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Easy Redis Java client and Real-Time Data Platform. Valkey compatible. Sync/Async/RxJava3/Reactive API. Client side caching. Over 50 Redis based Java objects and services: JCache API, Apache Tomcat, Hibernate, Spring, Set, Multimap, SortedSet, Map, List, Queue, Deque, Semaphore, Lock, AtomicLong, Map Reduce, Bloom filter, Scheduler, RPC
/*
* Copyright (c) 2016-2023 VMware Inc. or its affiliates, All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package reactor.core.publisher;
import java.util.Objects;
import java.util.Queue;
import java.util.concurrent.atomic.AtomicIntegerFieldUpdater;
import java.util.concurrent.atomic.AtomicLongFieldUpdater;
import java.util.concurrent.atomic.AtomicReferenceFieldUpdater;
import java.util.function.Function;
import java.util.function.Supplier;
import java.util.stream.Stream;
import org.reactivestreams.Publisher;
import org.reactivestreams.Subscriber;
import org.reactivestreams.Subscription;
import reactor.core.CoreSubscriber;
import reactor.core.Exceptions;
import reactor.core.Fuseable;
import reactor.core.Fuseable.QueueSubscription;
import reactor.core.Scannable;
import reactor.core.publisher.FluxConcatMap.ErrorMode;
import reactor.util.annotation.Nullable;
import reactor.util.concurrent.Queues;
import reactor.util.context.Context;
/**
* Maps each upstream value into a Publisher and concatenates them into one
* sequence of items.
*
* @param the source value type
* @param the output value type
* @see Reactive-Streams-Commons
*/
final class FluxMergeSequential extends InternalFluxOperator {
final ErrorMode errorMode;
final Function> mapper;
final int maxConcurrency;
final int prefetch;
final Supplier>> queueSupplier;
FluxMergeSequential(Flux source,
Function> mapper,
int maxConcurrency, int prefetch, ErrorMode errorMode) {
this(source, mapper, maxConcurrency, prefetch, errorMode,
Queues.get(Math.max(prefetch, maxConcurrency)));
}
//for testing purpose
FluxMergeSequential(Flux source,
Function> mapper,
int maxConcurrency, int prefetch, ErrorMode errorMode,
Supplier>> queueSupplier) {
super(source);
if (prefetch <= 0) {
throw new IllegalArgumentException("prefetch > 0 required but it was " + prefetch);
}
if (maxConcurrency <= 0) {
throw new IllegalArgumentException("maxConcurrency > 0 required but it was " + maxConcurrency);
}
this.mapper = Objects.requireNonNull(mapper, "mapper");
this.maxConcurrency = maxConcurrency;
this.prefetch = prefetch;
this.errorMode = errorMode;
this.queueSupplier = queueSupplier;
}
@Override
public CoreSubscriber subscribeOrReturn(CoreSubscriber actual) {
//for now mergeSequential doesn't support onErrorContinue, so the scalar version shouldn't either
if (FluxFlatMap.trySubscribeScalarMap(source, actual, mapper, false, false)) {
return null;
}
return new MergeSequentialMain(actual,
mapper,
maxConcurrency,
prefetch,
errorMode,
queueSupplier);
}
@Override
public Object scanUnsafe(Attr key) {
if (key == Attr.RUN_STYLE) return Attr.RunStyle.SYNC;
return super.scanUnsafe(key);
}
static final class MergeSequentialMain implements InnerOperator {
/** the mapper giving the inner publisher for each source value */
final Function> mapper;
/** how many eagerly subscribed inner stream at a time, at most */
final int maxConcurrency;
/** request size for inner subscribers (size of the inner queues) */
final int prefetch;
final Queue> subscribers;
/** whether or not errors should be delayed until the very end of all inner
* publishers or just until the completion of the currently merged inner publisher
*/
final ErrorMode errorMode;
final CoreSubscriber actual;
Subscription s;
volatile boolean done;
volatile boolean cancelled;
volatile Throwable error;
static final AtomicReferenceFieldUpdater ERROR =
AtomicReferenceFieldUpdater.newUpdater(MergeSequentialMain.class, Throwable.class, "error");
MergeSequentialInner current;
/** guard against multiple threads entering the drain loop. allows thread
* stealing by continuing the loop if wip has been incremented externally by
* a separate thread. */
volatile int wip;
