Mega Code Archive
0094 enum as Class
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You can give constructors, add instance variables and methods, and implement interfaces for enum types.
When you define a constructor for an enum, the constructor is called when each enumeration constant is created.
Each enumeration constant has its own copy of any instance variables defined by the enumeration.
// Use an enum constructor, instance variable, and method.
enum Direction {
South(10), East(9), North(12), West(8);
private int myValue;
// Constructor
Direction(int p) {
myValue = p;
}
int getMyValue() {
return myValue;
}
}
public class Main {
public static void main(String args[]) {
System.out.println(Direction.East.getMyValue());
for (Direction a : Direction.values())
System.out.println(a + " costs " + a.getMyValue());
}
}
Two restrictions that apply to enumerations.
an enumeration can't inherit another class.
an enum cannot be a superclass.
You can add fields, constructors, and methods to an enum. You can have the enum implement interfaces.
enum Coin {
PENNY(1), NICKEL(5), DIME(10), QUARTER(25);
private final int denomValue;
Coin(int denomValue) {
this.denomValue = denomValue;
}
int denomValue() {
return denomValue;
}
int toDenomination(int numPennies) {
return numPennies / denomValue;
}
}
public class Main {
public static void main(String[] args) {
int numPennies = 1;
int numQuarters = Coin.QUARTER.toDenomination(numPennies);
numPennies = Coin.QUARTER.denomValue();
int numDimes = Coin.DIME.toDenomination(numPennies);
numPennies = Coin.DIME.denomValue();
int numNickels = Coin.NICKEL.toDenomination(numPennies);
numPennies = Coin.NICKEL.denomValue();
for (int i = 0; i < Coin.values().length; i++) {
System.out.println(Coin.values()[i].denomValue());
}
}
}
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