chain of responsibility

DesignPatternGuru/ChainOfResponsibility/COR/AbstractHandler.cs

@@ -0,0 +1,27 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace ChainOfResponsibility.COR
+{
+    internal abstract class AbstractHandler : IHandler
+    {
+        private IHandler _nextHandler;
+
+        public IHandler SetNext(IHandler handler)
+        {
+            _nextHandler = handler;
+            return _nextHandler;
+        }
+
+        public virtual object Handle(object request)
+        {
+            if (_nextHandler == null)
+                return null;
+
+            return _nextHandler.Handle(request);
+        }
+    }
+}

DesignPatternGuru/ChainOfResponsibility/COR/DogHandler.cs

@@ -0,0 +1,19 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace ChainOfResponsibility.COR
+{
+    internal class DogHandler : AbstractHandler
+    {
+        public override object Handle(object request)
+        {
+            if ((request as string) == "MeatBall")
+                return $"Dog: I'll eat the {request.ToString()}";
+            else
+                return base.Handle(request);
+        }
+    }
+}

DesignPatternGuru/ChainOfResponsibility/COR/IHandler.cs

@@ -0,0 +1,15 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace ChainOfResponsibility.COR
+{
+    internal interface IHandler
+    {
+        IHandler SetNext(IHandler handler);
+
+        object Handle(object request);
+    }
+}

DesignPatternGuru/ChainOfResponsibility/COR/MonkeyHandler.cs

@@ -0,0 +1,19 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace ChainOfResponsibility.COR
+{
+    internal class MonkeyHandler : AbstractHandler
+    {
+        public override object Handle(object request)
+        {
+            if ((request as string) == "Banana")
+                return $"Monkey: I'll eat the {request.ToString()}";
+            else
+                return base.Handle(request);
+        }
+    }
+}

DesignPatternGuru/ChainOfResponsibility/COR/SquirrelHandler.cs

@@ -0,0 +1,19 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace ChainOfResponsibility.COR
+{
+    internal class SquirrelHandler : AbstractHandler
+    {
+        public override object Handle(object request)
+        {
+            if ((request as string) == "Nut")
+                return $"Squirrel: I'll eat the {request.ToString()}";
+            else
+                return base.Handle(request) ;
+        }
+    }
+}

DesignPatternGuru/ChainOfResponsibility/ChainOfResponsibility.csproj

@@ -0,0 +1,10 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net6.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>

DesignPatternGuru/ChainOfResponsibility/Client.cs

@@ -0,0 +1,33 @@
+using ChainOfResponsibility.COR;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace ChainOfResponsibility
+{
+    internal class Client
+    {
+        public static void ClientCode(AbstractHandler handler)
+        {
+            List<string> foods = new List<string>()
+            {
+                "Nut",
+                "Banana",
+                "Cup of coffee",
+                "MeatBall"
+            };
+
+            foreach (string food in foods)
+            {
+                Console.WriteLine($"Client: Who wants a {food}");
+                var result = handler.Handle(food);
+                if (result == null)
+                    Console.WriteLine($"    {food} was left untouched");
+                else
+                    Console.WriteLine($"    {result}");
+            }
+        }
+    }
+}

DesignPatternGuru/ChainOfResponsibility/Program.cs

@@ -0,0 +1,24 @@
+using ChainOfResponsibility.COR;
+
+namespace ChainOfResponsibility
+{
+    internal class Program
+    {
+        static void Main(string[] args)
+        {
+            var monkey = new MonkeyHandler();
+            var squirrel = new SquirrelHandler();
+            var dog = new DogHandler();
+
+            monkey.SetNext(squirrel).SetNext(dog);
+
+            Console.WriteLine("Chain: Monkey → Squirrel → Dog");
+            Client.ClientCode(monkey);
+            Console.WriteLine();
+
+            Console.WriteLine("Subchain: Squirrel → Dog");
+            Client.ClientCode(squirrel);
+
+        }
+    }
+}

DesignPatternGuru/DesignPatternGuru.sln

@@ -29,7 +29,11 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Facade", "Facade\Facade.csp
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Flyweight", "Flyweight\Flyweight.csproj", "{D414F5DF-8FB2-4D77-A0C8-77B623A902DD}"
 EndProject
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Proxy", "Proxy\Proxy.csproj", "{F0E63700-B550-4D57-B912-18C28B3FEAC6}"
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Proxy", "Proxy\Proxy.csproj", "{F0E63700-B550-4D57-B912-18C28B3FEAC6}"
+EndProject
+Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "BehavioralPatterns", "BehavioralPatterns", "{E3B8A482-1A9A-4B6E-8310-050A44C8E379}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ChainOfResponsibility", "ChainOfResponsibility\ChainOfResponsibility.csproj", "{9626EF73-1F68-46C8-B7C1-434F02768452}"
 EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
@@ -85,6 +89,10 @@ Global
 		{F0E63700-B550-4D57-B912-18C28B3FEAC6}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{F0E63700-B550-4D57-B912-18C28B3FEAC6}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{F0E63700-B550-4D57-B912-18C28B3FEAC6}.Release|Any CPU.Build.0 = Release|Any CPU
+		{9626EF73-1F68-46C8-B7C1-434F02768452}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{9626EF73-1F68-46C8-B7C1-434F02768452}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{9626EF73-1F68-46C8-B7C1-434F02768452}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{9626EF73-1F68-46C8-B7C1-434F02768452}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -102,6 +110,7 @@ Global
 		{7D6D306D-BC44-407A-9A39-104C90A3FA39} = {0B9333EC-FB73-4FEE-B600-9ECCD5A356B1}
 		{D414F5DF-8FB2-4D77-A0C8-77B623A902DD} = {0B9333EC-FB73-4FEE-B600-9ECCD5A356B1}
 		{F0E63700-B550-4D57-B912-18C28B3FEAC6} = {0B9333EC-FB73-4FEE-B600-9ECCD5A356B1}
+		{9626EF73-1F68-46C8-B7C1-434F02768452} = {E3B8A482-1A9A-4B6E-8310-050A44C8E379}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {3E5A9C6B-2E8A-466E-B5E0-4379902EFFAC}