state pattern (vending machine example)

DesignPattern/DesignPattern.sln

@@ -41,6 +41,8 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Template", "Template\Templa
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "State", "State\State.csproj", "{008D8C56-8546-4EB1-83C6-68FAF2051895}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "State-VendingMachineExample", "State-VendingMachineExample\State-VendingMachineExample.csproj", "{ED14B6E2-04BB-4F77-80E7-C5F0E945B750}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -123,6 +125,10 @@ Global
 		{008D8C56-8546-4EB1-83C6-68FAF2051895}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{008D8C56-8546-4EB1-83C6-68FAF2051895}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{008D8C56-8546-4EB1-83C6-68FAF2051895}.Release|Any CPU.Build.0 = Release|Any CPU
+		{ED14B6E2-04BB-4F77-80E7-C5F0E945B750}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{ED14B6E2-04BB-4F77-80E7-C5F0E945B750}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{ED14B6E2-04BB-4F77-80E7-C5F0E945B750}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{ED14B6E2-04BB-4F77-80E7-C5F0E945B750}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE

DesignPattern/State-VendingMachineExample/App.config

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<configuration>
+    <startup> 
+        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.8.1" />
+    </startup>
+</configuration>

DesignPattern/State-VendingMachineExample/Client.cs

@@ -0,0 +1,21 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace State_VendingMachineExample
+{
+    internal class Client
+    {
+        public static void HowToTest()
+        {
+            VendingMachine vm = new VendingMachine();
+            vm.AddMoney(1);
+            vm.AddMoney(1);
+            vm.AddMoney(1);
+            vm.AddMoney(1);
+            vm.SelectItem(101);
+        }
+    }
+}

DesignPattern/State-VendingMachineExample/DispenseChangeState.cs

@@ -0,0 +1,38 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace State_VendingMachineExample
+{
+    internal class DispenseChangeState : VMState
+    {
+        public DispenseChangeState(VendingMachine context)
+        {
+            vendingMachine = context;
+        }
+
+        public override void AddMoney(decimal money)
+        {
+            throw new ApplicationException();
+        }
+
+        public override void ReturnChange(decimal money)
+        {
+            // Return charge here
+            if (vendingMachine.Money > 0)
+            {
+                Console.WriteLine($"Return charge ${money}");
+                vendingMachine.Money -= money;
+            }
+
+            vendingMachine.State = vendingMachine.ReadyState;
+        }
+
+        public override void SelectItem(int itemId)
+        {
+            throw new ApplicationException();
+        }
+    }
+}

DesignPattern/State-VendingMachineExample/DispenseItemState.cs

@@ -0,0 +1,39 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace State_VendingMachineExample
+{
+    internal class DispenseItemState : VMState
+    {
+        public DispenseItemState(VendingMachine context)
+        {
+            vendingMachine = context;
+        }
+
+        public override void AddMoney(decimal money)
+        {
+            throw new ApplicationException();
+        }
+
+        public override void ReturnChange(decimal money)
+        {
+            throw new ApplicationException();
+        }
+
+        public override void SelectItem(int itemId)
+        {
+            decimal? price = vendingMachine.GetPrice(itemId).Value;
+
+            // Dispense item here
+            Console.WriteLine($"Dispense Item#{itemId} ({price.Value})");
+
+            vendingMachine.Money -= price.Value;
+
+            vendingMachine.State = vendingMachine.DispenseChangeState;
+            vendingMachine.State.ReturnChange(vendingMachine.Money);
+        }
+    }
+}

DesignPattern/State-VendingMachineExample/HasMoneyState.cs

@@ -0,0 +1,46 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace State_VendingMachineExample
+{
+    internal class HasMoneyState : VMState
+    {
+        public HasMoneyState(VendingMachine context)
+        {
+            vendingMachine = context;
+        }
+
+        public override void AddMoney(decimal money)
+        {
+            vendingMachine.Money += money;
+            Console.WriteLine($"Add ${money}, Balance: {vendingMachine.Money}");
+        }
+
+        public override void ReturnChange(decimal money)
+        {
+            throw new ApplicationException();
+        }
+
+        public override void SelectItem(int itemId)
+        {
+            decimal? price = vendingMachine.GetPrice(itemId).Value;
+            if (!price.HasValue)
+            {
+                Console.WriteLine($"{itemId} not found");
+                return;
+            }
+
+            if (vendingMachine.Money < price.Value)
+            {
+                Console.WriteLine("Insufficient money");
+                return;
+            }
+
+            vendingMachine.State = vendingMachine.DispenseItemState;
+            vendingMachine.State.SelectItem(itemId);
+        }
+    }
+}

