flyweight

DesignPatternGuru/Flyweight/Flyweight.csproj

@@ -7,4 +7,8 @@
     <Nullable>enable</Nullable>
   </PropertyGroup>
 
+  <ItemGroup>
+    <PackageReference Include="Newtonsoft.Json" Version="13.0.3" />
+  </ItemGroup>
+
 </Project>

DesignPatternGuru/Flyweight/Flyweights/Flyweight.cs

@@ -1,4 +1,6 @@
-using System;
+using Flyweight.Objects;
+using Newtonsoft.Json;
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Text;
@@ -8,6 +10,18 @@ namespace Flyweight.Flyweights
 {
 	internal class Flyweight
 	{
+		private Car _sharedState;
 
+		public Flyweight(Car car)
+		{
+			_sharedState = car;
+		}
+
+		public void Operation(Car uniqueState)
+		{
+			string s = JsonConvert.SerializeObject(_sharedState);
+			string u = JsonConvert.SerializeObject(uniqueState);
+			Console.WriteLine($"Flyweight: Displaying shared {s} and unique {u} state.");
+		}
 	}
 }

DesignPatternGuru/Flyweight/Flyweights/FlyweightFactory.cs

@@ -0,0 +1,67 @@
+using Flyweight.Objects;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Flyweight.Flyweights
+{
+    internal 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), GetKey(elem)));
+            }
+        }
+
+        public string GetKey(Car car)
+        {
+            List<string> elements = new List<string>();
+
+            elements.Add(car.Model);
+            elements.Add(car.Color);
+            elements.Add(car.Company);
+            
+            if (car.Owner != null && car.Number != null)
+            {
+                elements.Add(car.Number);
+                elements.Add(car.Owner);
+            }
+
+            elements.Sort();
+
+            return String.Join("_", elements);
+        }
+
+        public Flyweight GetFlyweight(Car sharedState)
+        {
+            string key = GetKey(sharedState);
+            if (_flyweights.Where(t => t.Item2 == key).Count() == 0)
+            {
+                Console.WriteLine("FlyweightFactory: Can't find a flyweight, creating new one.");
+                _flyweights.Add(new Tuple<Flyweight, string>(new Flyweight(sharedState), key));
+            }
+            else
+            {
+                Console.WriteLine("FlyweightFactory: Reusing existing flyweight.");
+            }
+
+            return _flyweights.Where(t => t.Item2 == key).FirstOrDefault().Item1;
+        }
+
+        public void ListFlyweights()
+        {
+            int count = _flyweights.Count;
+            Console.WriteLine($"FlyweightFactory: I have {count} flyweights");
+            foreach (var flyweight in _flyweights)
+            {
+                Console.WriteLine(flyweight.Item2);
+            }
+        }
+    }
+}

DesignPatternGuru/Flyweight/Program.cs

@@ -1,10 +1,53 @@
-namespace Flyweight
+using Flyweight.Flyweights;
+using Flyweight.Objects;
+
+namespace Flyweight
 {
 	internal class Program
 	{
 		static void Main(string[] args)
 		{
-			Console.WriteLine("Hello, World!");
+            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("Client: Adding a car to database.");
+			var flyweight = factory.GetFlyweight(new Car
+			{
+				Color = car.Color,
+				Model = car.Model,
+				Company = car.Company,
+			});
+
+			flyweight.Operation(car);
 		}
 	}
 }