CSharp: Flyweight Pattern in donet core 3

 

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/// <summary>    /// The 'Flyweight' interface    ///享元模式 Flyweight Pattern    /// geovindu,Geovin Du edit    /// 车辆    /// </summary>    interface IVehicle    {        /*         * Client will supply the color.         * It is extrinsic state.        */        /// <summary>        ///        /// </summary>        /// <param name="color">输入颜色</param>        void AboutMe(string color);    }    /// <summary>    /// A 'ConcreteFlyweight' class called Car    /// 汽车    /// </summary>    class Car : IVehicle    {        /*         * It is intrinsic state and         * it is independent of flyweight context.         * this can be shared.So, our factory method will supply         * this value inside the flyweight object.         */        /// <summary>        /// 描述        /// </summary>        private string description;        /*         * Flyweight factory will supply this         * inside the flyweight object.        */        /// <summary>        ///        /// </summary>        /// <param name="description">输入描述</param>        public Car(string description)        {            this.description = description;        }        //Client will supply the color        /// <summary>        ///        /// </summary>        /// <param name="color">输入颜色</param>        public void AboutMe(string color)        {            Console.WriteLine($"{description} 为 {color} .");        }    }    /// <summary>    /// A 'ConcreteFlyweight' class called Bus    /// 公交车    /// </summary>    class Bus : IVehicle    {        /*         * It is intrinsic state and         * it is independent of flyweight context.         * this can be shared.So, our factory method will supply         * this value inside the flyweight object.         */        /// <summary>        /// 描述        /// </summary>        private string description;        /// <summary>        ///        /// </summary>        /// <param name="description">输入描述</param>        public Bus(string description)        {            this.description = description;        }        //Client will supply the color        /// <summary>        ///        /// </summary>        /// <param name="color">输入颜色</param>        public void AboutMe(string color)        {            Console.WriteLine($"{description} 为 {color} .");        }    }    /// <summary>    /// A 'ConcreteFlyweight' class called FutureVehicle    /// 未来车辆    /// </summary>    class FutureVehicle : IVehicle    {        /*         * It is intrinsic state and         * it is independent of flyweight context.         * this can be shared.So, our factory method will supply         * this value inside the flyweight object.         */        /// <summary>        /// 描述        /// </summary>        private string description;        /// <summary>        ///        /// </summary>        /// <param name="description">输入描述</param>        public FutureVehicle(string description)        {            this.description = description;        }        //Client cannot choose color for FutureVehicle        //since it's unshared flyweight,ignoring client's input        /// <summary>        ///        /// </summary>        /// <param name="color">输入颜色</param>        public void AboutMe(string color)        {            Console.WriteLine($"{description} 为 {color} .");        }    }      /// <summary>    /// The factory class for flyweights implemented as singleton.    /// 车辆工厂类    /// </summary>    class VehicleFactory    {          /// <summary>        ///        /// </summary>        private static readonly VehicleFactory Instance = new VehicleFactory();        /// <summary>        ///        /// </summary>        private Dictionary<string, IVehicle> vehicles = new Dictionary<string, IVehicle>();        /// <summary>        ///        /// </summary>        private VehicleFactory()        {            vehicles.Add("小汽车", new Car("一辆小汽车制造"));            vehicles.Add("公交车", new Bus("一辆公交车制造"));            vehicles.Add("概念车", new FutureVehicle("概念车 T2050 制造"));        }        /// <summary>        ///        /// </summary>        public static VehicleFactory GetInstance        {            get            {                return Instance;            }        }        /*         * To count different type of vehicle         * in a given moment.        */        /// <summary>        /// 数量        /// </summary>        public int TotalObjectsCreated        {            get            {                return vehicles.Count;            }        }        /// <summary>        ///        /// </summary>        /// <param name="vehicleType"></param>        /// <returns></returns>        /// <exception cref="Exception"></exception>        public IVehicle GetVehicleFromVehicleFactory(string vehicleType)        {            IVehicle vehicleCategory = null;            if (vehicles.ContainsKey(vehicleType))            {                vehicleCategory = vehicles[vehicleType];                return vehicleCategory;            }            else            {                throw new Exception("Currently, the vehicle factory can have cars and buses only.");            }        }    }

　　

