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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.Map;
import java.util.Objects;
import java.util.Queue;
import java.util.concurrent.ConcurrentHashMap;
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.Subscriber;
import org.reactivestreams.Subscription;
import reactor.core.CoreSubscriber;
import reactor.core.Exceptions;
import reactor.core.Fuseable;
import reactor.core.Scannable;
import reactor.util.annotation.Nullable;
import reactor.util.context.Context;
/**
* Groups upstream items into their own Publisher sequence based on a key selector.
*
* @param the source value type
* @param the key value type
* @param the group item value type
*
* @see Reactive-Streams-Commons
*/
final class FluxGroupBy extends InternalFluxOperator>
implements Fuseable {
final Function super T, ? extends K> keySelector;
final Function super T, ? extends V> valueSelector;
final Supplier extends Queue> groupQueueSupplier;
final Supplier extends Queue>> mainQueueSupplier;
final int prefetch;
FluxGroupBy(Flux extends T> source,
Function super T, ? extends K> keySelector,
Function super T, ? extends V> valueSelector,
Supplier extends Queue>> mainQueueSupplier,
Supplier extends Queue> groupQueueSupplier,
int prefetch) {
super(source);
if (prefetch <= 0) {
throw new IllegalArgumentException("prefetch > 0 required but it was " + prefetch);
}
this.keySelector = Objects.requireNonNull(keySelector, "keySelector");
this.valueSelector = Objects.requireNonNull(valueSelector, "valueSelector");
this.mainQueueSupplier =
Objects.requireNonNull(mainQueueSupplier, "mainQueueSupplier");
this.groupQueueSupplier =
Objects.requireNonNull(groupQueueSupplier, "groupQueueSupplier");
this.prefetch = prefetch;
}
@Override
public CoreSubscriber super T> subscribeOrReturn(CoreSubscriber super GroupedFlux> actual) {
return new GroupByMain<>(actual,
mainQueueSupplier.get(),
groupQueueSupplier,
prefetch,
keySelector, valueSelector);
}
@Override
public int getPrefetch() {
return prefetch;
}
@Override
public Object scanUnsafe(Attr key) {
if (key == Attr.RUN_STYLE) return Attr.RunStyle.SYNC;
return super.scanUnsafe(key);
}
static final class GroupByMain
implements QueueSubscription>,
InnerOperator> {
final Function super T, ? extends K> keySelector;
final Function super T, ? extends V> valueSelector;
final Queue> queue;
final Supplier extends Queue> groupQueueSupplier;
final int prefetch;
final Map> groupMap;
final CoreSubscriber super GroupedFlux> actual;
volatile int wip;
@SuppressWarnings("rawtypes")
static final AtomicIntegerFieldUpdater WIP =
AtomicIntegerFieldUpdater.newUpdater(GroupByMain.class, "wip");
volatile long requested;
@SuppressWarnings("rawtypes")
static final AtomicLongFieldUpdater REQUESTED =
AtomicLongFieldUpdater.newUpdater(GroupByMain.class, "requested");
volatile boolean done;
volatile Throwable error;
@SuppressWarnings("rawtypes")
static final AtomicReferenceFieldUpdater ERROR =
AtomicReferenceFieldUpdater.newUpdater(GroupByMain.class,
Throwable.class,
"error");
volatile int cancelled;
@SuppressWarnings("rawtypes")
static final AtomicIntegerFieldUpdater CANCELLED =
AtomicIntegerFieldUpdater.newUpdater(GroupByMain.class, "cancelled");
volatile int groupCount;
@SuppressWarnings("rawtypes")
static final AtomicIntegerFieldUpdater GROUP_COUNT =
AtomicIntegerFieldUpdater.newUpdater(GroupByMain.class, "groupCount");
Subscription s;
volatile boolean enableAsyncFusion;
GroupByMain(CoreSubscriber super GroupedFlux> actual,
Queue> queue,
Supplier extends Queue> groupQueueSupplier,
int prefetch,
Function super T, ? extends K> keySelector,
