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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) 2017-2023 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.ArrayDeque;
import java.util.Deque;
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 org.reactivestreams.Publisher;
import org.reactivestreams.Subscriber;
import org.reactivestreams.Subscription;
import reactor.core.CorePublisher;
import reactor.core.CoreSubscriber;
import reactor.core.Exceptions;
import reactor.util.annotation.Nullable;
import reactor.util.concurrent.Queues;
import reactor.util.context.Context;
/**
* A {@link Flux} that emits items from upstream and recursively expand them into
* inner sequences that are also replayed. The type of recursion is driven by the
* {@code breadthFirst} parameter.
*
* @param
*
* @author David Karnok
* @author Simon Baslé
*/
//adapted from RxJava2Extensions: https://github.com/akarnokd/RxJava2Extensions/blob/master/src/main/java/hu/akarnokd/rxjava2/operators/FlowableExpand.java
final class FluxExpand extends InternalFluxOperator {
final boolean breadthFirst;
final Function super T, ? extends Publisher extends T>> expander;
final int capacityHint;
FluxExpand(Flux source,
Function super T, ? extends Publisher extends T>> expander,
boolean breadthFirst, int capacityHint) {
super(source);
this.expander = expander;
this.breadthFirst = breadthFirst;
this.capacityHint = capacityHint;
}
@Override
public CoreSubscriber super T> subscribeOrReturn(CoreSubscriber super T> s) {
if (breadthFirst) {
ExpandBreathSubscriber parent =
new ExpandBreathSubscriber<>(s, expander, capacityHint);
parent.queue.offer(source);
s.onSubscribe(parent);
parent.drainQueue();
}
else {
ExpandDepthSubscription parent =
new ExpandDepthSubscription<>(s, expander, capacityHint);
parent.source = source;
s.onSubscribe(parent);
}
return null;
}
@Override
public Object scanUnsafe(Attr key) {
if (key == Attr.RUN_STYLE) return Attr.RunStyle.SYNC;
return super.scanUnsafe(key);
}
static final class ExpandBreathSubscriber
extends Operators.MultiSubscriptionSubscriber {
final Function super T, ? extends Publisher extends T>> expander;
final Queue> queue;
volatile boolean active;
volatile int wip;
static final AtomicIntegerFieldUpdater WIP =
AtomicIntegerFieldUpdater.newUpdater(ExpandBreathSubscriber.class, "wip");
long produced;
ExpandBreathSubscriber(CoreSubscriber super T> actual,
Function super T, ? extends Publisher extends T>> expander,
int capacityHint) {
super(actual);
this.expander = expander;
this.queue = Queues.>unbounded(capacityHint).get();
}
@Override
public void onSubscribe(Subscription s) {
set(s);
}
@Override
public void onNext(T t) {
produced++;
actual.onNext(t);
Publisher extends T> p;
try {
p = Operators.toFluxOrMono(Objects.requireNonNull(expander.apply(t),
"The expander returned a null Publisher"));
}
catch (Throwable ex) {
Exceptions.throwIfFatal(ex);
super.cancel();
actual.onError(ex);
drainQueue();
return;
}
queue.offer(p);
}
@Override
public void onError(Throwable t) {
set(Operators.cancelledSubscription());
super.cancel();
actual.onError(t);
drainQueue();
}
@Override
public void onComplete() {
active = false;
drainQueue();
}
@Override
public void cancel() {
super.cancel();
drainQueue();
}
void drainQueue() {
if (WIP.getAndIncrement(this) == 0) {
do {
Queue> q = queue;
if (isCancelled()) {
q.clear();
}
else {
if (!active) {
if (q.isEmpty()) {
set(Operators.cancelledSubscription());
super.cancel();
actual.onComplete();
}
else {
Publisher extends T> p = q.poll();
long c = produced;
if (c != 0L) {
produced = 0L;
produced(c);
}
active = true;
p.subscribe(this);
}
}
}
}
while (WIP.decrementAndGet(this) != 0);
}
}
@Nullable
@Override
public Object scanUnsafe(Attr key) {
if (key == Attr.BUFFERED) return queue != null ? queue.size() : 0;
if (key == Attr.RUN_STYLE) return Attr.RunStyle.SYNC;
return super.scanUnsafe(key);
}
}
static final class ExpandDepthSubscription implements InnerProducer {
final CoreSubscriber super T> actual;
final Function super T, ? extends Publisher extends T>> expander;
volatile Throwable error;
static final AtomicReferenceFieldUpdater ERROR =
AtomicReferenceFieldUpdater.newUpdater(ExpandDepthSubscription.class, Throwable.class, "error");
volatile int active;
static final AtomicIntegerFieldUpdater ACTIVE =
AtomicIntegerFieldUpdater.newUpdater(ExpandDepthSubscription.class, "active");
volatile long requested;
static final AtomicLongFieldUpdater REQUESTED =
AtomicLongFieldUpdater.newUpdater(ExpandDepthSubscription.class, "requested");
volatile Object current;
static final AtomicReferenceFieldUpdater CURRENT =
AtomicReferenceFieldUpdater.newUpdater(ExpandDepthSubscription.class, Object.class, "current");
volatile int wip;
static final AtomicIntegerFieldUpdater WIP =
AtomicIntegerFieldUpdater.newUpdater(ExpandDepthSubscription.class, "wip");
Deque> subscriptionStack;
