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * is encountered, in which case the exception is rethrown. If 712a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * more than one task encounters an exception, then this method 713a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * throws any one of these exceptions. If any task encounters an 714a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * exception, others may be cancelled. However, the execution 715a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * status of individual tasks is not guaranteed upon exceptional 716a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * return. The status of each task may be obtained using {@link 717a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * #getException()} and related methods to check if they have been 718a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * cancelled, completed normally or exceptionally, or left 719a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * unprocessed. 720a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 721a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * <p>This method may be invoked only from within {@code 722a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * ForkJoinPool} computations (as may be determined using method 723a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * {@link #inForkJoinPool}). Attempts to invoke in other contexts 724a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * result in exceptions or errors, possibly including {@code 725a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * ClassCastException}. 726a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 727a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @param tasks the collection of tasks 728a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return the tasks argument, to simplify usage 729a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @throws NullPointerException if tasks or any element are null 730a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 731a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public static <T extends ForkJoinTask<?>> Collection<T> invokeAll(Collection<T> tasks) { 732a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (!(tasks instanceof RandomAccess) || !(tasks instanceof List<?>)) { 733a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson invokeAll(tasks.toArray(new ForkJoinTask<?>[tasks.size()])); 734a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return tasks; 735a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 736a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson @SuppressWarnings("unchecked") 737a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson List<? extends ForkJoinTask<?>> ts = 738a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson (List<? extends ForkJoinTask<?>>) tasks; 739a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson Throwable ex = null; 740a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson int last = ts.size() - 1; 741a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson for (int i = last; i >= 0; --i) { 742a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson ForkJoinTask<?> t = ts.get(i); 743a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (t == null) { 744a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (ex == null) 745a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson ex = new NullPointerException(); 746a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 747a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson else if (i != 0) 748a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson t.fork(); 749a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson else if (t.doInvoke() < NORMAL && ex == null) 750a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson ex = t.getException(); 751a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 752a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson for (int i = 1; i <= last; ++i) { 753a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson ForkJoinTask<?> t = ts.get(i); 754a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (t != null) { 755a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (ex != null) 756a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson t.cancel(false); 757a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson else if (t.doJoin() < NORMAL) 758a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson ex = t.getException(); 759a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 760a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 761a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (ex != null) 762a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson SneakyThrow.sneakyThrow(ex); // android-changed 763a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return tasks; 764a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 765a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 766a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 767a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Attempts to cancel execution of this task. This attempt will 768a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * fail if the task has already completed or could not be 769a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * cancelled for some other reason. If successful, and this task 770a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * has not started when {@code cancel} is called, execution of 771a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * this task is suppressed. After this method returns 772a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * successfully, unless there is an intervening call to {@link 773a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * #reinitialize}, subsequent calls to {@link #isCancelled}, 774a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * {@link #isDone}, and {@code cancel} will return {@code true} 775a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * and calls to {@link #join} and related methods will result in 776a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * {@code CancellationException}. 777a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 778a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * <p>This method may be overridden in subclasses, but if so, must 779a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * still ensure that these properties hold. In particular, the 780a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * {@code cancel} method itself must not throw exceptions. 781a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 782a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * <p>This method is designed to be invoked by <em>other</em> 783a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * tasks. To terminate the current task, you can just return or 784a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * throw an unchecked exception from its computation method, or 785a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * invoke {@link #completeExceptionally}. 786a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 787a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @param mayInterruptIfRunning this value has no effect in the 788a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * default implementation because interrupts are not used to 789a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * control cancellation. 790a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 791a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return {@code true} if this task is now cancelled 792a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 793a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public boolean cancel(boolean mayInterruptIfRunning) { 794a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return setCompletion(CANCELLED) == CANCELLED; 795a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 796a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 797a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 798a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Cancels, ignoring any exceptions thrown by cancel. Used during 799a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * worker and pool shutdown. Cancel is spec'ed not to throw any 800a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * exceptions, but if it does anyway, we have no recourse during 801a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * shutdown, so guard against this case. 802a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 803a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson final void cancelIgnoringExceptions() { 804a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson try { 805a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson cancel(false); 806a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } catch (Throwable ignore) { 807a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 808a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 809a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 810a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public final boolean isDone() { 811a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return status < 0; 812a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 813a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 814a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public final boolean isCancelled() { 815a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return status == CANCELLED; 816a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 817a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 818a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 819a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Returns {@code true} if this task threw an exception or was cancelled. 