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/* |
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* Written by Doug Lea with assistance from members of JCP JSR-166 |
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* Expert Group and released to the public domain, as explained at |
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* http://creativecommons.org/publicdomain/zero/1.0/ |
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*/ |
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|
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package java.util.concurrent; |
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import java.util.function.Supplier; |
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import java.util.function.Consumer; |
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import java.util.function.BiConsumer; |
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import java.util.function.Function; |
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import java.util.function.BiFunction; |
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import java.util.concurrent.Future; |
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import java.util.concurrent.TimeUnit; |
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import java.util.concurrent.ForkJoinPool; |
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import java.util.concurrent.ForkJoinTask; |
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import java.util.concurrent.Executor; |
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import java.util.concurrent.ThreadLocalRandom; |
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import java.util.concurrent.ExecutionException; |
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import java.util.concurrent.TimeoutException; |
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import java.util.concurrent.CancellationException; |
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import java.util.concurrent.CompletionException; |
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import java.util.concurrent.CompletionStage; |
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import java.util.concurrent.locks.LockSupport; |
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|
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/** |
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* A {@link Future} that may be explicitly completed (setting its |
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* value and status), and may be used as a {@link CompletionStage}, |
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* supporting dependent functions and actions that trigger upon its |
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* completion. |
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* |
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* <p>When two or more threads attempt to |
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* {@link #complete complete}, |
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* {@link #completeExceptionally completeExceptionally}, or |
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* {@link #cancel cancel} |
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* a CompletableFuture, only one of them succeeds. |
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* |
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* <p>In addition to these and related methods for directly |
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* manipulating status and results, CompletableFuture implements |
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* interface {@link CompletionStage} with the following policies: <ul> |
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* |
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* <li>Actions supplied for dependent completions of |
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* <em>non-async</em> methods may be performed by the thread that |
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* completes the current CompletableFuture, or by any other caller of |
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* a completion method.</li> |
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* |
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* <li>All <em>async</em> methods without an explicit Executor |
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* argument are performed using the {@link ForkJoinPool#commonPool()} |
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* (unless it does not support a parallelism level of at least two, in |
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* which case, a new Thread is used). To simplify monitoring, |
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* debugging, and tracking, all generated asynchronous tasks are |
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* instances of the marker interface {@link |
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* AsynchronousCompletionTask}. </li> |
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* |
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* <li>All CompletionStage methods are implemented independently of |
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* other public methods, so the behavior of one method is not impacted |
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* by overrides of others in subclasses. </li> </ul> |
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* |
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* <p>CompletableFuture also implements {@link Future} with the following |
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* policies: <ul> |
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* |
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* <li>Since (unlike {@link FutureTask}) this class has no direct |
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* control over the computation that causes it to be completed, |
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* cancellation is treated as just another form of exceptional |
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* completion. Method {@link #cancel cancel} has the same effect as |
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* {@code completeExceptionally(new CancellationException())}. Method |
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* {@link #isCompletedExceptionally} can be used to determine if a |
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* CompletableFuture completed in any exceptional fashion.</li> |
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* |
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* <li>In case of exceptional completion with a CompletionException, |
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* methods {@link #get()} and {@link #get(long, TimeUnit)} throw an |
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* {@link ExecutionException} with the same cause as held in the |
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* corresponding CompletionException. To simplify usage in most |
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* contexts, this class also defines methods {@link #join()} and |
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* {@link #getNow} that instead throw the CompletionException directly |
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* in these cases.</li> </ul> |
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* |
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* @author Doug Lea |
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* @since 1.8 |
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*/ |
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public class CompletableFuture<T> implements Future<T>, CompletionStage<T> { |
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|
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/* |
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* Overview: |
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* |
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* A CompletableFuture may have dependent completion actions, |
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* collected in a linked stack. It atomically completes by CASing |
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* a result field, and then pops off and runs those actions. This |
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* applies across normal vs exceptional outcomes, sync vs async |
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* actions, binary triggers, and various forms of completions. |
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* |
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* Non-nullness of field result (set via CAS) indicates done. An |
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* AltResult is used to box null as a result, as well as to hold |
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* exceptions. Using a single field makes completion simple to |
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* detect and trigger. Encoding and decoding is straightforward |
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* but adds vertical sprawl. One minor simplification relies on |
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* the (static) NIL (to box null results) being the only AltResult |
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* with a null exception field, so we don't usually need explicit |
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* comparisons with NIL. Exception propagation mechanics |
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* surrounding decoding rely on unchecked casts of decoded results |
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* really being unchecked, and user type errors being caught at |
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* point of use, as is currently the case in Java. These are |
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* highlighted by using SuppressWarnings annotated temporaries. |
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* |
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* Dependent actions are represented by Completion objects linked |
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* as Treiber stacks headed by field completions. There are four |
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* kinds of Completions: single-source (UniCompletion), two-source |
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* (BiCompletion), shared (CoCompletion, used by the second |
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* source of a BiCompletion), and Signallers that unblock waiters. |
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* |
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* The same patterns of methods and classes are used for each form |
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* of Completion (apply, combine, etc), and are written in a |
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* similar style. For each form X there is, when applicable: |
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* |
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* * Method nowX (for example nowApply) that immediately executes |
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* a supplied function and sets result |
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* * Class AsyncX class (for example AsyncApply) that calls nowX |
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* from another task, |
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* * Class DelayedX (for example DelayedApply) that holds |
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* arguments and calls nowX when ready. |
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* |
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* For each public CompletionStage method M* (for example |
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* thenApply{Async}), there is a method doM (for example |
