/*
* Written by Doug Lea with assistance from members of JCP JSR-166
* Expert Group and released to the public domain, as explained at
* http://creativecommons.org/publicdomain/zero/1.0/
*/
package java.util.concurrent;
import java.util.function.Supplier;
import java.util.function.Block;
import java.util.function.BiBlock;
import java.util.function.Function;
import java.util.function.BiFunction;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.ForkJoinPool;
import java.util.concurrent.ForkJoinTask;
import java.util.concurrent.Executor;
import java.util.concurrent.ThreadLocalRandom;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.TimeoutException;
import java.util.concurrent.CancellationException;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.locks.LockSupport;
/**
* A {@link Future} that may be explicitly completed (setting its
* value and status), and may include dependent functions and actions
* that trigger upon its completion.
*
*
Similar methods are available for Functions, Blocks, and
* Runnables, depending on whether actions require arguments and/or
* produce results. Functions and actions supplied for dependent
* completions (mainly using methods with prefix {@code then}) may be
* performed by the thread that completes the current
* CompletableFuture, or by any other caller of these methods. There
* are no guarantees about the order of processing completions unless
* constrained by method {@code then} and related methods.
*
*
When two or more threads attempt to {@link #complete} or {@link
* #completeExceptionally} a CompletableFuture, only one of them will
* succeed. Upon exceptional completion, or when a completion entails
* computation of a function or action, and it terminates abruptly
* with an exception, then further completions act as {@code
* completeExceptionally} with that exception.
*
*
CompletableFutures themselves do not execute asynchronously.
* However, the {@code async} methods provide commonly useful ways to
* commence asynchronous processing, using either a given {@link
* Executor} or by default the {@link ForkJoinPool#commonPool()}, of a
* function or action that will result in the completion of a new
* CompletableFuture.
*
* @author Doug Lea
* @since 1.8
*/
public class CompletableFuture implements Future {
/*
* Quick overview (more to come):
*
* 1. Non-nullness of field result indicates done. An AltResult is
* used to box null as a result, as well as to hold exceptions.
*
* 2. Waiters are held in a Treiber stack similar to the one used
* in FutureTask.
*
* 3. Completions are also kept in a list/stack, and pulled off
* and run when completion is triggered.
*/
static final class AltResult {
final Throwable ex; // null only for NIL
AltResult(Throwable ex) { this.ex = ex; }
}
static final AltResult NIL = new AltResult(null);
/**
* Simple linked list nodes to record waiting threads in a Treiber
* stack. See other classes such as Phaser and SynchronousQueue
* for more detailed explanation.
*/
static final class WaitNode {
volatile Thread thread;
volatile WaitNode next;
}
/**
* Simple linked list nodes to record completions, used in
* basically the same way as WaitNodes
*/
static final class CompletionNode {
final Completion completion;
volatile CompletionNode next;
CompletionNode(Completion completion) { this.completion = completion; }
}
volatile Object result; // either the result or boxed AltResult
volatile WaitNode waiters; // Treiber stack of threads blocked on get()
volatile CompletionNode completions; // list (Treiber stack) of completions
/**
* Creates a new incomplete CompletableFuture.
*/
public CompletableFuture() {
}
/**
* Asynchronously executes in the {@link
* ForkJoinPool#commonPool()}, a task that completes the returned
* CompletableFuture with the result of the given Supplier.
*
* @param supplier a function returning the value to be used
* to complete the returned CompletableFuture.
* @return the CompletableFuture
*/
public static CompletableFuture supplyAsync(Supplier supplier) {
if (supplier == null) throw new NullPointerException();
CompletableFuture f = new CompletableFuture();
ForkJoinPool.commonPool().
execute((ForkJoinTask>)new AsyncSupplier(supplier, f));
return f;
}
/**
* Asynchronously executes using the given executor, a task that
* completes the returned CompletableFuture with the result of the
* given Supplier.
*
* @param supplier a function returning the value to be used
* to complete the returned CompletableFuture
* @param executor the executor to use for asynchronous execution
* @return the CompletableFuture
*/
public static CompletableFuture supplyAsync(Supplier supplier,
Executor executor) {
if (executor == null || supplier == null)
throw new NullPointerException();
CompletableFuture f = new CompletableFuture();
executor.execute(new AsyncSupplier(supplier, f));
return f;
}
/**
* Asynchronously executes in the {@link
* ForkJoinPool#commonPool()} a task that runs the given action,
* and then completes the returned CompletableFuture.
*
* @param runnable the action to run before completing the
* returned CompletableFuture
* @return the CompletableFuture
*/
public static CompletableFuture runAsync(Runnable runnable) {
if (runnable == null) throw new NullPointerException();
CompletableFuture f = new CompletableFuture();
ForkJoinPool.commonPool().
execute((ForkJoinTask>)new AsyncRunnable(runnable, f));
return f;
}
/**
* Asynchronously executes using the given executor, a task that
* runs the given action, and then completes the returned
* CompletableFuture.
*
* @param runnable the action to run before completing the
* returned CompletableFuture
* @param executor the executor to use for asynchronous execution
* @return the CompletableFuture
*/
public static CompletableFuture runAsync(Runnable runnable,
Executor executor) {
if (executor == null || runnable == null)
throw new NullPointerException();
CompletableFuture f = new CompletableFuture();
executor.execute(new AsyncRunnable(runnable, f));
return f;
}
/**
* Returns {@code true} if completed in any fashion: normally,
* exceptionally, or cancellation.
*
* @return {@code true} if completed
*/
public boolean isDone() {
return result != null;
}
/**
* Returns the result value when complete, or throws an
* (unchecked) exception if completed exceptionally. To better
* conform with the use of common functional forms, this method
* transforms any checked exception possible with {@link
* Future#get} into an (unchecked) {@link RuntimeException} with
* the underlying exception as its cause. (The checked exception
* convention is available using the timed form of get.)
*
* @return the result value
*/
public T get() {
Object r; Throwable ex;
if ((r = result) == null)
return waitingGet();
if (r instanceof AltResult) {
if ((ex = ((AltResult)r).ex) != null) {
if (ex instanceof Error)
throw (Error)ex;
if (ex instanceof RuntimeException)
throw (RuntimeException)ex;
throw new RuntimeException(ex);
}
return null;
}
return (T)r;
}
/**
* Returns the result value (or throws any encountered exception)
* if completed, else returns the given valueIfAbsent.
*
* @param valueIfAbsent the value to return if not completed
* @return the result value, if completed, else the given valueIfAbsent
*/
public T getNow(T valueIfAbsent) {
Object r; Throwable ex;
if ((r = result) == null)
return valueIfAbsent;
if (r instanceof AltResult) {
if ((ex = ((AltResult)r).ex) != null) {
if (ex instanceof Error)
throw (Error)ex;
if (ex instanceof RuntimeException)
throw (RuntimeException)ex;
throw new RuntimeException(ex);
}
return null;
}
return (T)r;
}
/**
* Waits if necessary for at most the given time for completion,
* and then retrieves its result, if available.
*
* @param timeout the maximum time to wait
* @param unit the time unit of the timeout argument
* @return the computed result
* @throws CancellationException if the computation was cancelled
* @throws ExecutionException if the computation threw an
* exception
* @throws InterruptedException if the current thread was interrupted
* while waiting
* @throws TimeoutException if the wait timed out
*/
public T get(long timeout, TimeUnit unit)
throws InterruptedException, ExecutionException, TimeoutException {
Object r; Throwable ex;
long nanos = unit.toNanos(timeout);
if (Thread.interrupted())
throw new InterruptedException();
if ((r = result) == null)
r = timedAwaitDone(nanos);
if (r instanceof AltResult) {
if ((ex = ((AltResult)r).ex) != null) {
if (ex instanceof ExecutionException) // avoid re-wrap
throw (ExecutionException)ex;
throw new ExecutionException(ex);
}
return null;
}
return (T)r;
}
/**
* If not already completed, sets the value returned by {@link
* #get()} and related methods to the given value.