820a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 821a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return {@code true} if this task threw an exception or was cancelled 822a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 823a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public final boolean isCompletedAbnormally() { 824a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return status < NORMAL; 825a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 826a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 827a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 828a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Returns {@code true} if this task completed without throwing an 829a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * exception and was not cancelled. 830a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 831a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return {@code true} if this task completed without throwing an 832a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * exception and was not cancelled 833a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 834a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public final boolean isCompletedNormally() { 835a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return status == NORMAL; 836a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 837a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 838a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 839a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Returns the exception thrown by the base computation, or a 840a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * {@code CancellationException} if cancelled, or {@code null} if 841a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * none or if the method has not yet completed. 842a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 843a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return the exception, or {@code null} if none 844a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 845a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public final Throwable getException() { 846a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson int s = status; 847a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return ((s >= NORMAL) ? null : 848a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson (s == CANCELLED) ? new CancellationException() : 849a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson getThrowableException()); 850a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 851a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 852a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 853a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Completes this task abnormally, and if not already aborted or 854a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * cancelled, causes it to throw the given exception upon 855a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * {@code join} and related operations. This method may be used 856a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * to induce exceptions in asynchronous tasks, or to force 857a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * completion of tasks that would not otherwise complete. Its use 858a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * in other situations is discouraged. This method is 859a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * overridable, but overridden versions must invoke {@code super} 860a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * implementation to maintain guarantees. 861a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 862a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @param ex the exception to throw. If this exception is not a 863a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * {@code RuntimeException} or {@code Error}, the actual exception 864a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * thrown will be a {@code RuntimeException} with cause {@code ex}. 865a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 866a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public void completeExceptionally(Throwable ex) { 867a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson setExceptionalCompletion((ex instanceof RuntimeException) || 868a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson (ex instanceof Error) ? ex : 869a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson new RuntimeException(ex)); 870a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 871a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 872a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 873a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Completes this task, and if not already aborted or cancelled, 874a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * returning the given value as the result of subsequent 875a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * invocations of {@code join} and related operations. This method 876a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * may be used to provide results for asynchronous tasks, or to 877a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * provide alternative handling for tasks that would not otherwise 878a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * complete normally. Its use in other situations is 879a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * discouraged. This method is overridable, but overridden 880a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * versions must invoke {@code super} implementation to maintain 881a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * guarantees. 882a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 883a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @param value the result value for this task 884a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 885a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public void complete(V value) { 886a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson try { 887a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson setRawResult(value); 888a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } catch (Throwable rex) { 889a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson setExceptionalCompletion(rex); 890a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return; 891a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 892a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson setCompletion(NORMAL); 893a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 894a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 895a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 896a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Waits if necessary for the computation to complete, and then 897a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * retrieves its result. 898a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 899a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return the computed result 900a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @throws CancellationException if the computation was cancelled 901a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @throws ExecutionException if the computation threw an 902a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * exception 903a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @throws InterruptedException if the current thread is not a 904a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * member of a ForkJoinPool and was interrupted while waiting 905a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 906a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public final V get() throws InterruptedException, ExecutionException { 907a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson int s = (Thread.currentThread() instanceof ForkJoinWorkerThread) ? 908a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson doJoin() : externalInterruptibleAwaitDone(0L); 909a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson Throwable ex; 910a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (s == CANCELLED) 911a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson throw new CancellationException(); 912a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (s == EXCEPTIONAL && (ex = getThrowableException()) != null) 913a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson throw new ExecutionException(ex); 914a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return getRawResult(); 915a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 916a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 917a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 918a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Waits if necessary for at most the given time for the computation 919a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * to complete, and then retrieves its result, if available. 