visitor pattern example

Author: anupavanm

DesignPatterns.sln

@@ -39,6 +39,8 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "MementoPattern", "Memento\M
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ObserverPattern", "ObserverPattern\ObserverPattern.csproj", "{88754C6C-4DA4-4C4B-8E53-4DDD9425A387}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "VisitorPattern", "VisitorPattern\VisitorPattern.csproj", "{C33B3A5D-E92B-455B-A9CD-4DFB6DF985A6}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -117,6 +119,10 @@ Global
 		{88754C6C-4DA4-4C4B-8E53-4DDD9425A387}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{88754C6C-4DA4-4C4B-8E53-4DDD9425A387}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{88754C6C-4DA4-4C4B-8E53-4DDD9425A387}.Release|Any CPU.Build.0 = Release|Any CPU
+		{C33B3A5D-E92B-455B-A9CD-4DFB6DF985A6}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{C33B3A5D-E92B-455B-A9CD-4DFB6DF985A6}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{C33B3A5D-E92B-455B-A9CD-4DFB6DF985A6}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{C33B3A5D-E92B-455B-A9CD-4DFB6DF985A6}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE

VisitorPattern/Program.cs

@@ -0,0 +1,123 @@
+using System;
+
+namespace VisitorPattern
+{
+// Visitee
+interface IAnimal
+{
+  void Accept(IAnimalOperation operation);
+}
+
+// Visitor
+interface IAnimalOperation
+{
+  void VisitMonkey(Monkey monkey);
+  void VisitLion(Lion lion);
+  void VisitDolphin(Dolphin dolphin);
+}
+
+class Monkey : IAnimal
+{
+  public void Shout()
+  {
+    Console.WriteLine("Oooh o aa aa!");
+  }
+
+  public void Accept(IAnimalOperation operation)
+  {
+    throw new NotImplementedException();
+  }
+}
+
+class Lion : IAnimal
+{
+  public void Roar()
+  {
+    Console.WriteLine("Roaar!");
+  }
+
+  public void Accept(IAnimalOperation operation)
+  {
+    throw new NotImplementedException();
+  }
+}
+
+class Dolphin : IAnimal
+{
+  public void Speak()
+  {
+    Console.WriteLine("Tuut tittu tuutt!");
+  }
+
+  public void Accept(IAnimalOperation operation)
+  {
+    throw new NotImplementedException();
+  }
+}
+
+class Speak : IAnimalOperation
+{
+  public void VisitDolphin(Dolphin dolphin)
+  {
+    dolphin.Speak();
+  }
+
+  public void VisitLion(Lion lion)
+  {
+    lion.Roar();
+  }
+
+  public void VisitMonkey(Monkey monkey)
+  {
+    monkey.Shout();
+  }
+}
+
+class Jump : IAnimalOperation
+{
+  public void VisitDolphin(Dolphin dolphin)
+  {
+    Console.WriteLine("Jumped 20 feet high! on to the tree!");
+  }
+
+  public void VisitLion(Lion lion)
+  {
+    Console.WriteLine("Jumped 7 feet! Back on the ground!");
+  }
+
+  public void VisitMonkey(Monkey monkey)
+  {
+    Console.WriteLine("Walked on water a little and disappeared!");
+  }
+}
+
+
+  class Program
+  {
+    static void Main(string[] args)
+    {
+var monkey = new Monkey();
+var lion = new Lion();
+var dolphin = new Dolphin();
+
+var speak = new Speak();
+
+monkey.Accept(speak);    // Ooh oo aa aa!    
+lion.Accept(speak);      // Roaaar!
+dolphin.Accept(speak);   // Tuut tutt tuutt!
+
+var jump = new Jump();
+
+monkey.Accept(speak);   // Ooh oo aa aa!
+monkey.Accept(jump);    // Jumped 20 feet high! on to the tree!
+
+lion.Accept(speak);     // Roaaar!
+lion.Accept(jump);      // Jumped 7 feet! Back on the ground!
+
+dolphin.Accept(speak);  // Tuut tutt tuutt!
+dolphin.Accept(jump);   // Walked on water a little and disappeared
+
+      Console.ReadLine();
+    }
+  }
+}

VisitorPattern/VisitorPattern.csproj

@@ -0,0 +1,8 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>netcoreapp2.0</TargetFramework>
+  </PropertyGroup>
+
+</Project>