*
* @param value the result value
* @return true if this invocation caused this CompletableFuture
* to transition to a completed state, else false.
*/
public boolean complete(T value) {
if (result == null &&
UNSAFE.compareAndSwapObject(this, RESULT, null,
(value == null) ? NIL : value)) {
postComplete();
return true;
}
return false;
}
/**
* If not already completed, causes invocations of {@link #get()}
* and related methods to throw the given exception.
*
* @param ex the exception
* @return true if this invocation caused this CompletableFuture
* to transition to a completed state, else false.
*/
public boolean completeExceptionally(Throwable ex) {
if (ex == null) throw new NullPointerException();
if (result == null) {
Object r = new AltResult(ex);
if (UNSAFE.compareAndSwapObject(this, RESULT, null, r)) {
postComplete();
return true;
}
}
return false;
}
/**
* Creates and returns a CompletableFuture that is completed with
* the result of the given function of this CompletableFuture.
* If this CompletableFuture completes exceptionally,
* then the returned CompletableFuture also does so,
* with a RuntimeException having this exception as
* its cause.
*
* @param fn the function to use to compute the value of
* the returned CompletableFuture
* @return the new CompletableFuture
*/
public CompletableFuture thenApply(Function super T,? extends U> fn) {
return thenFunction(fn, null);
}
/**
* Creates and returns a CompletableFuture that is asynchronously
* completed using the {@link ForkJoinPool#commonPool()} with the
* result of the given function of this CompletableFuture. If
* this CompletableFuture completes exceptionally, then the
* returned CompletableFuture also does so, with a
* RuntimeException having this exception as its cause.
*
* @param fn the function to use to compute the value of
* the returned CompletableFuture
* @return the new CompletableFuture
*/
public CompletableFuture thenApplyAsync(Function super T,? extends U> fn) {
return thenFunction(fn, ForkJoinPool.commonPool());
}
/**
* Creates and returns a CompletableFuture that is asynchronously
* completed using the given executor with the result of the given
* function of this CompletableFuture. If this CompletableFuture
* completes exceptionally, then the returned CompletableFuture
* also does so, with a RuntimeException having this exception as
* its cause.
*
* @param fn the function to use to compute the value of
* the returned CompletableFuture
* @param executor the executor to use for asynchronous execution
* @return the new CompletableFuture
*/
public CompletableFuture thenApplyAsync(Function super T,? extends U> fn,
Executor executor) {
if (executor == null) throw new NullPointerException();
return thenFunction(fn, executor);
}
/**
* Creates and returns a CompletableFuture that is completed after
* performing the given action with this CompletableFuture's
* result when it completes. If this CompletableFuture
* completes exceptionally, then the returned CompletableFuture
* also does so, with a RuntimeException having this exception as
* its cause.
*
* @param block the action to perform before completing the
* returned CompletableFuture
* @return the new CompletableFuture
*/
public CompletableFuture thenAccept(Block super T> block) {
return thenBlock(block, null);
}
/**
* Creates and returns a CompletableFuture that is asynchronously
* completed using the {@link ForkJoinPool#commonPool()} with this
* CompletableFuture's result when it completes. If this
* CompletableFuture completes exceptionally, then the returned
* CompletableFuture also does so, with a RuntimeException having
* this exception as its cause.
*
* @param block the action to perform before completing the
* returned CompletableFuture
* @return the new CompletableFuture
*/
public CompletableFuture thenAcceptAsync(Block super T> block) {
return thenBlock(block, ForkJoinPool.commonPool());
}
/**
* Creates and returns a CompletableFuture that is asynchronously
* completed using the given executor with this
* CompletableFuture's result when it completes. If this
* CompletableFuture completes exceptionally, then the returned
* CompletableFuture also does so, with a RuntimeException having
* this exception as its cause.
*
* @param block the action to perform before completing the
* returned CompletableFuture
* @param executor the executor to use for asynchronous execution
* @return the new CompletableFuture
*/
public CompletableFuture thenAcceptAsync(Block super T> block,
Executor executor) {
if (executor == null) throw new NullPointerException();
return thenBlock(block, executor);
}
/**
* Creates and returns a CompletableFuture that is completed after
* performing the given action when this CompletableFuture
* completes. If this CompletableFuture completes exceptionally,
* then the returned CompletableFuture also does so, with a
* RuntimeException having this exception as its cause.
*
* @param action the action to perform before completing the
* returned CompletableFuture
* @return the new CompletableFuture
*/
public CompletableFuture thenRun(Runnable action) {
return thenRunnable(action, null);
}
/**
* Creates and returns a CompletableFuture that is asynchronously
* completed using the {@link ForkJoinPool#commonPool()} after
* performing the given action when this CompletableFuture
* completes. If this CompletableFuture completes exceptionally,
* then the returned CompletableFuture also does so, with a
* RuntimeException having this exception as its cause.
*
* @param action the action to perform before completing the
* returned CompletableFuture
* @return the new CompletableFuture
*/
public CompletableFuture thenRunAsync(Runnable action) {
return thenRunnable(action, ForkJoinPool.commonPool());
}
/**
* Creates and returns a CompletableFuture that is asynchronously
* completed using the given executor after performing the given
* action when this CompletableFuture completes. If this
* CompletableFuture completes exceptionally, then the returned
* CompletableFuture also does so, with a RuntimeException having
* this exception as its cause.
*
* @param action the action to perform before completing the
* returned CompletableFuture
* @param executor the executor to use for asynchronous execution
* @return the new CompletableFuture
*/
public CompletableFuture thenRunAsync(Runnable action, Executor executor) {
if (executor == null) throw new NullPointerException();
return thenRunnable(action, executor);
}
/**
* Creates and returns a CompletableFuture that is completed with
* the result of the given function of this and the other given
* CompletableFuture's results when both complete. If this or
* the other CompletableFuture complete exceptionally, then the
* returned CompletableFuture also does so, with a
* RuntimeException having the exception as its cause.
*
* @param other the other CompletableFuture
* @param fn the function to use to compute the value of
* the returned CompletableFuture
* @return the new CompletableFuture
*/
public CompletableFuture thenApply(CompletableFuture extends U> other,
BiFunction super T,? super U,? extends V> fn) {
return andFunction(other, fn, null);
}
/**
* Creates and returns a CompletableFuture that is asynchronously
* completed using the {@link ForkJoinPool#commonPool()} with
* the result of the given function of this and the other given
* CompletableFuture's results when both complete. If this or
* the other CompletableFuture complete exceptionally, then the
* returned CompletableFuture also does so, with a
* RuntimeException having the exception as its cause.
*
* @param other the other CompletableFuture
* @param fn the function to use to compute the value of
* the returned CompletableFuture
* @return the new CompletableFuture
*/
public CompletableFuture thenApplyAsync(CompletableFuture extends U> other,
BiFunction super T,? super U,? extends V> fn) {
return andFunction(other, fn, ForkJoinPool.commonPool());
}
/**
* Creates and returns a CompletableFuture that is
* asynchronously completed using the given executor with the
* result of the given function of this and the other given
* CompletableFuture's results when both complete. If this or
* the other CompletableFuture complete exceptionally, then the
* returned CompletableFuture also does so, with a
* RuntimeException having the exception as its cause.
*
* @param other the other CompletableFuture
* @param fn the function to use to compute the value of
* the returned CompletableFuture
* @param executor the executor to use for asynchronous execution
* @return the new CompletableFuture
*/
public CompletableFuture thenApplyAsync(CompletableFuture extends U> other,
BiFunction super T,? super U,? extends V> fn,
Executor executor) {
if (executor == null) throw new NullPointerException();
return andFunction(other, fn, executor);
}
/**
* Creates and returns a CompletableFuture that is completed with
* the results of this and the other given CompletableFuture if
* both complete. If this and/or the other CompletableFuture
* complete exceptionally, then the returned CompletableFuture
* also does so, with a RuntimeException having the one of the
* exceptions as its cause.
