Enums allow you to make a list of values, like an array and these can be assigned to a variable. The order the values are listed is taken into account, just as they are in an array. The values are constants and should be in capital letters.
You can treat the values in enums like objects and assign instance variables to each of those objects.
Here is an example that I�ve customized myself from an example in the
SCJP Exam Study Guide (Page 63 & 64). I�ve looked into this subject and taken the code to pieces to try and understand the subject myself. I�ve also made the code a little more complicated than it is in the book. I�m currently studying for the exam.
Save this in a file called Engines.java in your java directory:
public class Engines {
enum EngineSize {
SPORTS_CAR(2.0),
SALOON(1.6),
OFF_ROADER(4.0);
EngineSize(double litres) {
this.litres = litres;
}
public double litres;
public double getLitres() {
return litres;
}
}
}
Save this in the same directory, in a file called Car.java
class Car extends Engines {
EngineSize size;
public static void main(
String[] args) {
Car engine1 = new Car();
engine1.size = EngineSize.SPORTS_CAR;
Car engine2 = new Car();
engine2.size = EngineSize.SALOON;
Car engine3 = new Car();
engine3.size = EngineSize.OFF_ROADER;
System.out.println("The Sports Car's engine size is " + (engine1.size.getLitres()) + " litres");
System.out.println("The Saloon's engine size is " + (engine2.size.getLitres()) + " litres");
System.out.println("The Off Roader's engine size is " + (engine3.size.getLitres()) + " litres");
}
}
End of code
Compile both the files separately and run Car.java. You have to run this, because it contains the Main method.
