Package com.linecorp.armeria.common.stream

Class DeferredStreamMessage<T>

java.lang.Object

com.linecorp.armeria.common.stream.AggregationSupport

com.linecorp.armeria.common.stream.DeferredStreamMessage<T>

Type Parameters:

T - the type of element signaled

All Implemented Interfaces:

StreamMessage<T>, org.reactivestreams.Publisher<T>

@UnstableApi
public class DeferredStreamMessage<T>
extends AggregationSupport

A StreamMessage whose stream is published later by another StreamMessage. It is useful when your StreamMessage will not be instantiated early.

Constructor Summary

Constructors

Constructor	Description
DeferredStreamMessage()	Creates a new instance.
DeferredStreamMessage(EventExecutor defaultSubscriberExecutor)	Creates a new instance.

Method Summary

Modifier and Type	Method	Description
final void	abort()	Closes this stream with AbortedStreamException and prevents further subscription.
final void	abort(Throwable cause)	Closes this stream with the specified Throwable and prevents further subscription.
final void	close()	Closes the deferred stream without setting a delegate.
final void	close(Throwable cause)	Closes the deferred stream without setting a delegate.
CompletableFuture<List<T>>	collect(EventExecutor executor, SubscriptionOption... options)	Collects the elements published by this StreamMessage with the specified EventExecutor and SubscriptionOptions.
EventExecutor	defaultSubscriberExecutor()	Returns the default EventExecutor which will be used when a user subscribes using StreamMessage.subscribe(Subscriber), StreamMessage.subscribe(Subscriber, SubscriptionOption...).
protected final void	delegate(StreamMessage<T> upstream)	Sets the upstream StreamMessage which will actually publish the stream.
protected final void	delegateOnCompletion(CompletionStage<? extends org.reactivestreams.Publisher<T>> stage)	Delegates when the specified CompletionStage is complete.
final long	demand()	Returns the current demand of this stream.
final boolean	isEmpty()	Returns true if this stream has been closed and did not publish any elements.
final boolean	isOpen()	Returns true if this stream is not closed yet.
protected void	onRemoval(T obj)	Invoked after an element is removed from the StreamMessage and before Subscriber.onNext(Object) is invoked.
final void	subscribe(org.reactivestreams.Subscriber<? super T> subscriber, EventExecutor executor)	Requests to start streaming data to the specified Subscriber.
final void	subscribe(org.reactivestreams.Subscriber<? super T> subscriber, EventExecutor executor, SubscriptionOption... options)	Requests to start streaming data to the specified Subscriber.
final CompletableFuture<Void>	whenComplete()	Returns a CompletableFuture that completes when this stream is complete, either successfully or exceptionally, including cancellation and abortion.

Methods inherited from class com.linecorp.armeria.common.stream.AggregationSupport

aggregate

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.linecorp.armeria.common.stream.StreamMessage

collect, collect, decode, decode, endWith, filter, isComplete, map, mapAsync, mapError, mapParallel, mapParallel, peek, peek, peekError, recoverAndResume, recoverAndResume, subscribe, subscribe, subscribe, subscribe, subscribeOn, toDuplicator, toDuplicator, toInputStream, toInputStream, writeTo

Constructor Details

DeferredStreamMessage

public DeferredStreamMessage()

Creates a new instance.

DeferredStreamMessage

public DeferredStreamMessage(EventExecutor defaultSubscriberExecutor)

Creates a new instance.

Method Details

defaultSubscriberExecutor

public EventExecutor defaultSubscriberExecutor()

Description copied from interface: StreamMessage

Returns the default EventExecutor which will be used when a user subscribes using StreamMessage.subscribe(Subscriber), StreamMessage.subscribe(Subscriber, SubscriptionOption...).

Please note that if this method is called multiple times, the returned EventExecutors can be different depending on this StreamMessage implementation.

delegateOnCompletion

protected final void delegateOnCompletion(CompletionStage<? extends org.reactivestreams.Publisher<T>> stage)

Delegates when the specified CompletionStage is complete.

delegate

protected final void delegate(StreamMessage<T> upstream)

Sets the upstream StreamMessage which will actually publish the stream.

Throws:

IllegalStateException - if the upstream has been set already or if close() or close(Throwable) was called already.

close

public final void close()

Closes the deferred stream without setting a delegate.

