com.hivemq.client.internal.rx.WithSingleStrictSubscriber Maven / Gradle / Ivy
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HiveMQ MQTT Client is an MQTT 5.0 and MQTT 3.1.1 compatible and feature-rich high-performance Java client library with different API flavours and backpressure support
/*
* Copyright 2018 dc-square and the HiveMQ MQTT Client Project
*
* 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
*
* http://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 com.hivemq.client.internal.rx;
import com.hivemq.client.rx.FlowableWithSingleSubscriber;
import com.hivemq.client.rx.reactivestreams.WithSingleSubscriber;
import io.reactivex.internal.subscriptions.SubscriptionHelper;
import io.reactivex.internal.util.BackpressureHelper;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;
import org.reactivestreams.Subscription;
import java.util.concurrent.atomic.AtomicLong;
import java.util.concurrent.atomic.AtomicReference;
/**
* @author Silvio Giebl
*/
public class WithSingleStrictSubscriber implements FlowableWithSingleSubscriber, Subscription {
private final @NotNull WithSingleSubscriber subscriber;
private final @NotNull AtomicReference<@Nullable Subscription> subscription = new AtomicReference<>();
private final @NotNull AtomicLong requested = new AtomicLong();
public WithSingleStrictSubscriber(final @NotNull WithSingleSubscriber subscriber) {
this.subscriber = subscriber;
}
@Override
public void onSubscribe(final @NotNull Subscription subscription) {
subscriber.onSubscribe(subscription);
if (this.subscription.compareAndSet(null, subscription)) {
final long requested = this.requested.getAndSet(0);
if (requested != 0) {
subscription.request(requested);
}
} else {
subscription.cancel();
}
}
@Override
public void onSingle(final @NotNull S s) {
subscriber.onSingle(s);
}
@Override
public void onNext(final @NotNull F f) {
subscriber.onNext(f);
}
@Override
public void onError(final @NotNull Throwable throwable) {
subscriber.onError(throwable);
}
@Override
public void onComplete() {
subscriber.onComplete();
}
@Override
public void request(final long n) {
Subscription subscription = this.subscription.get();
if (subscription != null) {
subscription.request(n);
} else {
BackpressureHelper.add(requested, n);
subscription = this.subscription.get();
if (subscription != null) {
final long requested = this.requested.getAndSet(0);
if (requested != 0) {
subscription.request(requested);
}
}
}
}
@Override
public void cancel() {
final Subscription subscription = this.subscription.getAndSet(SubscriptionHelper.CANCELLED);
if ((subscription != null) && (subscription != SubscriptionHelper.CANCELLED)) {
subscription.cancel();
}
}
}