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)


In the same way that Either stands for an effect of possible alternative results, Try denotes the effect of throwing an Exception by the function. In a sense, it is just a subset of Either, but it is so common that it has its own implementation. Unsurprisingly, the simplified representation of it looks quite familiar:

sealed abstract class Try[+T]
final case class Success[+T](value: T) extends Try[T]
final case class Failure[+T](exception: Throwable) extends Try[T]

Obviously, Success represents the happy-path outcome of the operation, and Failure is for exceptional conditions. The type for the contents of the Failure is fixed to be a subclass of Throwable, so we're back to the single type parameter for the whole ADT, which is similar to Option.

We'll study Try in the same way as we did with Option and Either – by creating, reading from, and abstracting over...