Function super T, ? extends V> valueSelector) {
this.actual = actual;
this.queue = queue;
this.groupQueueSupplier = groupQueueSupplier;
this.prefetch = prefetch;
this.groupMap = new ConcurrentHashMap<>();
this.keySelector = keySelector;
this.valueSelector = valueSelector;
GROUP_COUNT.lazySet(this, 1);
}
@Override
public final CoreSubscriber super GroupedFlux> actual() {
return actual;
}
@Override
public void onSubscribe(Subscription s) {
if (Operators.validate(this.s, s)) {
this.s = s;
actual.onSubscribe(this);
s.request(Operators.unboundedOrPrefetch(prefetch));
}
}
@Override
public void onNext(T t) {
if(done){
Operators.onNextDropped(t, actual.currentContext());
return;
}
K key;
V value;
try {
key = Objects.requireNonNull(keySelector.apply(t), "The keySelector returned a null value");
value = Objects.requireNonNull(valueSelector.apply(t), "The valueSelector returned a null value");
}
catch (Throwable ex) {
onError(Operators.onOperatorError(s, ex, t, actual.currentContext()));
return;
}
UnicastGroupedFlux g = groupMap.get(key);
if (g == null) {
// if the main is cancelled, don't create new groups
if (cancelled == 0) {
Queue q = groupQueueSupplier.get();
GROUP_COUNT.getAndIncrement(this);
g = new UnicastGroupedFlux<>(key, q, this, prefetch);
g.onNext(value);
groupMap.put(key, g);
queue.offer(g);
drain();
}
}
else {
g.onNext(value);
}
}
@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() {
if(done){
return;
}
for (UnicastGroupedFlux g : groupMap.values()) {
g.onComplete();
}
groupMap.clear();
done = true;
drain();
}
@Override
@Nullable
public Object scanUnsafe(Attr key) {
if (key == Attr.PARENT) return s;
if (key == Attr.TERMINATED) return done;
if (key == Attr.REQUESTED_FROM_DOWNSTREAM) return requested;
if (key == Attr.PREFETCH) return prefetch;
if (key == Attr.BUFFERED) return queue.size();
if (key == Attr.CANCELLED) return cancelled == 1;
if (key == Attr.ERROR) return error;
if (key == Attr.RUN_STYLE) return Attr.RunStyle.SYNC;
return InnerOperator.super.scanUnsafe(key);
}
@Override
public Stream extends Scannable> inners() {
return groupMap.values().stream();
}
void signalAsyncError() {
Throwable e = Exceptions.terminate(ERROR, this); //TODO investigate if e == null
if (e == null) {
e = new IllegalStateException("FluxGroupBy.signalAsyncError called without error set");
}
groupCount = 0;
for (UnicastGroupedFlux g : groupMap.values()) {
g.onError(e);
}
actual.onError(e);
groupMap.clear();
}
@Override
public void request(long n) {
if (Operators.validate(n)) {
Operators.addCap(REQUESTED, this, n);
drain();
}
}
@Override
public void cancel() {
if (CANCELLED.compareAndSet(this, 0, 1)) {
if (GROUP_COUNT.decrementAndGet(this) == 0) {
s.cancel();
}
else if (!enableAsyncFusion) {
if (WIP.getAndIncrement(this) == 0) {
// remove queued up but unobservable groups from the mapping
GroupedFlux g;
while ((g = queue.poll()) != null) {
((UnicastGroupedFlux) g).cancel();
}
if (WIP.decrementAndGet(this) == 0) {
return;
}
drainLoop();
}
}
}
}
void groupTerminated(K key) {
if (groupCount == 0) {
return;
}
groupMap.remove(key);
int groupRemaining = GROUP_COUNT.decrementAndGet(this);
if (groupRemaining == 0) {
s.cancel();
}
else if (groupRemaining == 1) {
//there is an "extra" group count for the global cancellation, so the operator as a whole is still active
//we want at least one more group
s.request(Operators.unboundedOrPrefetch(prefetch));
}
}
void drain() {
if (WIP.getAndIncrement(this) != 0) {
return;
}
if (enableAsyncFusion) {
drainFused();
}
else {
drainLoop();
}
}
void drainFused() {
int missed = 1;
final Subscriber super GroupedFlux> a = actual;