DesignPattern/State-VendingMachineExample/Product.cs

@@ -0,0 +1,36 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace State_VendingMachineExample
+{
+    internal class Product
+    {
+        private List<Item> items;
+
+        public Product()
+        {
+            items = new List<Item>()
+            {
+                new Item() { Id = 101, Price = 3.50M },
+                new Item() { Id = 201, Price = 4.50M },
+                new Item() { Id = 301, Price = 4.50M }
+            };
+        }
+
+        public decimal? GetPrice(int itemId)
+        {
+            Item item = items.SingleOrDefault(x => x.Id == itemId);
+
+            return item == null ? null : (decimal?)item.Price;
+        }
+
+        private class Item
+        {
+            public int Id { get; set; }
+            public decimal Price { get; set; }
+        }
+    }
+}

DesignPattern/State-VendingMachineExample/Program.cs

@@ -0,0 +1,18 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace State_VendingMachineExample
+{
+    internal class Program
+    {
+        static void Main(string[] args)
+        {
+            Client.HowToTest();
+
+            Console.ReadKey();
+        }
+    }
+}

DesignPattern/State-VendingMachineExample/Properties/AssemblyInfo.cs

@@ -0,0 +1,36 @@
+using System.Reflection;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+
+// 어셈블리에 대한 일반 정보는 다음 특성 집합을 통해 
+// 제어됩니다. 어셈블리와 관련된 정보를 수정하려면
+// 이러한 특성 값을 변경하세요.
+[assembly: AssemblyTitle("State-VendingMachineExample")]
+[assembly: AssemblyDescription("")]
+[assembly: AssemblyConfiguration("")]
+[assembly: AssemblyCompany("")]
+[assembly: AssemblyProduct("State-VendingMachineExample")]
+[assembly: AssemblyCopyright("Copyright ©  2022")]
+[assembly: AssemblyTrademark("")]
+[assembly: AssemblyCulture("")]
+
+// ComVisible을 false로 설정하면 이 어셈블리의 형식이 COM 구성 요소에 
+// 표시되지 않습니다. COM에서 이 어셈블리의 형식에 액세스하려면
+// 해당 형식에 대해 ComVisible 특성을 true로 설정하세요.
+[assembly: ComVisible(false)]
+
+// 이 프로젝트가 COM에 노출되는 경우 다음 GUID는 typelib의 ID를 나타냅니다.
+[assembly: Guid("ed14b6e2-04bb-4f77-80e7-c5f0e945b750")]
+
+// 어셈블리의 버전 정보는 다음 네 가지 값으로 구성됩니다.
+//
+//      주 버전
+//      부 버전 
+//      빌드 번호
+//      수정 버전
+//
+// 모든 값을 지정하거나 아래와 같이 '*'를 사용하여 빌드 번호 및 수정 번호를
+// 기본값으로 할 수 있습니다.
+// [assembly: AssemblyVersion("1.0.*")]
+[assembly: AssemblyVersion("1.0.0.0")]
+[assembly: AssemblyFileVersion("1.0.0.0")]

DesignPattern/State-VendingMachineExample/ReadyState.cs

@@ -0,0 +1,33 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace State_VendingMachineExample
+{
+    // Concrete State
+    internal class ReadyState : VMState
+    {
+        public ReadyState(VendingMachine context)
+        {
+            vendingMachine = context;
+        }
+
+        public override void AddMoney(decimal money)
+        {
+            vendingMachine.State = vendingMachine.HasMoneyState;
+            vendingMachine.State.AddMoney(money);
+        }
+
+        public override void ReturnChange(decimal money)
+        {
+            throw new ApplicationException();
+        }
+
+        public override void SelectItem(int itemId)
+        {
+            throw new ApplicationException();
+        }
+    }
+}

