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)

Akka Typed – beyond the basics

We've defined the behavior of the Chef actor to distribute work across mixers but left the waiting part uncovered, so let's look at that now.

We left the Chef definition for the mixing behavior as follows:

def mixing = Behaviors.unhandled[Command]

Actually, the Chef needs to know about the mixers that were created by its idle behavior. Though technically it is possible to do a children lookup, as described earlier, doing so will introduce an implicit assumption that, at the moment, we'll get the listing stating that all of the mixers are still processing jobs. This assumption might be wrong in a highly concurrent environment or in the case of failed mixers.

Therefore, we need to refactor the behavior constructor a bit:

def mixing(mixers: Set[ActorRef[Mixer.Mix]],
collected: Int,
manager: ActorRef[Manager...