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* doThenApply) that creates and/or invokes the appropriate form. |
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* Each deals with three cases that can arise when adding a |
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* dependent completion to CompletableFuture f: |
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* |
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* * f is already complete, so the dependent action is run |
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* immediately, via a "now" method, which, if async, |
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* starts the action in a new task. |
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* * f is not complete, so a Completion action is created and |
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* pushed to f's completions. It is triggered via |
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* f.postComplete when f completes. |
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* * f is not complete, but completes while adding the completion |
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* action, so we try to trigger it upon adding (see method |
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* unipush and derivatives) to cover races. |
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* |
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* Methods with two sources (for example thenCombine) must deal |
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* with races across both while pushing actions. The second |
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* completion is a CoCompletion pointing to the first, shared to |
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* ensure that at most one claims and performs the action. The |
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* multiple-arity method allOf does this pairwise to form a tree |
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* of completions. (Method anyOf just uses a depth-one Or tree.) |
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* |
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* Upon setting results, method postComplete is called unless |
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* the target is guaranteed not to be observable (i.e., not yet |
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* returned or linked). Multiple threads can call postComplete, |
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* which atomically pops each dependent action, and tries to |
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* trigger it via method tryAct. Any such action must be performed |
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* only once, even if called from several threads, so Completions |
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* maintain status via CAS, and on success run one of the "now" |
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* methods. Triggering can propagate recursively, so tryAct |
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* returns a completed dependent (if one exists) for further |
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* processing by its caller. |
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* |
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* Blocking methods get() and join() rely on Signaller Completions |
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* that wake up waiting threads. The mechanics are similar to |
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* Treiber stack wait-nodes used in FutureTask, Phaser, and |
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* SynchronousQueue. See their internal documentation for |
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* algorithmic details. |
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* |
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* Without precautions, CompletableFutures would be prone to |
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* garbage accumulation as chains of completions build up, each |
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* pointing back to its sources. So we detach (null out) most |
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* Completion fields as soon as possible. To support this, |
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* internal methods check for and harmlessly ignore null arguments |
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* that may have been obtained during races with threads nulling |
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* out fields. (Some of these checked cases cannot currently |
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* happen.) Fields of Async classes can be but currently are not |
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* fully detached, because they do not in general form cycles. |
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*/ |
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|
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volatile Object result; // Either the result or boxed AltResult |
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volatile Completion completions; // Treiber stack of dependent actions |
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|
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final boolean internalComplete(Object r) { // CAS from null to r |
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return UNSAFE.compareAndSwapObject(this, RESULT, null, r); |
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} |
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|
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final boolean casCompletions(Completion cmp, Completion val) { |
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return UNSAFE.compareAndSwapObject(this, COMPLETIONS, cmp, val); |
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} |
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|
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/* ------------- Encoding and decoding outcomes -------------- */ |
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|
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static final class AltResult { // See above |
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final Throwable ex; // null only for NIL |
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AltResult(Throwable x) { this.ex = x; } |
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} |
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|
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static final AltResult NIL = new AltResult(null); |
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|
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/** |
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* Returns the encoding of the given (non-null) exception as a |
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* wrapped CompletionException unless it is one already. |
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*/ |
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static AltResult altThrowable(Throwable x) { |
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return new AltResult((x instanceof CompletionException) ? x : |
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new CompletionException(x)); |
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} |
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|
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/** |
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* Returns the encoding of the given arguments: if the exception |
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* is non-null, encodes as altThrowable. Otherwise uses the given |
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* value, boxed as NIL if null. |
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*/ |
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static Object encodeOutcome(Object v, Throwable x) { |
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return (x != null) ? altThrowable(x) : (v == null) ? NIL : v; |
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} |
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|
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/** |
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* Decodes outcome to return result or throw unchecked exception. |
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*/ |
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private static <T> T reportJoin(Object r) { |
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if (r instanceof AltResult) { |
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Throwable x; |
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if ((x = ((AltResult)r).ex) == null) |
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return null; |
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if (x instanceof CancellationException) |
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throw (CancellationException)x; |
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if (x instanceof CompletionException) |
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throw (CompletionException)x; |
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throw new CompletionException(x); |
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} |
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@SuppressWarnings("unchecked") T tr = (T) r; |
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return tr; |
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} |
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|
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/** |
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* Reports result using Future.get conventions. |
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*/ |
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private static <T> T reportGet(Object r) |
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throws InterruptedException, ExecutionException { |
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if (r == null) // by convention below, null means interrupted |
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throw new InterruptedException(); |
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if (r instanceof AltResult) { |
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Throwable x, cause; |
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if ((x = ((AltResult)r).ex) == null) |
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return null; |
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if (x instanceof CancellationException) |
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throw (CancellationException)x; |
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if ((x instanceof CompletionException) && |
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(cause = x.getCause()) != null) |
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x = cause; |
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throw new ExecutionException(x); |
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} |
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@SuppressWarnings("unchecked") T tr = (T) r; |
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return tr; |
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} |
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|
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/* ------------- Async Tasks -------------- */ |
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|
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/** |
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* A marker interface identifying asynchronous tasks produced by |
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* {@code async} methods. This may be useful for monitoring, |
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* debugging, and tracking asynchronous activities. |