*
* @param other the other CompletableFuture
* @param block the action to perform before completing the
* returned CompletableFuture
* @return the new CompletableFuture
*/
public CompletableFuture thenAccept(CompletableFuture extends U> other,
BiBlock super T, ? super U> block) {
return andBlock(other, block, null);
}
/**
* Creates and returns a CompletableFuture that is completed
* asynchronously using the {@link ForkJoinPool#commonPool()} with
* the results of this and the other given CompletableFuture when
* both complete. If this and/or the other CompletableFuture
* complete exceptionally, then the returned CompletableFuture
* also does so, with a RuntimeException having the one of the
* exceptions as its cause.
*
* @param other the other CompletableFuture
* @param block the action to perform before completing the
* returned CompletableFuture
* @return the new CompletableFuture
*/
public CompletableFuture thenAcceptAsync(CompletableFuture extends U> other,
BiBlock super T, ? super U> block) {
return andBlock(other, block, ForkJoinPool.commonPool());
}
/**
* Creates and returns a CompletableFuture that is completed
* asynchronously using the given executor with the results of
* this and the other given CompletableFuture when both complete.
* If this and/or the other CompletableFuture complete
* exceptionally, then the returned CompletableFuture also does
* so, with a RuntimeException having the one of the exceptions as
* its cause.
*
* @param other the other CompletableFuture
* @param block the action to perform before completing the
* returned CompletableFuture
* @param executor the executor to use for asynchronous execution
* @return the new CompletableFuture
*/
public CompletableFuture thenAcceptAsync(CompletableFuture extends U> other,
BiBlock super T, ? super U> block,
Executor executor) {
if (executor == null) throw new NullPointerException();
return andBlock(other, block, executor);
}
/**
* Creates and returns a CompletableFuture that is completed
* when this and the other given CompletableFuture both
* complete. If this and/or the other CompletableFuture complete
* exceptionally, then the returned CompletableFuture also does
* so, with a RuntimeException having the one of the exceptions as
* its cause.
*
* @param other the other CompletableFuture
* @param action the action to perform before completing the
* returned CompletableFuture
* @return the new CompletableFuture
*/
public CompletableFuture thenRun(CompletableFuture> other,
Runnable action) {
return andRunnable(other, action, null);
}
/**
* Creates and returns a CompletableFuture that is completed
* asynchronously using the {@link ForkJoinPool#commonPool()}
* when this and the other given CompletableFuture both
* complete. If this and/or the other CompletableFuture complete
* exceptionally, then the returned CompletableFuture also does
* so, with a RuntimeException having the one of the exceptions as
* its cause.
*
* @param other the other CompletableFuture
* @param action the action to perform before completing the
* returned CompletableFuture
* @return the new CompletableFuture
*/
public CompletableFuture thenRunAsync(CompletableFuture> other,
Runnable action) {
return andRunnable(other, action, ForkJoinPool.commonPool());
}
/**
* Creates and returns a CompletableFuture that is completed
* asynchronously using the given executor
* when this and the other given CompletableFuture both
* complete. If this and/or the other CompletableFuture complete
* exceptionally, then the returned CompletableFuture also does
* so, with a RuntimeException having the one of the exceptions as
* its cause.
*
* @param other the other CompletableFuture
* @param action the action to perform before completing the
* returned CompletableFuture
* @param executor the executor to use for asynchronous execution
* @return the new CompletableFuture
*/
public CompletableFuture thenRunAsync(CompletableFuture> other,
Runnable action,
Executor executor) {
if (executor == null) throw new NullPointerException();
return andRunnable(other, action, executor);
}
/**
* Creates and returns a CompletableFuture that is completed with
* the result of the given function of either this or the other
* given CompletableFuture's results when either complete. If
* this and/or the other CompletableFuture complete exceptionally,
* then the returned CompletableFuture may also do so, with a
* RuntimeException having one of these exceptions as its cause.
* No guarantees are made about which result or exception is used
* in the returned CompletableFuture.
*
* @param other the other CompletableFuture
* @param fn the function to use to compute the value of
* the returned CompletableFuture
* @return the new CompletableFuture
*/
public CompletableFuture orApply(CompletableFuture extends T> other,
Function super T, U> fn) {
return orFunction(other, fn, null);
}
/**
* Creates and returns a CompletableFuture that is completed
* asynchronously using the {@link ForkJoinPool#commonPool()} with
* the result of the given function of either this or the other
* given CompletableFuture's results when either complete. If
* this and/or the other CompletableFuture complete exceptionally,
* then the returned CompletableFuture may also do so, with a
* RuntimeException having one of these exceptions as its cause.
* No guarantees are made about which result or exception is used
* in the returned CompletableFuture.
*
* @param other the other CompletableFuture
* @param fn the function to use to compute the value of
* the returned CompletableFuture
* @return the new CompletableFuture
*/
public CompletableFuture orApplyAsync(CompletableFuture extends T> other,
Function super T, U> fn) {
return orFunction(other, fn, ForkJoinPool.commonPool());
}
/**
* Creates and returns a CompletableFuture that is completed
* asynchronously using the given executor with the result of the
* given function of either this or the other given
* CompletableFuture's results when either complete. If this
* and/or the other CompletableFuture complete exceptionally, then
* the returned CompletableFuture may also do so, with a
* RuntimeException having one of these exceptions as its cause.
* No guarantees are made about which result or exception is used
* in the returned CompletableFuture.
*
* @param other the other CompletableFuture
* @param fn the function to use to compute the value of
* the returned CompletableFuture
* @param executor the executor to use for asynchronous execution
* @return the new CompletableFuture
*/
public CompletableFuture orApplyAsync(CompletableFuture extends T> other,
Function super T, U> fn,
Executor executor) {
if (executor == null) throw new NullPointerException();
return orFunction(other, fn, executor);
}
/**
* Creates and returns a CompletableFuture that is completed after
* performing the given action with the result of either this or the
* other given CompletableFuture's result, when either complete.
* If this and/or the other CompletableFuture complete
* exceptionally, then the returned CompletableFuture may also do
* so, with a RuntimeException having one of these exceptions as
* its cause. No guarantees are made about which exception is
* used in the returned CompletableFuture.
*
* @param other the other CompletableFuture
* @param block the action to perform before completing the
* returned CompletableFuture
* @return the new CompletableFuture
*/
public CompletableFuture orAccept(CompletableFuture extends T> other,
Block super T> block) {
return orBlock(other, block, null);
}
/**
* Creates and returns a CompletableFuture that is completed
* asynchronously using the {@link ForkJoinPool#commonPool()},
* performing the given action with the result of either this or
* the other given CompletableFuture's result, when either
* complete. If this and/or the other CompletableFuture complete
* exceptionally, then the returned CompletableFuture may also do
* so, with a RuntimeException having one of these exceptions as
* its cause. No guarantees are made about which exception is
* used in the returned CompletableFuture.
*
* @param other the other CompletableFuture
* @param block the action to perform before completing the
* returned CompletableFuture
* @return the new CompletableFuture
*/
public CompletableFuture orAcceptAsync(CompletableFuture extends T> other,
Block super T> block) {
return orBlock(other, block, ForkJoinPool.commonPool());
}
/**
* Creates and returns a CompletableFuture that is completed
* asynchronously using the given executor,
* performing the given action with the result of either this or
* the other given CompletableFuture's result, when either
* complete. If this and/or the other CompletableFuture complete
* exceptionally, then the returned CompletableFuture may also do
* so, with a RuntimeException having one of these exceptions as
* its cause. No guarantees are made about which exception is
* used in the returned CompletableFuture.
