INTRODUCTION

A working knowledge of Scala puts you in demand. As both the language and applications expand, so do the opportunities for experienced Scala programmers—and many positions are going unfilled. Major enterprises across industries are using Scala every day, in a number of different applications and capacities. Professional Scala helps you update your skills quickly to start advancing your career.

Scala bridges the gap between functional and object-oriented programming, and this book details that link with a clear discussion of both Java compatibility and the read-eval-print loop used in declarative programming. You'll learn the details of Scala testing, design patterns, concurrency, and much more as you build the in-demand skill set required to utilize Scala in a real-world production environment.

WHO THIS BOOK IS FOR

This book is for experienced programmers who already have some understanding of the Scala language and are looking for more depth. You should have a basic working knowledge of the language because this book skips over the fundamentals of programming, and the discussion launches directly into practical Scala topics.

WHAT THIS BOOK COVERS

This book explains everything professional programmers need to start using Scala quickly and effectively.

Link functional and object-oriented programming.
Master syntax, the SBT interactive build tool, and the REPL workflow.
Explore functional design patterns, the type system, concurrency, and testing.
Work effectively with Maven, Scala.js, and more.

HOW THIS BOOK IS STRUCTURED

This book was written in three parts. The first part of the book discusses language structure including syntax, practical functional programming, and Java compatibility.

The second part of the book takes the reader through tooling, including discussions of SBT, Maven, lint tools, testing, and Scaladoc. The last portion of the book continues to examine Scala through advanced topics such as polymorphism, dynamic programming, concurrency, Scala.js, and more.

WHAT YOU NEED TO USE THIS BOOK

For this book, we have used Scala version 2.11.7. The source code for the samples is available for download from the Wrox website at www.wrox.com/go/professionalscala or from GitHub at https://github.com/backstopmedia/scalabook.

CONVENTIONS

To help you get the most from the text and keep track of what's happening, we've used a number of conventions throughout the book.

As for styles in the text:

We highlight new terms and important words when we introduce them.
We show code within the text like so: persistence.properties.

We show all code snippets in the book using this style:

        FileSystem fs = FileSystem.get(URI.create(uri), conf);
        InputStream in = null;
        try {

We show URLs in text like this:
```
http://<Slave Hostname>:50075
```

SOURCE CODE

As you work through the examples in this book, you may choose either to type in all the code manually, or to use the source code files that accompany the book. All the source code used in this book is available for download at www.wrox.com. Specifically for this book, the code download is on the Download Code tab at: www.wrox.com/go/professionalscala

You can also search for the book at www.wrox.com by ISBN (the ISBN for this book is 9781119267225 to find the code. And a complete list of code downloads for all current Wrox books is available at www.wrox.com/dynamic/books/download.aspx.

Once you download the code, just decompress it with your favorite compression tool. Alternatively, you can go to the main Wrox code download page at www.wrox.com/dynamic/books/download.aspx to see the code available for this book and all other Wrox books.

ERRATA

We make every effort to ensure that there are no errors in the text or in the code. However, no one is perfect, and mistakes do occur. If you find an error in one of our books, like a spelling mistake or faulty piece of code, we would be very grateful for your feedback. By sending in errata, you may save another reader hours of frustration, and at the same time, you will be helping us provide even higher quality information.

To find the errata page for this book, go to

www.wrox.com/go/professionalscala

and click the Errata link. On this page you can view all errata that has been submitted for this book and posted by Wrox editors.

If you don't spot “your” error on the Book Errata page, go to www.wrox.com/contact/techsupport.shtml and complete the form there to send us the error you have found. We'll check the information and, if appropriate, post a message to the book's errata page and fix the problem in subsequent editions of the book.

P2P.WROX.COM

For author and peer discussion, join the P2P forums at http://p2p.wrox.com. The forums are a web-based system for you to post messages relating to Wrox books and related technologies and interact with other readers and technology users. The forums offer a subscription feature to e-mail you topics of interest of your choosing when new posts are made to the forums. Wrox authors, editors, other industry experts, and your fellow readers are present on these forums.

At http://p2p.wrox.com, you will find a number of different forums that will help you, not only as you read this book, but also as you develop your own applications. To join the forums, just follow these steps:

Go to http://p2p.wrox.com and click the Register link.
Read the terms of use and click Agree.
Complete the required information to join, as well as any optional information you wish to provide, and click Submit.
You will receive an e-mail with information describing how to verify your account and complete the joining process.

Once you join, you can post new messages and respond to messages other users post. You can read messages at any time on the web. If you would like to have new messages from a particular forum e-mailed to you, click the Subscribe to This Forum icon by the forum name in the forum listing.

For more information about how to use the Wrox P2P, be sure to read the P2P FAQs for answers to questions about how the forum software works, as well as many common questions specific to P2P and Wrox books. To read the FAQs, click the FAQ link on any P2P page.