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* |
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* @since 1.8 |
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*/ |
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public static interface AsynchronousCompletionTask { |
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} |
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|
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/** |
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* Base class for tasks that can act as either FJ or plain |
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* Runnables. Abstract method compute calls an associated "now" |
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* method. Method exec calls compute if its CompletableFuture is |
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* not already done, and runs completions if done. Fields are not |
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* in general final and can be nulled out after use (but most |
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* currently are not). Classes include serialVersionUIDs even |
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* though they are currently never serialized. |
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*/ |
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abstract static class Async<T> extends ForkJoinTask<Void> |
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implements Runnable, AsynchronousCompletionTask { |
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CompletableFuture<T> dep; // the CompletableFuture to trigger |
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Async(CompletableFuture<T> dep) { this.dep = dep; } |
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|
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abstract void compute(); // call the associated "now" method |
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|
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public final boolean exec() { |
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CompletableFuture<T> d; |
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if ((d = dep) != null) { |
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if (d.result == null) // suppress if cancelled |
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compute(); |
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if (d.result != null) |
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d.postComplete(); |
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dep = null; // detach |
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} |
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return true; |
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} |
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public final Void getRawResult() { return null; } |
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public final void setRawResult(Void v) { } |
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public final void run() { exec(); } |
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private static final long serialVersionUID = 5232453952276885070L; |
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} |
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|
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/** |
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* Default executor -- ForkJoinPool.commonPool() unless it cannot |
298 |
* support parallelism. |
299 |
*/ |
300 |
static final Executor asyncPool = |
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(ForkJoinPool.getCommonPoolParallelism() > 1) ? |
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ForkJoinPool.commonPool() : new ThreadPerTaskExecutor(); |
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|
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/** Fallback if ForkJoinPool.commonPool() cannot support parallelism */ |
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static final class ThreadPerTaskExecutor implements Executor { |
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public void execute(Runnable r) { new Thread(r).start(); } |
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} |
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|
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/** |
310 |
* Null-checks user executor argument, and translates uses of |
311 |
* commonPool to asyncPool in case parallelism disabled. |
312 |
*/ |
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static Executor screenExecutor(Executor e) { |
314 |
if (e == null) throw new NullPointerException(); |
315 |
return (e == ForkJoinPool.commonPool()) ? asyncPool : e; |
316 |
} |
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|
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/* ------------- Completions -------------- */ |
319 |
|
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abstract static class Completion { // See above |
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volatile Completion next; // Treiber stack link |
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|
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/** |
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* Performs completion action if enabled, returning a |
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* completed dependent CompletableFuture, if one exists. |
326 |
*/ |
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abstract CompletableFuture<?> tryAct(); |
328 |
} |
329 |
|
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/** |
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* Triggers all reachable enabled dependents. Call only when |
332 |
* known to be done. |
333 |
*/ |
334 |
final void postComplete() { |
335 |
/* |
336 |
* On each step, variable f holds current completions to pop |
337 |
* and run. It is extended along only one path at a time, |
338 |
* pushing others to avoid StackOverflowErrors on recursion. |
339 |
*/ |
340 |
CompletableFuture<?> f = this; Completion h; |
341 |
while ((h = f.completions) != null || |
342 |
(f != this && (h = (f = this).completions) != null)) { |
343 |
CompletableFuture<?> d; Completion t; |
344 |
if (f.casCompletions(h, t = h.next)) { |
345 |
if (t != null) { |
346 |
if (f != this) { // push |
347 |
do {} while (!casCompletions(h.next = completions, h)); |
348 |
continue; |
349 |
} |
350 |
h.next = null; // detach |
351 |
} |
352 |
f = (d = h.tryAct()) == null ? this : d; |
353 |
} |
354 |
} |
355 |
} |
356 |
|
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/* ------------- One-source Completions -------------- */ |
358 |
|
359 |
/** |
360 |
* A Completion with a source and dependent. The "dep" field acts |
361 |
* as a claim, nulled out to disable further attempts to |
362 |
* trigger. Fields can only be observed by other threads upon |
363 |
* successful push; and should be nulled out after claim. |
364 |
*/ |
365 |
abstract static class UniCompletion<T> extends Completion { |
366 |
Executor async; // executor to use (null if none) |
367 |
CompletableFuture<T> dep; // the dependent to complete |
368 |
CompletableFuture<?> src; // source of value for tryAct |
369 |
|
370 |
UniCompletion(Executor async, CompletableFuture<T> dep, |
371 |
CompletableFuture<?> src) { |
372 |
this.async = async; this.dep = dep; this.src = src; |
373 |
} |
374 |
|
375 |
/** Tries to claim completion action by CASing dep to null */ |
376 |
final boolean claim(CompletableFuture<T> d) { |
377 |
return UNSAFE.compareAndSwapObject(this, DEP, d, null); |
378 |
} |
379 |
|
380 |
private static final sun.misc.Unsafe UNSAFE; |
381 |
private static final long DEP; |
382 |
static { |
383 |
try { |
384 |
UNSAFE = sun.misc.Unsafe.getUnsafe(); |
385 |
Class<?> k = UniCompletion.class; |
386 |
DEP = UNSAFE.objectFieldOffset |
387 |
(k.getDeclaredField("dep")); |
388 |
} catch (Exception x) { |
389 |
throw new Error(x); |
390 |
} |
391 |
} |
392 |
} |
393 |
|
394 |
/** Pushes c on to completions, and triggers c if done. */ |
395 |
private void unipush(Completion c) { |
396 |
if (c != null) { |
397 |
CompletableFuture<?> d; |
398 |
while (result == null && !casCompletions(c.next = completions, c)) |
399 |
c.next = null; // clear on CAS failure |
400 |
if ((d = c.tryAct()) != null) // cover races |
401 |
d.postComplete(); |
402 |
if (result != null) // clean stack |
403 |
postComplete(); |
404 |
} |
405 |
} |
406 |
|
407 |
// Immediate, async, delayed, and routing support for Function/apply |
408 |
|
409 |
static <T,U> void nowApply(Executor e, CompletableFuture<U> d, Object r, |
410 |
Function<? super T,? extends U> f) { |
411 |
if (d != null && f != null) { |
412 |
T t; U u; Throwable x; |
413 |
if (r instanceof AltResult) { |
414 |
t = null; |
415 |
x = ((AltResult)r).ex; |
416 |
} |
417 |
else { |
418 |
@SuppressWarnings("unchecked") T tr = (T) r; t = tr; |
419 |
x = null; |
420 |
} |
421 |
if (x == null) { |
422 |
try { |
423 |
if (e != null) { |
424 |
e.execute(new AsyncApply<T,U>(d, t, f)); |
425 |
return; |
426 |
} |
427 |
u = f.apply(t); |
428 |
} catch (Throwable ex) { |
429 |
x = ex; |
430 |
u = null; |
431 |
} |
432 |
} |
433 |
else |
434 |
u = null; |
435 |
d.internalComplete(encodeOutcome(u, x)); |
436 |
} |
437 |
} |
438 |
|
439 |
static final class AsyncApply<T,U> extends Async<U> { |
440 |
T arg; Function<? super T,? extends U> fn; |
441 |
AsyncApply(CompletableFuture<U> dep, T arg, |
442 |
Function<? super T,? extends U> fn) { |
443 |
super(dep); this.arg = arg; this.fn = fn; |
444 |
} |
445 |
final void compute() { nowApply(null, dep, arg, fn); } |
446 |
private static final long serialVersionUID = 5232453952276885070L; |
447 |
} |
448 |
|
449 |
static final class DelayedApply<T,U> extends UniCompletion<U> { |
450 |
Function<? super T,? extends U> fn; |
451 |
DelayedApply(Executor async, CompletableFuture<U> dep, |
452 |
CompletableFuture<?> src, |
453 |
Function<? super T,? extends U> fn) { |
454 |
super(async, dep, src); this.fn = fn; |
455 |
} |
456 |
final CompletableFuture<?> tryAct() { |
457 |
CompletableFuture<U> d; CompletableFuture<?> a; Object r; |
458 |
if ((d = dep) != null && (a = src) != null && |
459 |
(r = a.result) != null && claim(d)) { |
460 |
nowApply(async, d, r, fn); |
461 |
src = null; fn = null; |
462 |
if (d.result != null) return d; |
463 |
} |
464 |
return null; |
465 |
} |
466 |
} |
467 |
|
468 |
private <U> CompletableFuture<U> doThenApply( |
469 |
Function<? super T,? extends U> fn, Executor e) { |
470 |
if (fn == null) throw new NullPointerException(); |
471 |
CompletableFuture<U> d = new CompletableFuture<U>(); |
472 |
Object r = result; |
473 |
if (r == null) |
474 |
unipush(new DelayedApply<T,U>(e, d, this, fn)); |
475 |
else |
476 |
nowApply(e, d, r, fn); |
477 |
return d; |
478 |
} |
479 |
|
480 |
// Consumer/accept |
481 |
|
482 |
static <T,U> void nowAccept(Executor e, CompletableFuture<U> d, |
483 |
Object r, Consumer<? super T> f) { |
484 |
if (d != null && f != null) { |
485 |
T t; Throwable x; |
486 |
if (r instanceof AltResult) { |
487 |
t = null; |
488 |
x = ((AltResult)r).ex; |
489 |
} |
490 |
else { |
491 |
@SuppressWarnings("unchecked") T tr = (T) r; t = tr; |
492 |
x = null; |
493 |
} |
494 |
if (x == null) { |
495 |
try { |
496 |
if (e != null) { |
497 |
e.execute(new AsyncAccept<T,U>(d, t, f)); |
498 |
return; |
499 |
} |
500 |
f.accept(t); |
501 |
} catch (Throwable ex) { |
502 |
x = ex; |
503 |
} |
504 |
} |
505 |
d.internalComplete(encodeOutcome(null, x)); |
506 |
} |
507 |
} |
508 |
|
509 |
static final class AsyncAccept<T,U> extends Async<U> { |
510 |
T arg; Consumer<? super T> fn; |
511 |
AsyncAccept(CompletableFuture<U> dep, T arg, |
512 |
Consumer<? super T> fn) { |
513 |
super(dep); this.arg = arg; this.fn = fn; |
514 |
} |
515 |
final void compute() { nowAccept(null, dep, arg, fn); } |
516 |
private static final long serialVersionUID = 5232453952276885070L; |
517 |
} |
518 |
|
519 |
static final class DelayedAccept<T> extends UniCompletion<Void> { |
520 |
Consumer<? super T> fn; |
521 |
