autodispose2.HalfSerializer Maven / Gradle / Ivy
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/*
* Copyright (c) 2016-present, RxJava Contributors.
*
* 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 autodispose2;
import io.reactivex.rxjava3.core.Observer;
import io.reactivex.rxjava3.plugins.RxJavaPlugins;
import java.util.concurrent.atomic.AtomicInteger;
import org.reactivestreams.Subscriber;
/**
* Utility methods to perform half-serialization: a form of serialization
* where onNext is guaranteed to be called from a single thread but
* onError or onComplete may be called from any threads.
*
* The onNext methods have been modified to return a boolean indicating whether or not the delegate
* observer was sent a terminal event.
*/
final class HalfSerializer {
/** Utility class. */
private HalfSerializer() {
throw new IllegalStateException("No instances!");
}
/**
* Emits the given value if possible and terminates if there was an onComplete or onError
* while emitting, drops the value otherwise.
*
* @param the value type
* @param subscriber the target Subscriber to emit to
* @param value the value to emit
* @param wip the serialization work-in-progress counter/indicator
* @param error the holder of Throwables
* @return true if a terminal event was emitted to {@code observer}, false if not
*/
public static boolean onNext(Subscriber subscriber,
T value,
AtomicInteger wip,
AtomicThrowable error) {
if (wip.get() == 0 && wip.compareAndSet(0, 1)) {
subscriber.onNext(value);
if (wip.decrementAndGet() != 0) {
Throwable ex = error.terminate();
if (ex != null) {
subscriber.onError(ex);
} else {
subscriber.onComplete();
}
return true;
}
}
return false;
}
/**
* Emits the given exception if possible or adds it to the given error container to
* be emitted by a concurrent onNext if one is running.
* Undeliverable exceptions are sent to the RxJavaPlugins.onError.
*
* @param subscriber the target Subscriber to emit to
* @param ex the Throwable to emit
* @param wip the serialization work-in-progress counter/indicator
* @param error the holder of Throwables
*/
public static void onError(Subscriber subscriber, Throwable ex, AtomicInteger wip, AtomicThrowable error) {
if (error.addThrowable(ex)) {
if (wip.getAndIncrement() == 0) {
subscriber.onError(error.terminate());
}
} else {
RxJavaPlugins.onError(ex);
}
}
/**
* Emits an onComplete signal or an onError signal with the given error or indicates
* the concurrently running onNext should do that.
*
* @param subscriber the target Subscriber to emit to
* @param wip the serialization work-in-progress counter/indicator
* @param error the holder of Throwables
*/
public static void onComplete(Subscriber subscriber, AtomicInteger wip, AtomicThrowable error) {
if (wip.getAndIncrement() == 0) {
Throwable ex = error.terminate();
if (ex != null) {
subscriber.onError(ex);
} else {
subscriber.onComplete();
}
}
}
/**
* Emits the given value if possible and terminates if there was an onComplete or onError
* while emitting, drops the value otherwise.
*
* @param the value type
* @param observer the target Observer to emit to
* @param value the value to emit
* @param wip the serialization work-in-progress counter/indicator
* @param error the holder of Throwables
* @return true if a terminal event was emitted to {@code observer}, false if not
*/
public static boolean onNext(Observer observer, T value, AtomicInteger wip, AtomicThrowable error) {
if (wip.get() == 0 && wip.compareAndSet(0, 1)) {
observer.onNext(value);
if (wip.decrementAndGet() != 0) {
Throwable ex = error.terminate();
if (ex != null) {
observer.onError(ex);
} else {
observer.onComplete();
}
return true;
}
}
return false;
}
/**
* Emits the given exception if possible or adds it to the given error container to
* be emitted by a concurrent onNext if one is running.
* Undeliverable exceptions are sent to the RxJavaPlugins.onError.
*
* @param observer the target Subscriber to emit to
* @param ex the Throwable to emit
* @param wip the serialization work-in-progress counter/indicator
* @param error the holder of Throwables
*/
public static void onError(Observer observer, Throwable ex, AtomicInteger wip, AtomicThrowable error) {
if (error.addThrowable(ex)) {
if (wip.getAndIncrement() == 0) {
observer.onError(error.terminate());
}
} else {
RxJavaPlugins.onError(ex);
}
}
/**
* Emits an onComplete signal or an onError signal with the given error or indicates
* the concurrently running onNext should do that.
*
* @param observer the target Subscriber to emit to
* @param wip the serialization work-in-progress counter/indicator
* @param error the holder of Throwables
*/
public static void onComplete(Observer observer, AtomicInteger wip, AtomicThrowable error) {
if (wip.getAndIncrement() == 0) {
Throwable ex = error.terminate();
if (ex != null) {
observer.onError(ex);
} else {
observer.onComplete();
}
}
}
}