Class Subject<T>

java.lang.Object

io.reactivex.rxjava4.core.Observable<T>

io.reactivex.rxjava4.subjects.Subject<T>

Type Parameters:

T - the item value type

All Implemented Interfaces:

ObservableSource<T>, Observer<T>

Direct Known Subclasses:

AsyncSubject, BehaviorSubject, PublishSubject, ReplaySubject, UnicastSubject

public abstract class Subject<T>
extends Observable<T>
implements Observer<T>

Represents an Observer and an Observable at the same time, allowing multicasting events from a single source to multiple child Observers.

All methods except the Observer.onSubscribe(io.reactivex.rxjava4.disposables.Disposable), Observer.onNext(Object), Observer.onError(Throwable) and Observer.onComplete() are thread-safe. Use toSerialized() to make these methods thread-safe as well.

Constructor Summary

Constructors

Constructor	Description
Subject()

Method Summary

Modifier and Type	Method	Description
abstract @Nullable Throwable	getThrowable()	Returns the error that caused the Subject to terminate or null if the Subject hasn't terminated yet.
abstract boolean	hasComplete()	Returns true if the subject has reached a terminal state through a complete event.
abstract boolean	hasObservers()	Returns true if the subject has any Observers.
abstract boolean	hasThrowable()	Returns true if the subject has reached a terminal state through an error event.
final @NonNull Subject<T>	toSerialized()	Wraps this Subject and serializes the calls to the onSubscribe, onNext, onError and onComplete methods, making them thread-safe.