*
* @param other the other CompletableFuture
* @param block the action to perform before completing the
* returned CompletableFuture
* @param executor the executor to use for asynchronous execution
* @return the new CompletableFuture
*/
public CompletableFuture orRunAsync(CompletableFuture extends T> other,
Block super T> block,
Executor executor) {
if (executor == null) throw new NullPointerException();
return orBlock(other, block, executor);
}
/**
* Creates and returns a CompletableFuture that is completed
* after this or the other given CompletableFuture complete. If
* this and/or the other CompletableFuture complete exceptionally,
* then the returned CompletableFuture may also do so, with a
* RuntimeException having one of these exceptions as its cause.
* No guarantees are made about which exception is used in the
* returned CompletableFuture.
*
* @param other the other CompletableFuture
* @param action the action to perform before completing the
* returned CompletableFuture
* @return the new CompletableFuture
*/
public CompletableFuture orRun(CompletableFuture> other,
Runnable action) {
return orRunnable(other, action, null);
}
/**
* Creates and returns a CompletableFuture that is completed
* asynchronously using the {@link ForkJoinPool#commonPool()}
* after this or the other given CompletableFuture complete. If
* this and/or the other CompletableFuture complete exceptionally,
* then the returned CompletableFuture may also do so, with a
* RuntimeException having one of these exceptions as its cause.
* No guarantees are made about which exception is used in the
* returned CompletableFuture.
*
* @param other the other CompletableFuture
* @param action the action to perform before completing the
* returned CompletableFuture
* @return the new CompletableFuture
*/
public CompletableFuture orRunAsync(CompletableFuture> other,
Runnable action) {
return orRunnable(other, action, ForkJoinPool.commonPool());
}
/**
* Creates and returns a CompletableFuture that is completed
* asynchronously using the given executor after this or the other
* given CompletableFuture complete. If this and/or the other
* CompletableFuture complete exceptionally, then the returned
* CompletableFuture may also do so, with a RuntimeException
* having one of these exceptions as its cause. No guarantees are
* made about which exception is used in the returned
* CompletableFuture.
*
* @param other the other CompletableFuture
* @param action the action to perform before completing the
* returned CompletableFuture
* @param executor the executor to use for asynchronous execution
* @return the new CompletableFuture
*/
public CompletableFuture orRunAsync(CompletableFuture> other,
Runnable action,
Executor executor) {
if (executor == null) throw new NullPointerException();
return orRunnable(other, action, executor);
}
/**
* Creates and returns a CompletableFuture that is completed with
* the result of the given function of the exception triggering
* this CompletableFuture's completion when it completes
* exceptionally; Otherwise, if this CompletableFuture completes
* normally, then the returned CompletableFuture also completes
* normally with the same value.
*
* @param fn the function to use to compute the value of the
* returned CompletableFuture if this CompletableFuture completed
* exceptionally
* @return the new CompletableFuture
*/
public CompletableFuture exceptionally(Function fn) {
if (fn == null) throw new NullPointerException();
CompletableFuture dst = new CompletableFuture();
ExceptionAction d = null;
Object r;
if ((r = result) == null) {
CompletionNode p =
new CompletionNode(d = new ExceptionAction(this, fn, dst));
while ((r = result) == null) {
if (UNSAFE.compareAndSwapObject(this, COMPLETIONS,
p.next = completions, p))
break;
}
}
if (r != null && (d == null || d.compareAndSet(0, 1))) {
T t; Throwable ex = null;
if (r instanceof AltResult) {
if ((ex = ((AltResult)r).ex) != null) {
try {
dst.complete(fn.apply(ex));
} catch (Throwable rex) {
dst.completeExceptionally(rex);
}
}
t = null;
}
else
t = (T) r;
if (ex == null)
dst.complete(t);
}
if (r != null)
postComplete();
return dst;
}
/**
* Attempts to complete this CompletableFuture with
* a {@link CancellationException}.
*
* @param mayInterruptIfRunning this value has no effect in this
* implementation because interrupts are not used to control
* processing.
*
* @return {@code true} if this task is now cancelled
*/
public boolean cancel(boolean mayInterruptIfRunning) {
Object r;
while ((r = result) == null) {
r = new AltResult(new CancellationException());
if (UNSAFE.compareAndSwapObject(this, RESULT, null, r)) {
postComplete();
return true;
}
}
return ((r instanceof AltResult) &&
(((AltResult)r).ex instanceof CancellationException));
}
/**
* Returns {@code true} if this CompletableFuture was cancelled
* before it completed normally.
*
* @return {@code true} if this CompletableFuture was cancelled
* before it completed normally
*/
public boolean isCancelled() {
Object r;
return ((r = result) != null &&
(r instanceof AltResult) &&
(((AltResult)r).ex instanceof CancellationException));
}
/**
* Forcibly sets or resets the value subsequently returned by
* method get() and related methods, whether or not already
* completed. This method is designed for use only in error
* recovery actions, and even in such situations may result in
* ongoing dependent completions using established versus
* overwritten values.
*
* @param value the completion value
*/
public void obtrudeValue(T value) {
result = (value == null) ? NIL : value;
postComplete();
}
/**
* Removes and signals all waiting threads and runs all completions.
*/
private void postComplete() {
WaitNode q; Thread t;
while ((q = waiters) != null) {
if (UNSAFE.compareAndSwapObject(this, WAITERS, q, q.next) &&
(t = q.thread) != null) {
q.thread = null;
LockSupport.unpark(t);
}
}
CompletionNode h; Completion c;
while ((h = completions) != null) {
if (UNSAFE.compareAndSwapObject(this, COMPLETIONS, h, h.next) &&
(c = h.completion) != null)
c.run();
}
}
/* ------------- waiting for completions -------------- */
/**
* Heuristic spin value for waitingGet() before blocking on
* multiprocessors
*/
static final int WAITING_GET_SPINS = 256;
/**
* Returns result after waiting.
*/
private T waitingGet() {
WaitNode q = null;
boolean queued = false, interrupted = false;
int h = 0, spins = 0;
for (Object r;;) {
if ((r = result) != null) {
Throwable ex;
if (q != null) // suppress unpark
q.thread = null;
postComplete(); // help release others
if (interrupted)
Thread.currentThread().interrupt();
if (r instanceof AltResult) {
if ((ex = ((AltResult)r).ex) != null) {
if (ex instanceof Error)
throw (Error)ex;
if (ex instanceof RuntimeException)
throw (RuntimeException)ex;
throw new RuntimeException(ex);
}
return null;
}
return (T)r;
}
else if (h == 0) {
h = ThreadLocalRandom.current().nextInt();
if (Runtime.getRuntime().availableProcessors() > 1)
spins = WAITING_GET_SPINS;
}
else if (spins > 0) {
h ^= h << 1; // xorshift
h ^= h >>> 3;
if ((h ^= h << 10) >= 0)
--spins;
}
else if (q == null)
q = new WaitNode();
else if (!queued)
queued = UNSAFE.compareAndSwapObject(this, WAITERS,
q.next = waiters, q);
else if (Thread.interrupted())
interrupted = true;
else if (q.thread == null)
q.thread = Thread.currentThread();
else
LockSupport.park(this);
}
}
/**
* Awaits completion or aborts on interrupt or timeout.
