From 494b80da610fe2b4cb1790ae237437a17ac6ef62 Mon Sep 17 00:00:00 2001 From: Jakob Odersky Date: Sat, 2 Mar 2013 12:06:03 +0100 Subject: simplify scala implementation --- .../com/github/jodersky/ace/ReactiveLayer.scala | 38 ++++++++++++++++++++++ 1 file changed, 38 insertions(+) create mode 100644 scala/ace/src/main/scala/com/github/jodersky/ace/ReactiveLayer.scala (limited to 'scala/ace/src/main/scala/com/github/jodersky/ace/ReactiveLayer.scala') diff --git a/scala/ace/src/main/scala/com/github/jodersky/ace/ReactiveLayer.scala b/scala/ace/src/main/scala/com/github/jodersky/ace/ReactiveLayer.scala new file mode 100644 index 0000000..9d426d3 --- /dev/null +++ b/scala/ace/src/main/scala/com/github/jodersky/ace/ReactiveLayer.scala @@ -0,0 +1,38 @@ +package com.github.jodersky.ace + +import scala.concurrent.Future + +/** Represents a layer in a reactive protocol. + * @tparam L data type this layer receives from or writes to a lower layer + * @tparam T data type this layer sends to a higher layer or receives from a higher */ +trait ReactiveLayer[L, T] { + private var lowerLayer: Option[ReactiveLayer[_, L]] = None + private var higherLayer: Option[ReactiveLayer[T, _]] = None + + /** Notifies a higher layer that data is available. */ + protected def notifyHigher(data: T): Unit = higherLayer match { + case Some(higher) => higher.receive(data) + case None => throw new UnsupportedOperationException("Higher layer doesn't exist.") + } + + /** Sends data to a lower layer. */ + protected def sendToLower(l: L): Future[L] = lowerLayer match { + case Some(lower) => lower.send(l) + case None => Future.failed(new UnsupportedOperationException("Lower layer doesn't exist.")) + } + + /** Connects this layer with a higher layer, effectively linking calls + * `notifyHigher` to `higher.receive` and `higher.sendToLower` to `send`. */ + def connect[A](higher: ReactiveLayer[T, A]) = { + this.higherLayer = Some(higher) + higher.lowerLayer = Some(this) + higher + } + + /** Called from lower layer. */ + protected def receive(data: L): Unit + + /** Send data to this layer. + * @return a future value containing the data sent, or an error */ + def send(data: T): Future[T] +} \ No newline at end of file -- cgit v1.2.3