DelayedAccept(Executor async, CompletableFuture<Void> dep, |
522 |
CompletableFuture<?> src, Consumer<? super T> fn) { |
523 |
super(async, dep, src); this.fn = fn; |
524 |
} |
525 |
final CompletableFuture<?> tryAct() { |
526 |
CompletableFuture<Void> d; CompletableFuture<?> a; Object r; |
527 |
if ((d = dep) != null && (a = src) != null && |
528 |
(r = a.result) != null && claim(d)) { |
529 |
nowAccept(async, d, r, fn); |
530 |
src = null; fn = null; |
531 |
if (d.result != null) return d; |
532 |
} |
533 |
return null; |
534 |
} |
535 |
} |
536 |
|
537 |
private CompletableFuture<Void> doThenAccept(Consumer<? super T> fn, |
538 |
Executor e) { |
539 |
if (fn == null) throw new NullPointerException(); |
540 |
CompletableFuture<Void> d = new CompletableFuture<Void>(); |
541 |
Object r = result; |
542 |
if (r == null) |
543 |
unipush(new DelayedAccept<T>(e, d, this, fn)); |
544 |
else |
545 |
nowAccept(e, d, r, fn); |
546 |
return d; |
547 |
} |
548 |
|
549 |
// Runnable/run |
550 |
|
551 |
static <T> void nowRun(Executor e, CompletableFuture<T> d, Object r, |
552 |
Runnable f) { |
553 |
if (d != null && f != null) { |
554 |
Throwable x = (r instanceof AltResult) ? ((AltResult)r).ex : null; |
555 |
if (x == null) { |
556 |
try { |
557 |
if (e != null) { |
558 |
e.execute(new AsyncRun<T>(d, f)); |
559 |
return; |
560 |
} |
561 |
f.run(); |
562 |
} catch (Throwable ex) { |
563 |
x = ex; |
564 |
} |
565 |
} |
566 |
d.internalComplete(encodeOutcome(null, x)); |
567 |
} |
568 |
} |
569 |
|
570 |
static final class AsyncRun<T> extends Async<T> { |
571 |
Runnable fn; |
572 |
AsyncRun(CompletableFuture<T> dep, Runnable fn) { |
573 |
super(dep); this.fn = fn; |
574 |
} |
575 |
final void compute() { nowRun(null, dep, null, fn); } |
576 |
private static final long serialVersionUID = 5232453952276885070L; |
577 |
} |
578 |
|
579 |
static final class DelayedRun extends UniCompletion<Void> { |
580 |
Runnable fn; |
581 |
DelayedRun(Executor async, CompletableFuture<Void> dep, |
582 |
CompletableFuture<?> src, Runnable fn) { |
583 |
super(async, dep, src); this.fn = fn; |
584 |
} |
585 |
final CompletableFuture<?> tryAct() { |
586 |
CompletableFuture<Void> d; CompletableFuture<?> a; Object r; |
587 |
if ((d = dep) != null && (a = src) != null && |
588 |
(r = a.result) != null && claim(d)) { |
589 |
nowRun(async, d, r, fn); |
590 |
src = null; fn = null; // clear refs |
591 |
if (d.result != null) return d; |
592 |
} |
593 |
return null; |
594 |
} |
595 |
} |
596 |
|
597 |
private CompletableFuture<Void> doThenRun(Runnable fn, Executor e) { |
598 |
if (fn == null) throw new NullPointerException(); |
599 |
CompletableFuture<Void> d = new CompletableFuture<Void>(); |
600 |
Object r = result; |
601 |
if (r == null) |
602 |
unipush(new DelayedRun(e, d, this, fn)); |
603 |
else |
604 |
nowRun(e, d, r, fn); |
605 |
return d; |
606 |
} |
607 |
|
608 |
// Supplier/get |
609 |
|
610 |
static <T> void nowSupply(CompletableFuture<T> d, Supplier<T> f) { |
611 |
if (d != null && f != null) { |
612 |
T t; Throwable x; |
613 |
try { |
614 |
t = f.get(); |
615 |
x = null; |
616 |
} catch (Throwable ex) { |
617 |
x = ex; |
618 |
t = null; |
619 |
} |
620 |
d.internalComplete(encodeOutcome(t, x)); |
621 |
} |
622 |
} |
623 |
|
624 |
static final class AsyncSupply<T> extends Async<T> { |
625 |
Supplier<T> fn; |
626 |
AsyncSupply(CompletableFuture<T> dep, Supplier<T> fn) { |
627 |
super(dep); this.fn = fn; |
628 |
} |
629 |
final void compute() { nowSupply(dep, fn); } |
630 |
private static final long serialVersionUID = 5232453952276885070L; |
631 |
} |
632 |
|
633 |
// WhenComplete |
634 |
|
635 |
static <T> void nowWhen(Executor e, CompletableFuture<T> d, Object r, |
636 |
BiConsumer<? super T,? super Throwable> f) { |
637 |
if (d != null && f != null) { |
638 |
T t; Throwable x, dx; |
639 |
if (r instanceof AltResult) { |
640 |
t = null; |
641 |
x = ((AltResult)r).ex; |
642 |
} |
643 |
else { |
644 |
@SuppressWarnings("unchecked") T tr = (T) r; t = tr; |
645 |
x = null; |
646 |
} |
647 |
try { |
648 |
if (e != null) { |
649 |
e.execute(new AsyncWhen<T>(d, r, f)); |
650 |
return; |
651 |
} |
652 |
f.accept(t, x); |
653 |
dx = null; |
654 |
} catch (Throwable ex) { |
655 |
dx = ex; |
656 |
} |
657 |
d.internalComplete(encodeOutcome(t, x != null ? x : dx)); |
658 |
} |
659 |
} |
660 |
|
661 |
static final class AsyncWhen<T> extends Async<T> { |
662 |
Object arg; BiConsumer<? super T,? super Throwable> fn; |
663 |
AsyncWhen(CompletableFuture<T> dep, Object arg, |
664 |
BiConsumer<? super T,? super Throwable> fn) { |
665 |
super(dep); this.arg = arg; this.fn = fn; |
666 |
} |
667 |
final void compute() { nowWhen(null, dep, arg, fn); } |
668 |
private static final long serialVersionUID = 5232453952276885070L; |
669 |
} |
670 |
|
671 |
static final class DelayedWhen<T> extends UniCompletion<T> { |
672 |
BiConsumer<? super T, ? super Throwable> fn; |
673 |
DelayedWhen(Executor async, CompletableFuture<T> dep, |
674 |
CompletableFuture<?> src, |
675 |
BiConsumer<? super T, ? super Throwable> fn) { |
676 |
super(async, dep, src); this.fn = fn; |
677 |
} |
678 |
final CompletableFuture<?> tryAct() { |
679 |
CompletableFuture<T> d; CompletableFuture<?> a; Object r; |
680 |
if ((d = dep) != null && (a = src) != null && |
681 |
(r = a.result) != null && claim(d)) { |
682 |
nowWhen(async, d, r, fn); |
683 |
src = null; fn = null; |
684 |
if (d.result != null) return d; |
685 |
} |
686 |
return null; |
687 |
} |
688 |
} |
689 |
|
690 |
private CompletableFuture<T> doWhenComplete( |
691 |
BiConsumer<? super T, ? super Throwable> fn, Executor e) { |
692 |
if (fn == null) throw new NullPointerException(); |
693 |
CompletableFuture<T> d = new CompletableFuture<T>(); |
694 |
Object r = result; |
695 |
if (r == null) |
696 |
unipush(new DelayedWhen<T>(e, d, this, fn)); |
697 |
else |
698 |
nowWhen(e, d, r, fn); |
699 |
return d; |
700 |
} |
701 |
|
702 |
// Handle |
703 |
|
704 |
static <T,U> void nowHandle(Executor e, CompletableFuture<U> d, Object r, |
705 |
BiFunction<? super T, Throwable, ? extends U> f) { |
706 |
if (d != null && f != null) { |
707 |
T t; U u; Throwable x, dx; |
708 |
if (r instanceof AltResult) { |
709 |
t = null; |
710 |
x = ((AltResult)r).ex; |
711 |
} |
712 |
else { |
713 |
@SuppressWarnings("unchecked") T tr = (T) r; t = tr; |
714 |
x = null; |
715 |
} |
716 |
try { |
717 |
if (e != null) { |
718 |
e.execute(new AsyncCombine<T,Throwable,U>(d, t, x, f)); |
719 |
return; |
720 |
} |
721 |
u = f.apply(t, x); |
722 |
dx = null; |
723 |
} catch (Throwable ex) { |
724 |
dx = ex; |
725 |
u = null; |
726 |
} |
727 |
d.internalComplete(encodeOutcome(u, dx)); |
728 |
} |
729 |
} |
730 |
|
731 |
static final class DelayedHandle<T,U> extends UniCompletion<U> { |
732 |
BiFunction<? super T, Throwable, ? extends U> fn; |
733 |
DelayedHandle(Executor async, CompletableFuture<U> dep, |
734 |
CompletableFuture<?> src, |
735 |
BiFunction<? super T, Throwable, ? extends U> fn) { |
736 |
super(async, dep, src); this.fn = fn; |
737 |
} |
738 |
final CompletableFuture<?> tryAct() { |
739 |
CompletableFuture<U> d; CompletableFuture<?> a; Object r; |
740 |
if ((d = dep) != null && (a = src) != null && |
741 |
(r = a.result) != null && claim(d)) { |
742 |
nowHandle(async, d, r, fn); |
743 |
src = null; fn = null; |
744 |
if (d.result != null) return d; |
745 |
} |
746 |
return null; |
747 |
} |
748 |
} |
749 |
|
750 |
private <U> CompletableFuture<U> doHandle( |
751 |
BiFunction<? super T, Throwable, ? extends U> fn, |
752 |
Executor e) { |
753 |
if (fn == null) throw new NullPointerException(); |
754 |
CompletableFuture<U> d = new CompletableFuture<U>(); |
755 |
Object r = result; |
756 |
if (r == null) |
757 |
unipush(new DelayedHandle<T,U>(e, d, this, fn)); |
758 |
else |
759 |
nowHandle(e, d, r, fn); |
760 |
return d; |
761 |
} |
762 |
|
763 |
// Exceptionally |
764 |
|
765 |
static <T> void nowExceptionally(CompletableFuture<T> d, Object r, |
766 |
Function<? super Throwable, ? extends T> f) { |
767 |
if (d != null && f != null) { |
768 |
T t; Throwable x, dx; |
769 |
if ((r instanceof AltResult) && (x = ((AltResult)r).ex) != null) { |
770 |
try { |
771 |
t = f.apply(x); |
772 |
dx = null; |
773 |
} catch (Throwable ex) { |
774 |
dx = ex; |
775 |
t = null; |
776 |
} |
777 |
} |
778 |
else { |
779 |
@SuppressWarnings("unchecked") T tr = (T) r; t = tr; |
780 |
dx = null; |
781 |
} |
782 |
d.internalComplete(encodeOutcome(t, dx)); |
783 |
} |
784 |
} |
785 |
|
786 |
static final class DelayedExceptionally<T> extends UniCompletion<T> { |
787 |
Function<? super Throwable, ? extends T> fn; |
788 |
DelayedExceptionally(CompletableFuture<T> dep, CompletableFuture<?> src, |
789 |
Function<? super Throwable, ? extends T> fn) { |
790 |
super(null, dep, src); this.fn = fn; |
791 |
} |
792 |
final CompletableFuture<?> tryAct() { |
793 |
CompletableFuture<T> d; CompletableFuture<?> a; Object r; |
794 |
if ((d = dep) != null && (a = src) != null && |
795 |
(r = a.result) != null && claim(d)) { |
796 |
nowExceptionally(d, r, fn); |
797 |
src = null; fn = null; |
798 |
if (d.result != null) return d; |
799 |
} |
800 |
return null; |
801 |
} |
802 |
} |
803 |
|
804 |
private CompletableFuture<T> doExceptionally( |
805 |
Function<Throwable, ? extends T> fn) { |
806 |
if (fn == null) throw new NullPointerException(); |
807 |
CompletableFuture<T> d = new CompletableFuture<T>(); |
808 |
Object r = result; |
809 |
if (r == null) |
810 |
unipush(new DelayedExceptionally<T>(d, this, fn)); |
811 |
else |
812 |
nowExceptionally(d, r, fn); |
813 |
return d; |
814 |
} |
815 |
|
816 |
// Identity function used by nowCompose and anyOf |
817 |
|
818 |
static <T> void nowCopy(CompletableFuture<T> d, Object r) { |
819 |
if (d != null && d.result == null) { |
820 |
Throwable x; |
821 |
d.internalComplete(((r instanceof AltResult) && |
822 |
(x = ((AltResult)r).ex) != null && |
823 |
!(x instanceof CompletionException)) ? |
824 |
new AltResult(new CompletionException(x)): r); |
825 |
} |
826 |
} |
827 |
|
828 |
static final class DelayedCopy<T> extends UniCompletion<T> { |
829 |
DelayedCopy(CompletableFuture<T> dep, CompletableFuture<?> src) { |
830 |
super(null, dep, src); |
831 |
} |
832 |
final CompletableFuture<?> tryAct() { |
833 |
CompletableFuture<T> d; CompletableFuture<?> a; Object r; |
834 |
if ((d = dep) != null && (a = src) != null && |
835 |
(r = a.result) != null && claim(d)) { |
836 |
nowCopy(d, r); |
837 |
src = null; |
838 |
if (d.result != null) return d; |
839 |
} |
840 |
return null; |
841 |
} |
842 |
} |
843 |
|
844 |
// Compose |
845 |
|
846 |
static <T,U> void nowCompose(Executor e, CompletableFuture<U> d, Object r, |
847 |
Function<? super T, ? extends CompletionStage<U>> f) { |
848 |
if (d != null && f != null) { |
849 |
T t; Throwable x; |
850 |
if (r instanceof AltResult) { |
851 |
t = null; |
852 |
x = ((AltResult)r).ex; |
853 |
} |
854 |
else { |
855 |
@SuppressWarnings("unchecked") T tr = (T) r; t = tr; |
856 |
x = null; |
857 |
} |
858 |
if (x == null) { |
859 |
try { |
860 |
if (e != null) |
861 |
e.execute(new AsyncCompose<T,U>(d, t, f)); |
862 |
else { |
863 |
CompletableFuture<U> c = |
864 |
f.apply(t).toCompletableFuture(); |
865 |
Object s = c.result; |
866 |
if (s == null) |
867 |
c.unipush(new DelayedCopy<U>(d, c)); |
868 |
else |
869 |
nowCopy(d, s); |
870 |
} |
871 |
return; |
872 |
} catch (Throwable ex) { |
873 |
x = ex; |
874 |
} |
875 |
} |
876 |
d.internalComplete(encodeOutcome(null, x)); |
877 |
} |
878 |
} |
879 |
|
880 |
static final class AsyncCompose<T,U> extends Async<U> { |
881 |
T arg; Function<? super T, ? extends CompletionStage<U>> fn; |
882 |
AsyncCompose(CompletableFuture<U> dep, T arg, |
883 |
Function<? super T, ? extends CompletionStage<U>> fn) { |
884 |
super(dep); this.arg = arg; this.fn = fn; |
885 |
} |
886 |
final void compute() { nowCompose(null, dep, arg, fn); } |
887 |
private static final long serialVersionUID = 5232453952276885070L; |
888 |
} |
889 |
|
890 |
static final class DelayedCompose<T,U> extends UniCompletion<U> { |
891 |
Function<? super T, ? extends CompletionStage<U>> fn; |
892 |
DelayedCompose(Executor async, CompletableFuture<U> dep, |
893 |
CompletableFuture<?> src, |
894 |
