/*
* 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 jsr166e;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
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. Methods are available for adding
* those based on Functions, Blocks, and Runnables, depending on
* whether they require arguments and/or produce results, as well as
* those triggered after either or both the current and another
* CompletableFuture complete. 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 these methods.
*
* When two or more threads attempt to {@link #complete} or {@link
* #completeExceptionally} a CompletableFuture, only one of them
* succeeds.
*
*
Upon exceptional completion, or when a completion entails
* computation of a function or action, and it terminates abruptly
* with an (unchecked) exception or error, then further completions
* act as {@code completeExceptionally} with a {@link
* CompletionException} holding that exception as its cause. If a
* CompletableFuture completes exceptionally, and is not followed by a
* {@link #exceptionally} or {@link #handle} completion, then all of
* its dependents (and their dependents) also complete exceptionally
* with CompletionExceptions holding the ultimate cause. In case of a
* CompletionException, methods {@link #get()} and {@link #get(long,
* TimeUnit)} throw an {@link ExecutionException} with the same cause
* as would be held in the corresponding CompletionException. However,
* in these cases, methods {@link #join()} and {@link #getNow} throw
* the CompletionException, which simplifies usage especially within
* other completion functions.
*
*
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. To simplify monitoring, debugging, and tracking,
* all generated asynchronous tasks are instances of the tagging
* interface {@link AsynchronousCompletionTask}.
*
*
jsr166e note: During transition, this class
* uses nested functional interfaces with different names but the
* same forms as those expected for JDK8.
*
* @author Doug Lea
* @since 1.8
*/
public class CompletableFuture implements Future {
// jsr166e nested interfaces
/** Interface describing a void action of one argument */
public interface Action { void accept(A a); }
/** Interface describing a void action of two arguments */
public interface BiAction { void accept(A a, B b); }
/** Interface describing a function of one argument */
public interface Fun { T apply(A a); }
/** Interface describing a function of two arguments */
public interface BiFun { T apply(A a, B b); }
/** Interface describing a function of no arguments */
public interface Generator { T get(); }
/*
* Overview:
*
* 1. Non-nullness of field result (set via CAS) indicates done.
* An AltResult is used to box null as a result, as well as to
* hold exceptions. Using a single field makes completion fast
* and simple to detect and trigger, at the expense of a lot of
* encoding and decoding that infiltrates many methods. One minor
* simplification relies on the (static) NIL (to box null results)
* being the only AltResult with a null exception field, so we
* don't usually need explicit comparisons with NIL. The CF
* exception propagation mechanics surrounding decoding rely on
* unchecked casts of decoded results really being unchecked,
* where user type errors are caught at point of use, as is
* currently the case in Java. These are highlighted by using
* SuppressWarnings-annotated temporaries.
*
* 2. Waiters are held in a Treiber stack similar to the one used
* in FutureTask, Phaser, and SynchronousQueue. See their
* internal documentation for algorithmic details.
*
* 3. Completions are also kept in a list/stack, and pulled off
* and run when completion is triggered. (We could even use the
* same stack as for waiters, but would give up the potential
* parallelism obtained because woken waiters help release/run
* others -- see method postComplete). Because post-processing
* may race with direct calls, class Completion opportunistically
* extends AtomicInteger so callers can claim the action via
* compareAndSet(0, 1). The Completion.run methods are all
* written a boringly similar uniform way (that sometimes includes
* unnecessary-looking checks, kept to maintain uniformity). There
* are enough dimensions upon which they differ that factoring to
* use common code isn't worthwhile.
*
* 4. The exported then/and/or methods do support a bit of
* factoring (see doThenApply etc). They must cope with the
* intrinsic races surrounding addition of a dependent action
* versus performing the action directly because the task is
* already complete. For example, a CF may not be complete upon
* entry, so a dependent completion is added, but by the time it
* is added, the target CF is complete, so must be directly
* executed. This is all done while avoiding unnecessary object
* construction in safe-bypass cases.
*/
// preliminaries
static final class AltResult {
final Throwable ex; // null only for NIL
AltResult(Throwable ex) { this.ex = ex; }
}
static final AltResult NIL = new AltResult(null);
// Fields
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
// Basic utilities for triggering and processing completions
/**
* Removes and signals all waiting threads and runs all completions.
*/
final 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();
}
}
/**
* Triggers completion with the encoding of the given arguments:
* if the exception is non-null, encodes it as a wrapped
* CompletionException unless it is one already. Otherwise uses
* the given result, boxed as NIL if null.
*/
final void internalComplete(Object v, Throwable ex) {
if (result == null)
UNSAFE.compareAndSwapObject
(this, RESULT, null,
(ex == null) ? (v == null) ? NIL : v :
new AltResult((ex instanceof CompletionException) ? ex :
new CompletionException(ex)));
postComplete(); // help out even if not triggered
}
/**
* If triggered, helps release and/or process completions.
*/
final void helpPostComplete() {
if (result != null)
postComplete();
}
/* ------------- waiting for completions -------------- */
/**
* Heuristic spin value for waitingGet() before blocking on
* multiprocessors
*/
static final int WAITING_GET_SPINS = 256;
/**
* Linked nodes to record waiting threads in a Treiber stack. See
* other classes such as Phaser and SynchronousQueue for more
* detailed explanation. This class implements ManagedBlocker to
* avoid starvation when blocking actions pile up in
* ForkJoinPools.
*/
static final class WaitNode implements ForkJoinPool.ManagedBlocker {
long nanos; // wait time if timed
final long deadline; // non-zero if timed
volatile int interruptControl; // > 0: interruptible, < 0: interrupted
volatile Thread thread;
volatile WaitNode next;
WaitNode(boolean interruptible, long nanos, long deadline) {
this.thread = Thread.currentThread();
this.interruptControl = interruptible ? 1 : 0;
this.nanos = nanos;
this.deadline = deadline;
}
public boolean isReleasable() {
if (thread == null)
return true;
if (Thread.interrupted()) {
int i = interruptControl;
interruptControl = -1;
if (i > 0)
return true;
}
if (deadline != 0L &&
(nanos <= 0L || (nanos = deadline - System.nanoTime()) <= 0L)) {
thread = null;
return true;
}
return false;
}
public boolean block() {
if (isReleasable())
return true;
else if (deadline == 0L)
LockSupport.park(this);
else if (nanos > 0L)
LockSupport.parkNanos(this, nanos);
return isReleasable();
}
}
/**
* Returns raw result after waiting, or null if interruptible and
* interrupted.