*
* @param nanos time to wait
* @return raw result
*/
private Object timedAwaitDone(long nanos)
throws InterruptedException, TimeoutException {
final long deadline = System.nanoTime() + nanos;
WaitNode q = null;
boolean queued = false;
for (Object r;;) {
if (Thread.interrupted()) {
removeWaiter(q);
throw new InterruptedException();
}
else if ((r = result) != null) {
if (q != null)
q.thread = null;
postComplete();
return r;
}
else if (q == null)
q = new WaitNode();
else if (!queued)
queued = UNSAFE.compareAndSwapObject(this, WAITERS,
q.next = waiters, q);
else if ((nanos = deadline - System.nanoTime()) <= 0L) {
removeWaiter(q);
throw new TimeoutException();
}
else if (q.thread == null)
q.thread = Thread.currentThread();
else
LockSupport.parkNanos(this, nanos);
}
}
/**
* Tries to unlink a timed-out or interrupted wait node to avoid
* accumulating garbage. Internal nodes are simply unspliced
* without CAS since it is harmless if they are traversed anyway
* by releasers. To avoid effects of unsplicing from already
* removed nodes, the list is retraversed in case of an apparent
* race. This is slow when there are a lot of nodes, but we don't
* expect lists to be long enough to outweigh higher-overhead
* schemes.
*/
private void removeWaiter(WaitNode node) {
if (node != null) {
node.thread = null;
retry:
for (;;) { // restart on removeWaiter race
for (WaitNode pred = null, q = waiters, s; q != null; q = s) {
s = q.next;
if (q.thread != null)
pred = q;
else if (pred != null) {
pred.next = s;
if (pred.thread == null) // check for race
continue retry;
}
else if (!UNSAFE.compareAndSwapObject(this, WAITERS, q, s))
continue retry;
}
break;
}
}
}
/* ------------- Async tasks -------------- */
/** Base class can act as either FJ or plain Runnable */
static abstract class Async extends ForkJoinTask implements Runnable {
public final Void getRawResult() { return null; }
public final void setRawResult(Void v) { }
public final void run() { exec(); }
}
static final class AsyncRunnable extends Async {
final Runnable runnable;
final CompletableFuture dst;
AsyncRunnable(Runnable runnable, CompletableFuture dst) {
this.runnable = runnable; this.dst = dst;
}
public final boolean exec() {
Runnable fn;
CompletableFuture d;
if ((fn = this.runnable) == null || (d = this.dst) == null)
throw new NullPointerException();
try {
fn.run();
d.complete(null);
} catch (Throwable ex) {
d.completeExceptionally(ex);
}
return true;
}
private static final long serialVersionUID = 5232453952276885070L;
}
static final class AsyncSupplier extends Async {
final Supplier supplier;
final CompletableFuture dst;
AsyncSupplier(Supplier supplier, CompletableFuture dst) {
this.supplier = supplier; this.dst = dst;
}
public final boolean exec() {
Supplier fn;
CompletableFuture d;
if ((fn = this.supplier) == null || (d = this.dst) == null)
throw new NullPointerException();
try {
d.complete(fn.get());
} catch (Throwable ex) {
d.completeExceptionally(ex);
}
return true;
}
private static final long serialVersionUID = 5232453952276885070L;
}
static final class AsyncFunction extends Async {
Function super T,? extends U> fn;
T arg;
final CompletableFuture dst;
AsyncFunction(T arg, Function super T,? extends U> fn,
CompletableFuture dst) {
this.arg = arg; this.fn = fn; this.dst = dst;
}
public final boolean exec() {
Function super T,? extends U> fn;
CompletableFuture d;
if ((fn = this.fn) == null || (d = this.dst) == null)
throw new NullPointerException();
try {
d.complete(fn.apply(arg));
} catch (Throwable ex) {
d.completeExceptionally(ex);
}
return true;
}
private static final long serialVersionUID = 5232453952276885070L;
}
static final class AsyncBiFunction extends Async {
final BiFunction super T,? super U,? extends V> fn;
final T arg1;
final U arg2;
final CompletableFuture dst;
AsyncBiFunction(T arg1, U arg2,
BiFunction super T,? super U,? extends V> fn,
CompletableFuture dst) {
this.arg1 = arg1; this.arg2 = arg2; this.fn = fn; this.dst = dst;
}
public final boolean exec() {
BiFunction super T,? super U,? extends V> fn;
CompletableFuture d;
if ((fn = this.fn) == null || (d = this.dst) == null)
throw new NullPointerException();
try {
d.complete(fn.apply(arg1, arg2));
} catch (Throwable ex) {
d.completeExceptionally(ex);
}
return true;
}
private static final long serialVersionUID = 5232453952276885070L;
}
static final class AsyncBlock extends Async {
Block super T> fn;
T arg;
final CompletableFuture dst;
AsyncBlock(T arg, Block super T> fn,
CompletableFuture dst) {
this.arg = arg; this.fn = fn; this.dst = dst;
}
public final boolean exec() {
Block super T> fn;
CompletableFuture d;
if ((fn = this.fn) == null || (d = this.dst) == null)
throw new NullPointerException();
try {
fn.accept(arg);
d.complete(null);
} catch (Throwable ex) {
d.completeExceptionally(ex);
}
return true;
}
private static final long serialVersionUID = 5232453952276885070L;
}
static final class AsyncBiBlock extends Async {
final BiBlock super T,? super U> fn;
final T arg1;
final U arg2;
final CompletableFuture dst;
AsyncBiBlock(T arg1, U arg2,
BiBlock super T,? super U> fn,
CompletableFuture dst) {
this.arg1 = arg1; this.arg2 = arg2; this.fn = fn; this.dst = dst;
}
public final boolean exec() {
BiBlock super T,? super U> fn;
CompletableFuture d;
if ((fn = this.fn) == null || (d = this.dst) == null)
throw new NullPointerException();
try {
fn.accept(arg1, arg2);
d.complete(null);
} catch (Throwable ex) {
d.completeExceptionally(ex);
}
return true;
}
private static final long serialVersionUID = 5232453952276885070L;
}
/* ------------- Completions -------------- */
// Opportunistically subclass AtomicInteger to use compareAndSet to claim.
