reactor.core.publisher.FluxOnBackpressureLatest Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of redisson-all Show documentation
Show all versions of redisson-all Show documentation
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) 2016-2021 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.concurrent.atomic.AtomicIntegerFieldUpdater;
import java.util.concurrent.atomic.AtomicLongFieldUpdater;
import java.util.concurrent.atomic.AtomicReferenceFieldUpdater;
import org.reactivestreams.Subscriber;
import org.reactivestreams.Subscription;
import reactor.core.CoreSubscriber;
import reactor.util.annotation.Nullable;
import reactor.util.context.Context;
/**
* Runs the source in unbounded mode and emits only the latest value
* if the subscriber can't keep up properly.
*
* @param the value type
* @see Reactive-Streams-Commons
*/
final class FluxOnBackpressureLatest extends InternalFluxOperator {
FluxOnBackpressureLatest(Flux extends T> source) {
super(source);
}
@Override
public CoreSubscriber super T> subscribeOrReturn(CoreSubscriber super T> actual) {
return new LatestSubscriber<>(actual);
}
@Override
public int getPrefetch() {
return Integer.MAX_VALUE;
}
@Override
public Object scanUnsafe(Attr key) {
if (key == Attr.RUN_STYLE) return Attr.RunStyle.SYNC;
return super.scanUnsafe(key);
}
static final class LatestSubscriber
implements InnerOperator {
final CoreSubscriber super T> actual;
final Context ctx;
volatile long requested;
@SuppressWarnings("rawtypes")
static final AtomicLongFieldUpdater REQUESTED =
AtomicLongFieldUpdater.newUpdater(LatestSubscriber.class, "requested");
volatile int wip;
@SuppressWarnings("rawtypes")
static final AtomicIntegerFieldUpdater WIP =
AtomicIntegerFieldUpdater.newUpdater(LatestSubscriber.class, "wip");
Subscription s;
Throwable error;
volatile boolean done;
volatile boolean cancelled;
volatile T value;
@SuppressWarnings("rawtypes")
static final AtomicReferenceFieldUpdater VALUE =
AtomicReferenceFieldUpdater.newUpdater(LatestSubscriber.class, Object.class, "value");
LatestSubscriber(CoreSubscriber super T> actual) {
this.actual = actual;
this.ctx = actual.currentContext();
}
@Override
public void request(long n) {
if (Operators.validate(n)) {
Operators.addCap(REQUESTED, this, n);
drain();
}
}
@Override
public void cancel() {
if (!cancelled) {
cancelled = true;
s.cancel();
if (WIP.getAndIncrement(this) == 0) {
Object toDiscard = VALUE.getAndSet(this, null);
if (toDiscard != null) {
Operators.onDiscard(toDiscard, ctx);
}
}
}
}
@Override
public void onSubscribe(Subscription s) {
if (Operators.validate(this.s, s)) {
this.s = s;
actual.onSubscribe(this);
s.request(Long.MAX_VALUE);
}
}
@Override
public void onNext(T t) {
Object toDiscard = VALUE.getAndSet(this, t);
if (toDiscard != null) {
Operators.onDiscard(toDiscard, ctx);
}
drain();
}
@Override
public void onError(Throwable t) {
error = t;
done = true;
drain();
}
@Override
public void onComplete() {
done = true;
drain();
}
void drain() {
if (WIP.getAndIncrement(this) != 0) {
return;
}
final Subscriber super T> a = actual;
int missed = 1;
for (; ; ) {
if (checkTerminated(done, value == null, a)) {
return;
}
long r = requested;
long e = 0L;
while (r != e) {
boolean d = done;
@SuppressWarnings("unchecked")
T v = (T) VALUE.getAndSet(this, null);
boolean empty = v == null;
if (checkTerminated(d, empty, a)) {
return;
}
if (empty) {
break;
}
a.onNext(v);
e++;
}
if (r == e && checkTerminated(done, value == null, a)) {
return;
}
if (e != 0L && r != Long.MAX_VALUE) {
Operators.produced(REQUESTED, this, e);
}
missed = WIP.addAndGet(this, -missed);
if (missed == 0) {
break;
}
}
}
boolean checkTerminated(boolean d, boolean empty, Subscriber super T> a) {
if (cancelled) {
Object toDiscard = VALUE.getAndSet(this, null);
if (toDiscard != null) {
Operators.onDiscard(toDiscard, ctx);
}return true;
}
if (d) {
Throwable e = error;
if (e != null) {
Object toDiscard = VALUE.getAndSet(this, null);
if (toDiscard != null) {
Operators.onDiscard(toDiscard, ctx);
}
a.onError(e);
return true;
} else if (empty) {
a.onComplete();
return true;
}
}
return false;
}
@Override
public CoreSubscriber super T> actual() {
return actual;
}
@Override
@Nullable
public Object scanUnsafe(Attr key) {
if (key == Attr.PARENT) return s;
if (key == Attr.REQUESTED_FROM_DOWNSTREAM) return requested;
if (key == Attr.TERMINATED) return done;
if (key == Attr.CANCELLED) return cancelled;
if (key == Attr.BUFFERED) return value != null ? 1 : 0;
if (key == Attr.ERROR) return error;
if (key == Attr.PREFETCH) return Integer.MAX_VALUE;
if (key == Attr.RUN_STYLE) return Attr.RunStyle.SYNC;
return InnerOperator.super.scanUnsafe(key);
}
}
}
© 2015 - 2024 Weber Informatics LLC | Privacy Policy