C# 享元模式

using Newtonsoft.Json;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.InteropServices.ComTypes;
using System.Text.Json.Serialization;

namespace ConsoleApp1
{
    class Program
    {
        static void Main(string[] args)
        {
            // The client code usually creates a bunch of pre-populated
            // flyweights in the initialization stage of the application.
            var factory = new FlyweightFactory(
                new Car { Company = "Chevrolet", Model = "Camaro2018", Color = "pink" },
                new Car { Company = "Mercedes Benz", Model = "C300", Color = "black" },
                new Car { Company = "Mercedes Benz", Model = "C500", Color = "red" },
                new Car { Company = "BMW", Model = "M5", Color = "red" },
                new Car { Company = "BMW", Model = "X6", Color = "white" }
            );
            factory.listFlyweights();

            addCarToPoliceDatabase(factory, new Car
            {
                Number = "CL234IR",
                Owner = "James Doe",
                Company = "BMW",
                Model = "M5",
                Color = "red"
            });

            addCarToPoliceDatabase(factory, new Car
            {
                Number = "CL234IR",
                Owner = "James Doe",
                Company = "BMW",
                Model = "X1",
                Color = "red"
            });

            factory.listFlyweights();

        }

        public static void addCarToPoliceDatabase(FlyweightFactory factory, Car car)
        {
            Console.WriteLine("\nClient:Adding a car to database");
            var flyweight = factory.GetFlyweight(new Car { Color = car.Color,Model = car.Model,Company = car.Company });

            flyweight.Operation(car);
        }

    }



    public class Flyweight
    {
        private Car _sharedState;

        public Flyweight(Car car)
        {
            this._sharedState = car;
        }

        public void Operation(Car uniqueState)
        {
            string s = JsonConvert.SerializeObject(this._sharedState);
            string u = JsonConvert.SerializeObject(uniqueState);
            Console.WriteLine($"Flyweight:Displaying shared {s} and unique {u} state");
        
        }

    }


    public class FlyweightFactory
    {
        private List<Tuple<Flyweight, string>> flyweights = new List<Tuple<Flyweight, string>>();

        public FlyweightFactory(params Car[] args)
        {
            foreach (var elem in args)
            {
                flyweights.Add(new Tuple<Flyweight, string>(new Flyweight(elem), this.getKey(elem)));
            }
        }


        public string getKey(Car key)
        {
            List<string> elements = new List<string>();

            elements.Add(key.Model);
            elements.Add(key.Color);
            elements.Add(key.Company);


            if (key.Owner != null && key.Number != null)
            {
                elements.Add(key.Number);
                elements.Add(key.Owner);

            }

            elements.Sort();

            return string.Join("_", elements);

        }



        public Flyweight GetFlyweight(Car sharedState)
        {
            string key = this.getKey(sharedState);

            if (flyweights.Where(t => t.Item2 == key).Count() == 0)
            {
                Console.WriteLine("FlyweightFactory:Can't find a flyweight,creating new one.");
                this.flyweights.Add(new Tuple<Flyweight, string>(new Flyweight(sharedState), key));
            }
            else
            {
                Console.WriteLine("FlyweightFactory:Reusing existing flyweight");
            }

            return this.flyweights.Where(t => t.Item2 == key).FirstOrDefault().Item1;

        }


        public void listFlyweights()
        {
            var count = flyweights.Count;
            Console.WriteLine($"FlyweightFactory: I Have {count} flyweights\n");

            foreach (var flyweight in flyweights)
                Console.WriteLine(flyweight.Item2);
            
        }


    }


    public class Car
    { 
        public string Owner { get; set; }
        public string Number { get; set; }
        public string Company { get; set; }
        public string Model { get; set; }
        public string Color { get; set; }

    
    }
}