Nilanjan Raychaudhuri - Scala in Action

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Youre standing in front of a huge, steep wall of rock. Your neck is straining as you bend your head back as far as it will go to take it all in. If you squint, you can barely see something moving around at the top. Theres probably some really good stuff up there. Youve heard from people you trust that its worth climbing this wall. But, youre damned sure going to hurt yourself on the way up. You can already see some of the jagged edges jutting out. And what if it turns out that you dont like what you see when you get there?

Learning difficult things is like thisand make no mistake: Scala is difficult to learn. And you may very well not like what you see when you get to the top. Id guess that only a small fraction of developers learning a language like Scala ever put it to use. But its almost always the climb that makes a challenge worth the effort. Scala is a lot to chew on. Its got what seems way too many features. Its going to appear, at least initially, overdesigned. Youre going to hurt yourself on the way.

By the time you reach the top, youll understand why those features exist, how they make your Scala programs better, and, more important, how they make you a more effective programmer. Youll still be sore from the bumps along the way but that pain will help you remember the lessons learned. You may even find yourself happily and productively working full-time in Scala for years to come!

As worthwhile as a journey like this may be, you dont want to climb a mountain this high alone, if you can help it. When covering unfamiliareven alienterritory you want a guide who can make it look easy. Thats Nilanjan Raychaudhuri. He has a way of putting people at ease when describing complex subjects. Scala itself isnt that complexits really just a bunch of simple pieces that join to form a deceptively capable whole. Nilanjan has a talent for making us believe that those pieces really are simple and are there for unearthing the underlying principles that bind them together. Indeed, even for the nuts and bolts of installation, configuration, and project compilation, reading this book is like having an experienced mentor accompany you every step of the way.

Some of the concepts in Scala in Action are going to be more foreign than others. When you hit these bumps, take your time. Musicians dont become great by playing the songs they know over and over. Elite athletes dont consistently stay in their comfort zones. Its the jagged edges that improve us.

If you approach this climb properly, youll reach the top sharper, more open-minded, and, best of all, less afraid.

C HAD F OWLER

A UTHOR , S PEAKER , AND

P ROGRAMMING L IFESTYLE E NGINEER

Why write Scala in Action when there are plenty of other Scala books on the market? What sets this book apart?

Scala in Action targets developers who not only want to learn the language but also want to build real-world applications using Scala. This book, in other words, covers not only the language and its latest features but also its ecosystem. My goal was to pack a sufficient number of real-world examples along with the right mix of theory so readers can easily become comfortable with the language.

Scala is a feature-rich language and it is not possible to cover all of its features in one book, at least one of a reasonable size. For that reason, I deliberately avoided some of the more advanced features of Scala. I encourage you to think of this book as your first on Scala, a foundation on which to build, before you dive into the more advanced features Scala has to offer.

I had a great time writing this book and I hope you have a great time learning this new and exciting language. I know you had a choice when it comes to Scala books; thank you for choosing this one.

First I thank Martin Ordesky, the creator of Scala, for his thoughtful creation, which takes language design to the next level. Without his work, this book would not exist.

I also thank all of the members of the Scala community. Without their help and comments, I never could have imagined writing this book.

At Manning, I give my thanks to Marjan Bace, Mike Stephens, my editors Cynthia Kane and Katharine Osborne for helping me improve my writing, and the production team of Corbin Collins, Elizabeth Martin, Dottie Marsico, Mary Piergies, Toma Mulligan, and Janet Vail. Special thanks go to Ivan Kirkpatrick and Clint Combs, my technical proofreaders, for their in-depth feedback on the text and the code.

Numerous reviewers read the book at various stages of its development and offered helpful comments and criticisms, and I acknowledge them here: Alexandre Alves, Andrew Rhine, Andy Dingley, Ben Hall, Cheryl Jerozal, Dan Dobrin, Daniel Bretoi, Dave Pawson, David Greco, Dennis Leung, Edmon Begoli, Eric Weinberg, Marco Ughetti, Mark Needham, Michael Smolyak, Peter Crosbie, Peter Thomas, Robert MacGregor, and Tom Belunis.

Thanks also to the readers of Mannings Early Access Program (MEAP). Their corrections and comments on the manuscript as it was being written were invaluable.

I extend a special thanks to Lutz Hankewitz for his help during the writing process. Without his thoughtful feedback, this book would have been incomplete. Special thanks also to Chad Fowler for contributing the foreword and for endorsing my work.

Last but definitely not least, I would like to thank my wife Manisha for her support and patience as I spent countless weekends working on this book while she took care of the family without any complaints.