*/
private Object waitingGet(boolean interruptible) {
WaitNode q = null;
boolean queued = false;
int h = 0, spins = 0;
for (Object r;;) {
if ((r = result) != null) {
if (q != null) { // suppress unpark
q.thread = null;
if (q.interruptControl < 0) {
if (interruptible) {
removeWaiter(q);
return null;
}
Thread.currentThread().interrupt();
}
}
postComplete(); // help release others
return 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(interruptible, 0L, 0L);
else if (!queued)
queued = UNSAFE.compareAndSwapObject(this, WAITERS,
q.next = waiters, q);
else if (interruptible && q.interruptControl < 0) {
removeWaiter(q);
return null;
}
else if (q.thread != null && result == null) {
try {
ForkJoinPool.managedBlock(q);
} catch (InterruptedException ex) {
q.interruptControl = -1;
}
}
}
}
/**
* Awaits completion or aborts on interrupt or timeout.
*
* @param nanos time to wait
* @return raw result
*/
private Object timedAwaitDone(long nanos)
throws InterruptedException, TimeoutException {
WaitNode q = null;
boolean queued = false;
for (Object r;;) {
if ((r = result) != null) {
if (q != null) {
q.thread = null;
if (q.interruptControl < 0) {
removeWaiter(q);
throw new InterruptedException();
}
}
postComplete();
return r;
}
else if (q == null) {
if (nanos <= 0L)
throw new TimeoutException();
long d = System.nanoTime() + nanos;
q = new WaitNode(true, nanos, d == 0L ? 1L : d); // avoid 0
}
else if (!queued)
queued = UNSAFE.compareAndSwapObject(this, WAITERS,
q.next = waiters, q);
else if (q.interruptControl < 0) {
removeWaiter(q);
throw new InterruptedException();
}
else if (q.nanos <= 0L) {
if (result == null) {
removeWaiter(q);
throw new TimeoutException();
}
}
else if (q.thread != null && result == null) {
try {
ForkJoinPool.managedBlock(q);
} catch (InterruptedException ex) {
q.interruptControl = -1;
}
}
}
}
/**
* 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 -------------- */
/**
* A tagging interface identifying asynchronous tasks produced by
* {@code async} methods. This may be useful for monitoring,
* debugging, and tracking asynchronous activities.
*/
public static interface AsynchronousCompletionTask {
}
/** Base class can act as either FJ or plain Runnable */
abstract static class Async extends ForkJoinTask
implements Runnable, AsynchronousCompletionTask {
public final Void getRawResult() { return null; }
public final void setRawResult(Void v) { }
public final void run() { exec(); }
}
static final class AsyncRun extends Async {
final Runnable fn;
final CompletableFuture dst;
AsyncRun(Runnable fn, CompletableFuture dst) {
this.fn = fn; this.dst = dst;
}
public final boolean exec() {
CompletableFuture d; Throwable ex;
if ((d = this.dst) != null && d.result == null) {
try {
fn.run();
ex = null;
} catch (Throwable rex) {
ex = rex;
}
d.internalComplete(null, ex);
}
return true;
}
private static final long serialVersionUID = 5232453952276885070L;
}
static final class AsyncSupply extends Async {
final Generator fn;
final CompletableFuture dst;
AsyncSupply(Generator fn, CompletableFuture dst) {
this.fn = fn; this.dst = dst;
}
public final boolean exec() {
CompletableFuture d; U u; Throwable ex;
if ((d = this.dst) != null && d.result == null) {
try {
u = fn.get();
ex = null;
} catch (Throwable rex) {
ex = rex;
u = null;
}
d.internalComplete(u, ex);
}
return true;
}
private static final long serialVersionUID = 5232453952276885070L;
}
static final class AsyncApply extends Async {
final Fun fn;
final T arg;
final CompletableFuture dst;
AsyncApply(T arg, Fun fn,
CompletableFuture dst) {
this.arg = arg; this.fn = fn; this.dst = dst;
}
public final boolean exec() {
CompletableFuture d; U u; Throwable ex;
if ((d = this.dst) != null && d.result == null) {
try {
u = fn.apply(arg);
ex = null;
} catch (Throwable rex) {
ex = rex;
u = null;
}
d.internalComplete(u, ex);
}
return true;
}
private static final long serialVersionUID = 5232453952276885070L;
}
static final class AsyncBiApply extends Async {
final BiFun fn;
final T arg1;
final U arg2;
final CompletableFuture dst;
AsyncBiApply(T arg1, U arg2,
BiFun fn,
CompletableFuture dst) {
this.arg1 = arg1; this.arg2 = arg2; this.fn = fn; this.dst = dst;
}
public final boolean exec() {
CompletableFuture d; V v; Throwable ex;
if ((d = this.dst) != null && d.result == null) {
try {
v = fn.apply(arg1, arg2);
ex = null;
} catch (Throwable rex) {
ex = rex;
v = null;
}
d.internalComplete(v, ex);
}
return true;
}
private static final long serialVersionUID = 5232453952276885070L;
}
static final class AsyncAccept extends Async {
final Action fn;
final T arg;
final CompletableFuture dst;
AsyncAccept(T arg, Action fn,
CompletableFuture dst) {
this.arg = arg; this.fn = fn; this.dst = dst;
}
public final boolean exec() {
CompletableFuture d; Throwable ex;
if ((d = this.dst) != null && d.result == null) {
try {
fn.accept(arg);
ex = null;
} catch (Throwable rex) {
ex = rex;
}
d.internalComplete(null, ex);
}
return true;
}
private static final long serialVersionUID = 5232453952276885070L;
}
static final class AsyncBiAccept extends Async {
final BiAction fn;
final T arg1;
final U arg2;
final CompletableFuture dst;
AsyncBiAccept(T arg1, U arg2,
BiAction fn,
CompletableFuture dst) {
this.arg1 = arg1; this.arg2 = arg2; this.fn = fn; this.dst = dst;
}
public final boolean exec() {
CompletableFuture d; Throwable ex;
if ((d = this.dst) != null && d.result == null) {
try {
fn.accept(arg1, arg2);
ex = null;
} catch (Throwable rex) {
ex = rex;
}
d.internalComplete(null, ex);
}
return true;
}
private static final long serialVersionUID = 5232453952276885070L;
}
/* ------------- Completions -------------- */
/**
* Simple linked list nodes to record completions, used in
* basically the same way as WaitNodes. (We separate nodes from
* the Completions themselves mainly because for the And and Or
* methods, the same Completion object resides in two lists.)
