pekko/akka-stream/src/main/scala-jdk-9/akka/stream/impl/JavaFlowAndRsConverters.scala
2019-12-19 01:57:55 -05:00

197 lines
9.2 KiB
Scala

/*
* Copyright (C) 2017-2019 Lightbend Inc. <https://www.lightbend.com>
*/
package akka.stream.impl
import java.util.concurrent.Flow
import akka.annotation.InternalApi
import org.{ reactivestreams => rs }
import JavaFlowAndRsConverters.Implicits._
/**
* INTERNAL API: Provides converters between Reactive Streams (reactive-streams.org) and their Java 9+ counter-parts,
* defined in `java.util.concurrent.Flow.*`. This API is internal because Reactive Streams will ship with such
* adapters itself at some point, and we'd not want to duplicate that effort for users to be confused about which ones
* to use. These adapters are used internally by Akka Streams to convert between the standards but you should not touch
* them directly - use thr `JavaFlowSupport` classes instead.
*
* Please note that either of these types are designed for *inter-op* and usually should not be used directly
* in applications. The intended use case is for shared libraries, like database drivers or similar to provide
* the inter-operable types, such that other libraries can co-operate with them directly, if that is your use case
* and you're using the j.u.c.Flow types, use the [[akka.stream.scaladsl.JavaFlowSupport]] sources/sinks/flows instead.
*
* The interfaces as well as semantic contract of these sets of interfaces.
* Please see https://github.com/reactive-streams/reactive-streams-jvm to learn more about the specification,
* and TCK that is available to verify an implementation is a valid implementation.
*/
@InternalApi
private[akka] object JavaFlowAndRsConverters {
/** Adds `asJava` and `asRs` enrichment methods to Reactive Streams and j.u.c.Flow types. */
object Implicits {
final implicit class FlowPublisherConverter[T](val p: rs.Publisher[T]) extends AnyVal {
def asJava: Flow.Publisher[T] =
if (p eq null) null else JavaFlowAndRsConverters.asJava(p)
}
final implicit class RsPublisherConverter[T](val p: Flow.Publisher[T]) extends AnyVal {
def asRs: rs.Publisher[T] = JavaFlowAndRsConverters.asRs(p)
}
final implicit class FlowSubscriberConverter[T](val s: rs.Subscriber[T]) extends AnyVal {
def asJava: Flow.Subscriber[T] = JavaFlowAndRsConverters.asJava(s)
}
final implicit class RsSubscriberConverter[T](val s: Flow.Subscriber[T]) extends AnyVal {
def asRs: rs.Subscriber[T] = JavaFlowAndRsConverters.asRs(s)
}
final implicit class FlowProcessorConverter[T, R](val s: rs.Processor[T, R]) extends AnyVal {
def asJava: Flow.Processor[T, R] = JavaFlowAndRsConverters.asJava(s)
}
final implicit class RsProcessorConverter[T, R](val s: Flow.Processor[T, R]) extends AnyVal {
def asRs: rs.Processor[T, R] = JavaFlowAndRsConverters.asRs(s)
}
final implicit class FlowSubscriptionConverter[T](val s: rs.Subscription) extends AnyVal {
def asJava: Flow.Subscription = JavaFlowAndRsConverters.asJava(s)
}
final implicit class RsSubscriptionConverter[T](val s: Flow.Subscription) extends AnyVal {
def asRs: rs.Subscription = JavaFlowAndRsConverters.asRs(s)
}
}
final def asJava[T](p: rs.Publisher[T]): Flow.Publisher[T] = p match {
case null => null // null remains null
case adapter: JavaFlowPublisherToRsAdapter[T] => adapter.delegate // unwrap adapter instead of wrapping again
case delegate => new RsPublisherToJavaFlowAdapter(delegate) // adapt, it is a real Publisher
}
final def asRs[T](p: Flow.Publisher[T]): rs.Publisher[T] = p match {
case null => null // null remains null
case adapter: RsPublisherToJavaFlowAdapter[T] => adapter.delegate // unwrap adapter instead of wrapping again
case _ => new JavaFlowPublisherToRsAdapter[T](p)
}
final def asJava[T](s: rs.Subscription): Flow.Subscription = s match {
case null => null // null remains null
case adapter: JavaFlowSubscriptionToRsAdapter => adapter.delegate // unwrap adapter instead of wrapping again
case _ => new RsSubscriptionToJavaFlowAdapter(s)
}
final def asRs[T](s: Flow.Subscription): rs.Subscription = s match {
case null => null // null remains null
case adapter: RsSubscriptionToJavaFlowAdapter => adapter.delegate // unwrap adapter instead of wrapping again
case _ => new JavaFlowSubscriptionToRsAdapter(s)
}
final def asJava[T](s: rs.Subscriber[T]): Flow.Subscriber[T] =
s match {
case null => null // null remains null