static abstract class Completion extends AtomicInteger implements Runnable {
}
static final class ThenFunction extends Completion {
final CompletableFuture extends T> src;
final Function super T,? extends U> fn;
final CompletableFuture dst;
final Executor executor;
ThenFunction(CompletableFuture extends T> src,
final Function super T,? extends U> fn,
final CompletableFuture dst, Executor executor) {
this.src = src; this.fn = fn; this.dst = dst;
this.executor = executor;
}
public void run() {
CompletableFuture extends T> a;
Function super T,? extends U> fn;
CompletableFuture dst;
Object r; T t; Throwable ex;
if ((dst = this.dst) != null &&
(fn = this.fn) != null &&
(a = this.src) != null &&
(r = a.result) != null &&
compareAndSet(0, 1)) {
if (r instanceof AltResult) {
if ((ex = ((AltResult)r).ex) != null) {
dst.completeExceptionally(new RuntimeException(ex));
return;
}
t = null;
}
else
t = (T) r;
try {
if (executor != null)
executor.execute(new AsyncFunction(t, fn, dst));
else
dst.complete(fn.apply(t));
} catch (Throwable rex) {
dst.completeExceptionally(rex);
}
}
}
}
static final class ThenBlock extends Completion {
final CompletableFuture extends T> src;
final Block super T> fn;
final CompletableFuture dst;
final Executor executor;
ThenBlock(CompletableFuture extends T> src,
final Block super T> fn,
final CompletableFuture dst, Executor executor) {
this.src = src; this.fn = fn; this.dst = dst;
this.executor = executor;
}
public void run() {
CompletableFuture extends T> a;
Block super T> fn;
CompletableFuture dst;
Object r; T t; Throwable ex;
if ((dst = this.dst) != null &&
(fn = this.fn) != null &&
(a = this.src) != null &&
(r = a.result) != null &&
compareAndSet(0, 1)) {
if (r instanceof AltResult) {
if ((ex = ((AltResult)r).ex) != null) {
dst.completeExceptionally(new RuntimeException(ex));
return;
}
t = null;
}
else
t = (T) r;
try {
if (executor != null)
executor.execute(new AsyncBlock(t, fn, dst));
else {
fn.accept(t);
dst.complete(null);
}
} catch (Throwable rex) {
dst.completeExceptionally(rex);
}
}
}
}
static final class ThenRunnable extends Completion {
final CompletableFuture extends T> src;
final Runnable fn;
final CompletableFuture dst;
final Executor executor;
ThenRunnable(CompletableFuture extends T> src,
Runnable fn,
CompletableFuture dst,
Executor executor) {
this.src = src; this.fn = fn; this.dst = dst;
this.executor = executor;
}
public void run() {
CompletableFuture extends T> a;
Runnable fn;
CompletableFuture dst;
Object r; Throwable ex;
if ((dst = this.dst) != null &&
(fn = this.fn) != null &&
(a = this.src) != null &&
(r = a.result) != null &&
compareAndSet(0, 1)) {
if (r instanceof AltResult) {
if ((ex = ((AltResult)r).ex) != null) {
dst.completeExceptionally(new RuntimeException(ex));
return;
}
}
try {
if (executor != null)
executor.execute(new AsyncRunnable(fn, dst));
else {
fn.run();
dst.complete(null);
}
} catch (Throwable rex) {
dst.completeExceptionally(rex);
}
}
}
}
static final class AndFunction extends Completion {
final CompletableFuture extends T> src;
final CompletableFuture extends U> snd;
final BiFunction super T,? super U,? extends V> fn;
final CompletableFuture dst;
final Executor executor;
AndFunction(CompletableFuture extends T> src,
CompletableFuture extends U> snd,
BiFunction super T,? super U,? extends V> fn,
CompletableFuture dst, Executor executor) {
this.src = src; this.snd = snd;
this.fn = fn; this.dst = dst;
this.executor = executor;
}
public void run() {
Object r, s; T t; U u; Throwable ex;
CompletableFuture extends T> a;
CompletableFuture extends U> b;
BiFunction super T,? super U,? extends V> fn;
CompletableFuture dst;
if ((dst = this.dst) != null &&
(fn = this.fn) != null &&
(a = this.src) != null &&
(r = a.result) != null &&
(b = this.snd) != null &&
(s = b.result) != null &&
compareAndSet(0, 1)) {
if (r instanceof AltResult) {
if ((ex = ((AltResult)r).ex) != null) {
dst.completeExceptionally(new RuntimeException(ex));
return;
}
t = null;
}
else
t = (T) r;
if (s instanceof AltResult) {
if ((ex = ((AltResult)s).ex) != null) {
dst.completeExceptionally(new RuntimeException(ex));
return;
}
u = null;
}
else
u = (U) s;
try {
if (executor != null)
executor.execute(new AsyncBiFunction(t, u, fn, dst));
else
dst.complete(fn.apply(t, u));
} catch (Throwable rex) {
dst.completeExceptionally(rex);
}
}
}
}
static final class AndBlock extends Completion {
final CompletableFuture extends T> src;
final CompletableFuture extends U> snd;
final BiBlock super T,? super U> fn;
final CompletableFuture dst;
final Executor executor;
AndBlock(CompletableFuture extends T> src,
CompletableFuture extends U> snd,
BiBlock super T,? super U> fn,
CompletableFuture dst, Executor executor) {
this.src = src; this.snd = snd;
this.fn = fn; this.dst = dst;
this.executor = executor;
}
public void run() {
Object r, s; T t; U u; Throwable ex;
CompletableFuture extends T> a;
CompletableFuture extends U> b;
BiBlock super T,? super U> fn;
CompletableFuture dst;
if ((dst = this.dst) != null &&
(fn = this.fn) != null &&
(a = this.src) != null &&
(r = a.result) != null &&
(b = this.snd) != null &&
(s = b.result) != null &&
compareAndSet(0, 1)) {
if (r instanceof AltResult) {
if ((ex = ((AltResult)r).ex) != null) {
dst.completeExceptionally(new RuntimeException(ex));
return;
}
t = null;
}
else
t = (T) r;
if (s instanceof AltResult) {
if ((ex = ((AltResult)s).ex) != null) {
dst.completeExceptionally(new RuntimeException(ex));
return;
}
u = null;
}
else
u = (U) s;
try {
if (executor != null)
executor.execute(new AsyncBiBlock(t, u, fn, dst));
else {
fn.accept(t, u);
dst.complete(null);
}
} catch (Throwable rex) {
dst.completeExceptionally(rex);
}
}
}
}
static final class AndRunnable extends Completion {
final CompletableFuture extends T> src;
final CompletableFuture> snd;
final Runnable fn;
final CompletableFuture dst;
final Executor executor;
AndRunnable(CompletableFuture extends T> src,
CompletableFuture> snd,
Runnable fn,
CompletableFuture dst, Executor executor) {
this.src = src; this.snd = snd;
this.fn = fn; this.dst = dst;
this.executor = executor;
}
public void run() {
Object r, s; Throwable ex;
final CompletableFuture extends T> a;
final CompletableFuture> b;
final Runnable fn;
final CompletableFuture dst;
if ((dst = this.dst) != null &&
(fn = this.fn) != null &&
(a = this.src) != null &&
(r = a.result) != null &&
(b = this.snd) != null &&
(s = b.result) != null &&
compareAndSet(0, 1)) {
if (r instanceof AltResult) {
if ((ex = ((AltResult)r).ex) != null) {
dst.completeExceptionally(new RuntimeException(ex));
return;
}
}
if (s instanceof AltResult) {
if ((ex = ((AltResult)s).ex) != null) {
dst.completeExceptionally(new RuntimeException(ex));
return;
}
}
try {
if (executor != null)
executor.execute(new AsyncRunnable(fn, dst));
else {
fn.run();
dst.complete(null);
}
} catch (Throwable rex) {
dst.completeExceptionally(rex);
}
}
}
}
static final class OrFunction extends Completion {
final CompletableFuture extends T> src;
final CompletableFuture extends T> snd;
final Function super T,? extends U> fn;
final CompletableFuture dst;
final Executor executor;
OrFunction(CompletableFuture extends T> src,
CompletableFuture extends T> snd,
Function super T,? extends U> fn,
CompletableFuture dst, Executor executor) {
this.src = src; this.snd = snd;
this.fn = fn; this.dst = dst;
this.executor = executor;
}
public void run() {
Object r; T t; Throwable ex;
CompletableFuture extends T> a;
CompletableFuture extends T> b;
Function super T,? extends U> fn;
CompletableFuture dst;