*/
static final class CompletionNode {
final Completion completion;
volatile CompletionNode next;
CompletionNode(Completion completion) { this.completion = completion; }
}
// Opportunistically subclass AtomicInteger to use compareAndSet to claim.
abstract static class Completion extends AtomicInteger implements Runnable {
}
static final class ApplyCompletion extends Completion {
final CompletableFuture src;
final Fun fn;
final CompletableFuture dst;
final Executor executor;
ApplyCompletion(CompletableFuture src,
Fun fn,
CompletableFuture dst, Executor executor) {
this.src = src; this.fn = fn; this.dst = dst;
this.executor = executor;
}
public final void run() {
final CompletableFuture a;
final Fun fn;
final 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) {
ex = ((AltResult)r).ex;
t = null;
}
else {
ex = null;
@SuppressWarnings("unchecked") T tr = (T) r;
t = tr;
}
Executor e = executor;
U u = null;
if (ex == null) {
try {
if (e != null)
e.execute(new AsyncApply(t, fn, dst));
else
u = fn.apply(t);
} catch (Throwable rex) {
ex = rex;
}
}
if (e == null || ex != null)
dst.internalComplete(u, ex);
}
}
private static final long serialVersionUID = 5232453952276885070L;
}
static final class AcceptCompletion extends Completion {
final CompletableFuture src;
final Action fn;
final CompletableFuture dst;
final Executor executor;
AcceptCompletion(CompletableFuture src,
Action fn,
CompletableFuture dst, Executor executor) {
this.src = src; this.fn = fn; this.dst = dst;
this.executor = executor;
}
public final void run() {
final CompletableFuture a;
final Action fn;
final 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) {
ex = ((AltResult)r).ex;
t = null;
}
else {
ex = null;
@SuppressWarnings("unchecked") T tr = (T) r;
t = tr;
}
Executor e = executor;
if (ex == null) {
try {
if (e != null)
e.execute(new AsyncAccept(t, fn, dst));
else
fn.accept(t);
} catch (Throwable rex) {
ex = rex;
}
}
if (e == null || ex != null)
dst.internalComplete(null, ex);
}
}
private static final long serialVersionUID = 5232453952276885070L;
}
static final class RunCompletion extends Completion {
final CompletableFuture src;
final Runnable fn;
final CompletableFuture dst;
final Executor executor;
RunCompletion(CompletableFuture src,
Runnable fn,
CompletableFuture dst,
Executor executor) {
this.src = src; this.fn = fn; this.dst = dst;
this.executor = executor;
}
public final void run() {
final CompletableFuture a;
final Runnable fn;
final 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)
ex = ((AltResult)r).ex;
else
ex = null;
Executor e = executor;
if (ex == null) {
try {
if (e != null)
e.execute(new AsyncRun(fn, dst));
else
fn.run();
} catch (Throwable rex) {
ex = rex;
}
}
if (e == null || ex != null)
dst.internalComplete(null, ex);
}
}
private static final long serialVersionUID = 5232453952276885070L;
}
static final class BiApplyCompletion extends Completion {
final CompletableFuture src;
final CompletableFuture snd;
final BiFun fn;
final CompletableFuture dst;
final Executor executor;
BiApplyCompletion(CompletableFuture src,
CompletableFuture snd,
BiFun fn,
CompletableFuture dst, Executor executor) {
this.src = src; this.snd = snd;
this.fn = fn; this.dst = dst;
this.executor = executor;
}
public final void run() {
final CompletableFuture a;
final CompletableFuture b;
final BiFun fn;
final CompletableFuture dst;
Object r, s; T t; U u; Throwable ex;
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) {
ex = ((AltResult)r).ex;
t = null;
}
else {
ex = null;
@SuppressWarnings("unchecked") T tr = (T) r;
t = tr;
}
if (ex != null)
u = null;
else if (s instanceof AltResult) {
ex = ((AltResult)s).ex;
u = null;
}
else {
@SuppressWarnings("unchecked") U us = (U) s;
u = us;
}
Executor e = executor;
V v = null;
if (ex == null) {
try {
if (e != null)
e.execute(new AsyncBiApply(t, u, fn, dst));
else
v = fn.apply(t, u);
} catch (Throwable rex) {
ex = rex;
}
}
if (e == null || ex != null)
dst.internalComplete(v, ex);
}
}
private static final long serialVersionUID = 5232453952276885070L;
}
static final class BiAcceptCompletion extends Completion {
final CompletableFuture src;
final CompletableFuture snd;
final BiAction fn;
final CompletableFuture dst;
final Executor executor;
BiAcceptCompletion(CompletableFuture src,
CompletableFuture snd,
BiAction fn,
CompletableFuture dst, Executor executor) {
this.src = src; this.snd = snd;
this.fn = fn; this.dst = dst;
this.executor = executor;
}
public final void run() {
final CompletableFuture a;
final CompletableFuture b;
final BiAction fn;
final CompletableFuture dst;
Object r, s; T t; U u; Throwable ex;
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) {
ex = ((AltResult)r).ex;
t = null;
}
else {
ex = null;
@SuppressWarnings("unchecked") T tr = (T) r;
t = tr;
}
if (ex != null)
u = null;
else if (s instanceof AltResult) {
ex = ((AltResult)s).ex;
u = null;
}
else {
@SuppressWarnings("unchecked") U us = (U) s;
u = us;
}
Executor e = executor;
if (ex == null) {
try {
if (e != null)
e.execute(new AsyncBiAccept(t, u, fn, dst));
else
fn.accept(t, u);
} catch (Throwable rex) {
ex = rex;
}
}
if (e == null || ex != null)
dst.internalComplete(null, ex);
}
}
private static final long serialVersionUID = 5232453952276885070L;
}
static final class BiRunCompletion extends Completion {
final CompletableFuture src;
final CompletableFuture snd;
final Runnable fn;
final CompletableFuture dst;
final Executor executor;