Function<? super T, ? extends CompletionStage<U>> fn) { |
895 |
super(async, dep, src); this.fn = fn; |
896 |
} |
897 |
final CompletableFuture<?> tryAct() { |
898 |
CompletableFuture<U> d; CompletableFuture<?> a; Object r; |
899 |
if ((d = dep) != null && (a = src) != null && |
900 |
(r = a.result) != null && claim(d)) { |
901 |
nowCompose(async, d, r, fn); |
902 |
src = null; fn = null; |
903 |
if (d.result != null) return d; |
904 |
} |
905 |
return null; |
906 |
} |
907 |
} |
908 |
|
909 |
private <U> CompletableFuture<U> doThenCompose( |
910 |
Function<? super T, ? extends CompletionStage<U>> fn, Executor e) { |
911 |
if (fn == null) throw new NullPointerException(); |
912 |
Object r = result; |
913 |
if (r == null || e != null) { |
914 |
CompletableFuture<U> d = new CompletableFuture<U>(); |
915 |
if (r == null) |
916 |
unipush(new DelayedCompose<T,U>(e, d, this, fn)); |
917 |
else |
918 |
nowCompose(e, d, r, fn); |
919 |
return d; |
920 |
} |
921 |
else { // try to return function result |
922 |
T t; Throwable x; |
923 |
if (r instanceof AltResult) { |
924 |
t = null; |
925 |
x = ((AltResult)r).ex; |
926 |
} |
927 |
else { |
928 |
@SuppressWarnings("unchecked") T tr = (T) r; t = tr; |
929 |
x = null; |
930 |
} |
931 |
if (x == null) { |
932 |
try { |
933 |
return fn.apply(t).toCompletableFuture(); |
934 |
} catch (Throwable ex) { |
935 |
x = ex; |
936 |
} |
937 |
} |
938 |
CompletableFuture<U> d = new CompletableFuture<U>(); |
939 |
d.result = encodeOutcome(null, x); |
940 |
return d; |
941 |
} |
942 |
} |
943 |
|
944 |
/* ------------- Two-source Completions -------------- */ |
945 |
|
946 |
/** A Completion with two sources */ |
947 |
abstract static class BiCompletion<T> extends UniCompletion<T> { |
948 |
CompletableFuture<?> snd; // second source for tryAct |
949 |
BiCompletion(Executor async, CompletableFuture<T> dep, |
950 |
CompletableFuture<?> src, CompletableFuture<?> snd) { |
951 |
super(async, dep, src); this.snd = snd; |
952 |
} |
953 |
} |
954 |
|
955 |
/** A Completion delegating to another Completion */ |
956 |
static final class CoCompletion extends Completion { |
957 |
Completion completion; |
958 |
CoCompletion(Completion completion) { |
959 |
this.completion = completion; |
960 |
} |
961 |
final CompletableFuture<?> tryAct() { |
962 |
Completion c; CompletableFuture<?> d; |
963 |
if ((c = completion) == null || (d = c.tryAct()) == null) |
964 |
return null; |
965 |
completion = null; // detach |
966 |
return d; |
967 |
} |
968 |
} |
969 |
|
970 |
/* ------------- Two-source Anded -------------- */ |
971 |
|
972 |
/** Pushes c on to completions and o's completions unless both done. */ |
973 |
private void bipushAnded(CompletableFuture<?> o, Completion c) { |
974 |
if (c != null && o != null) { |
975 |
Object r; CompletableFuture<?> d; |
976 |
while ((r = result) == null && |
977 |
!casCompletions(c.next = completions, c)) |
978 |
c.next = null; |
979 |
if (o.result == null) { |
980 |
Completion q = (r != null) ? c : new CoCompletion(c); |
981 |
while (o.result == null && |
982 |
!o.casCompletions(q.next = o.completions, q)) |
983 |
q.next = null; |
984 |
} |
985 |
if ((d = c.tryAct()) != null) |
986 |
d.postComplete(); |
987 |
if (o.result != null) |
988 |
o.postComplete(); |
989 |
if (result != null) |
990 |
postComplete(); |
991 |
} |
992 |
} |
993 |
|
994 |
// BiFunction/combine |
995 |
|
996 |
static <T,U,V> void nowCombine(Executor e, CompletableFuture<V> d, |
997 |
Object r, Object s, |
998 |
BiFunction<? super T,? super U,? extends V> f) { |
999 |
if (d != null && f != null) { |
1000 |
T t; U u; V v; Throwable x; |
1001 |
if (r instanceof AltResult) { |
1002 |
t = null; |
1003 |
x = ((AltResult)r).ex; |
1004 |
} |
1005 |
else { |
1006 |
@SuppressWarnings("unchecked") T tr = (T) r; t = tr; |
1007 |
x = null; |
1008 |
} |
1009 |
if (x != null) |
1010 |
u = null; |
1011 |
else if (s instanceof AltResult) { |
1012 |
x = ((AltResult)s).ex; |
1013 |
u = null; |
1014 |
} |
1015 |
else { |
1016 |
@SuppressWarnings("unchecked") U us = (U) s; u = us; |
1017 |
} |
1018 |
if (x == null) { |
1019 |
try { |
1020 |
if (e != null) { |
1021 |
e.execute(new AsyncCombine<T,U,V>(d, t, u, f)); |
1022 |
return; |
1023 |
} |
1024 |
v = f.apply(t, u); |
1025 |
} catch (Throwable ex) { |
1026 |
x = ex; |
1027 |
v = null; |
1028 |
} |
1029 |
} |
1030 |
else |
1031 |
v = null; |
1032 |
d.internalComplete(encodeOutcome(v, x)); |
1033 |
} |
1034 |
} |
1035 |
|
1036 |
static final class AsyncCombine<T,U,V> extends Async<V> { |
1037 |
T arg1; U arg2; BiFunction<? super T,? super U,? extends V> fn; |
1038 |
AsyncCombine(CompletableFuture<V> dep, T arg1, U arg2, |
1039 |
BiFunction<? super T,? super U,? extends V> fn) { |
1040 |
super(dep); this.arg1 = arg1; this.arg2 = arg2; this.fn = fn; |
1041 |
} |
1042 |
final void compute() { nowCombine(null, dep, arg1, arg2, fn); } |
1043 |
private static final long serialVersionUID = 5232453952276885070L; |
1044 |
} |
1045 |
|
1046 |
static final class DelayedCombine<T,U,V> extends BiCompletion<V> { |
1047 |
BiFunction<? super T,? super U,? extends V> fn; |
1048 |
DelayedCombine(Executor async, CompletableFuture<V> dep, |
1049 |
CompletableFuture<?> src, CompletableFuture<?> snd, |
1050 |
BiFunction<? super T,? super U,? extends V> fn) { |
1051 |
super(async, dep, src, snd); this.fn = fn; |
1052 |
} |
1053 |
final CompletableFuture<?> tryAct() { |
1054 |
CompletableFuture<V> d; CompletableFuture<?> a, b; Object r, s; |
1055 |
if ((d = dep) != null && (a = src) != null && (b = snd) != null && |
1056 |
(r = a.result) != null && (s = b.result) != null && claim(d)) { |
1057 |
nowCombine(async, d, r, s, fn); |
1058 |
src = null; snd = null; fn = null; |
1059 |
if (d.result != null) return d; |
1060 |
} |
1061 |
return null; |
1062 |
} |
1063 |
} |
1064 |
|
1065 |
private <U,V> CompletableFuture<V> doThenCombine( |
1066 |
CompletableFuture<? extends U> o, |
1067 |
BiFunction<? super T,? super U,? extends V> fn, |
1068 |
Executor e) { |
1069 |
if (o == null || fn == null) throw new NullPointerException(); |
1070 |
CompletableFuture<V> d = new CompletableFuture<V>(); |
1071 |
Object r = result, s = o.result; |
1072 |
if (r == null || s == null) |
1073 |
bipushAnded(o, new DelayedCombine<T,U,V>(e, d, this, o, fn)); |
1074 |
else |
1075 |
nowCombine(e, d, r, s, fn); |
1076 |
return d; |
1077 |
} |
1078 |
|
1079 |
// BiConsumer/AcceptBoth |
1080 |
|
1081 |
static <T,U,V> void nowAcceptBoth(Executor e, CompletableFuture<V> d, |
1082 |
Object r, Object s, |
1083 |
BiConsumer<? super T,? super U> f) { |
1084 |
if (d != null && f != null) { |
1085 |
T t; U u; Throwable x; |
1086 |
if (r instanceof AltResult) { |
1087 |
t = null; |
1088 |
x = ((AltResult)r).ex; |
1089 |
} |
1090 |
else { |
1091 |
@SuppressWarnings("unchecked") T tr = (T) r; t = tr; |
1092 |
x = null; |
1093 |
} |
1094 |
if (x != null) |
1095 |
u = null; |
1096 |
else if (s instanceof AltResult) { |
1097 |
x = ((AltResult)s).ex; |
1098 |
u = null; |
1099 |
} |
1100 |
else { |
1101 |
@SuppressWarnings("unchecked") U us = (U) s; u = us; |
1102 |
} |
1103 |
if (x == null) { |
1104 |
try { |
1105 |
if (e != null) { |
1106 |
e.execute(new AsyncAcceptBoth<T,U,V>(d, t, u, f)); |
1107 |
return; |
1108 |
} |
1109 |
f.accept(t, u); |
1110 |
} catch (Throwable ex) { |
1111 |
x = ex; |
1112 |
} |
1113 |
} |
1114 |
d.internalComplete(encodeOutcome(null, x)); |
1115 |
} |
1116 |
} |
1117 |
|
1118 |
static final class AsyncAcceptBoth<T,U,V> extends Async<V> { |
1119 |
T arg1; U arg2; BiConsumer<? super T,? super U> fn; |
1120 |
AsyncAcceptBoth(CompletableFuture<V> dep, T arg1, U arg2, |
1121 |
BiConsumer<? super T,? super U> fn) { |
1122 |
super(dep); this.arg1 = arg1; this.arg2 = arg2; this.fn = fn; |
1123 |
} |
1124 |
final void compute() { nowAcceptBoth(null, dep, arg1, arg2, fn); } |
1125 |
private static final long serialVersionUID = 5232453952276885070L; |
1126 |
} |
1127 |
|
1128 |
static final class DelayedAcceptBoth<T,U> extends BiCompletion<Void> { |
1129 |
BiConsumer<? super T,? super U> fn; |
1130 |
DelayedAcceptBoth(Executor async, CompletableFuture<Void> dep, |
1131 |
CompletableFuture<?> src, CompletableFuture<?> snd, |
1132 |
BiConsumer<? super T,? super U> fn) { |
1133 |
super(async, dep, src, snd); this.fn = fn; |
1134 |
} |
1135 |
final CompletableFuture<?> tryAct() { |
1136 |
CompletableFuture<Void> d; CompletableFuture<?> a, b; Object r, s; |
1137 |
if ((d = dep) != null && (a = src) != null && (b = snd) != null && |
1138 |
(r = a.result) != null && (s = b.result) != null && claim(d)) { |
1139 |
nowAcceptBoth(async, d, r, s, fn); |
1140 |
src = null; snd = null; fn = null; |
1141 |
if (d.result != null) return d; |
1142 |
} |
1143 |
return null; |
1144 |
} |
1145 |
} |
1146 |
|
1147 |
private <U> CompletableFuture<Void> doThenAcceptBoth( |
1148 |
CompletableFuture<? extends U> o, |
1149 |
BiConsumer<? super T, ? super U> fn, |
1150 |
Executor e) { |
1151 |
if (o == null || fn == null) throw new NullPointerException(); |
1152 |
CompletableFuture<Void> d = new CompletableFuture<Void>(); |
1153 |
Object r = result, s = o.result; |
1154 |
if (r == null || s == null) |
1155 |
bipushAnded(o, new DelayedAcceptBoth<T,U>(e, d, this, o, fn)); |
1156 |
else |
1157 |
nowAcceptBoth(e, d, r, s, fn); |
1158 |
return d; |
1159 |
} |
1160 |
|
1161 |
// Runnable/both |
1162 |
|
1163 |
static final class DelayedRunAfterBoth extends BiCompletion<Void> { |
1164 |
Runnable fn; |
1165 |
DelayedRunAfterBoth(Executor async, CompletableFuture<Void> dep, |
1166 |
CompletableFuture<?> src, CompletableFuture<?> snd, |
1167 |
Runnable fn) { |
1168 |
super(async, dep, src, snd); this.fn = fn; |
1169 |
} |
1170 |
final CompletableFuture<?> tryAct() { |
1171 |
CompletableFuture<Void> d; CompletableFuture<?> a, b; Object r, s; |
1172 |
if ((d = dep) != null && (a = src) != null && (b = snd) != null && |
1173 |
(r = a.result) != null && (s = b.result) != null && claim(d)) { |
1174 |
Throwable x = (r instanceof AltResult) ? |
1175 |
((AltResult)r).ex : null; |
1176 |
nowRun(async, d, (x == null) ? s : r, fn); |
1177 |
src = null; snd = null; fn = null; |
1178 |
if (d.result != null) return d; |
1179 |
} |
1180 |
return null; |
1181 |
} |
1182 |
} |
1183 |
|
1184 |
private CompletableFuture<Void> doRunAfterBoth( |
1185 |
CompletableFuture<?> o, Runnable fn, Executor e) { |
1186 |
if (o == null || fn == null) throw new NullPointerException(); |
1187 |
CompletableFuture<Void> d = new CompletableFuture<Void>(); |
1188 |
Object r = result, s = o.result; |
1189 |
if (r == null || s == null) |
1190 |
bipushAnded(o, new DelayedRunAfterBoth(e, d, this, o, fn)); |
1191 |
else { |
1192 |
Throwable x = (r instanceof AltResult) ? ((AltResult)r).ex : null; |
1193 |
nowRun(e, d, (x == null) ? s : r, fn); |
1194 |
} |
1195 |
return d; |
1196 |
} |
1197 |
|
1198 |
// allOf |
1199 |
|
1200 |
static <T> void nowAnd(CompletableFuture<T> d, Object r, Object s) { |
1201 |
if (d != null) { |
1202 |
Throwable x = (r instanceof AltResult) ? ((AltResult)r).ex : null; |
1203 |
if (x == null && (s instanceof AltResult)) |
1204 |
x = ((AltResult)s).ex; |
1205 |
d.internalComplete(encodeOutcome(null, x)); |
1206 |
} |
1207 |
} |
1208 |
|
1209 |
static final class DelayedAnd extends BiCompletion<Void> { |
1210 |
DelayedAnd(CompletableFuture<Void> dep, |
1211 |
CompletableFuture<?> src, CompletableFuture<?> snd) { |
1212 |
super(null, dep, src, snd); |
1213 |
} |
1214 |
final CompletableFuture<?> tryAct() { |
1215 |
CompletableFuture<Void> d; CompletableFuture<?> a, b; Object r, s; |
1216 |
if ((d = dep) != null && (a = src) != null && (b = snd) != null && |
1217 |
(r = a.result) != null && (s = b.result) != null && claim(d)) { |
1218 |
nowAnd(d, r, s); |
1219 |
src = null; snd = null; |
1220 |
if (d.result != null) return d; |
1221 |
} |
1222 |
return null; |
1223 |
} |
1224 |
} |
1225 |
|
1226 |
/** Recursively constructs a tree of And completions */ |
1227 |
private static CompletableFuture<Void> doAllOf(CompletableFuture<?>[] cfs, |
1228 |
int lo, int hi) { |
1229 |
CompletableFuture<Void> d = new CompletableFuture<Void>(); |
1230 |
if (lo > hi) // empty |
1231 |
d.result = NIL; |
1232 |
else { |
1233 |
int mid = (lo + hi) >>> 1; |
