C#でのオブジェクト指向学習サンプル9（コードの整理：リファクタリング）

class PurchasedItem
{
    public string BarCode { get; }

    public PurchasedItem(string barCode)
    {
        BarCode = barCode;
    }
}

abstract class Item
{
    public string BarCode { get; set; }
    public string Name { get; set; }
    private int price;

    public int Price
    {
        get => price;
        set => price = value < 0 ? 0 : value;
    }

    public void ShowBaseInfo()
    {
        Console.WriteLine($"{Name}の価格は{Price}円です");
    }

    public abstract void Show();
}

interface IPerishable
{
    DateTime ExpiryDate { get; set; }

    void CheckExpiryDate()
    {
        if (ExpiryDate < DateTime.Now)
        {
            Console.WriteLine("賞味期限が切れています");
            ExpirationDateProcessing();
        }
    }

    void ExpirationDateProcessing();
}

class MeatItem : Item, IPerishable
{
    public DateTime ExpiryDate { get; set; }

    public override void Show()
    {
        ShowBaseInfo();
        Console.WriteLine($"賞味期限 {ExpiryDate}");
    }

    public void ExpirationDateProcessing()
    {
        Console.WriteLine("お肉は生鮮担当が廃棄します");
    }
}

class BookItem : Item
{
    public string Author { get; set; }

    public override void Show()
    {
        ShowBaseInfo();
        Console.WriteLine($"著者 {Author}");
    }
}

class Customer
{
    public string Name { get; }
    public HashSet<PurchasedItem> Items { get; }

    public Customer(string name)
    {
        Name = name;
        Items = new HashSet<PurchasedItem>();
    }

    public void Buy()
    {
        Items.Clear();

        while (true)
        {
            Console.Write("バーコード： ");
            string barCode = Console.ReadLine();

            if (string.IsNullOrWhiteSpace(barCode))
            {
                break;
            }

            Items.Add(new PurchasedItem(barCode));
        }
    }
}

class Reg
{
    private List<Item> items = new List<Item>();

    public Reg()
    {
        RegisterItems();
    }

    private void RegisterItems()
    {
        items.Add(new MeatItem { Name = "鶏肉", BarCode = "1234", Price = 100, ExpiryDate = new DateTime(2023, 5, 10) });
        items.Add(new BookItem { Name = "三四郎", BarCode = "2345", Price = 200, Author = "夏目漱石" });
    }

    public void PrintReceipt(Customer customer)
    {
        Console.WriteLine($"{customer.Name}さんのレシート");
        Console.WriteLine("----------------------------");

        int totalPrice = 0;

        foreach (var purchasedItem in customer.Items)
        {
            var findItem = items.FirstOrDefault(item => item.BarCode == purchasedItem.BarCode);

            if (findItem == null)
            {
                continue;
            }

            findItem.Show();

            if (findItem is IPerishable perishableItem)
            {
                perishableItem.CheckExpiryDate();
            }

            totalPrice += findItem.Price;
        }

        Console.WriteLine("----------------------------");
        Console.WriteLine($"合計金額は{totalPrice}円です");
    }
}

class RegSystem
{
    public void Run()
    {
        Reg reg1 = new Reg();
        Customer customer1 = new Customer("山田");
        customer1.Buy();
        reg1.PrintReceipt(customer1);
    }
}

/*
Customer customer2 = new Customer("森本");
Customer customer3 = new Customer("太田");

// 森本さんが先に購入
customer2.Buy();
// 森本さんがそのまま清算
reg1.PrintReceipt(customer2);
customer3.Buy();

reg1.PrintReceipt(customer3);
*/

RegSystem regSystem = new RegSystem();
regSystem.Run();

@startuml
hide footbox
title 購入処理シーケンス図

participant Customer as C
participant PurchasedItem as PI
participant Reg as R
participant Item as I
participant BookItem as BI
participant MeatItem as MI
participant IPerishable as IP

C->R: RegSystem.Run()
activate R
R->C: new Reg()
activate C

loop 購入処理
    C->C: Buy()
    activate C

    loop 商品選択
        C->C: バーコード入力
    end

    C->C: バーコード入力(空)
    deactivate C

    C->R: PrintReceipt(Customer customer)
    activate R
    R->I: new MeatItem()
    activate I
    I->MI: MeatItemの設定
    activate MI
    MI->IP: CheckExpiryDate()
    activate IP
    IP->MI: ExpirationDateProcessing()
    deactivate IP
    MI->R: Show()
    deactivate MI
    R->C: 商品情報表示
    deactivate I