case adapter: JavaFlowSubscriberToRsAdapter[T] => adapter.delegate // unwrap adapter instead of wrapping again
case _ => new RsSubscriberToJavaFlowAdapter[T](s)
}
final def asRs[T](s: Flow.Subscriber[T]): rs.Subscriber[T] = s match {
case null => null // null remains null
case adapter: RsSubscriberToJavaFlowAdapter[T] => adapter.delegate // unwrap adapter instead of wrapping again
case _ => new JavaFlowSubscriberToRsAdapter[T](s)
}
final def asJava[T, R](p: rs.Processor[T, R]): Flow.Processor[T, R] = p match {
case null => null // null remains null
case adapter: JavaFlowProcessorToRsAdapter[T, R] => adapter.delegate // unwrap adapter instead of wrapping again
case _ => new RsProcessorToJavaFlowAdapter[T, R](p)
}
final def asRs[T, R](p: Flow.Processor[T, R]): rs.Processor[T, R] = p match {
case null => null // null remains null
case adapter: RsProcessorToJavaFlowAdapter[T, R] => adapter.delegate // unwrap adapter instead of wrapping again
case _ => new JavaFlowProcessorToRsAdapter[T, R](p)
}
}
/** INTERNAL API: Adapters are not meant to be touched directly */
@InternalApi private[akka] final class JavaFlowPublisherToRsAdapter[T](val delegate: Flow.Publisher[T]) extends rs.Publisher[T] {
override def subscribe(rsSubscriber: rs.Subscriber[_ >: T]): Unit =
delegate.subscribe(rsSubscriber.asJava)
}
/** INTERNAL API: Adapters are not meant to be touched directly */
@InternalApi private[akka] final class RsPublisherToJavaFlowAdapter[T](val delegate: rs.Publisher[T]) extends Flow.Publisher[T] {
override def subscribe(javaSubscriber: Flow.Subscriber[_ >: T]): Unit =
delegate.subscribe(javaSubscriber.asRs)
}
/** INTERNAL API: Adapters are not meant to be touched directly */
@InternalApi private[akka] final class RsSubscriberToJavaFlowAdapter[T](val delegate: rs.Subscriber[T]) extends Flow.Subscriber[T] {
override def onError(t: Throwable): Unit =
delegate.onError(t)
override def onComplete(): Unit =
delegate.onComplete()
override def onNext(elem: T): Unit =
delegate.onNext(elem)
override def onSubscribe(s: Flow.Subscription): Unit =
delegate.onSubscribe(s.asRs)
}
/** INTERNAL API: Adapters are not meant to be touched directly */
@InternalApi private[akka] final class JavaFlowSubscriberToRsAdapter[T](val delegate: Flow.Subscriber[T]) extends rs.Subscriber[T] {
override def onError(t: Throwable): Unit =
delegate.onError(t)
override def onComplete(): Unit =
delegate.onComplete()
override def onNext(elem: T): Unit =
delegate.onNext(elem)
override def onSubscribe(s: rs.Subscription): Unit =
delegate.onSubscribe(s.asJava)
}
/** INTERNAL API: Adapters are not meant to be touched directly */
@InternalApi private[akka] final class RsSubscriptionToJavaFlowAdapter(val delegate: rs.Subscription) extends Flow.Subscription {
override def cancel(): Unit = delegate.cancel()
override def request(n: Long): Unit = delegate.request(n)
}
/** INTERNAL API: Adapters are not meant to be touched directly */
@InternalApi private[akka] final class JavaFlowSubscriptionToRsAdapter(val delegate: Flow.Subscription) extends rs.Subscription {
override def cancel(): Unit = delegate.cancel()
override def request(n: Long): Unit = delegate.request(n)
}
/** INTERNAL API: Adapters are not meant to be touched directly */
@InternalApi private[akka] final class RsProcessorToJavaFlowAdapter[T, R](val delegate: rs.Processor[T, R]) extends Flow.Processor[T, R] {
override def onError(t: Throwable): Unit =
delegate.onError(t)
override def onComplete(): Unit =
delegate.onComplete()
override def onNext(elem: T): Unit =
delegate.onNext(elem)
override def onSubscribe(s: Flow.Subscription): Unit =
delegate.onSubscribe(s.asRs)
override def subscribe(javaSubscriber: Flow.Subscriber[_ >: R]): Unit =
delegate.subscribe(javaSubscriber.asRs)
}
/** INTERNAL API: Adapters are not meant to be touched directly */
@InternalApi private[akka] final class JavaFlowProcessorToRsAdapter[T, R](val delegate: Flow.Processor[T, R]) extends rs.Processor[T, R] {
override def onError(t: Throwable): Unit =
delegate.onError(t)
override def onComplete(): Unit =
delegate.onComplete()
override def onNext(elem: T): Unit =
delegate.onNext(elem)
override def onSubscribe(s: rs.Subscription): Unit =
delegate.onSubscribe(s.asJava)
override def subscribe(rsSubscriber: rs.Subscriber[_ >: R]): Unit =
delegate.subscribe(rsSubscriber.asJava)
}