Package rx.observables
Class AsyncOnSubscribe<S,T>
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- rx.observables.AsyncOnSubscribe<S,T>
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- Type Parameters:
S- the type of the user-define state used ingenerateState(S),next(S, Long, Observer), andonUnsubscribe(S).T- the type ofSubscribersthat will be compatible withthis.
- All Implemented Interfaces:
Action,Action1<Subscriber<? super T>>,Function,Observable.OnSubscribe<T>
- Direct Known Subclasses:
AsyncOnSubscribe.AsyncOnSubscribeImpl
@Experimental public abstract class AsyncOnSubscribe<S,T> extends java.lang.Object implements Observable.OnSubscribe<T>
A utility class to createOnSubscribe<T>functions that respond correctly to back pressure requests from subscribers. This is an improvement overObservable.create(OnSubscribe)which does not provide any means of managing back pressure requests out-of-the-box. This variant of an OnSubscribe function allows for the asynchronous processing of requests.
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Nested Class Summary
Nested Classes Modifier and Type Class Description (package private) static classAsyncOnSubscribe.AsyncOnSubscribeImpl<S,T>An implementation of AsyncOnSubscribe that delegatesnext(Object, long, Observer),generateState(), andonUnsubscribe(Object)to provided functions/closures.(package private) static classAsyncOnSubscribe.AsyncOuterManager<S,T>(package private) static classAsyncOnSubscribe.UnicastSubject<T>
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Constructor Summary
Constructors Constructor Description AsyncOnSubscribe()
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Method Summary
All Methods Static Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description voidcall(Subscriber<? super T> actualSubscriber)static <S,T>
AsyncOnSubscribe<S,T>createSingleState(Func0<? extends S> generator, Action3<? super S,java.lang.Long,? super Observer<Observable<? extends T>>> next)Generates a synchronousAsyncOnSubscribethat calls the providednextfunction to generate data to downstream subscribers.static <S,T>
AsyncOnSubscribe<S,T>createSingleState(Func0<? extends S> generator, Action3<? super S,java.lang.Long,? super Observer<Observable<? extends T>>> next, Action1<? super S> onUnsubscribe)Generates a synchronousAsyncOnSubscribethat calls the providednextfunction to generate data to downstream subscribers.static <S,T>
AsyncOnSubscribe<S,T>createStateful(Func0<? extends S> generator, Func3<? super S,java.lang.Long,? super Observer<Observable<? extends T>>,? extends S> next)Generates a synchronousAsyncOnSubscribethat calls the providednextfunction to generate data to downstream subscribers.static <S,T>
AsyncOnSubscribe<S,T>createStateful(Func0<? extends S> generator, Func3<? super S,java.lang.Long,? super Observer<Observable<? extends T>>,? extends S> next, Action1<? super S> onUnsubscribe)Generates a synchronousAsyncOnSubscribethat calls the providednextfunction to generate data to downstream subscribers.static <T> AsyncOnSubscribe<java.lang.Void,T>createStateless(Action2<java.lang.Long,? super Observer<Observable<? extends T>>> next)Generates a synchronousAsyncOnSubscribethat calls the providednextfunction to generate data to downstream subscribers.static <T> AsyncOnSubscribe<java.lang.Void,T>createStateless(Action2<java.lang.Long,? super Observer<Observable<? extends T>>> next, Action0 onUnsubscribe)Generates a synchronousAsyncOnSubscribethat calls the providednextfunction to generate data to downstream subscribers.protected abstract SgenerateState()Executed once when subscribed to by a subscriber (viacall(Subscriber)) to produce a state value.protected abstract Snext(S state, long requested, Observer<Observable<? extends T>> observer)Called to produce data to the downstream subscribers.protected voidonUnsubscribe(S state)Clean up behavior that is executed after the downstream subscriber's subscription is unsubscribed.
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Method Detail
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generateState
protected abstract S generateState()
Executed once when subscribed to by a subscriber (viacall(Subscriber)) to produce a state value. This value is passed intonext(S state, Observeron the first iteration. Subsequent iterations ofobserver) nextwill receive the state returned by the previous invocation ofnext.- Returns:
- the initial state value
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next
protected abstract S next(S state, long requested, Observer<Observable<? extends T>> observer)
Called to produce data to the downstream subscribers. To emit data to a downstream subscriber callobserver.onNext(t). To signal an error condition callobserver.onError(throwable)or throw an Exception. To signal the end of a data stream callobserver.onCompleted(). Implementations of this method must follow the following rules.- Must not call
observer.onNext(t)more than 1 time per invocation. - Must not call
observer.onNext(t)concurrently.
stateargument of the next invocation of this method.- Parameters:
state- the state value (fromgenerateState()on the first invocation or the previous invocation of this method.requested- the amount of data requested. An observable emitted to the observer should not exceed this amount.observer- the observer of data emitted by- Returns:
- the next iteration's state value
- Must not call
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onUnsubscribe
protected void onUnsubscribe(S state)
Clean up behavior that is executed after the downstream subscriber's subscription is unsubscribed. This method will be invoked exactly once.- Parameters:
state- the last state value returned fromnext(S, Long, Observer)orgenerateState()at the time when a terminal event is emitted fromnext(Object, long, Observer)or unsubscribing.
