Book Image

Learning Concurrent Programming in Scala - Second Edition

By : Aleksandar Prokopec
Book Image

Learning Concurrent Programming in Scala - Second Edition

By: Aleksandar Prokopec

Overview of this book

Scala is a modern, multiparadigm programming language designed to express common programming patterns in a concise, elegant, and type-safe way. Scala smoothly integrates the features of object-oriented and functional languages. In this second edition, you will find updated coverage of the Scala 2.12 platform. The Scala 2.12 series targets Java 8 and requires it for execution. The book starts by introducing you to the foundations of concurrent programming on the JVM, outlining the basics of the Java Memory Model, and then shows some of the classic building blocks of concurrency, such as the atomic variables, thread pools, and concurrent data structures, along with the caveats of traditional concurrency. The book then walks you through different high-level concurrency abstractions, each tailored toward a specific class of programming tasks, while touching on the latest advancements of async programming capabilities of Scala. It also covers some useful patterns and idioms to use with the techniques described. Finally, the book presents an overview of when to use which concurrency library and demonstrates how they all work together, and then presents new exciting approaches to building concurrent and distributed systems. Who this book is written for If you are a Scala programmer with no prior knowledge of concurrent programming, or seeking to broaden your existing knowledge about concurrency, this book is for you. Basic knowledge of the Scala programming language will be helpful.
Table of Contents (19 chapters)
Learning Concurrent Programming in Scala - Second Edition
About the Author
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Implementing custom parallel collections

Parallel collections in the Scala standard library are sufficient for most tasks, but in some cases we want to add parallel operations to our own collections. The Java String class does not have a direct parallel counterpart in the parallel collections framework. In this section, we will study how to implement a custom ParString class that supports parallel operations. We will then use our custom parallel collection class in several example programs.

The first step in implementing a custom parallel collection is to extend the correct parallel collection trait. A parallel string is a sequence of characters, so we need to extend the ParSeq trait with the Char type argument. Once a string is created, it can no longer be modified; we say that the string is an immutable collection. For this reason, we extend a subtype of the scala.collection.parallel.ParSeq trait, the ParSeq trait from the scala.collection.parallel.immutable package:

class ParString(val...