通俗易懂设计模式解析——享元模式

namespace Flyweight_Pattern
{
    class FlyweightPattern
    {
    }

    #region 抽象享元角色——抽象公共接口
    public abstract class Flyweight 
    {
        /// <summary>
        /// 表述输出的位置
        /// </summary>
        /// <param name="externalstate">外在的状态，随着环境改变而改变</param>
        public abstract void OutInput(int externalstate);
    }
    #endregion

    #region 具体享元角色——实现其具体
    public class SpecificFlyweight : Flyweight
    {
        private string Innerstate;
        /// <summary>
        /// 内部状态接收
        /// </summary>
        /// <param name="innerstate">内部状态</param>
        public SpecificFlyweight(string innerstate) 
        {
            this.Innerstate = innerstate;
        }
        /// <summary>
        /// 实现方法
        /// </summary>
        /// <param name="externalstate">外部状态</param>
        public override void OutInput(int externalstate)
        {
            Console.WriteLine($"内部状态：{Innerstate}————外部状态：{externalstate}");
        }
    }
    #endregion

    #region 享元工厂角色——对享元角色进行创建及管理的
    public class FlyweightFactory 
    {
        public Dictionary<string, SpecificFlyweight> keyValuePairs = new Dictionary<string, SpecificFlyweight>();

        public SpecificFlyweight GetFlyweight(string Key) 
        {
            SpecificFlyweight specific = null;
            if (!keyValuePairs.ContainsKey("A"))
            {
                Console.WriteLine("暂时未遇见该Key");
                keyValuePairs.Add(Key, new SpecificFlyweight(Key));
                Console.WriteLine("现已保存该Key"); 
            }
            else
            {
                 specific = keyValuePairs[Key] as SpecificFlyweight;
            }
            return specific;
        }
    }
    #endregion
}

namespace Flyweight_Pattern
{
    class Program
    {
        static void Main(string[] args)
        {

            ///初始化享元工厂
            FlyweightFactory factory = new FlyweightFactory();
            while (true)
            {
                Console.WriteLine("请输入字符的位置：");
                var indexstring = Console.ReadLine();
                if (int.TryParse(indexstring, out int index))
                {
                    Console.WriteLine("请输入字符:");
                    string str = Console.ReadLine();

                    ///判断字符是否创建
                    Flyweight flyweight = factory.GetFlyweight(str);

                    //如果存在则输出信息
                    if (flyweight != null)
                    {
                        flyweight.OutInput(index);
                    }
                }
                else
                {
                    Console.WriteLine("请输入数字!");
                }
                Console.WriteLine("结束请输入N");
                if (Console.ReadLine()=="N")
                {
                    break;
                }
            }

            Console.WriteLine("已结束");
            Console.ReadLine();
        }
    }
}