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
About the Reviewers
Customer Feedback

Communication between actors

We have learned that actors communicate by sending messages. While actors running on the same machine can access shared parts of memory in the presence of proper synchronization, sending messages allows isolating the actor from the rest of the system and ensures location transparency. The fundamental operation that allows you to send a message to an actor is the ! operator.

We have learned that the ! operator is a non-blocking operation-sending a message does not block the execution of the sender until the message is delivered. This way of sending messages is sometimes called the fire-and-forget pattern, because it does not wait for a reply from the message receiver, nor does it ensure that the message is delivered.

Sending messages in this way improves the throughput of programs built using actors, but can be limiting in some situations. For example, we might want to send a message and wait for the response from the target. In this section, we learn about patterns...