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)

Chapter 13

  1. Name two different modes associated with "classic" streams. Why are they problematic?

The two modes are push and pull. Push is problematic in the case of a slow consumer because it can lead to dropped stream elements or memory overflow. Pull is suboptimal in the case of a slow producer because it can lead to blocking or extensive resource consumption.

  1. Why are Reactive Streams considered to work in dynamic pull-push mode?

Reactive Streams introduce the notion of non-blocking back pressure. The consumer reports the demand it has and the producer pushes data in batches according to this demand. When the consumer is faster, the demand is always there so the producer is always pushing data as soon as it is available. If there is a producer which is faster, there is always data available and the consumer just pulls it as soon as it has some demand. The flow...