CSharp: Flyweight Pattern in donet core 3

 

 /// <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.");
            }
        }
    }

　　

 /// <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：

 

          //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：

***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