BiRunCompletion(CompletableFuture 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 final void run() {
final CompletableFuture a;
final CompletableFuture b;
final Runnable fn;
final CompletableFuture dst;
Object r, s; Throwable ex;
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)
ex = ((AltResult)r).ex;
else
ex = null;
if (ex == null && (s instanceof AltResult))
ex = ((AltResult)s).ex;
Executor e = executor;
if (ex == null) {
try {
if (e != null)
e.execute(new AsyncRun(fn, dst));
else
fn.run();
} catch (Throwable rex) {
ex = rex;
}
}
if (e == null || ex != null)
dst.internalComplete(null, ex);
}
}
private static final long serialVersionUID = 5232453952276885070L;
}
static final class OrApplyCompletion extends Completion {
final CompletableFuture src;
final CompletableFuture snd;
final Fun fn;
final CompletableFuture dst;
final Executor executor;
OrApplyCompletion(CompletableFuture src,
CompletableFuture snd,
Fun fn,
CompletableFuture dst, Executor executor) {
this.src = src; this.snd = snd;
this.fn = fn; this.dst = dst;
this.executor = executor;
}
public final void run() {
final CompletableFuture a;
final CompletableFuture b;
final Fun fn;
final 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) ||
((b = this.snd) != null && (r = b.result) != null)) &&
compareAndSet(0, 1)) {
if (r instanceof AltResult) {
ex = ((AltResult)r).ex;
t = null;
}
else {
ex = null;
@SuppressWarnings("unchecked") T tr = (T) r;
t = tr;
}
Executor e = executor;
U u = null;
if (ex == null) {
try {
if (e != null)
e.execute(new AsyncApply(t, fn, dst));
else
u = fn.apply(t);
} catch (Throwable rex) {
ex = rex;
}
}
if (e == null || ex != null)
dst.internalComplete(u, ex);
}
}
private static final long serialVersionUID = 5232453952276885070L;
}
static final class OrAcceptCompletion extends Completion {
final CompletableFuture src;
final CompletableFuture snd;
final Action fn;
final CompletableFuture dst;
final Executor executor;
OrAcceptCompletion(CompletableFuture src,
CompletableFuture snd,
Action fn,
CompletableFuture dst, Executor executor) {
this.src = src; this.snd = snd;
this.fn = fn; this.dst = dst;
this.executor = executor;
}
public final void run() {
final CompletableFuture a;
final CompletableFuture b;
final Action fn;
final 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) ||
((b = this.snd) != null && (r = b.result) != null)) &&
compareAndSet(0, 1)) {
if (r instanceof AltResult) {
ex = ((AltResult)r).ex;
t = null;
}
else {
ex = null;
@SuppressWarnings("unchecked") T tr = (T) r;
t = tr;
}
Executor e = executor;
if (ex == null) {
try {
if (e != null)
e.execute(new AsyncAccept(t, fn, dst));
else
fn.accept(t);
} catch (Throwable rex) {
ex = rex;
}
}
if (e == null || ex != null)
dst.internalComplete(null, ex);
}
}
private static final long serialVersionUID = 5232453952276885070L;
}
static final class OrRunCompletion extends Completion {
final CompletableFuture src;
final CompletableFuture snd;
final Runnable fn;
final CompletableFuture dst;
final Executor executor;
OrRunCompletion(CompletableFuture 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 final void run() {
final CompletableFuture a;
final CompletableFuture b;
final Runnable fn;
final CompletableFuture dst;
Object r; Throwable ex;
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;
else
ex = null;
Executor e = executor;
if (ex == null) {
try {
if (e != null)
e.execute(new AsyncRun(fn, dst));
else
fn.run();
} catch (Throwable rex) {
ex = rex;
}
}
if (e == null || ex != null)
dst.internalComplete(null, ex);
}
}
private static final long serialVersionUID = 5232453952276885070L;
}
static final class ExceptionCompletion extends Completion {
final CompletableFuture src;
final Fun fn;
final CompletableFuture dst;
ExceptionCompletion(CompletableFuture src,
Fun fn,
CompletableFuture dst) {
this.src = src; this.fn = fn; this.dst = dst;
}
public final void run() {
final CompletableFuture a;
final Fun fn;
final CompletableFuture dst;
Object r; T t = null; Throwable ex, dx = null;
if ((dst = this.dst) != null &&
(fn = this.fn) != null &&
(a = this.src) != null &&
(r = a.result) != null &&
compareAndSet(0, 1)) {
if ((r instanceof AltResult) &&
(ex = ((AltResult)r).ex) != null) {
try {
t = fn.apply(ex);
} catch (Throwable rex) {
dx = rex;
}
}
else {
@SuppressWarnings("unchecked") T tr = (T) r;
t = tr;
}
dst.internalComplete(t, dx);
}
}
private static final long serialVersionUID = 5232453952276885070L;
}
static final class ThenCopy extends Completion {
final CompletableFuture src;
final CompletableFuture dst;
ThenCopy(CompletableFuture src,
CompletableFuture dst) {
this.src = src; this.dst = dst;
}
public final void run() {
final CompletableFuture a;
final CompletableFuture dst;
Object r; Object t; Throwable ex;
if ((dst = this.dst) != null &&
(a = this.src) != null &&
(r = a.result) != null &&
compareAndSet(0, 1)) {
if (r instanceof AltResult) {
ex = ((AltResult)r).ex;
t = null;
}
else {
ex = null;
t = r;
}
dst.internalComplete(t, ex);
}
}
private static final long serialVersionUID = 5232453952276885070L;
}
static final class HandleCompletion extends Completion {
final CompletableFuture src;
final BiFun fn;
final CompletableFuture dst;
HandleCompletion(CompletableFuture src,
BiFun fn,
final CompletableFuture dst) {
this.src = src; this.fn = fn; this.dst = dst;
}
public final void run() {
final CompletableFuture a;
final BiFun fn;
final 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) {
ex = ((AltResult)r).ex;
t = null;
}
else {
ex = null;
