Book Image

Learning Scala Programming

By : Vikash Sharma
Book Image

Learning Scala Programming

By: Vikash Sharma

Overview of this book

Scala is a general-purpose programming language that supports both functional and object-oriented programming paradigms. Due to its concise design and versatility, Scala's applications have been extended to a wide variety of fields such as data science and cluster computing. You will learn to write highly scalable, concurrent, and testable programs to meet everyday software requirements. We will begin by understanding the language basics, syntax, core data types, literals, variables, and more. From here you will be introduced to data structures with Scala and you will learn to work with higher-order functions. Scala's powerful collections framework will help you get the best out of immutable data structures and utilize them effectively. You will then be introduced to concepts such as pattern matching, case classes, and functional programming features. From here, you will learn to work with Scala's object-oriented features. Going forward, you will learn about asynchronous and reactive programming with Scala, where you will be introduced to the Akka framework. Finally, you will learn the interoperability of Scala and Java. After reading this book, you'll be well versed with this language and its features, and you will be able to write scalable, concurrent, and reactive programs in Scala.
Table of Contents (21 chapters)
Title Page
Packt Upsell
Contributors
Preface
Index

The tell versus ask versus forward method


We use one of these three approaches to transmit messages from one actor to another. As we've already established, tell transmits messages and does not wait for the response; this way, we ensure at most once delivery. We can also use the ask method in cases where we expect our called actors to respond back with some messages of the response type. There might be scenarios where you want to forward a message of a particular type with the same actor reference (ActorRef) to another Actor. For this purpose, we can use the forward method:

class AnotherActor extends Actor { 
  override def receive = { 
    case ShowFootballPlayersRequest(url) => { 
      val playersInfoSource = Source.fromFile(url) 
 
      val players = asPlayers(bufferedSourceToList(playersInfoSource)) 
      players.foreach(player => println(player + "n")) 
    } 
  } 
} 
 
object AnotherActor { 
  val props = Props[AnotherActor] 
} 

We have defined AnotherActor, and we can make...