1234 |
CompletableFuture<?> fst = (lo == mid ? cfs[lo] : |
1235 |
doAllOf(cfs, lo, mid)); |
1236 |
CompletableFuture<?> snd = (lo == hi ? fst : // and fst with self |
1237 |
(hi == mid+1) ? cfs[hi] : |
1238 |
doAllOf(cfs, mid+1, hi)); |
1239 |
Object r = fst.result, s = snd.result; // throw NPE if null elements |
1240 |
if (r == null || s == null) { |
1241 |
DelayedAnd a = new DelayedAnd(d, fst, snd); |
1242 |
if (fst == snd) |
1243 |
fst.unipush(a); |
1244 |
else |
1245 |
fst.bipushAnded(snd, a); |
1246 |
} |
1247 |
else |
1248 |
nowAnd(d, r, s); |
1249 |
} |
1250 |
return d; |
1251 |
} |
1252 |
|
1253 |
/* ------------- Two-source Ored -------------- */ |
1254 |
|
1255 |
/** Pushes c on to completions and o's completions unless either done. */ |
1256 |
private void bipushOred(CompletableFuture<?> o, Completion c) { |
1257 |
if (c != null && o != null) { |
1258 |
CompletableFuture<?> d; |
1259 |
while (o.result == null && result == null) { |
1260 |
if (casCompletions(c.next = completions, c)) { |
1261 |
CoCompletion q = new CoCompletion(c); |
1262 |
while (result == null && o.result == null && |
1263 |
!o.casCompletions(q.next = o.completions, q)) |
1264 |
q.next = null; |
1265 |
break; |
1266 |
} |
1267 |
c.next = null; |
1268 |
} |
1269 |
if ((d = c.tryAct()) != null) |
1270 |
d.postComplete(); |
1271 |
if (o.result != null) |
1272 |
o.postComplete(); |
1273 |
if (result != null) |
1274 |
postComplete(); |
1275 |
} |
1276 |
} |
1277 |
|
1278 |
// Function/applyEither |
1279 |
|
1280 |
static final class DelayedApplyToEither<T,U> extends BiCompletion<U> { |
1281 |
Function<? super T,? extends U> fn; |
1282 |
DelayedApplyToEither(Executor async, CompletableFuture<U> dep, |
1283 |
CompletableFuture<?> src, CompletableFuture<?> snd, |
1284 |
Function<? super T,? extends U> fn) { |
1285 |
super(async, dep, src, snd); this.fn = fn; |
1286 |
} |
1287 |
final CompletableFuture<?> tryAct() { |
1288 |
CompletableFuture<U> d; CompletableFuture<?> a, b; Object r; |
1289 |
if ((d = dep) != null && (a = src) != null && (b = snd) != null && |
1290 |
((r = a.result) != null || (r = b.result) != null) && |
1291 |
claim(d)) { |
1292 |
nowApply(async, d, r, fn); |
1293 |
src = null; snd = null; fn = null; |
1294 |
if (d.result != null) return d; |
1295 |
} |
1296 |
return null; |
1297 |
} |
1298 |
} |
1299 |
|
1300 |
private <U> CompletableFuture<U> doApplyToEither( |
1301 |
CompletableFuture<? extends T> o, |
1302 |
Function<? super T, U> fn, Executor e) { |
1303 |
if (o == null || fn == null) throw new NullPointerException(); |
1304 |
CompletableFuture<U> d = new CompletableFuture<U>(); |
1305 |
Object r = result; |
1306 |
if (r == null && (r = o.result) == null) |
1307 |
bipushOred(o, new DelayedApplyToEither<T,U>(e, d, this, o, fn)); |
1308 |
else |
1309 |
nowApply(e, d, r, fn); |
1310 |
return d; |
1311 |
} |
1312 |
|
1313 |
// Consumer/acceptEither |
1314 |
|
1315 |
static final class DelayedAcceptEither<T> extends BiCompletion<Void> { |
1316 |
Consumer<? super T> fn; |
1317 |
DelayedAcceptEither(Executor async, CompletableFuture<Void> dep, |
1318 |
CompletableFuture<?> src, CompletableFuture<?> snd, |
1319 |
Consumer<? super T> fn) { |
1320 |
super(async, dep, src, snd); this.fn = fn; |
1321 |
} |
1322 |
final CompletableFuture<?> tryAct() { |
1323 |
CompletableFuture<Void> d; CompletableFuture<?> a, b; Object r; |
1324 |
if ((d = dep) != null && (a = src) != null && (b = snd) != null && |
1325 |
((r = a.result) != null || (r = b.result) != null) && |
1326 |
claim(d)) { |
1327 |
nowAccept(async, d, r, fn); |
1328 |
src = null; snd = null; fn = null; |
1329 |
if (d.result != null) return d; |
1330 |
} |
1331 |
return null; |
1332 |
} |
1333 |
} |
1334 |
|
1335 |
private CompletableFuture<Void> doAcceptEither( |
1336 |
CompletableFuture<? extends T> o, |
1337 |
Consumer<? super T> fn, Executor e) { |
1338 |
if (o == null || fn == null) throw new NullPointerException(); |
1339 |
CompletableFuture<Void> d = new CompletableFuture<Void>(); |
1340 |
Object r = result; |
1341 |
if (r == null && (r = o.result) == null) |
1342 |
bipushOred(o, new DelayedAcceptEither<T>(e, d, this, o, fn)); |
1343 |
else |
1344 |
nowAccept(e, d, r, fn); |
1345 |
return d; |
1346 |
} |
1347 |
|
1348 |
// Runnable/runEither |
1349 |
|
1350 |
static final class DelayedRunAfterEither extends BiCompletion<Void> { |
1351 |
Runnable fn; |
1352 |
DelayedRunAfterEither(Executor async, CompletableFuture<Void> dep, |
1353 |
CompletableFuture<?> src, |
1354 |
CompletableFuture<?> snd, Runnable fn) { |
1355 |
super(async, dep, src, snd); this.fn = fn; |
1356 |
} |
1357 |
final CompletableFuture<?> tryAct() { |
1358 |
CompletableFuture<Void> d; CompletableFuture<?> a, b; Object r; |
1359 |
if ((d = dep) != null && (a = src) != null && (b = snd) != null && |
1360 |
((r = a.result) != null || (r = b.result) != null) && |
1361 |
claim(d)) { |
1362 |
nowRun(async, d, r, fn); |
1363 |
src = null; snd = null; fn = null; |
1364 |
if (d.result != null) return d; |
1365 |
} |
1366 |
return null; |
1367 |
} |
1368 |
} |
1369 |
|
1370 |
private CompletableFuture<Void> doRunAfterEither( |
1371 |
CompletableFuture<?> o, Runnable fn, Executor e) { |
1372 |
if (o == null || fn == null) throw new NullPointerException(); |
1373 |
CompletableFuture<Void> d = new CompletableFuture<Void>(); |
1374 |
Object r = result; |
1375 |
if (r == null && (r = o.result) == null) |
1376 |
bipushOred(o, new DelayedRunAfterEither(e, d, this, o, fn)); |
1377 |
else |
1378 |
nowRun(e, d, r, fn); |
1379 |
return d; |
1380 |
} |
1381 |
|
1382 |
/* ------------- Signallers -------------- */ |
1383 |
|
1384 |
/** |
1385 |
* Heuristic spin value for waitingGet() before blocking on |
1386 |
* multiprocessors |
1387 |
*/ |
1388 |
static final int SPINS = (Runtime.getRuntime().availableProcessors() > 1 ? |
1389 |
1 << 8 : 0); |
1390 |
|
1391 |
/** |
1392 |
* Completion for recording and releasing a waiting thread. See |
1393 |
* other classes such as Phaser and SynchronousQueue for more |
1394 |
* detailed explanation. This class implements ManagedBlocker to |
1395 |
* avoid starvation when blocking actions pile up in |
1396 |
* ForkJoinPools. |
1397 |
*/ |
1398 |
static final class Signaller extends Completion |
1399 |
implements ForkJoinPool.ManagedBlocker { |
1400 |
long nanos; // wait time if timed |
1401 |
final long deadline; // non-zero if timed |
1402 |
volatile int interruptControl; // > 0: interruptible, < 0: interrupted |
1403 |
volatile Thread thread; |
1404 |
Signaller(boolean interruptible, long nanos, long deadline) { |
1405 |
this.thread = Thread.currentThread(); |
1406 |
this.interruptControl = interruptible ? 1 : 0; |
1407 |
this.nanos = nanos; |
1408 |
this.deadline = deadline; |
1409 |
} |
1410 |
final CompletableFuture<?> tryAct() { |
1411 |
Thread w = thread; |
1412 |
if (w != null) { |
1413 |
thread = null; // no need to CAS |
1414 |
LockSupport.unpark(w); |
1415 |
} |
1416 |
return null; |
1417 |
} |
1418 |
public boolean isReleasable() { |
1419 |
if (thread == null) |
1420 |
return true; |
1421 |
if (Thread.interrupted()) { |
1422 |
int i = interruptControl; |
1423 |
interruptControl = -1; |
1424 |
if (i > 0) |
1425 |
return true; |
1426 |
} |
1427 |
if (deadline != 0L && |
1428 |
(nanos <= 0L || (nanos = deadline - System.nanoTime()) <= 0L)) { |
1429 |
thread = null; |
1430 |
return true; |
1431 |
} |
1432 |
return false; |
1433 |
} |
1434 |
public boolean block() { |
1435 |
if (isReleasable()) |
1436 |
return true; |
1437 |
else if (deadline == 0L) |
1438 |
LockSupport.park(this); |
1439 |
else if (nanos > 0L) |
1440 |
LockSupport.parkNanos(this, nanos); |
1441 |
return isReleasable(); |
1442 |
} |
1443 |
} |
1444 |
|
1445 |
/** |
1446 |
* Returns raw result after waiting, or null if interruptible and |
1447 |
* interrupted. |
1448 |
*/ |
1449 |
private Object waitingGet(boolean interruptible) { |
1450 |
Signaller q = null; |
1451 |
boolean queued = false; |
1452 |
int spins = SPINS; |
1453 |
Object r; |
1454 |
while ((r = result) == null) { |
1455 |
if (spins > 0) { |
1456 |
if (ThreadLocalRandom.nextSecondarySeed() >= 0) |
1457 |
--spins; |
1458 |
} |
1459 |
else if (q == null) |
1460 |
q = new Signaller(interruptible, 0L, 0L); |
1461 |
else if (!queued) |
1462 |
queued = casCompletions(q.next = completions, q); |
1463 |
else if (interruptible && q.interruptControl < 0) { |
1464 |
q.thread = null; |
1465 |
removeCancelledSignallers(); |
1466 |
return null; |
1467 |
} |
1468 |
else if (q.thread != null && result == null) { |
1469 |
try { |
1470 |
ForkJoinPool.managedBlock(q); |
1471 |
} catch (InterruptedException ie) { |
1472 |
q.interruptControl = -1; |
1473 |
} |
1474 |
} |
1475 |
} |
1476 |
if (q != null) { |
1477 |
q.thread = null; |
1478 |
if (q.interruptControl < 0) { |
1479 |
if (interruptible) |
1480 |
r = null; // report interruption |
1481 |
else |
1482 |
Thread.currentThread().interrupt(); |
1483 |
} |
1484 |
} |
1485 |
postComplete(); |
1486 |
return r; |
1487 |
} |
1488 |
|
1489 |
/** |
1490 |
* Returns raw result after waiting, or null if interrupted, or |
1491 |
* throws TimeoutException on timeout. |
1492 |
*/ |
1493 |
private Object timedGet(long nanos) throws TimeoutException { |
1494 |
if (Thread.interrupted()) |
1495 |
return null; |
1496 |
if (nanos <= 0L) |
1497 |
throw new TimeoutException(); |
1498 |
long d = System.nanoTime() + nanos; |
1499 |
Signaller q = new Signaller(true, nanos, d == 0L ? 1L : d); // avoid 0 |
1500 |
boolean queued = false; |
1501 |
Object r; |
1502 |
while ((r = result) == null) { |
1503 |
if (!queued) |
1504 |
queued = casCompletions(q.next = completions, q); |
1505 |
else if (q.interruptControl < 0 || q.nanos <= 0L) { |
1506 |
q.thread = null; |
1507 |
removeCancelledSignallers(); |
1508 |
if (q.interruptControl < 0) |
1509 |
return null; |
1510 |
throw new TimeoutException(); |
1511 |
} |
1512 |
else if (q.thread != null && result == null) { |
1513 |
try { |
1514 |
ForkJoinPool.managedBlock(q); |
1515 |
} catch (InterruptedException ie) { |
1516 |
q.interruptControl = -1; |
1517 |
} |
1518 |
} |
1519 |
} |
1520 |
q.thread = null; |
1521 |
postComplete(); |
1522 |
return (q.interruptControl < 0) ? null : r; |
1523 |
} |
1524 |
|
1525 |
/** |
1526 |
* Unlinks cancelled Signallers to avoid accumulating garbage. |
1527 |
* Internal nodes are simply unspliced without CAS since it is |
1528 |
* harmless if they are traversed anyway. To avoid effects of |
1529 |
* unsplicing from already removed nodes, the list is retraversed |
1530 |
* in case of an apparent race. |
1531 |
*/ |
1532 |
private void removeCancelledSignallers() { |
1533 |
for (Completion p = null, q = completions; q != null;) { |
1534 |
Completion s = q.next; |
1535 |
if ((q instanceof Signaller) && ((Signaller)q).thread == null) { |
1536 |
if (p != null) { |
1537 |
p.next = s; |
1538 |
if (!(p instanceof Signaller) || |
1539 |
((Signaller)p).thread != null) |
1540 |
break; |
1541 |
} |
1542 |
else if (casCompletions(q, s)) |
1543 |
break; |
1544 |
p = null; // restart |
1545 |
q = completions; |
1546 |
} |
1547 |
else { |
1548 |
p = q; |
1549 |
q = s; |
1550 |
} |
1551 |
} |
1552 |
} |
1553 |
|
1554 |
/* ------------- public methods -------------- */ |
1555 |
|
1556 |
/** |
1557 |
* Creates a new incomplete CompletableFuture. |
1558 |
*/ |
1559 |
public CompletableFuture() { |
1560 |
} |
1561 |
|
1562 |
/** |
1563 |
* Returns a new CompletableFuture that is asynchronously completed |
1564 |
* by a task running in the {@link ForkJoinPool#commonPool()} with |
1565 |
* the value obtained by calling the given Supplier. |
1566 |
* |
1567 |
* @param supplier a function returning the value to be used |
1568 |
* to complete the returned CompletableFuture |
1569 |
* @param <U> the function's return type |
1570 |
* @return the new CompletableFuture |
1571 |
*/ |
1572 |
public static <U> CompletableFuture<U> supplyAsync(Supplier<U> supplier) { |
1573 |
if (supplier == null) throw new NullPointerException(); |
1574 |
CompletableFuture<U> d = new CompletableFuture<U>(); |
1575 |
asyncPool.execute(new AsyncSupply<U>(d, supplier)); |
1576 |
return d; |
1577 |
} |
1578 |
|
1579 |
/** |
1580 |