@SuppressWarnings("unchecked") T tr = (T) r;
t = tr;
}
U u = null; Throwable dx = null;
try {
u = fn.apply(t, ex);
} catch (Throwable rex) {
dx = rex;
}
dst.internalComplete(u, dx);
}
}
private static final long serialVersionUID = 5232453952276885070L;
}
static final class ComposeCompletion extends Completion {
final CompletableFuture src;
final Fun> fn;
final CompletableFuture dst;
ComposeCompletion(CompletableFuture src,
Fun> fn,
final CompletableFuture dst) {
this.src = src; this.fn = fn; this.dst = dst;
}
public final void run() {
final CompletableFuture a;
final Fun> fn;
final 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) {
ex = ((AltResult)r).ex;
t = null;
}
else {
ex = null;
@SuppressWarnings("unchecked") T tr = (T) r;
t = tr;
}
CompletableFuture c = null;
U u = null;
boolean complete = false;
if (ex == null) {
try {
c = fn.apply(t);
} catch (Throwable rex) {
ex = rex;
}
}
if (ex != null || c == null) {
if (ex == null)
ex = new NullPointerException();
}
else {
ThenCopy d = null;
Object s;
if ((s = c.result) == null) {
CompletionNode p = new CompletionNode
(d = new ThenCopy(c, dst));
while ((s = c.result) == null) {
if (UNSAFE.compareAndSwapObject
(c, COMPLETIONS, p.next = c.completions, p))
break;
}
}
if (s != null && (d == null || d.compareAndSet(0, 1))) {
complete = true;
if (s instanceof AltResult) {
ex = ((AltResult)s).ex; // no rewrap
u = null;
}
else {
@SuppressWarnings("unchecked") U us = (U) s;
u = us;
}
}
}
if (complete || ex != null)
dst.internalComplete(u, ex);
if (c != null)
c.helpPostComplete();
}
}
private static final long serialVersionUID = 5232453952276885070L;
}
// public methods
/**
* 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(Generator supplier) {
if (supplier == null) throw new NullPointerException();
CompletableFuture f = new CompletableFuture();
ForkJoinPool.commonPool().
execute((ForkJoinTask)new AsyncSupply(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(Generator supplier,
Executor executor) {
if (executor == null || supplier == null)
throw new NullPointerException();
CompletableFuture f = new CompletableFuture();
executor.execute(new AsyncSupply(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 AsyncRun(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 AsyncRun(runnable, f));
return f;
}
/**
* Returns {@code true} if completed in any fashion: normally,
* exceptionally, or via cancellation.
*
* @return {@code true} if completed
*/
public boolean isDone() {
return result != null;
}
/**
* Waits if necessary for the computation to complete, and then
* retrieves its result.
*
* @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
*/
public T get() throws InterruptedException, ExecutionException {
Object r; Throwable ex, cause;
if ((r = result) == null && (r = waitingGet(true)) == null)
throw new InterruptedException();
if (!(r instanceof AltResult)) {
@SuppressWarnings("unchecked") T tr = (T) r;
return tr;
}
if ((ex = ((AltResult)r).ex) == null)
return null;
if (ex instanceof CancellationException)
throw (CancellationException)ex;
if ((ex instanceof CompletionException) &&
(cause = ex.getCause()) != null)
ex = cause;
throw new ExecutionException(ex);
}
/**
* 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, cause;
long nanos = unit.toNanos(timeout);
if (Thread.interrupted())
throw new InterruptedException();
if ((r = result) == null)
r = timedAwaitDone(nanos);
if (!(r instanceof AltResult)) {
@SuppressWarnings("unchecked") T tr = (T) r;
return tr;
}
if ((ex = ((AltResult)r).ex) == null)
return null;
if (ex instanceof CancellationException)
throw (CancellationException)ex;
if ((ex instanceof CompletionException) &&
(cause = ex.getCause()) != null)
ex = cause;
throw new ExecutionException(ex);
}
/**
* Returns the result value when complete, or throws an
* (unchecked) exception if completed exceptionally. To better
* conform with the use of common functional forms, if a
* computation involved in the completion of this
* CompletableFuture threw an exception, this method throws an
* (unchecked) {@link CompletionException} with the underlying
* exception as its cause.
*
* @return the result value
* @throws CancellationException if the computation was cancelled
* @throws CompletionException if a completion computation threw
* an exception
*/
public T join() {
Object r; Throwable ex;
if ((r = result) == null)
r = waitingGet(false);
if (!(r instanceof AltResult)) {
@SuppressWarnings("unchecked") T tr = (T) r;
return tr;
}
if ((ex = ((AltResult)r).ex) == null)
return null;
if (ex instanceof CancellationException)
throw (CancellationException)ex;
if (ex instanceof CompletionException)
throw (CompletionException)ex;
throw new CompletionException(ex);
}
/**
* 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
* @throws CancellationException if the computation was cancelled
* @throws CompletionException if a completion computation threw
* an exception
*/
public T getNow(T valueIfAbsent) {
Object r; Throwable ex;
if ((r = result) == null)
return valueIfAbsent;
if (!(r instanceof AltResult)) {
@SuppressWarnings("unchecked") T tr = (T) r;
return tr;
}
if ((ex = ((AltResult)r).ex) == null)
return null;
if (ex instanceof CancellationException)
throw (CancellationException)ex;
if (ex instanceof CompletionException)
throw (CompletionException)ex;
throw new CompletionException(ex);
}
/**
* If not already completed, sets the value returned by {@link
* #get()} and related methods to the given value.
