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)

Ask Reactive Design Pattern

In a Reactive System, one component asks or delegates its computation to another component by sending a Message and continues its further steps in an asynchronous way. Once the other component finishes that computation, it will send a response to the original component.

In simple words, one component delegates its request and asks another component to serve that request.

For instance, Akka Toolkit has implemented this Ask pattern as akka.pattern.ask. Like Tell, it also has a function ask and has an operator—? (Ask operator).

Let's implement an Akka application to demonstrate this Ask operator:

  1. Develop a Data model, as shown here:
      case object GetWeather 
      case class WeatherForecast(city:String, temperature:String) 
  1. Develop the WF (Weather Forecasting) Actor, as shown here:
      class WFClient(wfTeller: ActorRef) extends Actor...