Re: Declaring members for Interfaces

Todd <>
Tue, 29 Apr 2008 11:04:07 -0700 (PDT)

This example is from the Sun Tutorial site:

public enum Planet {
    MERCURY (3.303e+23, 2.4397e6),
    VENUS (4.869e+24, 6.0518e6),
    EARTH (5.976e+24, 6.37814e6),
    MARS (6.421e+23, 3.3972e6),
    JUPITER (1.9e+27, 7.1492e7),
    SATURN (5.688e+26, 6.0268e7),
    URANUS (8.686e+25, 2.5559e7),
    NEPTUNE (1.024e+26, 2.4746e7);

    private final double mass; // in kilograms
    private final double radius; // in meters
    Planet(double mass, double radius) {
        this.mass = mass;
        this.radius = radius;
    private double mass() { return mass; }
    private double radius() { return radius; }

    // universal gravitational constant (m3 kg-1 s-2)
    public static final double G = 6.67300E-11;

    double surfaceGravity() {
        return G * mass / (radius * radius);
    double surfaceWeight(double otherMass) {
        return otherMass * surfaceGravity();
    public static void main(String[] args) {
        double earthWeight = Double.parseDouble(args[0]);
        double mass = earthWeight/EARTH.surfaceGravity();
        for (Planet p : Planet.values())
           System.out.printf("Your weight on %s is %f%n",
                             p, p.surfaceWeight(mass));

How do I get the value of mass without a getter from any
of the enumerated items from outside of the enumeration?

I took a walk, but apparently am not seeing the "magic"
you claim. Help me out?


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