New Design Patterns (Chain of Responsibility, Decorator, Facade)

Author: aleshotkotp

CSharp Code Samples/CodeSamples/CodeSamples.csproj

@@ -86,6 +86,7 @@
     <Compile Include="MultiThreading\BackgroundWorkerSample.cs" />
     <Compile Include="MultiThreading\MultithreadingSample.cs" />
     <Compile Include="MultiThreading\ThreadSample.cs" />
+    <Compile Include="Patterns\Behavioral\ChainOfResponsibilityPattern.cs" />
     <Compile Include="Patterns\Behavioral\ObserverPattern.cs" />
     <Compile Include="Patterns\Behavioral\StatePattern.cs" />
     <Compile Include="Patterns\Creational\AbstractFactoryPattern.cs" />
@@ -95,6 +96,8 @@
     <Compile Include="Patterns\PatternsSample.cs" />
     <Compile Include="Patterns\Creational\SingletonPattern.cs" />
     <Compile Include="Patterns\Behavioral\StrategyPattern.cs" />
+    <Compile Include="Patterns\Structural\DecoratorPattern.cs" />
+    <Compile Include="Patterns\Structural\FacadePattern.cs" />
     <Compile Include="Program.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="Properties\OtherSettings.Designer.cs">

CSharp Code Samples/CodeSamples/Patterns/Behavioral/ChainOfResponsibilityPattern.cs

@@ -0,0 +1,75 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace CodeSamples.Patterns.Behavioral
+{
+    public class ChainOfResponsibilityPatternSample : SampleExecute
+    {
+        internal abstract class Handler
+        {
+            protected Handler Successor { get; private set; }
+
+            public void SetSuccessor(Handler successor)
+            {
+                this.Successor = successor;
+            }
+
+            public abstract void HandleRequest(string deviceName, int request);
+        }
+
+        internal class HandlerDeviceKeyboard : Handler
+        {
+            public override void HandleRequest(string deviceName, int request)
+            {
+                if (deviceName.Equals("keyboard", StringComparison.OrdinalIgnoreCase))
+                {
+                    Console.WriteLine($"Handled Request {request} for device {deviceName} by {this.GetType().Name}");
+                }
+                else Successor?.HandleRequest(deviceName, request);
+            }
+        }
+
+        internal class HandlerDeviceMouse : Handler
+        {
+            public override void HandleRequest(string deviceName, int request)
+            {
+                if (deviceName.Equals("mouse", StringComparison.OrdinalIgnoreCase))
+                {
+                    Console.WriteLine($"Handled Request {request} for device {deviceName} by {this.GetType().Name}");
+                }
+                else Successor?.HandleRequest(deviceName, request);
+            }
+        }
+
+        internal class HandlerDeviceNetwork : Handler
+        {
+            public override void HandleRequest(string deviceName, int request)
+            {
+                if (deviceName.Equals("network", StringComparison.OrdinalIgnoreCase))
+                {
+                    Console.WriteLine($"Handled Request {request} for device {deviceName} by {this.GetType().Name}");
+                }
+                else Successor?.HandleRequest(deviceName, request);
+            }
+        }
+
+        public override void Execute()
+        {
+            Section("Chain of Responsibility Pattern");
+            var keyboard = new HandlerDeviceKeyboard();
+            var mouse = new HandlerDeviceMouse();
+            var network = new HandlerDeviceNetwork();
+
+            keyboard.SetSuccessor(mouse);
+            mouse.SetSuccessor(network);
+
+            keyboard.HandleRequest("mouse", 10);
+            keyboard.HandleRequest("network", 12);
+            keyboard.HandleRequest("keyboard", 102);
+            keyboard.HandleRequest("something", 11);
+        }
+    }
+}

