io.servicetalk.http.utils

Class BeforeFinallyHttpOperator

java.lang.Object

io.servicetalk.http.utils.BeforeFinallyHttpOperator

All Implemented Interfaces:

SingleOperator<StreamingHttpResponse,StreamingHttpResponse>, java.util.function.Function<SingleSource.Subscriber<? super StreamingHttpResponse>,SingleSource.Subscriber<? super StreamingHttpResponse>>

public final class BeforeFinallyHttpOperator
extends java.lang.Object
implements SingleOperator<StreamingHttpResponse,StreamingHttpResponse>

Helper operator for signaling the end of an HTTP Request/Response cycle.

StreamingHttpRequest and StreamingHttpResponse are nested sources (Single of meta-data containing a payload Publisher), which makes it non-trivial to get a single signal at the end of this Request/Response cycle. One needs to consider and coordinate between the multitude of outcomes: cancel/success/error across both sources.

This operator ensures that the provided callback is triggered just once whenever the sources reach a terminal state across both sources.

Example usage tracking the begin and end of a request:

     // coarse grained, any terminal signal calls the provided `Runnable`
     return requester.request(strategy, request)
                     .beforeOnSubscribe(__ -> tracker.requestStarted())
                     .liftSync(new BeforeFinallyHttpOperator(tracker::requestFinished));

     // fine grained, `tracker` implements `TerminalSignalConsumer`, terminal signal indicated by the callback method
     return requester.request(strategy, request)
                     .beforeOnSubscribe(__ -> tracker.requestStarted())
                     .liftSync(new BeforeFinallyHttpOperator(tracker));
 

Constructor Summary

Constructors

Constructor and Description
BeforeFinallyHttpOperator(java.lang.Runnable beforeFinally) Create a new instance.
BeforeFinallyHttpOperator(TerminalSignalConsumer beforeFinally) Create a new instance.

Method Summary

Modifier and Type	Method and Description
SingleSource.Subscriber<? super StreamingHttpResponse>	apply(SingleSource.Subscriber<? super StreamingHttpResponse> subscriber) Implementation of this operator.

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.function.Function

andThen, compose, identity

Constructor Detail

BeforeFinallyHttpOperator

public BeforeFinallyHttpOperator(TerminalSignalConsumer beforeFinally)

Create a new instance.

Parameters:

beforeFinally - the callback which is executed just once whenever the sources reach a terminal state across both sources.

BeforeFinallyHttpOperator

public BeforeFinallyHttpOperator(java.lang.Runnable beforeFinally)

Create a new instance.

Parameters:

beforeFinally - the callback which is executed just once whenever the sources reach a terminal state across both sources.

Method Detail

apply

public SingleSource.Subscriber<? super StreamingHttpResponse> apply(SingleSource.Subscriber<? super StreamingHttpResponse> subscriber)

Description copied from interface: SingleOperator

Implementation of this operator. See SingleOperator for definition of an operator.

Specified by:

apply in interface SingleOperator<StreamingHttpResponse,StreamingHttpResponse>

Specified by:

apply in interface java.util.function.Function<SingleSource.Subscriber<? super StreamingHttpResponse>,SingleSource.Subscriber<? super StreamingHttpResponse>>

Parameters:

subscriber - SingleSource.Subscriber that subscribed to this operator.

Returns:

SingleSource.Subscriber that is used to subscribe to the Single that this operator is applied to.