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

Stopping Actors


One way of stopping actors is by calling the stop method from the system or context for a particular actor. To do this, we can define a particular message that can be passed to the actor, telling it to stop. For example:

case "terminate" => context stop self 

Most of the times the preferred way of terminating an actor is by sending a PoisonPill message to it:

simpleActor ! PoisonPill 

This simple message passing can terminate the actor gracefully. The termination takes place after all the messages in the Actor's queue are processed before the poison pill is processed. Stopping an actor stops all of its child actors. Remember, we talked about those hook methods that can be called if we want to perform some logic when the actor is starting up or at termination. Let's take a look at those.