Throws:

IllegalStateException - if the upstream has been set already or if close() or close(Throwable) was called already.

close

public final void close(Throwable cause)

Closes the deferred stream without setting a delegate.

Throws:

IllegalStateException - if the delegate has been set already or if close() or close(Throwable) was called already.

isOpen

public final boolean isOpen()

Description copied from interface: StreamMessage

Returns true if this stream is not closed yet. Note that a stream may not be complete even if it's closed; a stream is complete when it's fully consumed by a Subscriber.

isEmpty

public final boolean isEmpty()

Description copied from interface: StreamMessage

Returns true if this stream has been closed and did not publish any elements. Note that this method will not return true when the stream is open even if it has not published anything so far, because it may publish something later.

demand

public final long demand()

Description copied from interface: StreamMessage

Returns the current demand of this stream.

abort

public final void abort()

Description copied from interface: StreamMessage

Closes this stream with AbortedStreamException and prevents further subscription. A Subscriber that attempts to subscribe to an aborted stream will be notified with an AbortedStreamException via Subscriber.onError(Throwable). Calling this method on a closed or aborted stream has no effect.

abort

public final void abort(Throwable cause)

Description copied from interface: StreamMessage

Closes this stream with the specified Throwable and prevents further subscription. A Subscriber that attempts to subscribe to an aborted stream will be notified with the specified Throwable via Subscriber.onError(Throwable). Calling this method on a closed or aborted stream has no effect.

collect

public CompletableFuture<List<T>> collect(EventExecutor executor,
 SubscriptionOption... options)

Description copied from interface: StreamMessage

Collects the elements published by this StreamMessage with the specified EventExecutor and SubscriptionOptions. The returned CompletableFuture will be notified when the elements are fully consumed.

Note that if this StreamMessage was subscribed by other Subscriber already, the returned CompletableFuture will be completed with an IllegalStateException.

subscribe

public final void subscribe(org.reactivestreams.Subscriber<? super T> subscriber,
 EventExecutor executor)

Description copied from interface: StreamMessage

Requests to start streaming data to the specified Subscriber. If there is a problem subscribing, Subscriber.onError(Throwable) will be invoked with one of the following exceptions:

• IllegalStateException if other Subscriber subscribed to this stream already.
• AbortedStreamException if this stream has been aborted.
• CancelledSubscriptionException if this stream has been cancelled and SubscriptionOption.NOTIFY_CANCELLATION is specified when subscribed.
• Other exceptions that occurred due to an error while retrieving the elements.

Specified by:

subscribe in interface StreamMessage<T>

Parameters:

executor - the executor to subscribe

subscribe

public final void subscribe(org.reactivestreams.Subscriber<? super T> subscriber,
 EventExecutor executor,
 SubscriptionOption... options)

Description copied from interface: StreamMessage

Requests to start streaming data to the specified Subscriber. If there is a problem subscribing, Subscriber.onError(Throwable) will be invoked with one of the following exceptions:

• IllegalStateException if other Subscriber subscribed to this stream already.
• AbortedStreamException if this stream has been aborted.
• CancelledSubscriptionException if this stream has been cancelled and SubscriptionOption.NOTIFY_CANCELLATION is specified when subscribed.
• Other exceptions that occurred due to an error while retrieving the elements.

Specified by:

subscribe in interface StreamMessage<T>

Parameters:

executor - the executor to subscribe

options - SubscriptionOptions to subscribe with

whenComplete

public final CompletableFuture<Void> whenComplete()

Description copied from interface: StreamMessage

Returns a CompletableFuture that completes when this stream is complete, either successfully or exceptionally, including cancellation and abortion.

A StreamMessage is complete (or 'fully consumed') when:

• the Subscriber consumes all elements and Subscriber.onComplete() is invoked,
• an error occurred and Subscriber.onError(Throwable) is invoked,
• the Subscription has been cancelled or
• StreamMessage.abort() has been requested.

Specified by:

whenComplete in interface StreamMessage<T>

onRemoval

protected void onRemoval(T obj)

Invoked after an element is removed from the StreamMessage and before Subscriber.onNext(Object) is invoked.

Parameters:

obj - the removed element