920a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 921a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @param timeout the maximum time to wait 922a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @param unit the time unit of the timeout argument 923a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return the computed result 924a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @throws CancellationException if the computation was cancelled 925a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @throws ExecutionException if the computation threw an 926a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * exception 927a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @throws InterruptedException if the current thread is not a 928a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * member of a ForkJoinPool and was interrupted while waiting 929a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @throws TimeoutException if the wait timed out 930a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 931a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public final V get(long timeout, TimeUnit unit) 932a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson throws InterruptedException, ExecutionException, TimeoutException { 933a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson Thread t = Thread.currentThread(); 934a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (t instanceof ForkJoinWorkerThread) { 935a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson ForkJoinWorkerThread w = (ForkJoinWorkerThread) t; 936a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson long nanos = unit.toNanos(timeout); 937a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (status >= 0) { 938a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson boolean completed = false; 939a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (w.unpushTask(this)) { 940a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson try { 941a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson completed = exec(); 942a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } catch (Throwable rex) { 943a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson setExceptionalCompletion(rex); 944a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 945a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 946a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (completed) 947a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson setCompletion(NORMAL); 948a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson else if (status >= 0 && nanos > 0) 949a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson w.pool.timedAwaitJoin(this, nanos); 950a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 951a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 952a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson else { 953a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson long millis = unit.toMillis(timeout); 954a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (millis > 0) 955a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson externalInterruptibleAwaitDone(millis); 956a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 957a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson int s = status; 958a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (s != NORMAL) { 959a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson Throwable ex; 960a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (s == CANCELLED) 961a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson throw new CancellationException(); 962a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (s != EXCEPTIONAL) 963a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson throw new TimeoutException(); 964a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if ((ex = getThrowableException()) != null) 965a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson throw new ExecutionException(ex); 966a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 967a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return getRawResult(); 968a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 969a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 970a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 971a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Joins this task, without returning its result or throwing its 972a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * exception. This method may be useful when processing 973a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * collections of tasks when some have been cancelled or otherwise 974a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * known to have aborted. 975a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 976a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public final void quietlyJoin() { 977a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson doJoin(); 978a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 979a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 980a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 981a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Commences performing this task and awaits its completion if 982a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * necessary, without returning its result or throwing its 983a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * exception. 984a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 985a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public final void quietlyInvoke() { 986a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson doInvoke(); 987a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 988a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 989a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 990a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Possibly executes tasks until the pool hosting the current task 991a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * {@link ForkJoinPool#isQuiescent is quiescent}. This method may 992a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * be of use in designs in which many tasks are forked, but none 993a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * are explicitly joined, instead executing them until all are 994a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * processed. 995a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 996a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * <p>This method may be invoked only from within {@code 997a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * ForkJoinPool} computations (as may be determined using method 998a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * {@link #inForkJoinPool}). Attempts to invoke in other contexts 999a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * result in exceptions or errors, possibly including {@code 1000a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * ClassCastException}. 1001a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 1002a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public static void helpQuiesce() { 1003a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson ((ForkJoinWorkerThread) Thread.currentThread()) 1004a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson .helpQuiescePool(); 1005a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1006a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1007a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 1008a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Resets the internal bookkeeping state of this task, allowing a 1009a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * subsequent {@code fork}. This method allows repeated reuse of 1010a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * this task, but only if reuse occurs when this task has either 1011a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * never been forked, or has been forked, then completed and all 1012a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * outstanding joins of this task have also completed. Effects 1013a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * under any other usage conditions are not guaranteed. 1014a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * This method may be useful when executing 1015a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * pre-constructed trees of subtasks in loops. 1016a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 1017a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * <p>Upon completion of this method, {@code isDone()} reports 1018a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * {@code false}, and {@code getException()} reports {@code 1019a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * null}. However, the value returned by {@code getRawResult} is 1020a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * unaffected. To clear this value, you can invoke {@code 1021a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * setRawResult(null)}. 1022a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 1023a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public void reinitialize() { 1024a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (status == EXCEPTIONAL) 1025a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson clearExceptionalCompletion(); 1026a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson else 1027a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson status = 0; 1028a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1029a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1030a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 1031a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Returns the pool hosting the current task execution, or null 1032a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * if this task is executing outside of any ForkJoinPool. 