// CSE 331
// Example of enum type with data  (taken from Effective Java by J. Bloch)

public enum Planet {
	MERCURY(3.302e+23, 2.439e6),
	VENUS(4.869e+24, 6.052e6),
	EARTH(5.975e+24, 6.378e6),
	MARS(6.419e+23, 3.393e6),
	JUPITER(1.899e+27, 7.149e7),
	SATURN(5.685e+26, 6.027e7),
	URANUS(8.683e+25, 2.556e7),
	NEPTUNE(1.024e+26, 2.477e7);          // no Pluto?
	
	private final double mass;            // in kilograms
	private final double radius;          // in meters
	
	// Universal gravitational constant in m^3 / kg s^2
	private static final double G = 6.67300E-11;
	
	// Constructor
	private Planet(double mass, double radius) {
		this.mass = mass;
		this.radius = radius;
	}
	
	public double mass() {
		return mass;
	}
	
	public double radius() {
		return radius;
	}
	
	public double surfaceGravity() {
		return G * mass / (radius * radius);
	}
	
	public double surfaceWeight(double mass) {
		return mass * surfaceGravity();  // F = ma
	}
}