[JAVA][Beginning Java 8 Games Development]

Chapter 3 ■ A Java 8 Primer: An Introduction to Java 8 Concepts and Principles
Let’s start with characteristics, which are things about an object that will not change and which are thus
represented using constants, variables that will not (cannot) change. An important bagel characteristic is the type
(flavor). We all have our favorites; mine are plain, egg, rye, onion, and pumpernickel. Another characteristic is the size
of bagel; as we all know, there are minibagels, normal-size bagels, and giant bagels.
private static final String FLAVOR_OF_BAGEL = "Pumpernickel";
private static final String SIZE_OF_BAGEL = "Mini Bagel";
Thus, constants are used to define the characteristics, or attributes, of an object. If you are defining a car, boat,
or plane, the color (paint), engine (type), and transmission (type) are attributes (constants), as they generally do not
change, unless you are a mechanic or own a body shop!
Things about an object that will change, such as its location, orientation, how it is traveling (flying, driving,
walking, running), and so on are called states and are defined using variables, which can constantly change in real
time, based on what is happening in real life. These variables will allow any Java object to mimic, or virtualize, the
real-world object that they are creating in your Java universe’s virtual reality. This is, of course, especially true in
games, which is why the topic of this book, Java and games, is especially relevant and applicable.
There will be more states (variables) than attributes (constants) for the InvinciBagel, as it is the game piece and
will be especially active trying to save its hole and score points. Some of the states that you will want to define as
variables include screen (x, y) location, orientation, travel direction, travel type, hits taken, and life span used.
public int invinciBagelX = 0;
// X screen location of the InvinciBagel
public int invinciBagelY = 0;
// Y screen location of the InvinciBagel
public String bagelOrientation = "side"; // Defines bagel orientation (front, side, top)
public int lifeIndex = 1000; // Defines units of lifespan used
public int hitsIndex = 0; // Defines units of damage (hits taken)
public String directionFacing = "E"; // Direction that the object is facing
public String movementType = "idle" // Type of movement (idle, fly, run, jump)
public boolean currentlyMoving = false; // Flag showing if the object is in motion
As you progress through this book and create the InvinciBagel game, you will be adding attributes, states, and
behaviors that will make the InvinciBagel, as well as its game environment and game play, more realistic, fun, and
exciting, just as you would do in real life. In fact, you are using Java objects and Java constructs to model, a realistic
virtual world in which InvinciBagel players can triumph over evil and shoot cream cheese balls at delicious targets.
Let’s look at a couple of the methods that you might develop to control the InvinciBagel behavior. You will be
creating complex methods over the course of this book to accomplish game play objectives, so I am just going to give
you an idea here of how methods provide behaviors to objects for the purpose of demonstrating how objects can be
created that reflect how real-world objects function.
For your game play of the InvinciBagel, the main behaviors will be 2D movement around the screen, relative to
the x (width) and y (height) dimension, which will access, use, and update the integer invinciBagelX, invinciBagelY,
and the boolean currentlyMoving data fields discussed previously; the InvinciBagel character’s orientation (front
facing, sideways, facing down, and so on), which will access, use, and update the bagelOrientation String field;
the life expectancy of the InvinciBagel, which will access, use, and update the lifeIndex variable; the health of the
InvinciBagel, which will access, use, and update the hitsIndex variable; the direction (East or West) in which the
InvinciBagel is traveling, which will access, use, and update the directionFacing String variable; and the type of
movement (flying, jumping, running, idle) that the InvinciBagel is using , which will access, use, and update the
movementType String variable.
Here is how you declare these methods (behaviors) and pseudocode regarding what they are going to do:
public void moveInvinciBagel(int x, int y) {
currentlyMoving = true;
invinciBagelX = x;
invinciBagelY = y;
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