Book Image

Learn Scala Programming

By : Slava Schmidt
Book Image

Learn Scala Programming

By: Slava Schmidt

Overview of this book

The second version of Scala has undergone multiple changes to support features and library implementations. Scala 2.13, with its main focus on modularizing the standard library and simplifying collections, brings with it a host of updates. Learn Scala Programming addresses both technical and architectural changes to the redesigned standard library and collections, along with covering in-depth type systems and first-level support for functions. You will discover how to leverage implicits as a primary mechanism for building type classes and look at different ways to test Scala code. You will also learn about abstract building blocks used in functional programming, giving you sufficient understanding to pick and use any existing functional programming library out there. In the concluding chapters, you will explore reactive programming by covering the Akka framework and reactive streams. By the end of this book, you will have built microservices and learned to implement them with the Scala and Lagom framework.
Table of Contents (19 chapters)

Basics of Akka Streams

Elements of the Akka Streams flow are usually defined using constructors of the appropriate type. We'll implement building blocks which constitute our diagram one by one, starting with the simplest and moving on to the increasingly complex as we go over them.

Sources and sinks

The simplest component of our flow is possibly the Consumer. It is just a sink which is supposed to print out information about incoming data. To construct it, we'll use the Sink factory, as follows:

val consumer: Sink[ReadyCookies, Future[Done]] =
Sink.foreach(cookie => println(s"$cookie, yummi..."))

The Sink factory offers more than two dozens different constructors to define a sink. We're utilizing...