*
* @param value the result value
* @return {@code true} if this invocation caused this CompletableFuture
* to transition to a completed state, else {@code false}
*/
public boolean complete(T value) {
boolean triggered = result == null &&
UNSAFE.compareAndSwapObject(this, RESULT, null,
value == null ? NIL : value);
postComplete();
return triggered;
}
/**
* If not already completed, causes invocations of {@link #get()}
* and related methods to throw the given exception.
*
* @param ex the exception
* @return {@code true} if this invocation caused this CompletableFuture
* to transition to a completed state, else {@code false}
*/
public boolean completeExceptionally(Throwable ex) {
if (ex == null) throw new NullPointerException();
boolean triggered = result == null &&
UNSAFE.compareAndSwapObject(this, RESULT, null, new AltResult(ex));
postComplete();
return triggered;
}
/**
* 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 CompletionException holding 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(Fun fn) {
return doThenApply(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
* CompletionException holding 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(Fun fn) {
return doThenApply(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 CompletionException holding 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(Fun fn,
Executor executor) {
if (executor == null) throw new NullPointerException();
return doThenApply(fn, executor);
}
private CompletableFuture doThenApply(Fun fn,
Executor e) {
if (fn == null) throw new NullPointerException();
CompletableFuture dst = new CompletableFuture();
ApplyCompletion d = null;
Object r;
if ((r = result) == null) {
CompletionNode p = new CompletionNode
(d = new ApplyCompletion(this, fn, dst, e));
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;
if (r instanceof AltResult) {
ex = ((AltResult)r).ex;
t = null;
}
else {
ex = null;
@SuppressWarnings("unchecked") T tr = (T) r;
t = tr;
}
U u = null;
if (ex == null) {
try {
if (e != null)
e.execute(new AsyncApply(t, fn, dst));
else
u = fn.apply(t);
} catch (Throwable rex) {
ex = rex;
}
}
if (e == null || ex != null)
dst.internalComplete(u, ex);
}
helpPostComplete();
return dst;
}
/**
* 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 CompletionException holding this exception as
* its cause.
*
* @param block the action to perform before completing the
* returned CompletableFuture
* @return the new CompletableFuture
*/
public CompletableFuture thenAccept(Action block) {
return doThenAccept(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 CompletionException holding
* this exception as its cause.
*
* @param block the action to perform before completing the
* returned CompletableFuture
* @return the new CompletableFuture
*/
public CompletableFuture thenAcceptAsync(Action block) {
return doThenAccept(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 CompletionException holding
* 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(Action block,
Executor executor) {
if (executor == null) throw new NullPointerException();
return doThenAccept(block, executor);
}
private CompletableFuture doThenAccept(Action fn,
Executor e) {
if (fn == null) throw new NullPointerException();
CompletableFuture dst = new CompletableFuture();
AcceptCompletion d = null;
Object r;
if ((r = result) == null) {
CompletionNode p = new CompletionNode
(d = new AcceptCompletion(this, fn, dst, e));
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;
if (r instanceof AltResult) {
ex = ((AltResult)r).ex;
t = null;
}
else {
ex = null;
@SuppressWarnings("unchecked") T tr = (T) r;
t = tr;
}
if (ex == null) {
try {
if (e != null)
e.execute(new AsyncAccept(t, fn, dst));
else
fn.accept(t);
} catch (Throwable rex) {
ex = rex;
}
}
if (e == null || ex != null)
dst.internalComplete(null, ex);
}
helpPostComplete();
return dst;
}
/**
* 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
* CompletionException holding 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 doThenRun(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
* CompletionException holding 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 doThenRun(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 CompletionException holding
* 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 doThenRun(action, executor);
}
private CompletableFuture doThenRun(Runnable action,
Executor e) {
if (action == null) throw new NullPointerException();
CompletableFuture dst = new CompletableFuture();
RunCompletion d = null;
Object r;
if ((r = result) == null) {
CompletionNode p = new CompletionNode
(d = new RunCompletion(this, action, dst, e));
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;
if (r instanceof AltResult)
ex = ((AltResult)r).ex;
else
ex = null;
if (ex == null) {
try {
if (e != null)
e.execute(new AsyncRun(action, dst));
else
action.run();
} catch (Throwable rex) {
ex = rex;
}
}
if (e == null || ex != null)
dst.internalComplete(null, ex);
}
helpPostComplete();
return dst;
}
/**
* 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
* CompletionException holding 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 thenCombine(CompletableFuture other,
BiFun fn) {
return doThenBiApply(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
* CompletionException holding 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 thenCombineAsync(CompletableFuture other,
BiFun fn) {
return doThenBiApply(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
* CompletionException holding 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 thenCombineAsync(CompletableFuture other,
BiFun fn,
Executor executor) {
if (executor == null) throw new NullPointerException();
return doThenBiApply(other, fn, executor);
}
private CompletableFuture doThenBiApply(CompletableFuture other,
BiFun fn,
Executor e) {
if (other == null || fn == null) throw new NullPointerException();
CompletableFuture dst = new CompletableFuture();
BiApplyCompletion d = null;
Object r, s = null;
if ((r = result) == null || (s = other.result) == null) {
d = new BiApplyCompletion(this, other, fn, dst, e);
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;
if (r instanceof AltResult) {
ex = ((AltResult)r).ex;
t = null;
}
else {
ex = null;
@SuppressWarnings("unchecked") T tr = (T) r;
t = tr;
}
if (ex != null)
u = null;
else if (s instanceof AltResult) {
ex = ((AltResult)s).ex;
u = null;
}
else {
@SuppressWarnings("unchecked") U us = (U) s;
u = us;
}
V v = null;
if (ex == null) {
try {
if (e != null)
e.execute(new AsyncBiApply(t, u, fn, dst));
else
v = fn.apply(t, u);
} catch (Throwable rex) {
ex = rex;
}
}
if (e == null || ex != null)
dst.internalComplete(v, ex);
}
helpPostComplete();
other.helpPostComplete();
return dst;
}
/**
* 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 CompletionException holding one of these
* 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 thenAcceptBoth(CompletableFuture other,
BiAction block) {
return doThenBiAccept(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 CompletionException holding one of these
* 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 thenAcceptBothAsync(CompletableFuture other,
BiAction block) {
return doThenBiAccept(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 CompletionException holding one of these 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 thenAcceptBothAsync(CompletableFuture other,
BiAction block,
Executor executor) {
if (executor == null) throw new NullPointerException();
return doThenBiAccept(other, block, executor);
