diff options
Diffstat (limited to 'scala/ace/src/main/scala/com/github/jodersky/ace/protocol/ReactiveLayer.scala')
-rw-r--r-- | scala/ace/src/main/scala/com/github/jodersky/ace/protocol/ReactiveLayer.scala | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/scala/ace/src/main/scala/com/github/jodersky/ace/protocol/ReactiveLayer.scala b/scala/ace/src/main/scala/com/github/jodersky/ace/protocol/ReactiveLayer.scala new file mode 100644 index 0000000..792947a --- /dev/null +++ b/scala/ace/src/main/scala/com/github/jodersky/ace/protocol/ReactiveLayer.scala @@ -0,0 +1,38 @@ +package com.github.jodersky.ace.protocol + +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.") + } + + /** Writes data to a lower layer. */ + protected def writeToLower(l: L): Future[L] = lowerLayer match { + case Some(lower) => lower.write(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.writeToLower` to `write`. */ + def connect[A](higher: ReactiveLayer[T, A]) = { + this.higherLayer = Some(higher) + higher.lowerLayer = Some(this) + higher + } + + /** Called from lower layer. */ + def receive(data: L): Unit + + /** Write data to this layer. + * @return a future value containing the data written, or an error */ + def write(data: T): Future[T] +}
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