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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-present HiveMQ and the HiveMQ Community
*
* 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 io.reactivex.*;
import io.reactivex.disposables.Disposable;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;
import java.util.Optional;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.function.BiConsumer;
/**
* @author Silvio Giebl
*/
public final class RxFutureConverter {
public static @NotNull CompletableFuture toFuture(final @NotNull Completable completable) {
return new RxCompletableFuture(completable);
}
public static @NotNull CompletableFuture<@NotNull Optional> toFuture(final @NotNull Maybe maybe) {
return new RxMaybeFuture<>(maybe);
}
public static @NotNull CompletableFuture<@NotNull T> toFuture(final @NotNull Single single) {
return new RxSingleFuture<>(single);
}
private static abstract class RxFuture extends CompletableFuture {
volatile @Nullable Disposable disposable;
volatile boolean cancelled;
public void onSubscribe(final @NotNull Disposable d) {
disposable = d;
if (cancelled) {
d.dispose();
}
}
public void onError(final @NotNull Throwable e) {
if (!cancelled) {
completeExceptionally(e);
}
}
@Override
public boolean cancel(final boolean mayInterruptIfRunning) {
cancelled = true;
final Disposable disposable = this.disposable;
if (disposable != null) {
disposable.dispose();
}
return super.cancel(mayInterruptIfRunning);
}
}
private static class RxCompletableFuture extends RxFuture implements CompletableObserver {
RxCompletableFuture(final @NotNull Completable completable) {
completable.subscribe(this);
}
@Override
public void onComplete() {
if (!cancelled) {
complete(null);
}
}
}
private static class RxMaybeFuture extends RxFuture> implements MaybeObserver {
RxMaybeFuture(final @NotNull Maybe maybe) {
maybe.subscribe(this);
}
@Override
public void onSuccess(final @NotNull T t) {
if (!cancelled) {
complete(Optional.of(t));
}
}
@Override
public void onComplete() {
if (!cancelled) {
complete(Optional.empty());
}
}
}
private static class RxSingleFuture extends RxFuture implements SingleObserver {
RxSingleFuture(final @NotNull Single single) {
single.subscribe(this);
}
@Override
public void onSuccess(final @NotNull T t) {
if (!cancelled) {
complete(t);
}
}
}
public static @NotNull Completable toCompletable(final @NotNull CompletableFuture future) {
return new FutureCompletable(future);
}
public static @NotNull Maybe toMaybe(final @NotNull CompletableFuture<@NotNull Optional> future) {
return new FutureMaybe<>(future);
}
public static @NotNull Single toSingle(final @NotNull CompletableFuture<@NotNull T> future) {
return new FutureSingle<>(future);
}
private static final int INITIAL = 0;
private static final int SUBSCRIBED_OR_COMPLETE = 1;
private static final int SUBSCRIBED_AND_COMPLETE_OR_CANCELLED = 2;
private static boolean checkComplete(final @NotNull AtomicInteger done) {
return !done.compareAndSet(INITIAL, SUBSCRIBED_OR_COMPLETE) &&
done.compareAndSet(SUBSCRIBED_OR_COMPLETE, SUBSCRIBED_AND_COMPLETE_OR_CANCELLED);
}
private static void dispose(final @NotNull AtomicInteger done, final @NotNull CompletableFuture future) {
done.set(SUBSCRIBED_AND_COMPLETE_OR_CANCELLED);
future.cancel(false);
}
private static boolean isDisposed(final @NotNull AtomicInteger done) {
return done.get() == SUBSCRIBED_AND_COMPLETE_OR_CANCELLED;
}
private static class FutureCompletable extends Completable implements Disposable, BiConsumer {
private final @NotNull CompletableFuture future;
private volatile @Nullable CompletableObserver observer;
private volatile @Nullable Throwable throwable;
private final @NotNull AtomicInteger done = new AtomicInteger(INITIAL);
FutureCompletable(final @NotNull CompletableFuture future) {
this.future = future;
future.whenComplete(this);
}