1033a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 1034a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @see #inForkJoinPool 1035a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return the pool, or {@code null} if none 1036a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 1037a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public static ForkJoinPool getPool() { 1038a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson Thread t = Thread.currentThread(); 1039a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return (t instanceof ForkJoinWorkerThread) ? 1040a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson ((ForkJoinWorkerThread) t).pool : null; 1041a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1042a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1043a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 1044a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Returns {@code true} if the current thread is a {@link 1045a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * ForkJoinWorkerThread} executing as a ForkJoinPool computation. 1046a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 1047a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return {@code true} if the current thread is a {@link 1048a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * ForkJoinWorkerThread} executing as a ForkJoinPool computation, 1049a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * or {@code false} otherwise 1050a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 1051a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public static boolean inForkJoinPool() { 1052a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return Thread.currentThread() instanceof ForkJoinWorkerThread; 1053a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1054a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1055a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 1056a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Tries to unschedule this task for execution. This method will 1057a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * typically succeed if this task is the most recently forked task 1058a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * by the current thread, and has not commenced executing in 1059a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * another thread. This method may be useful when arranging 1060a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * alternative local processing of tasks that could have been, but 1061a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * were not, stolen. 1062a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 1063a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * <p>This method may be invoked only from within {@code 1064a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * ForkJoinPool} computations (as may be determined using method 1065a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * {@link #inForkJoinPool}). Attempts to invoke in other contexts 1066a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * result in exceptions or errors, possibly including {@code 1067a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * ClassCastException}. 1068a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 1069a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return {@code true} if unforked 1070a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 1071a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public boolean tryUnfork() { 1072a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return ((ForkJoinWorkerThread) Thread.currentThread()) 1073a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson .unpushTask(this); 1074a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1075a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1076a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 1077a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Returns an estimate of the number of tasks that have been 1078a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * forked by the current worker thread but not yet executed. This 1079a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * value may be useful for heuristic decisions about whether to 1080a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * fork other tasks. 1081a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 1082a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * <p>This method may be invoked only from within {@code 1083a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * ForkJoinPool} computations (as may be determined using method 1084a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * {@link #inForkJoinPool}). Attempts to invoke in other contexts 1085a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * result in exceptions or errors, possibly including {@code 1086a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * ClassCastException}. 1087a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 1088a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return the number of tasks 1089a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 1090a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public static int getQueuedTaskCount() { 1091a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return ((ForkJoinWorkerThread) Thread.currentThread()) 1092a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson .getQueueSize(); 1093a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1094a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1095a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 1096a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Returns an estimate of how many more locally queued tasks are 1097a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * held by the current worker thread than there are other worker 1098a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * threads that might steal them. This value may be useful for 1099a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * heuristic decisions about whether to fork other tasks. In many 1100a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * usages of ForkJoinTasks, at steady state, each worker should 1101a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * aim to maintain a small constant surplus (for example, 3) of 1102a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * tasks, and to process computations locally if this threshold is 1103a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * exceeded. 1104a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 1105a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * <p>This method may be invoked only from within {@code 1106a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * ForkJoinPool} computations (as may be determined using method 1107a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * {@link #inForkJoinPool}). Attempts to invoke in other contexts 1108a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * result in exceptions or errors, possibly including {@code 1109a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * ClassCastException}. 1110a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 1111a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return the surplus number of tasks, which may be negative 1112a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 1113a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public static int getSurplusQueuedTaskCount() { 1114a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return ((ForkJoinWorkerThread) Thread.currentThread()) 1115a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson .getEstimatedSurplusTaskCount(); 1116a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1117a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1118a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson // Extension methods 1119a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1120a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 1121a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Returns the result that would be returned by {@link #join}, even 1122a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * if this task completed abnormally, or {@code null} if this task 1123a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * is not known to have been completed. This method is designed 1124a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * to aid debugging, as well as to support extensions. Its use in 1125a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * any other context is discouraged. 1126a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 1127a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return the result, or {@code null} if not completed 1128a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 1129a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public abstract V getRawResult(); 1130a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1131a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 1132a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Forces the given value to be returned as a result. This method 1133a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * is designed to support extensions, and should not in general be 1134a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * called otherwise. 