final Queue> q = queue;
for (; ; ) {
if (cancelled != 0) {
q.clear();
return;
}
boolean d = done;
a.onNext(null);
if (d) {
Throwable ex = error;
if (ex != null) {
signalAsyncError();
}
else {
a.onComplete();
}
return;
}
missed = WIP.addAndGet(this, -missed);
if (missed == 0) {
break;
}
}
}
void drainLoop() {
int missed = 1;
Subscriber super GroupedFlux> a = actual;
Queue> q = queue;
for (; ; ) {
long r = requested;
long e = 0L;
while (e != r) {
boolean d = done;
GroupedFlux v = q.poll();
boolean empty = v == null;
if (checkTerminated(d, empty, a, q)) {
return;
}
if (empty) {
break;
}
a.onNext(v);
e++;
}
if (e == r) {
if (checkTerminated(done, q.isEmpty(), a, q)) {
return;
}
}
if (e != 0L) {
s.request(e);
if (r != Long.MAX_VALUE) {
REQUESTED.addAndGet(this, -e);
}
}
missed = WIP.addAndGet(this, -missed);
if (missed == 0) {
break;
}
}
}
boolean checkTerminated(boolean d,
boolean empty,
Subscriber> a,
Queue> q) {
if (d) {
Throwable e = error;
if (e != null && e != Exceptions.TERMINATED) {
q.clear();
signalAsyncError();
return true;
}
else if (empty) {
a.onComplete();
return true;
}
}
return false;
}
@Override
@Nullable
public GroupedFlux poll() {
return queue.poll();
}
@Override
public int size() {
return queue.size();
}
@Override
public boolean isEmpty() {
return queue.isEmpty();
}
@Override
public void clear() {
queue.clear();
}
@Override
public int requestFusion(int requestedMode) {
if ((requestedMode & Fuseable.ASYNC) != 0) {
enableAsyncFusion = true;
return Fuseable.ASYNC;
}
return Fuseable.NONE;
}
}
static final class UnicastGroupedFlux extends GroupedFlux
implements Fuseable, QueueSubscription, InnerProducer {
final K key;
final int limit;
final Context context;
@Override
public K key() {
return key;
}
final Queue queue;
volatile GroupByMain, K, V> parent;
@SuppressWarnings("rawtypes")
static final AtomicReferenceFieldUpdater PARENT =
AtomicReferenceFieldUpdater.newUpdater(UnicastGroupedFlux.class,
GroupByMain.class,
"parent");
volatile boolean done;
Throwable error;
volatile CoreSubscriber super V> actual;
@SuppressWarnings("rawtypes")
static final AtomicReferenceFieldUpdater ACTUAL =
AtomicReferenceFieldUpdater.newUpdater(UnicastGroupedFlux.class,
CoreSubscriber.class,
"actual");
volatile boolean cancelled;
volatile int once;
@SuppressWarnings("rawtypes")
static final AtomicIntegerFieldUpdater ONCE =
AtomicIntegerFieldUpdater.newUpdater(UnicastGroupedFlux.class, "once");
volatile int wip;
@SuppressWarnings("rawtypes")
static final AtomicIntegerFieldUpdater WIP =
AtomicIntegerFieldUpdater.newUpdater(UnicastGroupedFlux.class, "wip");
volatile long requested;
@SuppressWarnings("rawtypes")
static final AtomicLongFieldUpdater REQUESTED =
AtomicLongFieldUpdater.newUpdater(UnicastGroupedFlux.class, "requested");
volatile boolean outputFused;
int produced;
boolean isFirstRequest = true;
UnicastGroupedFlux(K key,
Queue queue,
GroupByMain, K, V> parent,
int prefetch) {
this.key = key;
this.queue = queue;
this.context = parent.currentContext();
this.parent = parent;
this.limit = Operators.unboundedOrLimit(prefetch);
}
void doTerminate() {
GroupByMain, K, V> r = parent;
if (r != null && PARENT.compareAndSet(this, r, null)) {
r.groupTerminated(key);
}
}
void drainRegular(Subscriber super V> a) {
int missed = 1;
final Queue q = queue;
for (; ; ) {
long r = requested;
long e = 0L;
while (r != e) {
boolean d = done;
V t = q.poll();
boolean empty = t == null;
if (checkTerminated(d, empty, a, q)) {
return;
}
if (empty) {
break;
}
a.onNext(t);
e++;
}
if (r == e) {
if (checkTerminated(done, q.isEmpty(), a, q)) {
return;
}
}
if (e != 0) {
