Factory pattern

Author: Abhishek Kumar Singh

DesignPatterns.csproj

@@ -33,7 +33,7 @@
     <WarningLevel>4</WarningLevel>
   </PropertyGroup>
   <PropertyGroup>
-    <StartupObject>DesignPatterns.Adapter.Program</StartupObject>
+    <StartupObject>DesignPatterns.Factory.Program</StartupObject>
   </PropertyGroup>
   <ItemGroup>
     <Reference Include="System" />
@@ -54,6 +54,9 @@
     <Compile Include="Adapter\Program.cs" />
     <Compile Include="Adapter\ThirdPartyLogger.cs" />
     <Compile Include="Factory.cs" />
+    <Compile Include="Factory\VehicleFactory.cs" />
+    <Compile Include="Factory\Vehicle.cs" />
+    <Compile Include="Factory\Program.cs" />
     <Compile Include="Program.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="Singleton\Program.cs" />

Factory/Program.cs

@@ -0,0 +1,32 @@
+namespace DesignPatterns.Factory
+{
+    internal class Program
+    {
+        static void Main(string[] args)
+        {
+            // Normally without any pattern, we might do something like the below one,
+            // The client code directly depends on concrete classes(Car, Bike, Truck)
+
+            //Car car = new Car();
+            //car.Drive();
+
+            //Bike bike = new Bike();
+            //bike.Drive();
+
+            //Truck truck = new Truck();
+            //truck.Drive();
+
+
+            // Client uses Factory instead of new, and only knows about IVehicle, not about concrete classes
+
+            IVehicle car = VehicleFactory.GetVehicle("car");
+            car.Drive();
+
+            IVehicle bike = VehicleFactory.GetVehicle("bike");
+            bike.Drive();
+
+            IVehicle truck = VehicleFactory.GetVehicle("truck");
+            truck.Drive();
+        }
+    }
+}

Factory/Vehicle.cs

@@ -0,0 +1,31 @@
+using System;
+
+namespace DesignPatterns.Factory
+{
+    // My Product
+    interface IVehicle
+    {
+        void Drive();
+    }
+    internal class Car : IVehicle
+    {
+        public void Drive()
+        {
+            Console.WriteLine("Driving Car...");
+        }
+    }
+    internal class Bike : IVehicle
+    {
+        public void Drive()
+        {
+            Console.WriteLine("Driving Bike...");
+        }
+    }
+    internal class Truck : IVehicle
+    {
+        public void Drive()
+        {
+            Console.WriteLine("Driving Truck...");
+        }
+    }
+}

Factory/VehicleFactory.cs

@@ -0,0 +1,26 @@
+namespace DesignPatterns.Factory
+{
+    //  Factory manages object creation logic in one place,
+    //  So the client code depends only on an interface/abstract class, not on concrete implementations.
+    internal class VehicleFactory
+    {
+        public static IVehicle GetVehicle(string type)
+        {
+            IVehicle vehicle;
+
+            switch(type.ToUpper())
+            {
+                case "CAR":
+                    vehicle = new Car();
+                    break;
+                case "BIKE":
+                    vehicle = new Bike();
+                    break;
+                default:
+                    vehicle = new Truck();
+                    break;
+            }
+            return vehicle;
+        }
+    }
+}