io.reactivex.observable.subjects

Class BehaviorSubject<T>

java.lang.Object

io.reactivex.observable.Observable<T>

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

io.reactivex.observable.subjects.BehaviorSubject<T>

Type Parameters:

T - the type of item expected to be observed by the Subject

All Implemented Interfaces:

ObservableSource<T>, Observer<T>

public final class BehaviorSubject<T>
extends Subject<T>

Subject that emits the most recent item it has observed and all subsequent observed items to each subscribed Observer.

Example usage:

 

  // observer will receive all 4 events (including "default").
  BehaviorSubject<Object> subject = BehaviorSubject.createDefault("default");
  subject.subscribe(observer);
  subject.onNext("one");
  subject.onNext("two");
  subject.onNext("three");

  // observer will receive the "one", "two" and "three" events, but not "zero"
  BehaviorSubject<Object> subject = BehaviorSubject.create();
  subject.onNext("zero");
  subject.onNext("one");
  subject.subscribe(observer);
  subject.onNext("two");
  subject.onNext("three");

  // observer will receive only onComplete
  BehaviorSubject<Object> subject = BehaviorSubject.create();
  subject.onNext("zero");
  subject.onNext("one");
  subject.onComplete();
  subject.subscribe(observer);

  // observer will receive only onError
  BehaviorSubject<Object> subject = BehaviorSubject.create();
  subject.onNext("zero");
  subject.onNext("one");
  subject.onError(new RuntimeException("error"));
  subject.subscribe(observer);
   

Method Summary

Modifier and Type	Method and Description
static <T> BehaviorSubject<T>	create() Creates a BehaviorSubject without a default item.
static <T> BehaviorSubject<T>	createDefault(T defaultValue) Creates a BehaviorSubject that emits the last item it observed and all subsequent items to each Observer that subscribes to it.
java.lang.Throwable	getThrowable() Returns the error that caused the Subject to terminate or null if the Subject hasn't terminated yet.
T	getValue() Returns a single value the Subject currently has or null if no such value exists.
java.lang.Object[]	getValues() Returns an Object array containing snapshot all values of the Subject.
T[]	getValues(T[] array) Returns a typed array containing a snapshot of all values of the Subject.
boolean	hasComplete() Returns true if the subject has reached a terminal state through a complete event.
boolean	hasObservers() Returns true if the subject has any Observers.
boolean	hasThrowable() Returns true if the subject has reached a terminal state through an error event.
boolean	hasValue() Returns true if the subject has any value.
void	onComplete() Notifies the Observer that the Observable has finished sending push-based notifications.
void	onError(java.lang.Throwable t) Notifies the Observer that the Observable has experienced an error condition.
void	onNext(T t) Provides the Observer with a new item to observe.
void	onSubscribe(io.reactivex.common.Disposable s) Provides the Observer with the means of cancelling (disposing) the connection (channel) with the Observable in both synchronous (from within Observer.onNext(Object)) and asynchronous manner.
protected void	subscribeActual(Observer<? super T> observer) Operator implementations (both source and intermediate) should implement this method that performs the necessary business logic.

Methods inherited from class io.reactivex.observable.subjects.Subject

toSerialized

Methods inherited from class io.reactivex.observable.Observable

all, amb, ambArray, ambWith, any, blockingFirst, blockingFirst, blockingForEach, blockingIterable, blockingIterable, blockingLast, blockingLast, blockingLatest, blockingMostRecent, blockingNext, blockingSingle, blockingSingle, blockingSubscribe, blockingSubscribe, blockingSubscribe, blockingSubscribe, blockingSubscribe, buffer, buffer, buffer, buffer, buffer, buffer, buffer, buffer, buffer, buffer, buffer, buffer, buffer, buffer, buffer, buffer, buffer, buffer, buffer, bufferSize, cache, cacheWithInitialCapacity, cast, collect, collectInto, combineLatest, combineLatest, combineLatest, combineLatest, combineLatest, combineLatest, combineLatest, combineLatest, combineLatest, combineLatest, combineLatest, combineLatest, combineLatest, combineLatestDelayError, combineLatestDelayError, combineLatestDelayError, combineLatestDelayError, combineLatestDelayError, compose, concat, concat, concat, concat, concat, concat, concatArray, concatArrayDelayError, concatArrayEager, concatArrayEager, concatDelayError, concatDelayError, concatDelayError, concatEager, concatEager, concatEager, concatEager, concatMap, concatMap, concatMapDelayError, concatMapDelayError, concatMapEager, concatMapEager, concatMapEagerDelayError, concatMapEagerDelayError, concatMapIterable, concatMapIterable, concatWith, contains, count, create, 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, flatMap, flatMap, flatMap, flatMap, flatMap, flatMap, flatMap, flatMap, flatMap, flatMap, flatMap, flatMap, flatMapCompletable, flatMapCompletable, flatMapIterable, flatMapIterable, flatMapMaybe, flatMapMaybe, flatMapSingle, flatMapSingle, forEach, forEachWhile, forEachWhile, forEachWhile, fromArray, fromCallable, fromFuture, fromFuture, fromFuture, fromFuture, fromIterable, 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, lift, map, materialize, merge, merge, merge, merge, merge, merge, merge, merge, mergeArray, mergeArray, mergeArrayDelayError, mergeArrayDelayError, mergeDelayError, mergeDelayError, mergeDelayError, mergeDelayError, mergeDelayError, mergeDelayError, mergeDelayError, mergeDelayError, mergeWith, never, observeOn, observeOn, observeOn, ofType, onErrorResumeNext, onErrorResumeNext, onErrorReturn, onErrorReturnItem, onExceptionResumeNext, 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, retry, retry, retry, retry, retry, retryUntil, retryWhen, safeSubscribe, sample, sample, sample, sample, sample, sample, scan, scan, scanWith, sequenceEqual, sequenceEqual, sequenceEqual, sequenceEqual, serialize, share, single, singleElement, singleOrError, skip, skip, skip, skipLast, skipLast, skipLast, skipLast, skipLast, skipLast, skipUntil, skipWhile, sorted, sorted, startWith, startWith, startWith, startWithArray, subscribe, subscribe, subscribe, subscribe, subscribe, subscribe, subscribeOn, subscribeWith, switchIfEmpty, switchMap, switchMap, switchMapDelayError, switchMapDelayError, 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, throttleLast, throttleLast, throttleWithTimeout, throttleWithTimeout, timeInterval, timeInterval, timeInterval, timeInterval, timeout, timeout, timeout, timeout, timeout, timeout, timeout, timeout, timer, timer, timestamp, timestamp, timestamp, timestamp, to, 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, window, window, withLatestFrom, withLatestFrom, withLatestFrom, withLatestFrom, withLatestFrom, withLatestFrom, wrap, zip, zip, zip, zip, zip, zip, zip, zip, zip, zip, zip, zip, zipArray, zipIterable, zipWith, zipWith, zipWith, zipWith

