Book Image

Java 9 Programming By Example

By : Peter Verhas
Book Image

Java 9 Programming By Example

By: Peter Verhas

Overview of this book

This book gets you started with essential software development easily and quickly, guiding you through Java’s different facets. By adopting this approach, you can bridge the gap between learning and doing immediately. You will learn the new features of Java 9 quickly and experience a simple and powerful approach to software development. You will be able to use the Java runtime tools, understand the Java environment, and create Java programs. We then cover more simple examples to build your foundation before diving to some complex data structure problems that will solidify your Java 9 skills. With a special focus on modularity and HTTP 2.0, this book will guide you to get employed as a top notch Java developer. By the end of the book, you will have a firm foundation to continue your journey towards becoming a professional Java developer.
Table of Contents (17 chapters)
Title Page
Credits
About the Author
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface

Implementing the game


Collections without examples are boring. Fortunately, we have our game where we use a few collection classes and also other aspects that we will examine in this chapter.

ColorManager

We jumped into the pool filled with collection classes from the implementation of the ColorManager class. Let's refresh the part of the class that is interesting for us now—the constructor:

final protected int nrColors; 
 final protected Map<Color, Color> successor = new HashMap<>(); 
 final private Color first; 
  
 public ColorManager(int nrColors) { 
     this.nrColors = nrColors; 
     first = new Color(); 
     Color previousColor = first; 
  
     for (int i = 1; i < nrColors; i++) { 
         final Color thisColor = new Color(); 
         successor.put(previousColor, thisColor); 
         previousColor = thisColor; 
     } 
     successor.put(previousColor, Color.none); 
 }

We will use HashMap to keep the colors in an ordered list. At first, the choice of HashMap seems...