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createSingleState
@Experimental public static <S,T> AsyncOnSubscribe<S,T> createSingleState(Func0<? extends S> generator, Action3<? super S,java.lang.Long,? super Observer<Observable<? extends T>>> next)
Generates a synchronousAsyncOnSubscribethat calls the providednextfunction to generate data to downstream subscribers.- Type Parameters:
T- the type of the generated valuesS- the type of the associated state with each Subscriber- Parameters:
generator- generates the initial state value (seegenerateState())next- produces data to the downstream subscriber (seenext(S, long, Observer))- Returns:
- an AsyncOnSubscribe that emits data in a protocol compatible with back-pressure.
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createSingleState
@Experimental public static <S,T> AsyncOnSubscribe<S,T> createSingleState(Func0<? extends S> generator, Action3<? super S,java.lang.Long,? super Observer<Observable<? extends T>>> next, Action1<? super S> onUnsubscribe)
Generates a synchronousAsyncOnSubscribethat calls the providednextfunction to generate data to downstream subscribers. This overload creates a AsyncOnSubscribe without an explicit clean up step.- Type Parameters:
T- the type of the generated valuesS- the type of the associated state with each Subscriber- Parameters:
generator- generates the initial state value (seegenerateState())next- produces data to the downstream subscriber (seenext(S, long, Observer))onUnsubscribe- clean up behavior (seeonUnsubscribe(S))- Returns:
- an AsyncOnSubscribe that emits data downstream in a protocol compatible with back-pressure.
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createStateful
@Experimental public static <S,T> AsyncOnSubscribe<S,T> createStateful(Func0<? extends S> generator, Func3<? super S,java.lang.Long,? super Observer<Observable<? extends T>>,? extends S> next, Action1<? super S> onUnsubscribe)
Generates a synchronousAsyncOnSubscribethat calls the providednextfunction to generate data to downstream subscribers.- Type Parameters:
T- the type of the generated valuesS- the type of the associated state with each Subscriber- Parameters:
generator- generates the initial state value (seegenerateState())next- produces data to the downstream subscriber (seenext(S, long, Observer))onUnsubscribe- clean up behavior (seeonUnsubscribe(S))- Returns:
- an AsyncOnSubscribe that emits data downstream in a protocol compatible with back-pressure.
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createStateful
@Experimental public static <S,T> AsyncOnSubscribe<S,T> createStateful(Func0<? extends S> generator, Func3<? super S,java.lang.Long,? super Observer<Observable<? extends T>>,? extends S> next)
Generates a synchronousAsyncOnSubscribethat calls the providednextfunction to generate data to downstream subscribers.- Type Parameters:
T- the type of the generated valuesS- the type of the associated state with each Subscriber- Parameters:
generator- generates the initial state value (seegenerateState())next- produces data to the downstream subscriber (seenext(S, long, Observer))- Returns:
- an AsyncOnSubscribe that emits data downstream in a protocol compatible with back-pressure.
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createStateless
@Experimental public static <T> AsyncOnSubscribe<java.lang.Void,T> createStateless(Action2<java.lang.Long,? super Observer<Observable<? extends T>>> next)
Generates a synchronousAsyncOnSubscribethat calls the providednextfunction to generate data to downstream subscribers. This overload creates a "state-less" AsyncOnSubscribe which does not have an explicit state value. This should be used when thenextfunction closes over it's state.- Type Parameters:
T- the type of the generated values- Parameters:
next- produces data to the downstream subscriber (seenext(S, long, Observer))- Returns:
- an AsyncOnSubscribe that emits data downstream in a protocol compatible with back-pressure.
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createStateless
@Experimental public static <T> AsyncOnSubscribe<java.lang.Void,T> createStateless(Action2<java.lang.Long,? super Observer<Observable<? extends T>>> next, Action0 onUnsubscribe)
Generates a synchronousAsyncOnSubscribethat calls the providednextfunction to generate data to downstream subscribers. This overload creates a "state-less" AsyncOnSubscribe which does not have an explicit state value. This should be used when thenextfunction closes over it's state.- Type Parameters:
T- the type of the generated values- Parameters:
next- produces data to the downstream subscriber (seenext(S, long, Observer))onUnsubscribe- clean up behavior (seeonUnsubscribe(S))- Returns:
- an AsyncOnSubscribe that emits data downstream in a protocol compatible with back-pressure.
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call
public final void call(Subscriber<? super T> actualSubscriber)
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