* Returns a new CompletableFuture that is asynchronously completed |
1581 |
* by a task running in the given executor with the value obtained |
1582 |
* by calling the given Supplier. |
1583 |
* |
1584 |
* @param supplier a function returning the value to be used |
1585 |
* to complete the returned CompletableFuture |
1586 |
* @param executor the executor to use for asynchronous execution |
1587 |
* @param <U> the function's return type |
1588 |
* @return the new CompletableFuture |
1589 |
*/ |
1590 |
public static <U> CompletableFuture<U> supplyAsync(Supplier<U> supplier, |
1591 |
Executor executor) { |
1592 |
if (supplier == null) throw new NullPointerException(); |
1593 |
Executor e = screenExecutor(executor); |
1594 |
CompletableFuture<U> d = new CompletableFuture<U>(); |
1595 |
e.execute(new AsyncSupply<U>(d, supplier)); |
1596 |
return d; |
1597 |
} |
1598 |
|
1599 |
/** |
1600 |
* Returns a new CompletableFuture that is asynchronously completed |
1601 |
* by a task running in the {@link ForkJoinPool#commonPool()} after |
1602 |
* it runs the given action. |
1603 |
* |
1604 |
* @param runnable the action to run before completing the |
1605 |
* returned CompletableFuture |
1606 |
* @return the new CompletableFuture |
1607 |
*/ |
1608 |
public static CompletableFuture<Void> runAsync(Runnable runnable) { |
1609 |
if (runnable == null) throw new NullPointerException(); |
1610 |
CompletableFuture<Void> d = new CompletableFuture<Void>(); |
1611 |
asyncPool.execute(new AsyncRun<Void>(d, runnable)); |
1612 |
return d; |
1613 |
} |
1614 |
|
1615 |
/** |
1616 |
* Returns a new CompletableFuture that is asynchronously completed |
1617 |
* by a task running in the given executor after it runs the given |
1618 |
* action. |
1619 |
* |
1620 |
* @param runnable the action to run before completing the |
1621 |
* returned CompletableFuture |
1622 |
* @param executor the executor to use for asynchronous execution |
1623 |
* @return the new CompletableFuture |
1624 |
*/ |
1625 |
public static CompletableFuture<Void> runAsync(Runnable runnable, |
1626 |
Executor executor) { |
1627 |
if (runnable == null) throw new NullPointerException(); |
1628 |
Executor e = screenExecutor(executor); |
1629 |
CompletableFuture<Void> d = new CompletableFuture<Void>(); |
1630 |
e.execute(new AsyncRun<Void>(d, runnable)); |
1631 |
return d; |
1632 |
} |
1633 |
|
1634 |
/** |
1635 |
* Returns a new CompletableFuture that is already completed with |
1636 |
* the given value. |
1637 |
* |
1638 |
* @param value the value |
1639 |
* @param <U> the type of the value |
1640 |
* @return the completed CompletableFuture |
1641 |
*/ |
1642 |
public static <U> CompletableFuture<U> completedFuture(U value) { |
1643 |
CompletableFuture<U> d = new CompletableFuture<U>(); |
1644 |
d.result = (value == null) ? NIL : value; |
1645 |
return d; |
1646 |
} |
1647 |
|
1648 |
/** |
1649 |
* Returns {@code true} if completed in any fashion: normally, |
1650 |
* exceptionally, or via cancellation. |
1651 |
* |
1652 |
* @return {@code true} if completed |
1653 |
*/ |
1654 |
public boolean isDone() { |
1655 |
return result != null; |
1656 |
} |
1657 |
|
1658 |
/** |
1659 |
* Waits if necessary for this future to complete, and then |
1660 |
* returns its result. |
1661 |
* |
1662 |
* @return the result value |
1663 |
* @throws CancellationException if this future was cancelled |
1664 |
* @throws ExecutionException if this future completed exceptionally |
1665 |
* @throws InterruptedException if the current thread was interrupted |
1666 |
* while waiting |
1667 |
*/ |
1668 |
public T get() throws InterruptedException, ExecutionException { |
1669 |
Object r; |
1670 |
return reportGet((r = result) == null ? waitingGet(true) : r); |
1671 |
} |
1672 |
|
1673 |
/** |
1674 |
* Waits if necessary for at most the given time for this future |
1675 |
* to complete, and then returns its result, if available. |
1676 |
* |
1677 |
* @param timeout the maximum time to wait |
1678 |
* @param unit the time unit of the timeout argument |
1679 |
* @return the result value |
1680 |
* @throws CancellationException if this future was cancelled |
1681 |
* @throws ExecutionException if this future completed exceptionally |
1682 |
* @throws InterruptedException if the current thread was interrupted |
1683 |
* while waiting |
1684 |
* @throws TimeoutException if the wait timed out |
1685 |
*/ |
1686 |
public T get(long timeout, TimeUnit unit) |
1687 |
throws InterruptedException, ExecutionException, TimeoutException { |
1688 |
Object r; |
1689 |
long nanos = unit.toNanos(timeout); |
1690 |
return reportGet((r = result) == null ? timedGet(nanos) : r); |
1691 |
} |
1692 |
|
1693 |
/** |
1694 |
* Returns the result value when complete, or throws an |
1695 |
* (unchecked) exception if completed exceptionally. To better |
1696 |
* conform with the use of common functional forms, if a |
1697 |
* computation involved in the completion of this |
1698 |
* CompletableFuture threw an exception, this method throws an |
1699 |
* (unchecked) {@link CompletionException} with the underlying |
1700 |
* exception as its cause. |
1701 |
* |
1702 |
* @return the result value |
1703 |
* @throws CancellationException if the computation was cancelled |
1704 |
* @throws CompletionException if this future completed |
1705 |
* exceptionally or a completion computation threw an exception |
1706 |
*/ |
1707 |
public T join() { |
1708 |
Object r; |
1709 |
return reportJoin((r = result) == null ? waitingGet(false) : r); |
1710 |
} |
1711 |
|
1712 |
/** |
1713 |
* Returns the result value (or throws any encountered exception) |
1714 |
* if completed, else returns the given valueIfAbsent. |
1715 |
* |
1716 |
* @param valueIfAbsent the value to return if not completed |
1717 |
* @return the result value, if completed, else the given valueIfAbsent |
1718 |
* @throws CancellationException if the computation was cancelled |
1719 |
* @throws CompletionException if this future completed |
1720 |
* exceptionally or a completion computation threw an exception |
1721 |
*/ |
1722 |
public T getNow(T valueIfAbsent) { |
1723 |
Object r; |
1724 |
return ((r = result) == null) ? valueIfAbsent : reportJoin(r); |
1725 |
} |
1726 |
|
1727 |
/** |
1728 |
* If not already completed, sets the value returned by {@link |
1729 |
* #get()} and related methods to the given value. |
1730 |
* |
1731 |
* @param value the result value |
1732 |
* @return {@code true} if this invocation caused this CompletableFuture |
1733 |
* to transition to a completed state, else {@code false} |
1734 |
*/ |
1735 |
public boolean complete(T value) { |
1736 |
boolean triggered = internalComplete(value == null ? NIL : value); |
1737 |
postComplete(); |
1738 |
return triggered; |
1739 |
} |
1740 |
|
1741 |
/** |
1742 |
* If not already completed, causes invocations of {@link #get()} |
1743 |
* and related methods to throw the given exception. |
1744 |
* |
1745 |
* @param ex the exception |
1746 |
* @return {@code true} if this invocation caused this CompletableFuture |
1747 |
* to transition to a completed state, else {@code false} |
1748 |
*/ |
1749 |
public boolean completeExceptionally(Throwable ex) { |
1750 |
if (ex == null) throw new NullPointerException(); |
1751 |
boolean triggered = internalComplete(new AltResult(ex)); |
1752 |
postComplete(); |
1753 |
return triggered; |
1754 |
} |
1755 |
|
1756 |
public <U> CompletableFuture<U> thenApply( |
1757 |
Function<? super T,? extends U> fn) { |
1758 |
return doThenApply(fn, null); |
1759 |
} |
1760 |
|
1761 |
public <U> CompletableFuture<U> thenApplyAsync( |
1762 |
Function<? super T,? extends U> fn) { |
1763 |
return doThenApply(fn, asyncPool); |
1764 |
} |
1765 |
|
1766 |
public <U> CompletableFuture<U> thenApplyAsync( |
1767 |
Function<? super T,? extends U> fn, Executor executor) { |
1768 |
return doThenApply(fn, screenExecutor(executor)); |
1769 |
} |
1770 |
|
1771 |
public CompletableFuture<Void> thenAccept(Consumer<? super T> action) { |
1772 |
return doThenAccept(action, null); |
1773 |
} |
1774 |
|
1775 |
public CompletableFuture<Void> thenAcceptAsync(Consumer<? super T> action) { |
1776 |
return doThenAccept(action, asyncPool); |
1777 |
} |
1778 |
|
1779 |
public CompletableFuture<Void> thenAcceptAsync( |
1780 |
Consumer<? super T> action, Executor executor) { |
1781 |
return doThenAccept(action, screenExecutor(executor)); |
1782 |
} |
1783 |
|
1784 |
public CompletableFuture<Void> thenRun(Runnable action) { |
1785 |
return doThenRun(action, null); |
1786 |
} |
1787 |
|
1788 |
public CompletableFuture<Void> thenRunAsync(Runnable action) { |
1789 |
return doThenRun(action, asyncPool); |
1790 |
} |
1791 |
|
1792 |
public CompletableFuture<Void> thenRunAsync( |
1793 |
Runnable action, Executor executor) { |
1794 |
return doThenRun(action, screenExecutor(executor)); |
1795 |
} |
1796 |
|
1797 |
public <U,V> CompletableFuture<V> thenCombine( |
1798 |
CompletionStage<? extends U> other, |
1799 |
BiFunction<? super T,? super U,? extends V> fn) { |
1800 |
return doThenCombine(other.toCompletableFuture(), fn, null); |
1801 |
} |
1802 |
|
1803 |
public <U,V> CompletableFuture<V> thenCombineAsync( |
1804 |
CompletionStage<? extends U> other, |
1805 |
BiFunction<? super T,? super U,? extends V> fn) { |
1806 |
return doThenCombine(other.toCompletableFuture(), fn, asyncPool); |
1807 |
} |
1808 |
|
1809 |
public <U,V> CompletableFuture<V> thenCombineAsync( |
1810 |
CompletionStage<? extends U> other, |
1811 |
BiFunction<? super T,? super U,? extends V> fn, |
1812 |
Executor executor) { |
1813 |
return doThenCombine(other.toCompletableFuture(), fn, |
1814 |
screenExecutor(executor)); |
1815 |
} |
1816 |
|
1817 |
public <U> CompletableFuture<Void> thenAcceptBoth( |
1818 |
CompletionStage<? extends U> other, |
1819 |
BiConsumer<? super T, ? super U> action) { |
1820 |
return doThenAcceptBoth(other.toCompletableFuture(), action, null); |
1821 |
} |
1822 |
|
1823 |
public <U> CompletableFuture<Void> thenAcceptBothAsync( |
1824 |
CompletionStage<? extends U> other, |
1825 |
BiConsumer<? super T, ? super U> action) { |
1826 |
return doThenAcceptBoth(other.toCompletableFuture(), action, asyncPool); |
1827 |
} |
1828 |
|
1829 |
public <U> CompletableFuture<Void> thenAcceptBothAsync( |
1830 |
CompletionStage<? extends U> other, |
1831 |
BiConsumer<? super T, ? super U> action, |
1832 |
Executor executor) { |
1833 |
return doThenAcceptBoth(other.toCompletableFuture(), action, |
1834 |
screenExecutor(executor)); |
1835 |
} |
1836 |
|
1837 |
public CompletableFuture<Void> runAfterBoth( |
1838 |
CompletionStage<?> other, Runnable action) { |
1839 |
return doRunAfterBoth(other.toCompletableFuture(), action, null); |
1840 |
} |
1841 |
|
1842 |
public CompletableFuture<Void> runAfterBothAsync( |
1843 |
CompletionStage<?> other, Runnable action) { |
1844 |
return doRunAfterBoth(other.toCompletableFuture(), action, asyncPool); |
1845 |
} |
1846 |
|
1847 |
public CompletableFuture<Void> runAfterBothAsync( |
1848 |
CompletionStage<?> other, Runnable action, Executor executor) { |
1849 |
return doRunAfterBoth(other.toCompletableFuture(), action, |
1850 |
screenExecutor(executor)); |
1851 |
} |
1852 |
|
1853 |
public <U> CompletableFuture<U> applyToEither( |
1854 |
CompletionStage<? extends T> other, Function<? super T, U> fn) { |
1855 |
return doApplyToEither(other.toCompletableFuture(), fn, null); |
1856 |
} |
1857 |
|
1858 |
public <U> CompletableFuture<U> applyToEitherAsync( |
1859 |
CompletionStage<? extends T> other, Function<? super T, U> fn) { |
1860 |
return doApplyToEither(other.toCompletableFuture(), fn, asyncPool); |
1861 |
} |
1862 |
|
1863 |
public <U> CompletableFuture<U> applyToEitherAsync |
1864 |
(CompletionStage<? extends T> other, Function<? super T, U> fn, |
1865 |
Executor executor) { |
1866 |
return doApplyToEither(other.toCompletableFuture(), fn, |
1867 |
screenExecutor(executor)); |
1868 |
} |
1869 |
|
1870 |
public CompletableFuture<Void> acceptEither( |
1871 |
CompletionStage<? extends T> other, Consumer<? super T> action) { |
1872 |
return doAcceptEither(other.toCompletableFuture(), action, null); |
1873 |
} |
1874 |
|
1875 |
public CompletableFuture<Void> acceptEitherAsync |
1876 |
