Scala for Java Developers电子书

Scala for Java Developers

Table of Contents

Scala for Java Developers

Credits

Foreword

About the Author

Acknowledgments

About the Reviewers

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Preface

What this book covers

What you need for this book

Who this book is for

Conventions

Reader feedback

Customer support

Downloading the example code

Errata

Piracy

Questions

1. Programming Interactively within Your Project

Advantages of using Scala for Java projects

More concise and expressive

Increased productivity

Natural evolution from Java

Better fit for asynchronous and concurrent code

Learning Scala through the REPL

Declaring val/var variables

Defining classes

Explaining case classes

Operations on collections

Transforming collections containing primitive types

Collections of more complex objects

Filter and partition

Dealing with tuples

Introducing Map

Introducing the Option construct

A glimpse at pattern matching

The map method

Looking at String Interpolation

The groupBy method

The foldLeft method

Summary

2. Code Integration

Creating a REST API from an existing database

The sample database

Setting up a Maven project

Creating JPA entities and REST web services

Running and testing the project

Adding a unit test in Java

Adding a test in Scala

Setting up Scala within a Java Maven project

Scala and Java collaboration

Converting between collection types

JavaBean-style properties

Scala and Java object orientation

Scala traits as enhanced Java interfaces

Declaring objects

Introducing companion objects

Handling exceptions

Differences in style between Java and Scala code

Adjusting the code layout

Naming conventions

Summary

3. Understanding the Scala Ecosystem

Inheriting Java Integrated Development Environments (IDEs)

Building with Simple Build Tool (SBT)

Getting started with SBT

Creating a sample project

Importing the project in Eclipse, IntelliJ IDEA, and NetBeans

Creating a web application that runs on a servlet container

Using sbt-assembly to build a single .jar archive

Formatting code with Scalariform

Experimenting with Scala Worksheets

Working with HTTP

Scala's for comprehension

Taking advantage of Typesafe Activator

Creating an application based on activator templates

The REPL as a scripting engine

Summary

4. Testing Tools

Writing tests with ScalaTest

BDD-style testing

Functional testing

Mocking with ScalaMock

Testing with ScalaCheck

Summary

5. Getting Started with the Play Framework

Getting started with the classic Play distribution

Getting started with the Typesafe Activator

Architecture of a Play application

Visualizing the framework stack

Exploring the request-response lifecycle

Handling a request in the controller

Rendering the view

Playing with authentication

Practical tips when using Play

Debugging with Play

Dealing with version control

Summary

6. Database Access and the Future of ORM

Integrating an existing ORM – Hibernate and JPA

Making JPA available in Scala

Dealing with persistence in the Play Framework

A simple example using Anorm

Replacing ORM

Learning about Slick

Scaffolding a Play application

Importing test data

Visualizing the database in the H2browser

Exploring the code behind the app generation

Limitations of the playcrud utility

Summary

7. Working with Integration and Web Services

Binding XML data in Scala

Running scalaxb from a SOAP web service

Working with XML and JSON

Manipulating XML

Manipulating JSON

Using Play JSON

Handling Play requests with XML and JSON

Mocking Play responses with JSON

Calling web services from Play

Summary

8. Essential Properties of Modern Applications – Asynchrony and Concurrency

The pillars of Concurrency

The Async library – SIP-22-Async

Combining web services

Combining services without await

Getting started with Akka

Understanding the Actor model

Switching behavior

Supervising actors to handle failure

Testing actor systems

Exploring further with Akka

Summary

9. Building Reactive Web Applications

Describing reactive applications

Handling streams reactively

Understanding Iteratees in Play

Adapting Enumerator with Enumeratee

Experimenting with WebSockets and Iteratees in Play

Learning from activator templates

Reactive stocks

Reactive real-time search

The Play-Akka-Angular-WebSocket template

Playing with Actor Room

Summary

10. Scala Goodies

Exploring MongoDB

Entering Casbah

Applying MapReduce transformations

Scratching the surface of Big Data

Introducing DSLs in Scala

Observing internal DSLs

Tackling external DSLs through parser combinators

Introducing Scala.js

Final tips

Copying and pasting in the REPL

Timing code execution in the REPL

Summary

Index