[JAVA][Beginning Java 8 Games Development]

Chapter 8 ■ Creating Your Actor Engine: Design the Characters for Your Game and Define Their Capabilities
Figure 8-5. Create a constructor method to set up fixed Actor sprite subclasses with collision shape, Image list, location
Next, let’s code the other crucial method for this class, the abstract .update() method, and then we can add the
rest of the Actor class fixed sprite attributes that we will need. After that, we can initialize the additional variables
inside of the Actor() constructor method. Finally we will learn how to create “getter and setter” methods for the Actor
class, before we move on to use this new custom Actor superclass to create our other Hero motion sprites subclass.
Creating an .update() Method: Connect to GamePlayLoop Engine
The most important method for any sprite class, other than the constructor method that births it into existence, is the
.update() method. The .update() method will contain the Java 8 code that tells the sprite what to do on every pulse
of the GamePlayLoop. For this reason, this .update() method will serve to “wire” the Actor sprite subclasses created
using our Actor superclass and Hero subclass into the GamePlayLoop timing engine that we created in Chapter 7.
Because we need to have an .update() method as part of every Actor object (actor sprite) in our game, we’ll need
to include an “empty” (for now) abstract .update() method in the Actor superclass we are coding currently.
As you learned in Chapter 3, this public abstract method is left empty, or more accurately, unimplemented,
in the Actor superclass, but will need to be (that is, will be required to be) implemented (or alternatively, to again
be declared as an abstract method) in any Actor subclass, including the Hero subclass we are going to be coding
later on.
The method is declared public abstract void, as it does not return any values (it is simply executed on each
JavaFX pulse event) and does not include the {...} curly braces, as it does not (yet) have any body of code inside of it!
The single line of code that declares the public abstract (empty or unimplemented) method should look like this:
public abstract void update();
As you can see in Figure 8-6, the method is very simple to implement, and once you add this new method under
your Actor() constructor method, your Java 8 code is again error free, and you will be ready to add more code.
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