    R->I: new BookItem()
    activate I
    I->BI: BookItemの設定
    activate BI
    BI->R: Show()
    deactivate BI
    R->C: 商品情報表示
    deactivate I

    R->C: 合計金額表示
    deactivate R
end
@enduml

@startuml

actor Customer

Customer -> Reg : Buy()
Reg -> PurchasedItem : PurchasedItem(barCode)
Reg --> Customer : add item to items

activate Reg

loop
  Customer -> PurchasedItem : PurchasedItem(barCode)
  PurchasedItem -> Item : constructor(barCode)
  note over Item : Item creation
  Item -> MeatItem : constructor(name, barCode, Price, ExpiryDate)
  note over MeatItem : MeatItem creation
end

Customer --> Reg : Done (empty input)

Reg -> Reg : PrintReceipt(Customer)
activate Reg

Reg -> Customer : Print receipt header
Reg -> Customer : Get items
Customer --> Reg : items

loop for each item in items
  Reg -> Item : Show()
  Item --> Reg : ShowBaseInfo()
  note over Item : ShowBaseInfo call
  Reg -> Item : ExpiryDate
  alt item is IPerishable
    Item -> MeatItem : ExpirationDateProcessing()
    note over MeatItem : ExpirationDateProcessing call
  end
end

Reg -> Customer : Print total price
deactivate Reg

@enduml

@startuml

actor Customer

Customer -> Reg : Buy()
Reg -> PurchasedItem : PurchasedItem(barCode)
Reg --> Customer : add item to items

activate Reg

loop
  Customer -> PurchasedItem : PurchasedItem(barCode)
  PurchasedItem -> Item : constructor(barCode)
  note over Item : Item creation
  Item -> MeatItem : constructor(name, barCode, Price, ExpiryDate)
  note over MeatItem : MeatItem creation
end

Customer --> Reg : Done (empty input)

Reg -> Reg : PrintReceipt(Customer)
activate Reg

Reg -> Customer : Print receipt header
Reg -> Customer : Get items
Customer --> Reg : items

loop for each item in items
  Reg -> Item : Show()
  Item --> Reg : ShowBaseInfo()
  note over Item : ShowBaseInfo call
  Reg -> Item : ExpiryDate
  alt item is IPerishable
    Item -> MeatItem : ExpirationDateProcessing()
    note over MeatItem : ExpirationDateProcessing call
  end
end

Reg -> Customer : Print total price
deactivate Reg

@enduml

@startuml

class Program{
    -Main()
}

class Customer {
    +Name: string <<get;>>
    +items: List<PurchasedItem> <<get;>>
    +Customer(name: string)
    +Buy()
}

abstract class Item {
    + BarCode : string <<tet; set;>>
    + Name : string <<get;set;>>
    - price : int
    + Price : int <<get>> <<set>>
    + ShowBaseInfo() : void
    + {abstract} Show() : void
}

class MeatItem {
    + ExpiryDate : string <<get>> <<set>>
    + <<override>> Show() : void
    + ExpirationDateProcessing() : void
}

class BookItem {
    + Auther : string <<get;set;>>
    + <<override>> Show() : void
}

class PurchasedItem {
    +BarCode: string <<get;>>
    +PurchasedItem(barCode: string)
}

class Reg {
    -items: List<Item>
    +Reg()
    +RegisterItems() : void
    +PrintReceipt(customer: Customer)
}

interface IPerishable {
    +ExpiryDate : DateTime <<get>> <<set>>
    +CheckExpiryDate() : void
    +{abstract}ExpirationDateProcessing() : void
}

class RegSystem {
    +Run()
}

IPerishable <|.. MeatItem : < implementation

Customer --> PurchasedItem : has 1..* >
Reg --> Item : has 1..* >
Program --> RegSystem : creates >
RegSystem --> Customer : create >
RegSystem --> Reg : creates >
RegSystem --> Customer : uses >
RegSystem --> Reg : uses >
Item <|-- BookItem : < inheritance
Item <|-- MeatItem : < inheritance
@enduml