@Override
protected void subscribeActual(final @NotNull CompletableObserver observer) {
this.observer = observer;
observer.onSubscribe(this);
if (checkComplete(done)) {
complete(observer, throwable);
}
}
@Override
public void dispose() {
RxFutureConverter.dispose(done, future);
}
@Override
public boolean isDisposed() {
return RxFutureConverter.isDisposed(done);
}
@Override
public void accept(final @Nullable Object o, final @Nullable Throwable throwable) {
this.throwable = throwable;
if (checkComplete(done)) {
final CompletableObserver observer = this.observer;
assert observer != null;
complete(observer, throwable);
}
}
private static void complete(final @NotNull CompletableObserver observer, final @Nullable Throwable throwable) {
if (throwable == null) {
observer.onComplete();
} else {
observer.onError(throwable);
}
}
}
private static class FutureMaybe extends Maybe implements Disposable, BiConsumer, Throwable> {
private final @NotNull CompletableFuture> future;
private volatile @Nullable MaybeObserver observer;
private volatile @Nullable T t;
private volatile @Nullable Throwable throwable;
private final @NotNull AtomicInteger done = new AtomicInteger(INITIAL);
FutureMaybe(final @NotNull CompletableFuture> future) {
this.future = future;
future.whenComplete(this);
}
@Override
protected void subscribeActual(final @NotNull MaybeObserver observer) {
this.observer = observer;
observer.onSubscribe(this);
if (checkComplete(done)) {
complete(observer, t, throwable);
}
}
@Override
public void dispose() {
RxFutureConverter.dispose(done, future);
}
@Override
public boolean isDisposed() {
return RxFutureConverter.isDisposed(done);
}
@Override
@SuppressWarnings("OptionalAssignedToNull")
public void accept(final @Nullable Optional t, final @Nullable Throwable throwable) {
final T t1;
final Throwable throwable1;
if (throwable == null) {
if (t == null) {
t1 = null;
throwable1 = new NullPointerException();
} else {
t1 = t.orElse(null);
throwable1 = null;
}
} else {
t1 = null;
throwable1 = throwable;
}
this.t = t1;
this.throwable = throwable1;
if (checkComplete(done)) {
final MaybeObserver observer = this.observer;
assert observer != null;
complete(observer, t1, throwable1);
}
}
private static void complete(
final @NotNull MaybeObserver observer,
final @Nullable T t,
final @Nullable Throwable throwable) {
if (throwable != null) {
observer.onError(throwable);
} else if (t != null) {
observer.onSuccess(t);
} else {
observer.onComplete();
}
}
}
private static class FutureSingle extends Single implements Disposable, BiConsumer {
private final @NotNull CompletableFuture future;
private volatile @Nullable SingleObserver observer;
private volatile @Nullable T t;
private volatile @Nullable Throwable throwable;
private final @NotNull AtomicInteger done = new AtomicInteger(INITIAL);
FutureSingle(final @NotNull CompletableFuture future) {
this.future = future;
future.whenComplete(this);
}
@Override
protected void subscribeActual(final @NotNull SingleObserver observer) {
this.observer = observer;
observer.onSubscribe(this);
if (checkComplete(done)) {
complete(observer, t, throwable);
}
}
@Override
public void dispose() {
RxFutureConverter.dispose(done, future);
}
@Override
public boolean isDisposed() {
return RxFutureConverter.isDisposed(done);
}
@Override
public void accept(final @Nullable T t, final @Nullable Throwable throwable) {
this.t = t;
this.throwable = throwable;
if (checkComplete(done)) {
final SingleObserver observer = this.observer;
assert observer != null;
complete(observer, t, throwable);
}
}
private static void complete(
final @NotNull SingleObserver observer,
final @Nullable T t,
final @Nullable Throwable throwable) {
if (t != null) {
observer.onSuccess(t);
} else {
observer.onError((throwable != null) ? throwable : new NullPointerException());
}
}
}
private RxFutureConverter() {}
}