if ((dst = this.dst) != null &&
(fn = this.fn) != null &&
(((a = this.src) != null && (r = a.result) != null) ||
((b = this.snd) != null && (r = b.result) != null)) &&
compareAndSet(0, 1)) {
if (r instanceof AltResult) {
if ((ex = ((AltResult)r).ex) != null) {
dst.completeExceptionally(new RuntimeException(ex));
return;
}
t = null;
}
else
t = (T) r;
try {
if (executor != null)
executor.execute(new AsyncFunction(t, fn, dst));
else
dst.complete(fn.apply(t));
} catch (Throwable rex) {
dst.completeExceptionally(rex);
}
}
}
}
static final class OrBlock extends Completion {
final CompletableFuture extends T> src;
final CompletableFuture extends T> snd;
final Block super T> fn;
final CompletableFuture dst;
final Executor executor;
OrBlock(CompletableFuture extends T> src,
CompletableFuture extends T> snd,
Block super T> fn,
CompletableFuture dst, Executor executor) {
this.src = src; this.snd = snd;
this.fn = fn; this.dst = dst;
this.executor = executor;
}
public void run() {
Object r; T t; Throwable ex;
CompletableFuture extends T> a;
CompletableFuture extends T> b;
Block super T> fn;
CompletableFuture dst;
if ((dst = this.dst) != null &&
(fn = this.fn) != null &&
(((a = this.src) != null && (r = a.result) != null) ||
((b = this.snd) != null && (r = b.result) != null)) &&
compareAndSet(0, 1)) {
if (r instanceof AltResult) {
if ((ex = ((AltResult)r).ex) != null) {
dst.completeExceptionally(new RuntimeException(ex));
return;
}
t = null;
}
else
t = (T) r;
try {
if (executor != null)
executor.execute(new AsyncBlock(t, fn, dst));
else {
fn.accept(t);
dst.complete(null);
}
} catch (Throwable rex) {
dst.completeExceptionally(rex);
}
}
}
}
static final class OrRunnable extends Completion {
final CompletableFuture extends T> src;
final CompletableFuture> snd;
final Runnable fn;
final CompletableFuture dst;
final Executor executor;
OrRunnable(CompletableFuture extends T> src,
CompletableFuture> snd,
Runnable fn,
CompletableFuture dst, Executor executor) {
this.src = src; this.snd = snd;
this.fn = fn; this.dst = dst;
this.executor = executor;
}
public void run() {
Object r; Throwable ex;
CompletableFuture extends T> a;
final CompletableFuture> b;
final Runnable fn;
final CompletableFuture dst;
if ((dst = this.dst) != null &&
(fn = this.fn) != null &&
(((a = this.src) != null && (r = a.result) != null) ||
((b = this.snd) != null && (r = b.result) != null)) &&
compareAndSet(0, 1)) {
if ((r instanceof AltResult) &&
(ex = ((AltResult)r).ex) != null) {
dst.completeExceptionally(new RuntimeException(ex));
}
else {
try {
if (executor != null)
executor.execute(new AsyncRunnable(fn, dst));
else {
fn.run();
dst.complete(null);
}
} catch (Throwable rex) {
dst.completeExceptionally(rex);
}
}
}
}
}
static final class ExceptionAction extends Completion {
final CompletableFuture extends T> src;
final Function super Throwable, ? extends T> fn;
final CompletableFuture dst;
ExceptionAction(CompletableFuture extends T> src,
Function super Throwable, ? extends T> fn,
CompletableFuture dst) {
this.src = src; this.fn = fn; this.dst = dst;
}
public void run() {
CompletableFuture extends T> a;
Function super Throwable, ? extends T> fn;
CompletableFuture dst;
Object r; T t; Throwable ex;
if ((dst = this.dst) != null &&
(fn = this.fn) != null &&
(a = this.src) != null &&
(r = a.result) != null &&
compareAndSet(0, 1)) {
if (r instanceof AltResult) {
if ((ex = ((AltResult)r).ex) != null) {
try {
dst.complete(fn.apply(ex));
} catch (Throwable rex) {
dst.completeExceptionally(rex);
}
return;
}
t = null;
}
else
t = (T) r;
dst.complete(t);
}
}
}
/* ------------- then/and/or implementations -------------- */
private CompletableFuture thenFunction(Function super T,? extends U> fn,
Executor executor) {
if (fn == null) throw new NullPointerException();
CompletableFuture dst = new CompletableFuture();
ThenFunction d = null;
Object r;
if ((r = result) == null) {
CompletionNode p = new CompletionNode
(d = new ThenFunction(this, fn, dst, executor));
while ((r = result) == null) {
if (UNSAFE.compareAndSwapObject
(this, COMPLETIONS, p.next = completions, p))
break;
}
}
if (r != null && (d == null || d.compareAndSet(0, 1))) {
T t; Throwable ex = null;
if (r instanceof AltResult) {
if ((ex = ((AltResult)r).ex) != null)
dst.completeExceptionally(new RuntimeException(ex));
t = null;
}
else
t = (T) r;
if (ex == null) {
try {
if (executor != null)
executor.execute(new AsyncFunction(t, fn, dst));
else
dst.complete(fn.apply(t));
} catch (Throwable rex) {
dst.completeExceptionally(rex);
}
}
postComplete();
}
return dst;
}
private CompletableFuture thenBlock(Block super T> fn,
Executor executor) {
if (fn == null) throw new NullPointerException();
CompletableFuture dst = new CompletableFuture();
ThenBlock d = null;
Object r;
if ((r = result) == null) {
CompletionNode p = new CompletionNode
(d = new ThenBlock(this, fn, dst, executor));
while ((r = result) == null) {
if (UNSAFE.compareAndSwapObject
(this, COMPLETIONS, p.next = completions, p))
break;
}
}
if (r != null && (d == null || d.compareAndSet(0, 1))) {
T t; Throwable ex = null;
if (r instanceof AltResult) {
if ((ex = ((AltResult)r).ex) != null)
dst.completeExceptionally(new RuntimeException(ex));
t = null;
}
else
t = (T) r;
if (ex == null) {
try {
if (executor != null)
executor.execute(new AsyncBlock(t, fn, dst));
else {
fn.accept(t);
dst.complete(null);
}
} catch (Throwable rex) {
dst.completeExceptionally(rex);
}
}
postComplete();
}
return dst;
}
private CompletableFuture thenRunnable(Runnable action,
Executor executor) {
if (action == null) throw new NullPointerException();
CompletableFuture dst = new CompletableFuture();
ThenRunnable d = null;
Object r;
if ((r = result) == null) {
CompletionNode p = new CompletionNode
(d = new ThenRunnable(this, action, dst, executor));
while ((r = result) == null) {
if (UNSAFE.compareAndSwapObject
(this, COMPLETIONS, p.next = completions, p))
break;
}
}
if (r != null && (d == null || d.compareAndSet(0, 1))) {
Throwable ex = null;
if (r instanceof AltResult) {
if ((ex = ((AltResult)r).ex) != null)
dst.completeExceptionally(new RuntimeException(ex));
}
if (ex == null) {
try {
if (executor != null)
executor.execute(new AsyncRunnable(action, dst));
else {
action.run();
dst.complete(null);
}
} catch (Throwable rex) {
dst.completeExceptionally(rex);
}
}
postComplete();
}
return dst;
}
private CompletableFuture andFunction(CompletableFuture extends U> other,
BiFunction super T,? super U,? extends V> fn,
Executor executor) {
if (other == null || fn == null) throw new NullPointerException();
CompletableFuture dst = new CompletableFuture();
AndFunction d = null;
Object r, s = null;
if ((r = result) == null || (s = other.result) == null) {
d = new AndFunction(this, other, fn, dst, executor);
CompletionNode q = null, p = new CompletionNode(d);
while ((r == null && (r = result) == null) ||
(s == null && (s = other.result) == null)) {
if (q != null) {
if (s != null ||
UNSAFE.compareAndSwapObject
(other, COMPLETIONS, q.next = other.completions, q))
break;
}
else if (r != null ||
UNSAFE.compareAndSwapObject
(this, COMPLETIONS, p.next = completions, p)) {
if (s != null)
break;
q = new CompletionNode(d);
}
}
}
if (r != null && s != null && (d == null || d.compareAndSet(0, 1))) {
T t; U u; Throwable ex = null;
if (r instanceof AltResult) {
if ((ex = ((AltResult)r).ex) != null)
dst.completeExceptionally(new RuntimeException(ex));
t = null;
}
else
t = (T) r;
if (ex != null)
u = null;
else if (s instanceof AltResult) {
if ((ex = ((AltResult)s).ex) != null)