Methods inherited from class java.lang.Object

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

Method Detail

create

@CheckReturnValue
public static <T> BehaviorSubject<T> create()

Creates a BehaviorSubject without a default item.

Type Parameters:

T - the type of item the Subject will emit

Returns:

the constructed BehaviorSubject

createDefault

@CheckReturnValue
public static <T> BehaviorSubject<T> createDefault(T defaultValue)

Creates a BehaviorSubject that emits the last item it observed and all subsequent items to each Observer that subscribes to it.

Type Parameters:

T - the type of item the Subject will emit

Parameters:

defaultValue - the item that will be emitted first to any Observer as long as the BehaviorSubject has not yet observed any items from its source Observable

Returns:

the constructed BehaviorSubject

subscribeActual

protected void subscribeActual(Observer<? super T> observer)

Description copied from class: Observable

Operator implementations (both source and intermediate) should implement this method that performs the necessary business logic.

There is no need to call any of the plugin hooks on the current Observable instance or the Subscriber.

Specified by:

subscribeActual in class Observable<T>

Parameters:

observer - the incoming Observer, never null

onSubscribe

public void onSubscribe(io.reactivex.common.Disposable s)

Description copied from interface: Observer

Provides the Observer with the means of cancelling (disposing) the connection (channel) with the Observable in both synchronous (from within Observer.onNext(Object)) and asynchronous manner.

Parameters:

s - the Disposable instance whose Disposable.dispose() can be called anytime to cancel the connection

onNext

public void onNext(T t)

Description copied from interface: Observer

Provides the Observer with a new item to observe.

The Observable may call this method 0 or more times.

The Observable will not call this method again after it calls either Observer.onComplete() or Observer.onError(java.lang.Throwable).

Parameters:

t - the item emitted by the Observable

onError

public void onError(java.lang.Throwable t)

Description copied from interface: Observer

Notifies the Observer that the Observable has experienced an error condition.

If the Observable calls this method, it will not thereafter call Observer.onNext(T) or Observer.onComplete().

Parameters:

t - the exception encountered by the Observable

onComplete

public void onComplete()

Description copied from interface: Observer

Notifies the Observer that the Observable has finished sending push-based notifications.

The Observable will not call this method if it calls Observer.onError(java.lang.Throwable).

hasObservers

public boolean hasObservers()

Description copied from class: Subject

Returns true if the subject has any Observers.

The method is thread-safe.

Specified by:

hasObservers in class Subject<T>

Returns:

true if the subject has any Observers

getThrowable

public java.lang.Throwable getThrowable()

Description copied from class: Subject

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

The method is thread-safe.

Specified by:

getThrowable in class Subject<T>

Returns:

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

getValue

public T getValue()

Returns a single value the Subject currently has or null if no such value exists.

The method is thread-safe.

Returns:

a single value the Subject currently has or null if no such value exists

getValues

public java.lang.Object[] getValues()

Returns an Object array containing snapshot all values of the Subject.

The method is thread-safe.

Returns:

the array containing the snapshot of all values of the Subject

getValues

public T[] getValues(T[] array)

Returns a typed array containing a snapshot of all values of the Subject.

The method follows the conventions of Collection.toArray by setting the array element after the last value to null (if the capacity permits).

The method is thread-safe.

Parameters:

array - the target array to copy values into if it fits

Returns:

the given array if the values fit into it or a new array containing all values

hasComplete

public boolean hasComplete()

Description copied from class: Subject

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

The method is thread-safe.

Specified by:

hasComplete in class Subject<T>

Returns:

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

See Also:

Subject.hasThrowable()

hasThrowable

public boolean hasThrowable()

Description copied from class: Subject

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

The method is thread-safe.

Specified by:

hasThrowable in class Subject<T>

Returns:

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

See Also:

&see {@link #hasComplete()}

hasValue

public boolean hasValue()

Returns true if the subject has any value.

The method is thread-safe.

Returns:

true if the subject has any value