Methods inherited from class Observable

all, amb, ambArray, ambWith, any, blockingFirst, blockingFirst, blockingForEach, blockingForEach, blockingIterable, blockingIterable, blockingLast, blockingLast, blockingLatest, blockingMostRecent, blockingNext, blockingSingle, blockingSingle, blockingStream, blockingStream, blockingSubscribe, blockingSubscribe, blockingSubscribe, blockingSubscribe, blockingSubscribe, buffer, buffer, buffer, buffer, buffer, buffer, buffer, buffer, buffer, buffer, buffer, buffer, buffer, buffer, buffer, buffer, buffer, bufferSize, cache, cacheWithInitialCapacity, cast, collect, collect, collectInto, combineLatest, combineLatest, combineLatest, combineLatest, combineLatest, combineLatest, combineLatest, combineLatest, combineLatest, combineLatest, combineLatestArray, combineLatestArray, combineLatestArrayDelayError, combineLatestArrayDelayError, combineLatestDelayError, combineLatestDelayError, compose, concat, concat, concat, concat, concat, concat, concatArray, concatArrayDelayError, concatArrayEager, concatArrayEager, concatArrayEagerDelayError, concatArrayEagerDelayError, concatDelayError, concatDelayError, concatDelayError, concatEager, concatEager, concatEager, concatEager, concatEagerDelayError, concatEagerDelayError, concatEagerDelayError, concatEagerDelayError, concatMap, concatMap, concatMap, concatMapCompletable, concatMapCompletable, concatMapCompletableDelayError, concatMapCompletableDelayError, concatMapCompletableDelayError, concatMapDelayError, concatMapDelayError, concatMapDelayError, concatMapEager, concatMapEager, concatMapEagerDelayError, concatMapEagerDelayError, concatMapIterable, concatMapMaybe, concatMapMaybe, concatMapMaybeDelayError, concatMapMaybeDelayError, concatMapMaybeDelayError, concatMapSingle, concatMapSingle, concatMapSingleDelayError, concatMapSingleDelayError, concatMapSingleDelayError, concatMapStream, concatWith, concatWith, concatWith, concatWith, contains, count, create, debounce, debounce, debounce, debounce, defaultIfEmpty, defer, delay, delay, delay, delay, delay, delay, delaySubscription, delaySubscription, delaySubscription, dematerialize, distinct, distinct, distinct, distinctUntilChanged, distinctUntilChanged, distinctUntilChanged, doAfterNext, doAfterTerminate, doFinally, doOnComplete, doOnDispose, doOnEach, doOnEach, doOnError, doOnLifecycle, doOnNext, doOnSubscribe, doOnTerminate, elementAt, elementAt, elementAtOrError, empty, error, error, filter, first, firstElement, firstOrError, firstOrErrorStage, firstStage, flatMap, flatMap, flatMap, flatMap, flatMap, flatMap, flatMap, flatMap, flatMap, flatMap, flatMap, flatMap, flatMapCompletable, flatMapCompletable, flatMapIterable, flatMapIterable, flatMapMaybe, flatMapMaybe, flatMapSingle, flatMapSingle, flatMapStream, forEach, forEachWhile, forEachWhile, forEachWhile, fromAction, fromArray, fromCallable, fromCompletable, fromCompletionStage, fromFuture, fromFuture, fromIterable, fromMaybe, fromOptional, fromPublisher, fromRunnable, fromSingle, fromStream, fromSupplier, generate, generate, generate, generate, generate, groupBy, groupBy, groupBy, groupBy, groupBy, groupJoin, hide, ignoreElements, interval, interval, interval, interval, intervalRange, intervalRange, isEmpty, join, just, just, just, just, just, just, just, just, just, just, last, lastElement, lastOrError, lastOrErrorStage, lastStage, lift, map, mapOptional, materialize, merge, merge, merge, merge, merge, merge, merge, merge, mergeArray, mergeArray, mergeArrayDelayError, mergeArrayDelayError, mergeDelayError, mergeDelayError, mergeDelayError, mergeDelayError, mergeDelayError, mergeDelayError, mergeDelayError, mergeDelayError, mergeWith, mergeWith, mergeWith, mergeWith, never, observeOn, observeOn, observeOn, ofType, onErrorComplete, onErrorComplete, onErrorResumeNext, onErrorResumeWith, onErrorReturn, onErrorReturnItem, onTerminateDetach, publish, publish, range, rangeLong, reduce, reduce, reduceWith, repeat, repeat, repeatUntil, repeatWhen, replay, replay, replay, replay, replay, replay, replay, replay, replay, replay, replay, replay, replay, replay, replay, replay, replay, replay, retry, retry, retry, retry, retry, retryUntil, retryWhen, safeSubscribe, sample, sample, sample, sample, sample, sample, sample, scan, scan, scanWith, sequenceEqual, sequenceEqual, sequenceEqual, sequenceEqual, serialize, share, single, singleElement, singleOrError, singleOrErrorStage, singleStage, skip, skip, skip, skipLast, skipLast, skipLast, skipLast, skipLast, skipLast, skipUntil, skipWhile, sorted, sorted, startWith, startWith, startWith, startWith, startWithArray, startWithItem, startWithIterable, subscribe, subscribe, subscribe, subscribe, subscribe, subscribe, subscribeActual, subscribeOn, subscribeWith, switchIfEmpty, switchMap, switchMap, switchMapCompletable, switchMapCompletableDelayError, switchMapDelayError, switchMapDelayError, switchMapMaybe, switchMapMaybeDelayError, switchMapSingle, switchMapSingleDelayError, switchOnNext, switchOnNext, switchOnNextDelayError, switchOnNextDelayError, take, take, take, takeLast, takeLast, takeLast, takeLast, takeLast, takeLast, takeLast, takeLast, takeLast, takeUntil, takeUntil, takeWhile, test, test, throttleFirst, throttleFirst, throttleFirst, throttleLast, throttleLast, throttleLast, throttleLatest, throttleLatest, throttleLatest, throttleLatest, throttleLatest, throttleWithTimeout, throttleWithTimeout, throttleWithTimeout, timeInterval, timeInterval, timeInterval, timeInterval, timeout, timeout, timeout, timeout, timeout, timeout, timeout, timeout, timer, timer, timestamp, timestamp, timestamp, timestamp, to, toFlowable, toFuture, toList, toList, toList, toMap, toMap, toMap, toMultimap, toMultimap, toMultimap, toMultimap, toSortedList, toSortedList, toSortedList, toSortedList, unsafeCreate, unsubscribeOn, using, using, window, window, window, window, window, window, window, window, window, window, window, window, window, window, window, window, window, withLatestFrom, withLatestFrom, withLatestFrom, withLatestFrom, withLatestFrom, withLatestFrom, wrap, zip, zip, zip, zip, zip, zip, zip, zip, zip, zip, zip, zip, zipArray, zipWith, zipWith, zipWith, zipWith

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface Observer

onComplete, onError, onNext, onSubscribe

Constructor Details

Subject

public Subject()

Method Details

hasObservers

@CheckReturnValue
public abstract boolean hasObservers()

Returns true if the subject has any Observers.

The method is thread-safe.

Returns:

true if the subject has any Observers

hasThrowable

@CheckReturnValue
public abstract boolean hasThrowable()

Returns true if the subject has reached a terminal state through an error event.

The method is thread-safe.

Returns:

true if the subject has reached a terminal state through an error event

See Also:

• getThrowable()
• hasComplete()

hasComplete

@CheckReturnValue
public abstract boolean hasComplete()

Returns true if the subject has reached a terminal state through a complete event.

The method is thread-safe.

Returns:

true if the subject has reached a terminal state through a complete event

See Also:

• hasThrowable()

getThrowable

@Nullable
@CheckReturnValue
public abstract @Nullable Throwable getThrowable()

Returns the error that caused the Subject to terminate or null if the Subject hasn't terminated yet.

The method is thread-safe.

Returns:

the error that caused the Subject to terminate or null if the Subject hasn't terminated yet

toSerialized

@NonNull
@CheckReturnValue
public final @NonNull Subject<T> toSerialized()

Wraps this Subject and serializes the calls to the onSubscribe, onNext, onError and onComplete methods, making them thread-safe.

The method is thread-safe.

Returns:

the wrapped and serialized subject