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)

Akka parent-child Actors example

As we discussed in the previous sections, Akka's ActorSystem creates all top-level actors, which may act as parent or supervisor Actors. So, how do we create subordinate Actors?

When we execute the ActorSystem.actorOf() function, it creates all top-level Actors. However, Akka Toolkit has provided an implicit variable, context of the ActorContext type in the Actor class, as follows:

trait Actor { 
   implicit val context: ActorContext = { 
     // Code goes here 
   } 
} 

Like ActorSystem.actorOf(), the ActorSystem also has actorOf() with the same set of parameters to create child or subordinate Actors from a supervisor or parent Actor:

package com.packt.publishing.supervision 
import akka.actor.{Actor,Props,ActorSystem} 
 
sealed trait Work 
case object DevWork extends Work 
case object TestingWork extends Work 
class LeadDeveloperActor extends...