템플릿 메소드 패턴

Template method pattern

public abstract class Prepare
{
    public abstract void PrepareRecipe();
}

public abstract class CaffeineBeverage : Prepare
{
    public sealed override void PrepareRecipe()
    {
        BoilWater();
        Brew();
        PourInCup();
        if(CustomerWantsCondiments())
            AddCondiments();
    }
    public abstract void Brew();
    public abstract void AddCondiments();
    public void BoilWater() { Console.WriteLine("Boiling water"); }
    public void PourInCup() { Console.WriteLine("Pouring into cup"); }
    public virtual bool CustomerWantsCondiments() { /*Hook*/ return true; }
}

public class Espresso : CaffeineBeverage
{
    public override void Brew() { Console.WriteLine("Dripping Coffee through filter"); }
    public override void AddCondiments() { Console.WriteLine("Adding Sugar and Milk"); }

    public override bool CustomerWantsCondiments()
    {
        string input = GetInput();
        try
        {
            if (input == "yes") return true;
            else if (input == "no") return false;
            else throw new ArgumentException();
        }
        catch (ArgumentException)
        {
            Console.WriteLine("Invalid input");
            return CustomerWantsCondiments();
        }
    }
    
    private string GetInput()
    {
        Console.WriteLine("Do you want milk and sugar with your espresso?");
        Console.WriteLine("Enter yes or no");
        string input;
        try
        {
            var s = Console.ReadLine();
            if (s != "yes" && s != "no")
                throw new ArgumentException();
            else input = s;
        }
        catch (ArgumentException)
        {
            Console.WriteLine("Invalid input");
            return GetInput();
        }
        
        return input;
    }
}

public class HouseBlend : CaffeineBeverage
{
    public override void Brew() { Console.WriteLine("Stirring beans"); }
    public override void AddCondiments() { Console.WriteLine("Adding kakao syrup"); }
}

public class Test
{
    public static void Main(string[] args)
    {
        var beverage = new Espresso();
        Console.WriteLine("Preparing Espresso...");
        beverage.PrepareRecipe();
    }
}