1135a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 1136a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @param value the value 1137a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 1138a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson protected abstract void setRawResult(V value); 1139a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1140a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 1141a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Immediately performs the base action of this task. This method 1142a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * is designed to support extensions, and should not in general be 1143a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * called otherwise. The return value controls whether this task 1144a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * is considered to be done normally. It may return false in 1145a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * asynchronous actions that require explicit invocations of 1146a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * {@link #complete} to become joinable. It may also throw an 1147a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * (unchecked) exception to indicate abnormal exit. 1148a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 1149a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return {@code true} if completed normally 1150a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 1151a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson protected abstract boolean exec(); 1152a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1153a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 1154a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Returns, but does not unschedule or execute, a task queued by 1155a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * the current thread but not yet executed, if one is immediately 1156a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * available. There is no guarantee that this task will actually 1157a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * be polled or executed next. Conversely, this method may return 1158a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * null even if a task exists but cannot be accessed without 1159a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * contention with other threads. This method is designed 1160a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * primarily to support extensions, and is unlikely to be useful 1161a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * otherwise. 1162a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 1163a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * <p>This method may be invoked only from within {@code 1164a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * ForkJoinPool} computations (as may be determined using method 1165a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * {@link #inForkJoinPool}). Attempts to invoke in other contexts 1166a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * result in exceptions or errors, possibly including {@code 1167a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * ClassCastException}. 1168a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 1169a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return the next task, or {@code null} if none are available 1170a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 1171a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson protected static ForkJoinTask<?> peekNextLocalTask() { 1172a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return ((ForkJoinWorkerThread) Thread.currentThread()) 1173a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson .peekTask(); 1174a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1175a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1176a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 1177a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Unschedules and returns, without executing, the next task 1178a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * queued by the current thread but not yet executed. This method 1179a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * is designed primarily to support extensions, and is unlikely to 1180a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * be useful otherwise. 1181a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 1182a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * <p>This method may be invoked only from within {@code 1183a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * ForkJoinPool} computations (as may be determined using method 1184a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * {@link #inForkJoinPool}). Attempts to invoke in other contexts 1185a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * result in exceptions or errors, possibly including {@code 1186a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * ClassCastException}. 1187a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 1188a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return the next task, or {@code null} if none are available 1189a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 1190a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson protected static ForkJoinTask<?> pollNextLocalTask() { 1191a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return ((ForkJoinWorkerThread) Thread.currentThread()) 1192a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson .pollLocalTask(); 1193a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1194a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1195a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 1196a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Unschedules and returns, without executing, the next task 1197a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * queued by the current thread but not yet executed, if one is 1198a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * available, or if not available, a task that was forked by some 1199a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * other thread, if available. Availability may be transient, so a 1200a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * {@code null} result does not necessarily imply quiescence 1201a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * of the pool this task is operating in. This method is designed 1202a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * primarily to support extensions, and is unlikely to be useful 1203a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * otherwise. 1204a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 1205a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * <p>This method may be invoked only from within {@code 1206a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * ForkJoinPool} computations (as may be determined using method 1207a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * {@link #inForkJoinPool}). Attempts to invoke in other contexts 1208a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * result in exceptions or errors, possibly including {@code 1209a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * ClassCastException}. 1210a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 1211a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return a task, or {@code null} if none are available 1212a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 1213a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson protected static ForkJoinTask<?> pollTask() { 1214a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return ((ForkJoinWorkerThread) Thread.currentThread()) 1215a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson .pollTask(); 1216a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1217a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1218a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 1219a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Adaptor for Runnables. This implements RunnableFuture 1220a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * to be compliant with AbstractExecutorService constraints 1221a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * when used in ForkJoinPool. 1222a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 1223a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson static final class AdaptedRunnable<T> extends ForkJoinTask<T> 1224a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson implements RunnableFuture<T> { 1225a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson final Runnable runnable; 1226a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson final T resultOnCompletion; 1227a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson T result; 1228a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson AdaptedRunnable(Runnable runnable, T result) { 1229a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (runnable == null) throw new NullPointerException(); 1230a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson this.runnable = runnable; 1231a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson this.resultOnCompletion = result; 1232a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1233a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public T getRawResult() { return result; } 1234a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public void setRawResult(T v) { result = v; } 1235a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public boolean exec() { 1236a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson runnable.run(); 1237a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson result = resultOnCompletion; 1238a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return true; 1239a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1240a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public void run() { invoke(); } 1241a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson private static final long serialVersionUID = 5232453952276885070L; 1242a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1243a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1244a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 1245a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Adaptor