static final AtomicIntegerFieldUpdater WIP =
AtomicIntegerFieldUpdater.newUpdater(MergeSequentialMain.class, "wip");
volatile long requested;
static final AtomicLongFieldUpdater REQUESTED =
AtomicLongFieldUpdater.newUpdater(MergeSequentialMain.class, "requested");
MergeSequentialMain(CoreSubscriber actual,
Function> mapper,
int maxConcurrency, int prefetch, ErrorMode errorMode,
Supplier>> queueSupplier) {
this.actual = actual;
this.mapper = mapper;
this.maxConcurrency = maxConcurrency;
this.prefetch = prefetch;
this.errorMode = errorMode;
this.subscribers = queueSupplier.get();
}
@Override
public final CoreSubscriber actual() {
return actual;
}
@Override
public Stream inners() {
return Stream.of(subscribers.peek());
}
@Override
@Nullable
public Object scanUnsafe(Attr key) {
if (key == Attr.PARENT) return s;
if (key == Attr.ERROR) return error;
if (key == Attr.TERMINATED) return done && subscribers.isEmpty();
if (key == Attr.DELAY_ERROR) return errorMode != ErrorMode.IMMEDIATE;
if (key == Attr.PREFETCH) return maxConcurrency;
if (key == Attr.REQUESTED_FROM_DOWNSTREAM) return requested;
if (key == Attr.BUFFERED) return subscribers.size();
if (key == Attr.RUN_STYLE) return Attr.RunStyle.SYNC;
return InnerOperator.super.scanUnsafe(key);
}
@Override
public void onSubscribe(Subscription s) {
if (Operators.validate(this.s, s)) {
this.s = s;
actual.onSubscribe(this);
s.request(maxConcurrency == Integer.MAX_VALUE ? Long.MAX_VALUE :
maxConcurrency);
}
}
@Override
public void onNext(T t) {
Publisher publisher;
try {
publisher = Operators.toFluxOrMono(Objects.requireNonNull(mapper.apply(t), "publisher"));
}
catch (Throwable ex) {
onError(Operators.onOperatorError(s, ex, t, actual.currentContext()));
return;
}
MergeSequentialInner inner = new MergeSequentialInner<>(this, prefetch);
if (cancelled) {
return;
}
if (!subscribers.offer(inner)) {
int badSize = subscribers.size();
inner.cancel();
drainAndCancel();
onError(Operators.onOperatorError(s,
new IllegalStateException("Too many subscribers for " +
"fluxMergeSequential on item: " + t +
"; subscribers: " + badSize),
t, actual.currentContext()));
return;
}
if (cancelled) {
return;
}
publisher.subscribe(inner);
if (cancelled) {
inner.cancel();
drainAndCancel();
}
}
@Override
public void onError(Throwable t) {
if (Exceptions.addThrowable(ERROR, this, t)) {
done = true;
drain();
}
else {
Operators.onErrorDropped(t, actual.currentContext());
}
}
@Override
public void onComplete() {
done = true;
drain();
}
@Override
public void cancel() {
if (cancelled) {
return;
}
cancelled = true;
s.cancel();
drainAndCancel();
}
void drainAndCancel() {
if (WIP.getAndIncrement(this) == 0) {
do {
cancelAll();
}
while (WIP.decrementAndGet(this) != 0);
}
}
void cancelAll() {
MergeSequentialInner c = this.current;
if (c != null) {
c.cancel();
}
MergeSequentialInner inner;
while ((inner = subscribers.poll()) != null) {
inner.cancel();
}
}
@Override
public void request(long n) {
if (Operators.validate(n)) {
Operators.addCap(REQUESTED, this, n);
drain();
}
}
void innerNext(MergeSequentialInner inner, R value) {
if (inner.queue().offer(value)) {
drain();
}
else {
inner.cancel();
onError(Operators.onOperatorError(null, Exceptions.failWithOverflow(Exceptions.BACKPRESSURE_ERROR_QUEUE_FULL), value,
actual.currentContext()));
}
}
void innerError(MergeSequentialInner inner, Throwable e) {
e = Operators.onNextInnerError(e, currentContext(), s);
if (e != null) {
if (Exceptions.addThrowable(ERROR, this, e)) {
inner.setDone();
if (errorMode != ErrorMode.END) {
s.cancel();
}
drain();
}
else {
Operators.onErrorDropped(e, actual.currentContext());
}
}
else {
inner.setDone();
drain();
}
}
void innerComplete(MergeSequentialInner inner) {
inner.setDone();
drain();
}
void drain() {
if (WIP.getAndIncrement(this) != 0) {
return;
}
int missed = 1;
MergeSequentialInner inner = current;
Subscriber a = actual;
ErrorMode em = errorMode;
for (; ; ) {
long r = requested;
long e = 0L;
if (inner == null) {
if (em != ErrorMode.END) {
Throwable ex = error;
if (ex != null) {
cancelAll();
a.onError(ex);
return;
}
}
boolean outerDone = done;
inner = subscribers.poll();