CSharp Code Samples/CodeSamples/Patterns/PatternsSample.cs

@@ -1,5 +1,6 @@
 using CodeSamples.Patterns.Behavioral;
 using CodeSamples.Patterns.Creational;
+using CodeSamples.Patterns.Structural;
 
 namespace CodeSamples.Patterns
 {
@@ -8,6 +9,7 @@ public class PatternsSample : SampleExecute
         public override void Execute()
         {
             Title("PatternsSampleExecute");
+
             Section("Creational Patterns");
             var singleton = new SingletonPatternSample();
             singleton.Execute();
@@ -16,13 +18,24 @@ public override void Execute()
             var abstractFactory = new AbstractFactoryPatternSample();
             abstractFactory.Execute();
             LineBreak();
+
             Section("Behavioral Patterns");
             var strategy = new StrategyPatternSample();
             strategy.Execute();
             var observer = new ObserverPatternSample();
             observer.Execute();
             var state = new StatePatternSample();
             state.Execute();
+            var chainOfResponsibility = new ChainOfResponsibilityPatternSample();
+            chainOfResponsibility.Execute();
+            LineBreak();
+
+            Section("Structural Patterns");
+            var decorator = new DecoratorPatternSample();
+            decorator.Execute();
+            var facade = new FacadePatternSample();
+            facade.Execute();
+
             Finish();
         }
     }

CSharp Code Samples/CodeSamples/Patterns/Structural/DecoratorPattern.cs

@@ -0,0 +1,65 @@
+using System;
+
+namespace CodeSamples.Patterns.Structural
+{
+    public class DecoratorPatternSample : SampleExecute
+    {
+
+        internal interface IBird
+        {
+            string Fly();
+        }
+
+        internal class Bird : IBird
+        {
+            public string Fly()
+            {
+                return "Flying";
+            }
+        }
+
+        //decorator classes
+        internal class FasterBird : IBird
+        {
+            protected readonly IBird _bird;
+
+            public FasterBird(IBird bird)
+            {
+                _bird = bird;
+            }
+
+            public string Fly()
+            {
+                return $"{_bird.Fly()} faster";
+            }
+        }
+
+        internal class FastestBird : IBird
+        {
+            protected readonly IBird _bird;
+
+            public FastestBird(IBird bird)
+            {
+                _bird = bird;
+            }
+
+            public string Fly()
+            {
+                return $"{_bird.Fly()} like tail is on fire";
+            }
+        }
+
+        public override void Execute()
+        {
+            Section("Decorator Pattern");
+            var bird = new Bird();
+            Console.WriteLine(bird.Fly());
+
+            var fasterBird = new FasterBird(bird);
+            Console.WriteLine(fasterBird.Fly());
+
+            var fastestBird = new FastestBird(fasterBird);
+            Console.WriteLine(fastestBird.Fly());
+        }
+    }
+}

CSharp Code Samples/CodeSamples/Patterns/Structural/FacadePattern.cs

@@ -0,0 +1,73 @@
+using System;
+
+namespace CodeSamples.Patterns.Structural
+{
+    public class FacadePatternSample : SampleExecute
+    {
+
+        internal class SubSystemOne
+        {
+            public void DoSomething()
+            {
+                Console.WriteLine("Doing Something");
+            }
+        }
+
+        internal class SubSystemTwo
+        {
+            public void DoSomethingElse()
+            {
+                Console.WriteLine("Doing Something Else");
+            }
+        }
+
+        internal class SubSystemThree
+        {
+            public void WriteABook()
+            {
+                Console.WriteLine("Writing a book");
+            }
+        }
+
+        internal class SubSystemFour
+        {
+            public void Swim()
+            {
+                Console.WriteLine("Swimming");
+            }
+        }
+
+        internal class FacadeClass
+        {
+            private readonly SubSystemOne _one = new SubSystemOne();
+            private readonly SubSystemTwo _two = new SubSystemTwo();
+            private readonly SubSystemThree _three = new SubSystemThree();
+            private readonly SubSystemFour _four = new SubSystemFour();
+
+            public void GoLeisureTimeMethodOne()
+            {
+                _one.DoSomething();
+                _three.WriteABook();
+                _four.Swim();
+            }
+
+            public void GoLeisureTimeAll()
+            {
+                _one.DoSomething();
+                _two.DoSomethingElse();
+                _three.WriteABook();
+                _four.Swim();
+            }
+        }
+
+        public override void Execute()
+        {
+            Section("Facade Pattern");
+            var facade = new FacadeClass();
+
+            facade.GoLeisureTimeMethodOne();
+            Console.WriteLine();
+            facade.GoLeisureTimeAll();
+        }
+    }
+}