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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Atomic primitives

In Chapter 2, Concurrency on the JVM and the Java Memory Model, we learned that memory writes do not happen immediately unless proper synchronization is applied. A set of memory writes is not executed at once, that is, atomically. We saw that visibility is ensured by the happens-before relationship, and we relied on the synchronized statement to achieve it. Volatile fields were a more lightweight way of ensuring happens-before relationships, but a less powerful synchronization construct. Recall how volatile fields alone could not implement the getUniqueId method correctly.

In this section, we study atomic variables that provide basic support for executing multiple memory reads and writes at once. Atomic variables are close cousins of volatile variables, but are more expressive than them; they are used to build complex concurrent operations without relying on the synchronized statement.

Atomic variables

An atomic variable is a memory location that supports complex linearizable...