if (outerDone && inner == null) {
Throwable ex = error;
if (ex != null) {
a.onError(ex);
}
else {
a.onComplete();
}
return;
}
if (inner != null) {
current = inner;
}
}
boolean continueNextSource = false;
if (inner != null) {
Queue q = inner.queue();
//noinspection ConstantConditions
if (q != null) {
while (e != r) {
if (cancelled) {
cancelAll();
return;
}
if (em == ErrorMode.IMMEDIATE) {
Throwable ex = error;
if (ex != null) {
current = null;
inner.cancel();
cancelAll();
a.onError(ex);
return;
}
}
boolean d = inner.isDone();
R v;
try {
v = q.poll();
}
catch (Throwable ex) {
current = null;
inner.cancel();
ex = Operators.onOperatorError(ex,
actual.currentContext());
cancelAll();
a.onError(ex);
return;
}
boolean empty = v == null;
if (d && empty) {
inner = null;
current = null;
s.request(1);
continueNextSource = true;
break;
}
if (empty) {
break;
}
a.onNext(v);
e++;
inner.requestOne();
}
if (e == r) {
if (cancelled) {
cancelAll();
return;
}
if (em == ErrorMode.IMMEDIATE) {
Throwable ex = error;
if (ex != null) {
current = null;
inner.cancel();
cancelAll();
a.onError(ex);
return;
}
}
boolean d = inner.isDone();
boolean empty = q.isEmpty();
if (d && empty) {
inner = null;
current = null;
s.request(1);
continueNextSource = true;
}
}
}
}
if (e != 0L && r != Long.MAX_VALUE) {
REQUESTED.addAndGet(this, -e);
}
if (continueNextSource) {
continue;
}
missed = WIP.addAndGet(this, -missed);
if (missed == 0) {
break;
}
}
}
}
/**
* Represents the inner flux in a mergeSequential, that has an internal queue to
* hold items while they arrive out of order. The queue is drained as soon as correct
* order can be restored.
* @param the type of objects emitted by the inner flux
*/
static final class MergeSequentialInner implements InnerConsumer{
final MergeSequentialMain parent;
final int prefetch;
final int limit;
volatile Queue queue;
volatile Subscription subscription;
static final AtomicReferenceFieldUpdater
SUBSCRIPTION = AtomicReferenceFieldUpdater.newUpdater(
MergeSequentialInner.class, Subscription.class, "subscription");
volatile boolean done;
long produced;
int fusionMode;
MergeSequentialInner(MergeSequentialMain parent, int prefetch) {
this.parent = parent;
this.prefetch = prefetch;
this.limit = Operators.unboundedOrLimit(prefetch);
}
@Override
public Context currentContext() {
return parent.currentContext();
}
@Override
@Nullable
public Object scanUnsafe(Attr key) {
if (key == Attr.PARENT) return subscription;
if (key == Attr.ACTUAL) return parent;
if (key == Attr.TERMINATED) return done && (queue == null || queue.isEmpty());
if (key == Attr.CANCELLED) return subscription == Operators.cancelledSubscription();
if (key == Attr.BUFFERED) return queue == null ? 0 : queue.size();
if (key == Attr.PREFETCH) return prefetch;
if (key == Attr.RUN_STYLE) return Attr.RunStyle.SYNC;
return null;
}
@Override
public void onSubscribe(Subscription s) {
if (Operators.setOnce(SUBSCRIPTION, this, s)) {
if (s instanceof QueueSubscription) {
@SuppressWarnings("unchecked")
QueueSubscription qs = (QueueSubscription) s;
int m = qs.requestFusion(Fuseable.ANY | Fuseable.THREAD_BARRIER);
if (m == Fuseable.SYNC) {
fusionMode = m;
queue = qs;
done = true;
parent.innerComplete(this);
return;
}
if (m == Fuseable.ASYNC) {
fusionMode = m;
queue = qs;
s.request(Operators.unboundedOrPrefetch(prefetch));
return;
}
}
queue = Queues.get(prefetch).get();
s.request(Operators.unboundedOrPrefetch(prefetch));
}
}
@Override
public void onNext(R t) {
if (fusionMode == Fuseable.NONE) {
parent.innerNext(this, t);
} else {
parent.drain();
}
}
@Override
public void onError(Throwable t) {
parent.innerError(this, t);
}
@Override
public void onComplete() {
parent.innerComplete(this);
}
void requestOne() {
if (fusionMode != Fuseable.SYNC) {
long p = produced + 1;
if (p == limit) {
produced = 0L;
subscription.request(p);
} else {
produced = p;
}
}
}
void cancel() {
Operators.set(SUBSCRIPTION, this, Operators.cancelledSubscription());
}
boolean isDone() {
return done;
}
void setDone() {
this.done = true;
}
Queue queue() {
return queue;
}
}
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