GroupByMain, K, V> main = parent;
if (main != null) {
if (this.isFirstRequest) {
this.isFirstRequest = false;
long toRequest = e - 1;
if (toRequest > 0) {
main.s.request(toRequest);
}
} else {
main.s.request(e);
}
}
if (r != Long.MAX_VALUE) {
REQUESTED.addAndGet(this, -e);
}
}
missed = WIP.addAndGet(this, -missed);
if (missed == 0) {
break;
}
}
}
void drainFused(Subscriber super V> a) {
int missed = 1;
final Queue q = queue;
for (; ; ) {
if (cancelled) {
q.clear();
actual = null;
return;
}
boolean d = done;
a.onNext(null);
if (d) {
actual = null;
Throwable ex = error;
if (ex != null) {
a.onError(ex);
}
else {
a.onComplete();
}
return;
}
missed = WIP.addAndGet(this, -missed);
if (missed == 0) {
break;
}
}
}
void drain() {
Subscriber super V> a = actual;
if (a != null) {
if (WIP.getAndIncrement(this) != 0) {
return;
}
if (outputFused) {
drainFused(a);
}
else {
drainRegular(a);
}
}
}
boolean checkTerminated(boolean d, boolean empty, Subscriber> a, Queue> q) {
if (cancelled) {
q.clear();
actual = null;
return true;
}
if (d && empty) {
Throwable e = error;
actual = null;
if (e != null) {
a.onError(e);
}
else {
a.onComplete();
}
return true;
}
return false;
}
public void onNext(V t) {
Subscriber super V> a = actual;
if (!queue.offer(t)) {
onError(Operators.onOperatorError(this, Exceptions.failWithOverflow(Exceptions.BACKPRESSURE_ERROR_QUEUE_FULL), t,
actual.currentContext()));
return;
}
if (outputFused) {
if (a != null) {
a.onNext(null); // in op-fusion, onNext(null) is the indicator of more data
}
}
else {
drain();
}
}
public void onError(Throwable t) {
error = t;
done = true;
doTerminate();
drain();
}
public void onComplete() {
done = true;
doTerminate();
drain();
}
@Override
public void subscribe(CoreSubscriber super V> actual) {
if (once == 0 && ONCE.compareAndSet(this, 0, 1)) {
actual.onSubscribe(this);
ACTUAL.lazySet(this, actual);
drain();
}
else {
Operators.error(actual, new IllegalStateException(
"GroupedFlux allows only one Subscriber"));
}
}
@Override
public void request(long n) {
if (Operators.validate(n)) {
Operators.addCap(REQUESTED, this, n);
drain();
}
}
@Override
public void cancel() {
if (cancelled) {
return;
}
cancelled = true;
doTerminate();
if (!outputFused) {
if (WIP.getAndIncrement(this) == 0) {
queue.clear();
}
}
}
@Override
@Nullable
public V poll() {
V v = queue.poll();
if (v != null) {
produced++;
}
else {
tryReplenish();
}
return v;
}
void tryReplenish() {
int p = produced;
if (p != 0) {
produced = 0;
GroupByMain, K, V> main = parent;
if (main != null) {
if (this.isFirstRequest) {
this.isFirstRequest = false;
p--;
if (p > 0) {
main.s.request(p);
}
} else {
main.s.request(p);
}
}
}
}
@Override
public int size() {
return queue.size();
}
@Override
public boolean isEmpty() {
if (queue.isEmpty()) {
tryReplenish();
return true;
}
return false;
}
@Override
public void clear() {
queue.clear();
}
@Override
public int requestFusion(int requestedMode) {
if ((requestedMode & Fuseable.ASYNC) != 0) {
outputFused = true;
return Fuseable.ASYNC;
}
return Fuseable.NONE;
}
@Override
@Nullable
public Object scanUnsafe(Attr key) {
if (key == Attr.PARENT) return parent;
if (key == Attr.TERMINATED) return done;
if (key == Attr.CANCELLED) return cancelled;
if (key == Attr.ERROR) return error;
if (key == Attr.BUFFERED) return queue != null ? queue.size() : 0;
if (key == Attr.REQUESTED_FROM_DOWNSTREAM) return requested;
if (key == Attr.RUN_STYLE) return Attr.RunStyle.SYNC;
return InnerProducer.super.scanUnsafe(key);
}
@Override
public CoreSubscriber super V> actual() {
return actual;
}
}
}
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