Book Image

Scala Reactive Programming

By : Rambabu Posa
Book Image

Scala Reactive Programming

By: Rambabu Posa

Overview of this book

Reactive programming is a scalable, fast way to build applications, and one that helps us write code that is concise, clear, and readable. It can be used for many purposes such as GUIs, robotics, music, and others, and is central to many concurrent systems. This book will be your guide to getting started with Reactive programming in Scala. You will begin with the fundamental concepts of Reactive programming and gradually move on to working with asynchronous data streams. You will then start building an application using Akka Actors and extend it using the Play framework. You will also learn about reactive stream specifications, event sourcing techniques, and different methods to integrate Akka Streams into the Play Framework. This book will also take you one step forward by showing you the advantages of the Lagom framework while working with reactive microservices. You will also learn to scale applications using multi-node clusters and test, secure, and deploy your microservices to the cloud. By the end of the book, you will have gained the knowledge to build robust and distributed systems with Scala and Akka.
Table of Contents (16 chapters)

The Scala Future API in the Akka Toolkit

Both the Akka Toolkit and the Play Framework source code use Scala Futures extensively. The Akka Streams API also uses the Scala Future in all places.

Let's look at some Akka Streams source code examples here which are using the Scala Future API:

In the Akka Toolkit, the ask pattern returns a Future[Any], shown as follows:

def ask (actorRef: ActorRef, message: Any)(implicit timeout: Timeout): Future[Any]

Observe the following Akka Streams API:

val futureResult: Future[Seq[String]] = Source(in).runWith(Sink.seq)

Here, the Souce.runWith[T]() function returns its results as Future[T]. Not only this function, but most of the Akka Streams API uses Scala Futures extensively. We use the Scala Future API to write some unit tests, too.

Now you get what is the importance of this Scala Future API. Please experiment with some more examples to...