Book Image

Scala Programming Projects

By : Mikael Valot, Nicolas Jorand
Book Image

Scala Programming Projects

By: Mikael Valot, Nicolas Jorand

Overview of this book

Scala Programming Projects is a comprehensive project-based introduction for those who are new to Scala. Complete with step-by-step instructions and easy-to-follow tutorials that demonstrate best practices when building applications, this Scala book will have you building real-world projects in no time. Starting with the fundamentals of software development, you’ll begin with simple projects, such as developing a financial independence calculator, and then advance to more complex projects, such as a building a shopping application and a Bitcoin transaction analyzer. You’ll explore a variety of Scala features, including its OOP and FP capabilities, and learn how to write concise, reactive, and concurrent applications in a type-safe manner. You’ll also understand how to use libraries such as Akka and Play. Furthermore, you’ll be able to integrate your Scala apps with Kafka, Spark, and Zeppelin, along with deploying applications on a cloud platform. By the end of the book, you’ll have a firm foundation in Java programming that’ll enable you to solve a variety of real-world problems, and you’ll have built impressive projects to add to your professional portfolio.
Table of Contents (18 chapters)
Title Page
Copyright and Credits
Packt Upsell
Contributors
Preface
Index

Chapter 3. Handling Errors

In this chapter, we will continue working on the retirement calculator that we implemented in Chapter 2, Developing a Retirement Calculator. Our calculator worked correctly as long as we passed the right arguments, but would fail badly with a horrible stack trace if any of the parameters were wrong. Our program only worked for what we call the happy path.

The reality of writing production software is that all kinds of error scenarios can occur. Some of them are recoverable, some of them must be presented to the user in an attractive way, and, for some hardware-related errors, we might need to let the program crash.

In this chapter, we will introduce exception handling, explain what referential transparency is, and try to convince you that exceptions are not the best way to deal with errors. Then, we will explain how to use functional programming constructs to effectively handle the possibility of an error.

In each section, we will briefly introduce a new concept,...