}
private CompletableFuture doThenBiAccept(CompletableFuture other,
BiAction fn,
Executor e) {
if (other == null || fn == null) throw new NullPointerException();
CompletableFuture dst = new CompletableFuture();
BiAcceptCompletion d = null;
Object r, s = null;
if ((r = result) == null || (s = other.result) == null) {
d = new BiAcceptCompletion(this, other, fn, dst, e);
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;
if (r instanceof AltResult) {
ex = ((AltResult)r).ex;
t = null;
}
else {
ex = null;
@SuppressWarnings("unchecked") T tr = (T) r;
t = tr;
}
if (ex != null)
u = null;
else if (s instanceof AltResult) {
ex = ((AltResult)s).ex;
u = null;
}
else {
@SuppressWarnings("unchecked") U us = (U) s;
u = us;
}
if (ex == null) {
try {
if (e != null)
e.execute(new AsyncBiAccept(t, u, fn, dst));
else
fn.accept(t, u);
} catch (Throwable rex) {
ex = rex;
}
}
if (e == null || ex != null)
dst.internalComplete(null, ex);
}
helpPostComplete();
other.helpPostComplete();
return dst;
}
/**
* 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 CompletionException holding one of these 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 runAfterBoth(CompletableFuture other,
Runnable action) {
return doThenBiRun(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 CompletionException holding one of these 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 runAfterBothAsync(CompletableFuture other,
Runnable action) {
return doThenBiRun(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 CompletionException holding one of these 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 runAfterBothAsync(CompletableFuture other,
Runnable action,
Executor executor) {
if (executor == null) throw new NullPointerException();
return doThenBiRun(other, action, executor);
}
private CompletableFuture doThenBiRun(CompletableFuture other,
Runnable action,
Executor e) {
if (other == null || action == null) throw new NullPointerException();
CompletableFuture dst = new CompletableFuture();
BiRunCompletion d = null;
Object r, s = null;
if ((r = result) == null || (s = other.result) == null) {
d = new BiRunCompletion(this, other, action, dst, e);
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;
if (r instanceof AltResult)
ex = ((AltResult)r).ex;
else
ex = null;
if (ex == null && (s instanceof AltResult))
ex = ((AltResult)s).ex;
if (ex == null) {
try {
if (e != null)
e.execute(new AsyncRun(action, dst));
else
action.run();
} catch (Throwable rex) {
ex = rex;
}
}
if (e == null || ex != null)
dst.internalComplete(null, ex);
}
helpPostComplete();
other.helpPostComplete();
return dst;
}
/**
* 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
* CompletionException holding 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 applyToEither(CompletableFuture other,
Fun fn) {
return doOrApply(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
* CompletionException holding 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 applyToEitherAsync(CompletableFuture other,
Fun fn) {
return doOrApply(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
* CompletionException holding 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 applyToEitherAsync(CompletableFuture other,
Fun fn,
Executor executor) {
if (executor == null) throw new NullPointerException();
return doOrApply(other, fn, executor);
}
private CompletableFuture doOrApply(CompletableFuture other,
Fun fn,
Executor e) {
if (other == null || fn == null) throw new NullPointerException();
CompletableFuture dst = new CompletableFuture();
OrApplyCompletion d = null;
Object r;
if ((r = result) == null && (r = other.result) == null) {
d = new OrApplyCompletion(this, other, fn, dst, e);
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;
if (r instanceof AltResult) {
ex = ((AltResult)r).ex;
t = null;
}
else {
ex = null;
@SuppressWarnings("unchecked") T tr = (T) r;
t = tr;
}
U u = null;
if (ex == null) {
try {
if (e != null)
e.execute(new AsyncApply(t, fn, dst));
else
u = fn.apply(t);
} catch (Throwable rex) {
ex = rex;
}
}
if (e == null || ex != null)
dst.internalComplete(u, ex);
}
helpPostComplete();
other.helpPostComplete();
return dst;
}
/**
* 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 CompletionException holding 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 acceptEither(CompletableFuture other,
Action block) {
return doOrAccept(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 CompletionException holding 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 acceptEitherAsync(CompletableFuture other,
Action block) {
return doOrAccept(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 CompletionException holding 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 acceptEitherAsync(CompletableFuture other,
Action block,
Executor executor) {
if (executor == null) throw new NullPointerException();
return doOrAccept(other, block, executor);
}
private CompletableFuture doOrAccept(CompletableFuture other,
Action fn,
Executor e) {
if (other == null || fn == null) throw new NullPointerException();
CompletableFuture dst = new CompletableFuture();
OrAcceptCompletion d = null;
Object r;
if ((r = result) == null && (r = other.result) == null) {
d = new OrAcceptCompletion(this, other, fn, dst, e);
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;
if (r instanceof AltResult) {
ex = ((AltResult)r).ex;
t = null;
}
else {
ex = null;
@SuppressWarnings("unchecked") T tr = (T) r;
t = tr;
}
if (ex == null) {
try {
if (e != null)
e.execute(new AsyncAccept(t, fn, dst));
else
fn.accept(t);
} catch (Throwable rex) {
ex = rex;
}
}
if (e == null || ex != null)
dst.internalComplete(null, ex);
}
helpPostComplete();
other.helpPostComplete();
return dst;
}
/**
* 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
* CompletionException holding 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 runAfterEither(CompletableFuture other,
Runnable action) {
return doOrRun(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
* CompletionException holding 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 runAfterEitherAsync(CompletableFuture other,
Runnable action) {
return doOrRun(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 CompletionException
* holding 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 runAfterEitherAsync(CompletableFuture other,
Runnable action,
Executor executor) {
if (executor == null) throw new NullPointerException();
return doOrRun(other, action, executor);
}
private CompletableFuture doOrRun(CompletableFuture other,
Runnable action,
Executor e) {
if (other == null || action == null) throw new NullPointerException();
CompletableFuture dst = new CompletableFuture();
OrRunCompletion d = null;
Object r;
if ((r = result) == null && (r = other.result) == null) {
d = new OrRunCompletion(this, other, action, dst, e);
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;
if (r instanceof AltResult)
ex = ((AltResult)r).ex;
else
ex = null;
if (ex == null) {
try {
if (e != null)
e.execute(new AsyncRun(action, dst));
else
action.run();
} catch (Throwable rex) {
ex = rex;
}
}
if (e == null || ex != null)
dst.internalComplete(null, ex);
}
helpPostComplete();
other.helpPostComplete();
return dst;
}
/**
* Returns a CompletableFuture (or an equivalent one) produced by
* the given function of the result of this CompletableFuture when
* completed. If this CompletableFuture completes exceptionally,
* then the returned CompletableFuture also does so, with a
* CompletionException holding this exception as its cause.