(CompletionStage<? extends T> other, Consumer<? super T> action) { |
1877 |
return doAcceptEither(other.toCompletableFuture(), action, asyncPool); |
1878 |
} |
1879 |
|
1880 |
public CompletableFuture<Void> acceptEitherAsync( |
1881 |
CompletionStage<? extends T> other, Consumer<? super T> action, |
1882 |
Executor executor) { |
1883 |
return doAcceptEither(other.toCompletableFuture(), action, |
1884 |
screenExecutor(executor)); |
1885 |
} |
1886 |
|
1887 |
public CompletableFuture<Void> runAfterEither( |
1888 |
CompletionStage<?> other, Runnable action) { |
1889 |
return doRunAfterEither(other.toCompletableFuture(), action, null); |
1890 |
} |
1891 |
|
1892 |
public CompletableFuture<Void> runAfterEitherAsync( |
1893 |
CompletionStage<?> other, Runnable action) { |
1894 |
return doRunAfterEither(other.toCompletableFuture(), action, asyncPool); |
1895 |
} |
1896 |
|
1897 |
public CompletableFuture<Void> runAfterEitherAsync( |
1898 |
CompletionStage<?> other, Runnable action, Executor executor) { |
1899 |
return doRunAfterEither(other.toCompletableFuture(), action, |
1900 |
screenExecutor(executor)); |
1901 |
} |
1902 |
|
1903 |
public <U> CompletableFuture<U> thenCompose |
1904 |
(Function<? super T, ? extends CompletionStage<U>> fn) { |
1905 |
return doThenCompose(fn, null); |
1906 |
} |
1907 |
|
1908 |
public <U> CompletableFuture<U> thenComposeAsync( |
1909 |
Function<? super T, ? extends CompletionStage<U>> fn) { |
1910 |
return doThenCompose(fn, asyncPool); |
1911 |
} |
1912 |
|
1913 |
public <U> CompletableFuture<U> thenComposeAsync( |
1914 |
Function<? super T, ? extends CompletionStage<U>> fn, |
1915 |
Executor executor) { |
1916 |
return doThenCompose(fn, screenExecutor(executor)); |
1917 |
} |
1918 |
|
1919 |
public CompletableFuture<T> whenComplete( |
1920 |
BiConsumer<? super T, ? super Throwable> action) { |
1921 |
return doWhenComplete(action, null); |
1922 |
} |
1923 |
|
1924 |
public CompletableFuture<T> whenCompleteAsync( |
1925 |
BiConsumer<? super T, ? super Throwable> action) { |
1926 |
return doWhenComplete(action, asyncPool); |
1927 |
} |
1928 |
|
1929 |
public CompletableFuture<T> whenCompleteAsync( |
1930 |
BiConsumer<? super T, ? super Throwable> action, Executor executor) { |
1931 |
return doWhenComplete(action, screenExecutor(executor)); |
1932 |
} |
1933 |
|
1934 |
public <U> CompletableFuture<U> handle( |
1935 |
BiFunction<? super T, Throwable, ? extends U> fn) { |
1936 |
return doHandle(fn, null); |
1937 |
} |
1938 |
|
1939 |
public <U> CompletableFuture<U> handleAsync( |
1940 |
BiFunction<? super T, Throwable, ? extends U> fn) { |
1941 |
return doHandle(fn, asyncPool); |
1942 |
} |
1943 |
|
1944 |
public <U> CompletableFuture<U> handleAsync( |
1945 |
BiFunction<? super T, Throwable, ? extends U> fn, Executor executor) { |
1946 |
return doHandle(fn, screenExecutor(executor)); |
1947 |
} |
1948 |
|
1949 |
/** |
1950 |
* Returns this CompletableFuture. |
1951 |
* |
1952 |
* @return this CompletableFuture |
1953 |
*/ |
1954 |
public CompletableFuture<T> toCompletableFuture() { |
1955 |
return this; |
1956 |
} |
1957 |
|
1958 |
// not in interface CompletionStage |
1959 |
|
1960 |
/** |
1961 |
* Returns a new CompletableFuture that is completed when this |
1962 |
* CompletableFuture completes, with the result of the given |
1963 |
* function of the exception triggering this CompletableFuture's |
1964 |
* completion when it completes exceptionally; otherwise, if this |
1965 |
* CompletableFuture completes normally, then the returned |
1966 |
* CompletableFuture also completes normally with the same value. |
1967 |
* Note: More flexible versions of this functionality are |
1968 |
* available using methods {@code whenComplete} and {@code handle}. |
1969 |
* |
1970 |
* @param fn the function to use to compute the value of the |
1971 |
* returned CompletableFuture if this CompletableFuture completed |
1972 |
* exceptionally |
1973 |
* @return the new CompletableFuture |
1974 |
*/ |
1975 |
public CompletableFuture<T> exceptionally( |
1976 |
Function<Throwable, ? extends T> fn) { |
1977 |
return doExceptionally(fn); |
1978 |
} |
1979 |
|
1980 |
/* ------------- Arbitrary-arity constructions -------------- */ |
1981 |
|
1982 |
/** |
1983 |
* Returns a new CompletableFuture that is completed when all of |
1984 |
* the given CompletableFutures complete. If any of the given |
1985 |
* CompletableFutures complete exceptionally, then the returned |
1986 |
* CompletableFuture also does so, with a CompletionException |
1987 |
* holding this exception as its cause. Otherwise, the results, |
1988 |
* if any, of the given CompletableFutures are not reflected in |
1989 |
* the returned CompletableFuture, but may be obtained by |
1990 |
* inspecting them individually. If no CompletableFutures are |
1991 |
* provided, returns a CompletableFuture completed with the value |
1992 |
* {@code null}. |
1993 |
* |
1994 |
* <p>Among the applications of this method is to await completion |
1995 |
* of a set of independent CompletableFutures before continuing a |
1996 |
* program, as in: {@code CompletableFuture.allOf(c1, c2, |
1997 |
* c3).join();}. |
1998 |
* |
1999 |
* @param cfs the CompletableFutures |
2000 |
* @return a new CompletableFuture that is completed when all of the |
2001 |
* given CompletableFutures complete |
2002 |
* @throws NullPointerException if the array or any of its elements are |
2003 |
* {@code null} |
2004 |
*/ |
2005 |
public static CompletableFuture<Void> allOf(CompletableFuture<?>... cfs) { |
2006 |
return doAllOf(cfs, 0, cfs.length - 1); |
2007 |
} |
2008 |
|
2009 |
/** |
2010 |
* Returns a new CompletableFuture that is completed when any of |
2011 |
* the given CompletableFutures complete, with the same result. |
2012 |
* Otherwise, if it completed exceptionally, the returned |
2013 |
* CompletableFuture also does so, with a CompletionException |
2014 |
* holding this exception as its cause. If no CompletableFutures |
2015 |
* are provided, returns an incomplete CompletableFuture. |
2016 |
* |
2017 |
* @param cfs the CompletableFutures |
2018 |
* @return a new CompletableFuture that is completed with the |
2019 |
* result or exception of any of the given CompletableFutures when |
2020 |
* one completes |
2021 |
* @throws NullPointerException if the array or any of its elements are |
2022 |
* {@code null} |
2023 |
*/ |
2024 |
public static CompletableFuture<Object> anyOf(CompletableFuture<?>... cfs) { |
2025 |
CompletableFuture<Object> d = new CompletableFuture<Object>(); |
2026 |
for (int i = 0; i < cfs.length; ++i) { |
2027 |
CompletableFuture<?> c = cfs[i]; |
2028 |
Object r = c.result; // throw NPE if null element |
2029 |
if (d.result == null) { |
2030 |
if (r == null) |
2031 |
c.unipush(new DelayedCopy<Object>(d, c)); |
2032 |
else |
2033 |
nowCopy(d, r); |
2034 |
} |
2035 |
} |
2036 |
return d; |
2037 |
} |
2038 |
|
2039 |
/* ------------- Control and status methods -------------- */ |
2040 |
|
2041 |
/** |
2042 |
* If not already completed, completes this CompletableFuture with |
2043 |
* a {@link CancellationException}. Dependent CompletableFutures |
2044 |
* that have not already completed will also complete |
2045 |
* exceptionally, with a {@link CompletionException} caused by |
2046 |
* this {@code CancellationException}. |
2047 |
* |
2048 |
* @param mayInterruptIfRunning this value has no effect in this |
2049 |
* implementation because interrupts are not used to control |
2050 |
* processing. |
2051 |
* |
2052 |
* @return {@code true} if this task is now cancelled |
2053 |
*/ |
2054 |
public boolean cancel(boolean mayInterruptIfRunning) { |
2055 |
boolean cancelled = (result == null) && |
2056 |
internalComplete(new AltResult(new CancellationException())); |
2057 |
postComplete(); |
2058 |
return cancelled || isCancelled(); |
2059 |
} |
2060 |
|
2061 |
/** |
2062 |
* Returns {@code true} if this CompletableFuture was cancelled |
2063 |
* before it completed normally. |
2064 |
* |
2065 |
* @return {@code true} if this CompletableFuture was cancelled |
2066 |
* before it completed normally |
2067 |
*/ |
2068 |
public boolean isCancelled() { |
2069 |
Object r; |
2070 |
return ((r = result) instanceof AltResult) && |
2071 |
(((AltResult)r).ex instanceof CancellationException); |
2072 |
} |
2073 |
|
2074 |
/** |
2075 |
* Returns {@code true} if this CompletableFuture completed |
2076 |
* exceptionally, in any way. Possible causes include |
2077 |
* cancellation, explicit invocation of {@code |
2078 |
* completeExceptionally}, and abrupt termination of a |
2079 |
* CompletionStage action. |
2080 |
* |
2081 |
* @return {@code true} if this CompletableFuture completed |
2082 |
* exceptionally |
2083 |
*/ |
2084 |
public boolean isCompletedExceptionally() { |
2085 |
Object r; |
2086 |
return ((r = result) instanceof AltResult) && r != NIL; |
2087 |
} |
2088 |
|
2089 |
/** |
2090 |
* Forcibly sets or resets the value subsequently returned by |
2091 |
* method {@link #get()} and related methods, whether or not |
2092 |
* already completed. This method is designed for use only in |
2093 |
* error recovery actions, and even in such situations may result |
2094 |
* in ongoing dependent completions using established versus |
2095 |
* overwritten outcomes. |
2096 |
* |
2097 |
* @param value the completion value |
2098 |
*/ |
2099 |
public void obtrudeValue(T value) { |
2100 |
result = (value == null) ? NIL : value; |
2101 |
postComplete(); |
2102 |
} |
2103 |
|
2104 |
/** |
2105 |
* Forcibly causes subsequent invocations of method {@link #get()} |
2106 |
* and related methods to throw the given exception, whether or |
2107 |
* not already completed. This method is designed for use only in |
2108 |
* recovery actions, and even in such situations may result in |
2109 |
* ongoing dependent completions using established versus |
2110 |
* overwritten outcomes. |
2111 |
* |
2112 |
* @param ex the exception |
2113 |
*/ |
2114 |
public void obtrudeException(Throwable ex) { |
2115 |
if (ex == null) throw new NullPointerException(); |
2116 |
result = new AltResult(ex); |
2117 |
postComplete(); |
2118 |
} |
2119 |
|
2120 |
/** |
2121 |
* Returns the estimated number of CompletableFutures whose |
2122 |
* completions are awaiting completion of this CompletableFuture. |
2123 |
* This method is designed for use in monitoring system state, not |
2124 |
* for synchronization control. |
2125 |
* |
2126 |
* @return the number of dependent CompletableFutures |
2127 |
*/ |
2128 |
public int getNumberOfDependents() { |
2129 |
int count = 0; |
2130 |
for (Completion p = completions; p != null; p = p.next) |
2131 |
++count; |
2132 |
return count; |
2133 |
} |
2134 |
|
2135 |
/** |
2136 |
* Returns a string identifying this CompletableFuture, as well as |
2137 |
* its completion state. The state, in brackets, contains the |
2138 |
* String {@code "Completed Normally"} or the String {@code |
2139 |
* "Completed Exceptionally"}, or the String {@code "Not |
2140 |
* completed"} followed by the number of CompletableFutures |
2141 |
* dependent upon its completion, if any. |
2142 |
* |
2143 |
* @return a string identifying this CompletableFuture, as well as its state |
2144 |
*/ |
2145 |
public String toString() { |
2146 |
Object r = result; |
2147 |
int count; |
2148 |
return super.toString() + |
2149 |
((r == null) ? |
2150 |
(((count = getNumberOfDependents()) == 0) ? |
2151 |
"[Not completed]" : |
2152 |
"[Not completed, " + count + " dependents]") : |
2153 |
(((r instanceof AltResult) && ((AltResult)r).ex != null) ? |
2154 |
"[Completed exceptionally]" : |
2155 |
"[Completed normally]")); |
2156 |
} |
2157 |
|
2158 |
// Unsafe mechanics |
2159 |
private static final sun.misc.Unsafe UNSAFE; |
2160 |
private static final long RESULT; |
2161 |
private static final long COMPLETIONS; |
2162 |
static { |
2163 |
try { |
2164 |
UNSAFE = sun.misc.Unsafe.getUnsafe(); |
2165 |
Class<?> k = CompletableFuture.class; |
2166 |
RESULT = UNSAFE.objectFieldOffset |
2167 |
(k.getDeclaredField("result")); |
2168 |
COMPLETIONS = UNSAFE.objectFieldOffset |
2169 |
(k.getDeclaredField("completions")); |
2170 |
} catch (Exception x) { |
2171 |
throw new Error(x); |
2172 |
} |
2173 |
} |
2174 |
} |