io.reactivex.observable.subjects.CompletableSubject Maven / Gradle / Ivy
Show all versions of rxjava3-observable Show documentation
/**
* 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 io.reactivex.observable.subjects;
import java.util.concurrent.atomic.*;
import io.reactivex.common.*;
import io.reactivex.common.annotations.*;
import io.reactivex.observable.*;
/**
* Represents a hot Completable-like source and consumer of events similar to Subjects.
*
* All methods are thread safe. Calling onComplete multiple
* times has no effect. Calling onError multiple times relays the Throwable to
* the RxJavaPlugins' error handler.
*
* The CompletableSubject doesn't store the Disposables coming through onSubscribe but
* disposes them once the other onXXX methods were called (terminal state reached).
* @since 2.0.5 - experimental
*/
@Experimental
public final class CompletableSubject extends Completable implements CompletableObserver {
final AtomicReference observers;
static final CompletableDisposable[] EMPTY = new CompletableDisposable[0];
static final CompletableDisposable[] TERMINATED = new CompletableDisposable[0];
final AtomicBoolean once;
Throwable error;
/**
* Creates a fresh CompletableSubject.
* @return the new CompletableSubject instance
*/
@CheckReturnValue
public static CompletableSubject create() {
return new CompletableSubject();
}
CompletableSubject() {
once = new AtomicBoolean();
observers = new AtomicReference(EMPTY);
}
@Override
public void onSubscribe(Disposable d) {
if (observers.get() == TERMINATED) {
d.dispose();
}
}
@Override
public void onError(Throwable e) {
if (e == null) {
e = new NullPointerException("Null errors are not allowed in 2.x");
}
if (once.compareAndSet(false, true)) {
this.error = e;
for (CompletableDisposable md : observers.getAndSet(TERMINATED)) {
md.actual.onError(e);
}
} else {
RxJavaCommonPlugins.onError(e);
}
}
@Override
public void onComplete() {
if (once.compareAndSet(false, true)) {
for (CompletableDisposable md : observers.getAndSet(TERMINATED)) {
md.actual.onComplete();
}
}
}
@Override
protected void subscribeActual(CompletableObserver observer) {
CompletableDisposable md = new CompletableDisposable(observer, this);
observer.onSubscribe(md);
if (add(md)) {
if (md.isDisposed()) {
remove(md);
}
} else {
Throwable ex = error;
if (ex != null) {
observer.onError(ex);
} else {
observer.onComplete();
}
}
}
boolean add(CompletableDisposable inner) {
for (;;) {
CompletableDisposable[] a = observers.get();
if (a == TERMINATED) {
return false;
}
int n = a.length;
CompletableDisposable[] b = new CompletableDisposable[n + 1];
System.arraycopy(a, 0, b, 0, n);
b[n] = inner;
if (observers.compareAndSet(a, b)) {
return true;
}
}
}
void remove(CompletableDisposable inner) {
for (;;) {
CompletableDisposable[] a = observers.get();
int n = a.length;
if (n == 0) {
return;
}
int j = -1;
for (int i = 0; i < n; i++) {
if (a[i] == inner) {
j = i;
break;
}
}
if (j < 0) {
return;
}
CompletableDisposable[] b;
if (n == 1) {
b = EMPTY;
} else {
b = new CompletableDisposable[n - 1];
System.arraycopy(a, 0, b, 0, j);
System.arraycopy(a, j + 1, b, j, n - j - 1);
}
if (observers.compareAndSet(a, b)) {
return;
}
}
}
/**
* Returns the terminal error if this CompletableSubject has been terminated with an error, null otherwise.
* @return the terminal error or null if not terminated or not with an error
*/
public Throwable getThrowable() {
if (observers.get() == TERMINATED) {
return error;
}
return null;
}
/**
* Returns true if this CompletableSubject has been terminated with an error.
* @return true if this CompletableSubject has been terminated with an error
*/
public boolean hasThrowable() {
return observers.get() == TERMINATED && error != null;
}
/**
* Returns true if this CompletableSubject has been completed.
* @return true if this CompletableSubject has been completed
*/
public boolean hasComplete() {
return observers.get() == TERMINATED && error == null;
}
/**
* Returns true if this CompletableSubject has observers.
* @return true if this CompletableSubject has observers
*/
public boolean hasObservers() {
return observers.get().length != 0;
}
/**
* Returns the number of current observers.
* @return the number of current observers
*/
/* test */ int observerCount() {
return observers.get().length;
}
static final class CompletableDisposable
extends AtomicReference implements Disposable {
private static final long serialVersionUID = -7650903191002190468L;
final CompletableObserver actual;
CompletableDisposable(CompletableObserver actual, CompletableSubject parent) {
this.actual = actual;
lazySet(parent);
}
@Override
public void dispose() {
CompletableSubject parent = getAndSet(null);
if (parent != null) {
parent.remove(this);
}
}
@Override
public boolean isDisposed() {
return get() == null;
}
}
}