*
* @param fn the function returning a new CompletableFuture
* @return the CompletableFuture, that {@code isDone()} upon
* return if completed by the given function, or an exception
* occurs
*/
public CompletableFuture thenCompose(Fun> fn) {
if (fn == null) throw new NullPointerException();
CompletableFuture dst = null;
ComposeCompletion d = null;
Object r;
if ((r = result) == null) {
dst = new CompletableFuture();
CompletionNode p = new CompletionNode
(d = new ComposeCompletion(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;
if (r instanceof AltResult) {
ex = ((AltResult)r).ex;
t = null;
}
else {
ex = null;
@SuppressWarnings("unchecked") T tr = (T) r;
t = tr;
}
if (ex == null) {
try {
dst = fn.apply(t);
} catch (Throwable rex) {
ex = rex;
}
}
if (dst == null) {
dst = new CompletableFuture();
if (ex == null)
ex = new NullPointerException();
}
if (ex != null)
dst.internalComplete(null, ex);
}
helpPostComplete();
dst.helpPostComplete();
return dst;
}
/**
* 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(Fun fn) {
if (fn == null) throw new NullPointerException();
CompletableFuture dst = new CompletableFuture();
ExceptionCompletion d = null;
Object r;
if ((r = result) == null) {
CompletionNode p =
new CompletionNode(d = new ExceptionCompletion(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 = null; Throwable ex, dx = null;
if (r instanceof AltResult) {
if ((ex = ((AltResult)r).ex) != null) {
try {
t = fn.apply(ex);
} catch (Throwable rex) {
dx = rex;
}
}
}
else {
@SuppressWarnings("unchecked") T tr = (T) r;
t = tr;
}
dst.internalComplete(t, dx);
}
helpPostComplete();
return dst;
}
/**
* Creates and returns a CompletableFuture that is completed with
* the result of the given function of the result and exception of
* this CompletableFuture's completion when it completes. The
* given function is invoked with the result (or {@code null} if
* none) and the exception (or {@code null} if none) of this
* CompletableFuture when complete.
*
* @param fn the function to use to compute the value of the
* returned CompletableFuture
* @return the new CompletableFuture
*/
public CompletableFuture handle(BiFun fn) {
if (fn == null) throw new NullPointerException();
CompletableFuture dst = new CompletableFuture();
HandleCompletion d = null;
Object r;
if ((r = result) == null) {
CompletionNode p =
new CompletionNode(d = new HandleCompletion(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;
if (r instanceof AltResult) {
ex = ((AltResult)r).ex;
t = null;
}
else {
ex = null;
@SuppressWarnings("unchecked") T tr = (T) r;
t = tr;
}
U u; Throwable dx;
try {
u = fn.apply(t, ex);
dx = null;
} catch (Throwable rex) {
dx = rex;
u = null;
}
dst.internalComplete(u, dx);
}
helpPostComplete();
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) instanceof AltResult) &&
(((AltResult)r).ex instanceof CancellationException);
}
/**
* Forcibly sets or resets the value subsequently returned by
* method {@link #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 outcomes.
*
* @param value the completion value
*/
public void obtrudeValue(T value) {
result = (value == null) ? NIL : value;
postComplete();
}
/**
* Forcibly causes subsequent invocations of method {@link #get()}
* and related methods to throw the given exception, whether or
* not already completed. This method is designed for use only in
* recovery actions, and even in such situations may result in
* ongoing dependent completions using established versus
* overwritten outcomes.
*
* @param ex the exception
*/
public void obtrudeException(Throwable ex) {
if (ex == null) throw new NullPointerException();
result = new AltResult(ex);
postComplete();
}
// 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 = 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);
}
}
/**
* Returns a sun.misc.Unsafe. Suitable for use in a 3rd party package.
* Replace with a simple call to Unsafe.getUnsafe when integrating
* into a jdk.
*
* @return a sun.misc.Unsafe
*/
private static sun.misc.Unsafe getUnsafe() {
try {
return sun.misc.Unsafe.getUnsafe();
} catch (SecurityException tryReflectionInstead) {}
try {
return java.security.AccessController.doPrivileged
(new java.security.PrivilegedExceptionAction() {
public sun.misc.Unsafe run() throws Exception {
Class k = sun.misc.Unsafe.class;
for (java.lang.reflect.Field f : k.getDeclaredFields()) {
f.setAccessible(true);
Object x = f.get(null);
if (k.isInstance(x))
return k.cast(x);
}
throw new NoSuchFieldError("the Unsafe");
}});
} catch (java.security.PrivilegedActionException e) {
throw new RuntimeException("Could not initialize intrinsics",
e.getCause());
}
}
}