volatile boolean cancelled;
CorePublisher extends T> source;
long consumed;
ExpandDepthSubscription(CoreSubscriber super T> actual,
Function super T, ? extends Publisher extends T>> expander,
int capacityHint) {
this.actual = actual;
this.expander = expander;
this.subscriptionStack = new ArrayDeque<>(capacityHint);
}
@Override
public CoreSubscriber super T> actual() {
return actual;
}
@Override
public void request(long n) {
if (Operators.validate(n)) {
Operators.addCap(REQUESTED, this, n);
drainQueue();
}
}
@SuppressWarnings("unchecked")
@Override
public void cancel() {
if (!cancelled) {
cancelled = true;
Deque> q;
synchronized (this) {
q = subscriptionStack;
subscriptionStack = null;
}
if (q != null) {
while (!q.isEmpty()) {
q.poll().dispose();
}
}
Object o = CURRENT.getAndSet(this, this);
if (o != this && o != null) {
((ExpandDepthSubscriber) o).dispose();
}
}
}
@Nullable
ExpandDepthSubscriber pop() {
synchronized (this) {
Deque> q = subscriptionStack;
return q != null ? q.pollFirst() : null;
}
}
boolean push(ExpandDepthSubscriber subscriber) {
synchronized (this) {
Deque> q = subscriptionStack;
if (q != null) {
q.offerFirst(subscriber);
return true;
}
return false;
}
}
boolean setCurrent(ExpandDepthSubscriber inner) {
for (;;) {
Object o = CURRENT.get(this);
if (o == this) {
inner.dispose();
return false;
}
if (CURRENT.compareAndSet(this, o, inner)) {
return true;
}
}
}
void drainQueue() {
if (WIP.getAndIncrement(this) != 0) {
return;
}
int missed = 1;
Subscriber super T> a = actual;
long e = consumed;
for (;;) {
Object o = current;
if (cancelled || o == this) {
source = null;
return;
}
@SuppressWarnings("unchecked")
ExpandDepthSubscriber curr = (ExpandDepthSubscriber)o;
Publisher extends T> p = source;
if (curr == null && p != null) {
source = null;
ACTIVE.getAndIncrement(this);
ExpandDepthSubscriber eds = new ExpandDepthSubscriber<>(this);
if (setCurrent(eds)) {
p.subscribe(eds);
}
else {
return;
}
}
else if (curr == null) {
return;
}
else {
boolean currentDone = curr.done;
T v = curr.value;
boolean newSource = false;
if (v != null && e != requested) {
curr.value = null;
a.onNext(v);
e++;
try {
p = Objects.requireNonNull(expander.apply(v),
"The expander returned a null Publisher");
}
catch (Throwable ex) {
Exceptions.throwIfFatal(ex);
p = null;
curr.dispose();
curr.done = true;
currentDone = true;
v = null;
Exceptions.addThrowable(ERROR, this, ex);
}
if (p != null) {
if (push(curr)) {
ACTIVE.getAndIncrement(this);
curr = new ExpandDepthSubscriber<>(this);
if (setCurrent(curr)) {
p.subscribe(curr);
newSource = true;
}
else {
return;
}
}
}
}
if (!newSource) {
if (currentDone && v == null) {
if (ACTIVE.decrementAndGet(this) == 0) {
Throwable ex = Exceptions.terminate(ERROR, this);
if (ex != null) {
a.onError(ex);
}
else {
a.onComplete();
}
return;
}
curr = pop();
if (curr != null && setCurrent(curr)) {
curr.requestOne();
continue;
}
else {
return;
}
}
}
}
int w = wip;
if (missed == w) {
consumed = e;
missed = WIP.addAndGet(this, -missed);
if (missed == 0) {
break;
}
}
else {
missed = w;
}
}
}
void innerNext() {
drainQueue();
}
void innerError(ExpandDepthSubscriber inner, Throwable t) {
Exceptions.addThrowable(ERROR, this, t);
inner.done = true;
drainQueue();
}
void innerComplete(ExpandDepthSubscriber inner) {
inner.done = true;
drainQueue();
}
@Nullable
@Override
public Object scanUnsafe(Attr key) {
if (key == Attr.CANCELLED) return cancelled;
if (key == Attr.REQUESTED_FROM_DOWNSTREAM) return this.requested;
if (key == Attr.ERROR) return this.error;
return InnerProducer.super.scanUnsafe(key);
}
}
static final class ExpandDepthSubscriber implements InnerConsumer {
ExpandDepthSubscription parent;
volatile boolean done;
volatile T value;
volatile Subscription s;
static final AtomicReferenceFieldUpdater S =
AtomicReferenceFieldUpdater.newUpdater(ExpandDepthSubscriber.class, Subscription.class, "s");
ExpandDepthSubscriber(ExpandDepthSubscription parent) {
this.parent = parent;
}
@Override
public void onSubscribe(Subscription s) {
if (Operators.setOnce(S, this, s)) {
s.request(1);
}
}
@Override
public void onNext(T t) {
if (s != Operators.cancelledSubscription()) {
value = t;
parent.innerNext();
}
}
@Override
public void onError(Throwable t) {
if (s != Operators.cancelledSubscription()) {
parent.innerError(this, t);
}
}
@Override
public void onComplete() {
if (s != Operators.cancelledSubscription()) {
parent.innerComplete(this);
}
}
void requestOne() {
s.request(1);
}
void dispose() {
Operators.terminate(S, this);
}
@Nullable
@Override
public Object scanUnsafe(Attr key) {
if (key == Attr.PARENT) return s;
if (key == Attr.ACTUAL) return parent.actual;
if (key == Attr.TERMINATED) return this.done;
if (key == Attr.RUN_STYLE) return Attr.RunStyle.SYNC;
return null;
}
@Override
public Context currentContext() {
return parent.actual().currentContext();
}
}
}
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