public static final int APPLE_FUJI = 0;
public static final int APPLE_PIPPIN = 1;
public static final int APPLE_GRANNY_SMITH = 2;

public static final int ORANGE_NAVEL = 0;
public static final int ORANGE_TEMPLE = 1;
public static final int ORANGE_BLOOD = 2;

public final String APPLE_FUJI = "0";
public final int APPLE_PIPPIN = "1";
public final int APPLE_GRANNY_SMITH = "2";

public enum Apple {FUJI, PIPPIN, GRANNY_SMITH}
public enum Orange {NAVEL, TEMPLE, BLOOD}

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);

    private final double mass;           // 질량(단위: 킬로그램)
    private final double radius;         // 반지름(단위: 미터)
    private final double surfaceGravity; // 표면중력(단위: m / s^2)

    // 중력상수(단위: m^3 / kg s^2)
    private static final double G = 6.67300E-11;

    // 생성자
    Planet(double mass, double radius) {
        this.mass = mass;
        this.radius = radius;
        surfaceGravity = G * mass / (radius * radius);
    }

    public double mass()           { return mass; }
    public double radius()         { return radius; }
    public double surfaceGravity() { return surfaceGravity; }

    public double surfaceWeight(double mass) {
        return mass * surfaceGravity;  // F = ma
    }
}

public class WeightTable {
   public static void main(String[] args) {
      double earthWeight = Double.parseDouble(args[0]);
      double mass = earthWeight / Planet.EARTH.surfaceGravity();
      for (Planet p : Planet.values())
         System.out.printf("%s에서의 무게는 %f이다.%n",
                           p, p.surfaceWeight(mass));
   }
}

public static Operation inverse(Operation op) {
        switch(op) {
            case PLUS:   return Operation.MINUS;
            case MINUS:  return Operation.PLUS;
            case TIMES:  return Operation.DIVIDE;
            case DIVIDE: return Operation.TIMES;

            default:  throw new AssertionError("Unknown op: " + op);
        }
    }

public enum Operation {
    PLUS("+") {
        public double apply(double x, double y) { return x + y; }
    },
    MINUS("-") {
        public double apply(double x, double y) { return x - y; }
    },
    TIMES("*") {
        public double apply(double x, double y) { return x * y; }
    },
    DIVIDE("/") {
        public double apply(double x, double y) { return x / y; }
    };

    private final String symbol;

    Operation(String symbol) { this.symbol = symbol; }

    public abstract double apply(double x, double y); //추상메소드
}

    @Override public String toString() { return symbol; }

    private static final Map<String, Operation> stringToEnum =
            Stream.of(values()).collect(
                    toMap(Object::toString, e -> e));
 
    public static Optional<Operation> fromString(String symbol) {
        return Optional.ofNullable(stringToEnum.get(symbol));
    }

enum PayrollDay {
    MONDAY(WEEKDAY), TUESDAY(WEEKDAY), WEDNESDAY(WEEKDAY),
    THURSDAY(WEEKDAY), FRIDAY(WEEKDAY),
    SATURDAY(WEEKEND), SUNDAY(WEEKEND);

    private final PayType payType;

    PayrollDay(PayType payType) { this.payType = payType; }

    int pay(int minutesWorked, int payRate) {
        return payType.pay(minutesWorked, payRate);
    }
    //전략 열거 타입
   enum PayType {
        WEEKDAY {
            int overtimePay(int minsWorked, int payRate) {
                return minsWorked <= MINS_PER_SHIFT ? 0 :
                        (minsWorked - MINS_PER_SHIFT) * payRate / 2;
            }
        },
        WEEKEND {
            int overtimePay(int minsWorked, int payRate) {
                return minsWorked * payRate / 2;
            }
        };

        abstract int overtimePay(int mins, int payRate);
        private static final int MINS_PER_SHIFT = 8 * 60;

        int pay(int minsWorked, int payRate) {
            int basePay = minsWorked * payRate;
            return basePay + overtimePay(minsWorked, payRate);
        }
    }
   public static void main(String[] args) {
        for (PayrollDay day : values())
            System.out.printf("%-10s%d%n", day, day.pay(8 * 60, 1));
    }
}