Package com.linecorp.armeria.common.stream

Class FilteredStreamMessage<T,U>

java.lang.Object

com.linecorp.armeria.common.stream.FilteredStreamMessage<T,U>

All Implemented Interfaces:

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

Direct Known Subclasses:

FilteredHttpRequest, FilteredHttpResponse

public abstract class FilteredStreamMessage<T,U>
extends Object
implements StreamMessage<U>

A StreamMessage that filters objects as they are published. The filtering will happen from an I/O thread, meaning the order of the filtering will match the order that the delegate processes the objects in.

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	FilteredStreamMessage(StreamMessage<T> upstream)	Creates a new FilteredStreamMessage that filters objects published by upstream before passing to a subscriber.
protected	FilteredStreamMessage(StreamMessage<T> upstream, boolean withPooledObjects)	(Advanced users only) Creates a new FilteredStreamMessage that filters objects published by upstream before passing to a subscriber.

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.
protected void	beforeComplete(org.reactivestreams.Subscriber<? super U> subscriber)	A callback executed just before calling Subscriber.onComplete() on subscriber.
protected @Nullable Throwable	beforeError(org.reactivestreams.Subscriber<? super U> subscriber, Throwable cause)	A callback executed just before calling Subscriber.onError(Throwable) on subscriber.
protected void	beforeSubscribe(org.reactivestreams.Subscriber<? super U> subscriber, org.reactivestreams.Subscription subscription)	A callback executed just before calling Subscriber.onSubscribe(Subscription) on subscriber.
CompletableFuture<List<U>>	collect(EventExecutor executor, SubscriptionOption... options)	Collects the elements published by this StreamMessage with the specified EventExecutor and SubscriptionOptions.
final EventExecutor	defaultSubscriberExecutor()	Returns the default EventExecutor which will be used when a user subscribes using StreamMessage.subscribe(Subscriber), StreamMessage.subscribe(Subscriber, SubscriptionOption...).
final long	demand()	Returns the current demand of this stream.
protected abstract U	filter(T obj)	The filter to apply to published objects.
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	onCancellation(org.reactivestreams.Subscriber<? super U> subscriber)	A callback executed when this StreamMessage is canceled by the Subscriber.
final void	subscribe(org.reactivestreams.Subscriber<? super U> subscriber, EventExecutor executor)	Requests to start streaming data to the specified Subscriber.
final void	subscribe(org.reactivestreams.Subscriber<? super U> 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 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, filter, isComplete, map, mapAsync, mapError, mapParallel, mapParallel, peek, peek, peekError, recoverAndResume, recoverAndResume, subscribe, subscribe, subscribe, toDuplicator, toDuplicator, toInputStream, toInputStream, writeTo

Constructor Details

FilteredStreamMessage

protected FilteredStreamMessage(StreamMessage<T> upstream)

Creates a new FilteredStreamMessage that filters objects published by upstream before passing to a subscriber.

FilteredStreamMessage

@UnstableApi
protected FilteredStreamMessage(StreamMessage<T> upstream,
 boolean withPooledObjects)

(Advanced users only) Creates a new FilteredStreamMessage that filters objects published by upstream before passing to a subscriber.

Parameters:

withPooledObjects - if true, filter(Object) receives the pooled HttpData as is, without making a copy. If you don't know what this means, use FilteredStreamMessage(StreamMessage).

See Also:

• PooledObjects

Method Details

filter

protected abstract U filter(T obj)

The filter to apply to published objects. The result of the filter is passed on to the delegate subscriber.

beforeSubscribe

protected void beforeSubscribe(org.reactivestreams.Subscriber<? super U> subscriber,
 org.reactivestreams.Subscription subscription)

A callback executed just before calling Subscriber.onSubscribe(Subscription) on subscriber. Override this method to execute any initialization logic that may be needed.

beforeComplete

protected void beforeComplete(org.reactivestreams.Subscriber<? super U> subscriber)

A callback executed just before calling Subscriber.onComplete() on subscriber. Override this method to execute any cleanup logic that may be needed before completing the subscription.

beforeError

@Nullable
protected @Nullable Throwable beforeError(org.reactivestreams.Subscriber<? super U> subscriber,
 Throwable cause)

A callback executed just before calling Subscriber.onError(Throwable) on subscriber. Override this method to execute any cleanup logic that may be needed before failing the subscription. This method may rewrite the cause and then return a new one so that the new Throwable would be passed to Subscriber.onError(Throwable).

onCancellation

protected void onCancellation(org.reactivestreams.Subscriber<? super U> subscriber)

A callback executed when this StreamMessage is canceled by the Subscriber.

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.

Specified by:

isOpen in interface StreamMessage<T>

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.

Specified by:

isEmpty in interface StreamMessage<T>

demand

public final long demand()

Description copied from interface: StreamMessage

Returns the current demand of this stream.

Specified by:

demand in interface StreamMessage<T>

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>

collect

public CompletableFuture<List<U>> 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.

Specified by:

collect in interface StreamMessage<T>

subscribe

public final void subscribe(org.reactivestreams.Subscriber<? super U> 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>

executor - the executor to subscribe

subscribe

public final void subscribe(org.reactivestreams.Subscriber<? super U> 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>

executor - the executor to subscribe

options - SubscriptionOptions to subscribe with

defaultSubscriberExecutor

public final 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.

Specified by:

defaultSubscriberExecutor in interface StreamMessage<T>

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.

Specified by:

abort in interface StreamMessage<T>

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.

Specified by:

abort in interface StreamMessage<T>