for Callables 1246a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 1247a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson static final class AdaptedCallable<T> extends ForkJoinTask<T> 1248a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson implements RunnableFuture<T> { 1249a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson final Callable<? extends T> callable; 1250a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson T result; 1251a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson AdaptedCallable(Callable<? extends T> callable) { 1252a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (callable == null) throw new NullPointerException(); 1253a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson this.callable = callable; 1254a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1255a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public T getRawResult() { return result; } 1256a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public void setRawResult(T v) { result = v; } 1257a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public boolean exec() { 1258a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson try { 1259a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson result = callable.call(); 1260a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return true; 1261a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } catch (Error err) { 1262a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson throw err; 1263a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } catch (RuntimeException rex) { 1264a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson throw rex; 1265a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } catch (Exception ex) { 1266a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson throw new RuntimeException(ex); 1267a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1268a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1269a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public void run() { invoke(); } 1270a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson private static final long serialVersionUID = 2838392045355241008L; 1271a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1272a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1273a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 1274a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Returns a new {@code ForkJoinTask} that performs the {@code run} 1275a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * method of the given {@code Runnable} as its action, and returns 1276a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * a null result upon {@link #join}. 1277a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 1278a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @param runnable the runnable action 1279a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return the task 1280a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 1281a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public static ForkJoinTask<?> adapt(Runnable runnable) { 1282a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return new AdaptedRunnable<Void>(runnable, null); 1283a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1284a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1285a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 1286a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Returns a new {@code ForkJoinTask} that performs the {@code run} 1287a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * method of the given {@code Runnable} as its action, and returns 1288a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * the given result upon {@link #join}. 1289a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 1290a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @param runnable the runnable action 1291a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @param result the result upon completion 1292a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return the task 1293a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 1294a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public static <T> ForkJoinTask<T> adapt(Runnable runnable, T result) { 1295a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return new AdaptedRunnable<T>(runnable, result); 1296a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1297a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1298a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 1299a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Returns a new {@code ForkJoinTask} that performs the {@code call} 1300a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * method of the given {@code Callable} as its action, and returns 1301a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * its result upon {@link #join}, translating any checked exceptions 1302a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * encountered into {@code RuntimeException}. 1303a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 1304a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @param callable the callable action 1305a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @return the task 1306a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 1307a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson public static <T> ForkJoinTask<T> adapt(Callable<? extends T> callable) { 1308a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson return new AdaptedCallable<T>(callable); 1309a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1310a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1311a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson // Serialization support 1312a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1313a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson private static final long serialVersionUID = -7721805057305804111L; 1314a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1315a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 1316a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Saves the state to a stream (that is, serializes it). 1317a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 1318a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @serialData the current run status and the exception thrown 1319a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * during execution, or {@code null} if none 1320a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @param s the stream 1321a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 1322a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson private void writeObject(java.io.ObjectOutputStream s) 1323a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson throws java.io.IOException { 1324a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson s.defaultWriteObject(); 1325a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson s.writeObject(getException()); 1326a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1327a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1328a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson /** 1329a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * Reconstitutes the instance from a stream (that is, deserializes it). 1330a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * 1331a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson * @param s the stream 1332a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson */ 1333a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson private void readObject(java.io.ObjectInputStream s) 1334a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson throws java.io.IOException, ClassNotFoundException { 1335a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson s.defaultReadObject(); 1336a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson Object ex = s.readObject(); 1337a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson if (ex != null) 1338a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson setExceptionalCompletion((Throwable)ex); 1339a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1340a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1341a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson // Unsafe mechanics 1342a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson private static final sun.misc.Unsafe UNSAFE; 1343a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson private static final long statusOffset; 1344a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson static { 1345a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson exceptionTableLock = new ReentrantLock(); 1346a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson exceptionTableRefQueue = new ReferenceQueue<Object>(); 1347a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson exceptionTable = new ExceptionNode[EXCEPTION_MAP_CAPACITY]; 1348a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson try { 1349a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson UNSAFE = sun.misc.Unsafe.getUnsafe(); 1350a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson statusOffset = UNSAFE.objectFieldOffset 1351a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson (ForkJoinTask.class.getDeclaredField("status")); 1352a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } catch (Exception e) { 1353a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson throw new Error(e); 1354a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1355a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson } 1356a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson 1357a807b4d808d2591894daf13aab179b2e9c46a2f5Jesse Wilson} 1358