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/// <summary>    ///享元模式 Flyweight Pattern    /// geovindu,Geovin Du edit    /// </summary>    public class FormattedText    {          /// <summary>        ///        /// </summary>        private readonly string plainText;        /// <summary>        ///        /// </summary>        /// <param name="plainText"></param>        public FormattedText(string plainText)        {            this.plainText = plainText;            capitalize = new bool[plainText.Length];        }        /// <summary>        ///        /// </summary>        /// <param name="start"></param>        /// <param name="end"></param>        public void Capitalize(int start, int end)        {            for (int i = start; i <= end; ++i)                capitalize[i] = true;        }        /// <summary>        ///        /// </summary>        private readonly bool[] capitalize;        /// <summary>        /// 大写        /// </summary>        /// <returns></returns>        public override string ToString()        {            var sb = new StringBuilder();            for (var i = 0; i < plainText.Length; i++)            {                var c = plainText[i];                sb.Append(capitalize[i] ? char.ToUpper(c) : c);            }            return sb.ToString();        }    }    /// <summary>    ///    /// </summary>    public class BetterFormattedText    {        private readonly string plainText;        private readonly List<TextRange> formatting          = new List<TextRange>();        /// <summary>        ///        /// </summary>        /// <param name="plainText"></param>        public BetterFormattedText(string plainText)        {            this.plainText = plainText;        }        /// <summary>        ///        /// </summary>        /// <param name="start"></param>        /// <param name="end"></param>        /// <returns></returns>        public TextRange GetRange(int start, int end)        {            var range = new TextRange { Start = start, End = end };            formatting.Add(range);            return range;        }        /// <summary>        /// 大写        /// </summary>        /// <returns></returns>        public override string ToString()        {            var sb = new StringBuilder();              for (var i = 0; i < plainText.Length; i++)            {                var c = plainText[i];                foreach (var range in formatting)                    if (range.Covers(i) && range.Capitalize)                        c = char.ToUpperInvariant(c);                sb.Append(c);            }              return sb.ToString();        }        /// <summary>        ///        /// </summary>        public class TextRange        {            public int Start, End;            public bool Capitalize, Bold, Italic;              public bool Covers(int position)            {                return position >= Start && position <= End;            }        }    }

　　

调用：

 

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//享元模式 Flyweight Pattern    Console.WriteLine("***享元模式 Flyweight Pattern Demo.***\n");   //VehicleFactory vehiclefactory = new VehicleFactory();   VehicleFactory vehiclefactory = VehicleFactory.GetInstance;   IVehicle vehicle;   /*    * Now we are trying to get the 3 cars.    * Note that:we need not create additional cars if    * we have already created one of this category   */   for (int i = 0; i < 3; i++)   {       vehicle = vehiclefactory.GetVehicleFromVehicleFactory("小汽车");       vehicle.AboutMe("绿色");   }   int numOfDistinctRobots = vehiclefactory.TotalObjectsCreated;   Console.WriteLine($"\n Now, total numbers of distinct vehicle object(s) is = {numOfDistinctRobots}\n");   /*Here we are trying to get the 5 more buses.    * Note that: we need not create    * additional buses if we have    * already created one of this category */   for (int i = 0; i < 5; i++)   {       vehicle = vehiclefactory.GetVehicleFromVehicleFactory("公交车");       vehicle.AboutMe("红色");   }   numOfDistinctRobots = vehiclefactory.TotalObjectsCreated;   Console.WriteLine($"\n Now, total numbers of distinct vehicle object(s) is = {numOfDistinctRobots}\n");   /*Here we are trying to get the 2 future vehicles.    * Note that: we need not create    * additional future vehicle if we have    * already created one of this category */   for (int i = 0; i < 2; i++)   {       vehicle = vehiclefactory.GetVehicleFromVehicleFactory("概念车");       vehicle.AboutMe("白色");   }   numOfDistinctRobots = vehiclefactory.TotalObjectsCreated;   Console.WriteLine($"\n Now, total numbers of distinct vehicle object(s) is = {numOfDistinctRobots}\n");   #region test for in-built flyweight pattern   Console.WriteLine("**Testing String interning in .NET now.**");   string firstString = "A simple string";   string secondString = new StringBuilder().Append("A").Append(" simple").Append(" string").ToString();   string thirdString = String.Intern(secondString);   Console.WriteLine((Object)secondString == (Object)firstString); // Different references.   Console.WriteLine((Object)thirdString == (Object)firstString); // The same reference.     #endregion   //大写   var ft = new FormattedText("This is a geovindu new world");   ft.Capitalize(10, 17);   Console.WriteLine(ft);   //大写   var bft = new BetterFormattedText("This is a lukfook new world");   bft.GetRange(10, 16).Capitalize = true;   Console.WriteLine(bft);         Console.ReadKey();

　　

 

输出：

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***享元模式 Flyweight Pattern Demo.***   一辆小汽车制造 为 绿色 . 一辆小汽车制造 为 绿色 . 一辆小汽车制造 为 绿色 .    Now, total numbers of distinct vehicle object(s) is = 3   一辆公交车制造 为 红色 . 一辆公交车制造 为 红色 . 一辆公交车制造 为 红色 . 一辆公交车制造 为 红色 . 一辆公交车制造 为 红色 .    Now, total numbers of distinct vehicle object(s) is = 3   概念车 T2050 制造 为 白色 . 概念车 T2050 制造 为 白色 .    Now, total numbers of distinct vehicle object(s) is = 3   **Testing String interning in .NET now.** False True This is a GEOVINDU new world This is a LUKFOOK new world