dst.completeExceptionally(new RuntimeException(ex));
u = null;
}
else
u = (U) s;
if (ex == null) {
try {
if (executor != null)
executor.execute(new AsyncBiFunction(t, u, fn, dst));
else
dst.complete(fn.apply(t, u));
} catch (Throwable rex) {
dst.completeExceptionally(rex);
}
}
}
if (r != null)
postComplete();
if (s != null)
other.postComplete();
return dst;
}
private CompletableFuture andBlock(CompletableFuture extends U> other,
BiBlock super T,? super U> fn,
Executor executor) {
if (other == null || fn == null) throw new NullPointerException();
CompletableFuture dst = new CompletableFuture();
AndBlock d = null;
Object r, s = null;
if ((r = result) == null || (s = other.result) == null) {
d = new AndBlock(this, other, fn, dst, executor);
CompletionNode q = null, p = new CompletionNode(d);
while ((r == null && (r = result) == null) ||
(s == null && (s = other.result) == null)) {
if (q != null) {
if (s != null ||
UNSAFE.compareAndSwapObject
(other, COMPLETIONS, q.next = other.completions, q))
break;
}
else if (r != null ||
UNSAFE.compareAndSwapObject
(this, COMPLETIONS, p.next = completions, p)) {
if (s != null)
break;
q = new CompletionNode(d);
}
}
}
if (r != null && s != null && (d == null || d.compareAndSet(0, 1))) {
T t; U u; Throwable ex = null;
if (r instanceof AltResult) {
if ((ex = ((AltResult)r).ex) != null)
dst.completeExceptionally(new RuntimeException(ex));
t = null;
}
else
t = (T) r;
if (ex != null)
u = null;
else if (s instanceof AltResult) {
if ((ex = ((AltResult)s).ex) != null)
dst.completeExceptionally(new RuntimeException(ex));
u = null;
}
else
u = (U) s;
if (ex == null) {
try {
if (executor != null)
executor.execute(new AsyncBiBlock(t, u, fn, dst));
else {
fn.accept(t, u);
dst.complete(null);
}
} catch (Throwable rex) {
dst.completeExceptionally(rex);
}
}
}
if (r != null)
postComplete();
if (s != null)
other.postComplete();
return dst;
}
private CompletableFuture andRunnable(CompletableFuture> other,
Runnable action,
Executor executor) {
if (other == null || action == null) throw new NullPointerException();
CompletableFuture dst = new CompletableFuture();
AndRunnable d = null;
Object r, s = null;
if ((r = result) == null || (s = other.result) == null) {
d = new AndRunnable(this, other, action, dst, executor);
CompletionNode q = null, p = new CompletionNode(d);
while ((r == null && (r = result) == null) ||
(s == null && (s = other.result) == null)) {
if (q != null) {
if (s != null ||
UNSAFE.compareAndSwapObject
(other, COMPLETIONS, q.next = other.completions, q))
break;
}
else if (r != null ||
UNSAFE.compareAndSwapObject
(this, COMPLETIONS, p.next = completions, p)) {
if (s != null)
break;
q = new CompletionNode(d);
}
}
}
if (r != null && s != null && (d == null || d.compareAndSet(0, 1))) {
Throwable ex = null;
if ((r instanceof AltResult) &&
(ex = ((AltResult)r).ex) != null)
dst.completeExceptionally(new RuntimeException(ex));
else if ((s instanceof AltResult) &&
(ex = ((AltResult)s).ex) != null)
dst.completeExceptionally(new RuntimeException(ex));
else {
try {
if (executor != null)
executor.execute(new AsyncRunnable(action, dst));
else {
action.run();
dst.complete(null);
}
} catch (Throwable rex) {
dst.completeExceptionally(rex);
}
}
}
if (r != null)
postComplete();
if (s != null)
other.postComplete();
return dst;
}
private CompletableFuture orFunction(CompletableFuture extends T> other,
Function super T, U> fn,
Executor executor) {
if (other == null || fn == null) throw new NullPointerException();
CompletableFuture dst = new CompletableFuture();
OrFunction d = null;
Object r;
if ((r = result) == null && (r = other.result) == null) {
d = new OrFunction(this, other, fn, dst, executor);
CompletionNode q = null, p = new CompletionNode(d);
while ((r = result) == null && (r = other.result) == null) {
if (q != null) {
if (UNSAFE.compareAndSwapObject
(other, COMPLETIONS, q.next = other.completions, q))
break;
}
else if (UNSAFE.compareAndSwapObject
(this, COMPLETIONS, p.next = completions, p))
q = new CompletionNode(d);
}
}
if (r != null && (d == null || d.compareAndSet(0, 1))) {
T t; Throwable ex = null;
if (r instanceof AltResult) {
if ((ex = ((AltResult)r).ex) != null)
dst.completeExceptionally(new RuntimeException(ex));
t = null;
}
else
t = (T) r;
if (ex == null) {
try {
if (executor != null)
executor.execute(new AsyncFunction(t, fn, dst));
else
dst.complete(fn.apply(t));
} catch (Throwable rex) {
dst.completeExceptionally(rex);
}
}
}
if (r != null) {
if (result != null)
postComplete();
if (other.result != null)
other.postComplete();
}
return dst;
}
private CompletableFuture orBlock(CompletableFuture extends T> other,
Block super T> fn,
Executor executor) {
if (other == null || fn == null) throw new NullPointerException();
CompletableFuture dst = new CompletableFuture();
OrBlock d = null;
Object r;
if ((r = result) == null && (r = other.result) == null) {
d = new OrBlock(this, other, fn, dst, executor);
CompletionNode q = null, p = new CompletionNode(d);
while ((r = result) == null && (r = other.result) == null) {
if (q != null) {
if (UNSAFE.compareAndSwapObject
(other, COMPLETIONS, q.next = other.completions, q))
break;
}
else if (UNSAFE.compareAndSwapObject
(this, COMPLETIONS, p.next = completions, p))
q = new CompletionNode(d);
}
}
if (r != null && (d == null || d.compareAndSet(0, 1))) {
T t; Throwable ex = null;
if (r instanceof AltResult) {
if ((ex = ((AltResult)r).ex) != null)
dst.completeExceptionally(new RuntimeException(ex));
t = null;
}
else
t = (T) r;
if (ex == null) {
try {
if (executor != null)
executor.execute(new AsyncBlock(t, fn, dst));
else {
fn.accept(t);
dst.complete(null);
}
} catch (Throwable rex) {
dst.completeExceptionally(rex);
}
}
}
if (r != null) {
if (result != null)
postComplete();
if (other.result != null)
other.postComplete();
}
return dst;
}
private CompletableFuture orRunnable(CompletableFuture> other,
Runnable action,
Executor executor) {
if (other == null || action == null) throw new NullPointerException();
CompletableFuture dst = new CompletableFuture();
OrRunnable d = null;
Object r;
if ((r = result) == null && (r = other.result) == null) {
d = new OrRunnable(this, other, action, dst, executor);
CompletionNode q = null, p = new CompletionNode(d);
while ((r = result) == null && (r = other.result) == null) {
if (q != null) {
if (UNSAFE.compareAndSwapObject
(other, COMPLETIONS, q.next = other.completions, q))
break;
}
else if (UNSAFE.compareAndSwapObject
(this, COMPLETIONS, p.next = completions, p))
q = new CompletionNode(d);
}
}
if (r != null && (d == null || d.compareAndSet(0, 1))) {
Throwable ex = null;
if ((r instanceof AltResult) &&
(ex = ((AltResult)r).ex) != null)
dst.completeExceptionally(new RuntimeException(ex));
else {
try {
if (executor != null)
executor.execute(new AsyncRunnable(action, dst));
else {
action.run();
dst.complete(null);
}
} catch (Throwable rex) {
dst.completeExceptionally(rex);
}
}
}
if (r != null) {
if (result != null)
postComplete();
if (other.result != null)
other.postComplete();
}
return dst;
}
// Unsafe mechanics
private static final sun.misc.Unsafe UNSAFE;
private static final long RESULT;
private static final long WAITERS;
private static final long COMPLETIONS;
static {
try {
UNSAFE = sun.misc.Unsafe.getUnsafe();
Class> k = CompletableFuture.class;
RESULT = UNSAFE.objectFieldOffset
(k.getDeclaredField("result"));
WAITERS = UNSAFE.objectFieldOffset
(k.getDeclaredField("waiters"));
COMPLETIONS = UNSAFE.objectFieldOffset
(k.getDeclaredField("completions"));
} catch (Exception e) {
throw new Error(e);
}
}
}