C# 与 Java 中的枚举

 

C#代码： 利用扩展方法，扩展枚举功能

using System;
using System.Collections.Generic;
using System.Text;
using System.Linq;

namespace EnumExtension
{
    // Define an extension method in a non-nested static class.
    public static class Extensions
    {        
        public static Grades minPassing = Grades.D;
        public static bool Passing(this Grades grade)
        {
            return grade >= minPassing;
        }
    }

    public enum Grades { F = 0, D=1, C=2, B=3, A=4 };
    class Program
    {       
        static void Main(string[] args)
        {
            Grades g1 = Grades.D;
            Grades g2 = Grades.F;
            Console.WriteLine("First {0} a passing grade.", g1.Passing() ? "is" : "is not");
            Console.WriteLine("Second {0} a passing grade.", g2.Passing() ? "is" : "is not");

            Extensions.minPassing = Grades.C;
            Console.WriteLine("\r\nRaising the bar!\r\n");
            Console.WriteLine("First {0} a passing grade.", g1.Passing() ? "is" : "is not");
            Console.WriteLine("Second {0} a passing grade.", g2.Passing() ? "is" : "is not");
        }
    }
  }
}
/* Output:
    First is a passing grade.
    Second is not a passing grade.

    Raising the bar!

    First is not a passing grade.
    Second is not a passing grade.
 */

 

Java代码：

package com.mmb.csharp;

/**
 * 颜色枚举
 * 
 */
public enum Color {

    /**
     * 1
     */
    RED("红色", 1),
    /**
     * 2
     */
    GREEN("绿色", 2), 
    /**
     * 3
     */
    BLACK("黑色", 3), 
    /**
     * 4
     */
    YELLOW("黄色", 4);

    // 成员变量
    private String name;
    private int index;

    // 构造方法
    private Color(String name, int index) {
        this.name = name;
        this.index = index;
    }

    // 普通方法
    public static String getName(int index) {
        for (Color c : Color.values()) {
            if (c.getIndex() == index) {
                return c.name;
            }
        }
        return null;
    }
    
    public static Color getColor(int index) {
        for (Color c : Color.values()) {
            if (c.getIndex() == index) {
                return c;
            }
        }
        return null;
    }

    // get set 方法
    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getIndex() {
        return index;
    }

    public void setIndex(int index) {
        this.index = index;
    }
}

 

单单只着眼于枚举，Java要比C#做的好一些、要更加地方便使用。