{C#}设计模式辨析.建造者

背景

• 已定型步骤中，由director提取部分步骤并预制成多种产品
• 与模板的异同
  • 建造者时，负责人通知建造者完成多种步骤组合(预制品)
  • 模板时，步骤组合(产品)是唯一的，参考https://www.jianshu.com/p/0c4b97466142

示例

using static System.Console;

namespace DesignPattern_Builder
{
    public interface ICakeBuilder
    {
        void SetSize(bool big);
        void AddEggs(int amount);
        void AddVegitable(string name);
        void AddSauce(bool sweet);
    }

    // 主厨，相当于Builder
    public class Chef: ICakeBuilder
    {
        public void AddEggs(int amount)
            => WriteLine($"{amount} eggs {(amount > 1 ? "are" : "is")} added.");

        public void AddSauce(bool sweet)
            => WriteLine($"{(sweet ? "Sweet" : "Spicy")} sauce is added.");

        public void AddVegitable(string name)
            => WriteLine($"{name} is added.");

        public void SetSize(bool big)
            => WriteLine($"A {(big ? "big" : "small")} size of cake is set.");
    }

    // 服务员，相当于Director
    public class Waitor
    {
        // 允许多名建造者
        private readonly ICakeBuilder chef;

        public Director(ICakeBuilder chef)
        {
            this.chef= chef;
        }

        // 步骤需求不由建造者决定，在本类中预制产品，下同
        // 全套步骤
        public void CookNormal()
        {
            WriteLine();
            chef.SetSize(false);
            chef.AddEggs(1);
            chef.AddVegitable("Green onion");
            chef.AddSauce(true);

            ReadKey();
        }

        // 部分步骤
        public void CookSpicical()
        {
            WriteLine();
            chef.SetSize(true);  
            chef.AddEggs(2);  
            chef.AddSauce(false);  

            ReadKey();
        }
    }

    public class Client
    {
        public void Execute()
        {
            var builder= new Chef();
            var director= new Waitor(builder);
            director.CookNormal();
            director.CookSpicical();
        }
    }
    
    class Demo
    {
        static void Main(string[] args)
        {
            var client = new Client();
            client.Execute();
        }
    }
}