DesignPattern/State-VendingMachineExample/State-VendingMachineExample.csproj

@@ -0,0 +1,61 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
+  <PropertyGroup>
+    <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
+    <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
+    <ProjectGuid>{ED14B6E2-04BB-4F77-80E7-C5F0E945B750}</ProjectGuid>
+    <OutputType>Exe</OutputType>
+    <RootNamespace>State_VendingMachineExample</RootNamespace>
+    <AssemblyName>State-VendingMachineExample</AssemblyName>
+    <TargetFrameworkVersion>v4.8.1</TargetFrameworkVersion>
+    <FileAlignment>512</FileAlignment>
+    <AutoGenerateBindingRedirects>true</AutoGenerateBindingRedirects>
+    <Deterministic>true</Deterministic>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
+    <PlatformTarget>AnyCPU</PlatformTarget>
+    <DebugSymbols>true</DebugSymbols>
+    <DebugType>full</DebugType>
+    <Optimize>false</Optimize>
+    <OutputPath>bin\Debug\</OutputPath>
+    <DefineConstants>DEBUG;TRACE</DefineConstants>
+    <ErrorReport>prompt</ErrorReport>
+    <WarningLevel>4</WarningLevel>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
+    <PlatformTarget>AnyCPU</PlatformTarget>
+    <DebugType>pdbonly</DebugType>
+    <Optimize>true</Optimize>
+    <OutputPath>bin\Release\</OutputPath>
+    <DefineConstants>TRACE</DefineConstants>
+    <ErrorReport>prompt</ErrorReport>
+    <WarningLevel>4</WarningLevel>
+  </PropertyGroup>
+  <ItemGroup>
+    <Reference Include="System" />
+    <Reference Include="System.Core" />
+    <Reference Include="System.Xml.Linq" />
+    <Reference Include="System.Data.DataSetExtensions" />
+    <Reference Include="Microsoft.CSharp" />
+    <Reference Include="System.Data" />
+    <Reference Include="System.Net.Http" />
+    <Reference Include="System.Xml" />
+  </ItemGroup>
+  <ItemGroup>
+    <Compile Include="Client.cs" />
+    <Compile Include="DispenseChangeState.cs" />
+    <Compile Include="DispenseItemState.cs" />
+    <Compile Include="HasMoneyState.cs" />
+    <Compile Include="Product.cs" />
+    <Compile Include="Program.cs" />
+    <Compile Include="Properties\AssemblyInfo.cs" />
+    <Compile Include="ReadyState.cs" />
+    <Compile Include="VendingMachine.cs" />
+    <Compile Include="VMState.cs" />
+  </ItemGroup>
+  <ItemGroup>
+    <None Include="App.config" />
+  </ItemGroup>
+  <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
+</Project>

DesignPattern/State-VendingMachineExample/VMState.cs

@@ -0,0 +1,17 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace State_VendingMachineExample
+{
+    // State 인터페이스
+    internal abstract class VMState
+    {
+        protected VendingMachine vendingMachine;
+        public abstract void AddMoney(decimal money);
+        public abstract void SelectItem(int itemId);
+        public abstract void ReturnChange(decimal money);
+    }
+}

DesignPattern/State-VendingMachineExample/VendingMachine.cs

@@ -0,0 +1,47 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace State_VendingMachineExample
+{
+    // Context
+    internal class VendingMachine
+    {
+        private Product product = new Product();
+        internal decimal Money { get; set; }
+
+        internal VMState State { get; set; }
+
+        internal VMState ReadyState { get; private set; } 
+        internal VMState HasMoneyState { get; private set; } 
+        internal VMState DispenseItemState { get; private set; } 
+        internal VMState DispenseChangeState { get; private set; } 
+
+        public VendingMachine()
+        {
+            this.Money = 0;
+            this.ReadyState = new ReadyState(this);
+            this.HasMoneyState = new HasMoneyState(this);
+            this.DispenseItemState = new DispenseItemState(this);
+            this.DispenseChangeState = new DispenseChangeState(this);
+            this.State = this.ReadyState;
+        }
+
+        public void AddMoney(decimal money)
+        {
+            this.State.AddMoney(money);
+        }
+
+        public void SelectItem(int itemId)
+        {
+            this.State.SelectItem(itemId);
+        }
+
+        internal decimal? GetPrice(int itemId)
+        {
+            return product.GetPrice(itemId);
+        }
+    }
+}