Java编程：枚举enum中，将方法附加到枚举常量

package 枚举;
//将方法附加到枚举常量
public class UnitsConverter {
    private static double numberToConvert = 0;

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        if(args.length == 0)
        {
            System.out.println("Usage:java UnitsConverter<weight in pounds>");
            System.exit(0);
        }
        numberToConvert = Double.parseDouble(args[0]);
        System.out.println("lbs "+args[0]+" equals:\n");
        //遍历Converter枚举的所有元素
        for(Converter conv:Converter.values())
        {
            System.out.printf("%s：%f%n",conv,conv.performConversion(numberToConvert));
        }
    }
}
//枚举Converter:变换器
//Converter中的每个常量都需要实现这个方法。

enum Converter
{
    //把磅换算成千克，需要把指定值乘以常量0.45359237
    KG("KG"){
        double performConversion(double f){
            return f*=0.45359237;
        }
    },
    //把磅换算成克拉
    CARAT("carat"){
        double performConversion(double f){
            return f*=2267.96185;
        }
    },
    //
    GMS("gms"){
        double performConversion(double f){
            return f*=453.59237;
        }
    },
    //
    OUNCE("ounce"){
        double performConversion(double f){
            return f*=16;
        }
    },
    //
    STONE("stone"){
        double performConversion(double f){
            return f*=0.071428571429;
        }
    };

    private final String symbol;
    //构造方法
    Converter(String symbol)
    {
        this.symbol=symbol;
    }
    @Override
    public String toString()
    {
        return symbol;
    }
    //定义的抽象方法performConversion:执行转换
    abstract double performConversion(double f);
}

lbs 5.0 equals:

KG：2.267962
carat：11339.809250
gms：2267.961850
ounce：80.000000
stone：0.357143