大話設計-裝飾模式

裝飾模式的核心：被裝飾對象（最原始），裝飾對象（帶有裝飾功能的被裝飾對象）。

假設有一個被裝飾對象叫“ConcreteComponent ”，兩個裝飾對象叫“ConcreteDecoratorA”、“ConcreteDecoratorB”。裝飾是錦上添花的事情，ConcreteComponent 被裝飾之前已經最好了最基本的工作，ConcreteDecoratorA和ConcreteDecoratorB只是在這個基本工作里額外加了些工作。

裝飾是無序的，可以ConcreteDecoratorA先裝飾ConcreteComponent，然後ConcreteDecoratorB裝飾ConcreteDecoratorA。也可以ConcreteDecoratorB先裝飾ConcreteComponent，然後ConcreteDecoratorA裝飾ConcreteDecoratorB。

被裝飾對象和裝飾類是否需要抽象跟這裡的裝飾模式無關。

using System;

namespace ConsoleApp4
{
    class Program
    {
        public static void Main(string[] args)
        {
            ConcreteComponent concreteComponent = new ConcreteComponent();
            ConcreteDecoratorA concreteDecoratorA = new ConcreteDecoratorA();
            ConcreteDecoratorB concreteDecoratorB = new ConcreteDecoratorB();

            concreteDecoratorA.SetComponent(concreteComponent);
            concreteDecoratorB.SetComponent(concreteDecoratorA);
            concreteDecoratorB.Operation();
        }
    }
    
    abstract class Component
    {
        public abstract void Operation();
    }

    class ConcreteComponent:Component
    {
        public override void Operation()
        {
            Console.WriteLine("具體對象的操作");
        }
    }

     abstract class Decorator : Component
    {
        protected Component component;
        public void SetComponent(Component component)
        {
            this.component = component;
        }
        public override void Operation()
        {
            if (component != null)
            {
                component.Operation();
            }
        }
    }

     class ConcreteDecoratorA : Decorator
    {
        private string addState;
        public override void Operation()
        {
            base.Operation();
            addState = "A addState";
            Console.WriteLine("A類裝飾");
        }
    }

    class ConcreteDecoratorB : Decorator
    {
        private string addState;
        public override void Operation()
        {
            base.Operation();
            addState = "B addState";
            Console.WriteLine("B類裝飾");
        }
    }
}

using System;

namespace ConsoleApp4
{
    class Program
    {
        public static void Main(string[] args)
        {            
            Person person = new Person("白石");
            TShirts shirts = new TShirts();
            Overalls overalls = new Overalls();

            shirts.Decorate(person);
            overalls.Decorate(shirts);
        }
    }
    
   class Person
    {
        public Person()
        {

        }
        private string name;
        public Person (string name)
        {
            this.name = name;
        }
        public virtual void Show()
        {
            // 什麼裝飾都沒有的基本展示。
            Console.WriteLine($"{name} 一個人的基本show");
        }
    }

    abstract class Finery : Person
    {
        protected Person component;
        public void Decorate(Person person)
        {
            this.component = person;
        }
        public override void Show()
        {
            if (component != null)
            {
                component.Show();
            }
        }
    }

    class TShirts : Finery
    {
        public override void Show()
        {
            base.Show();
            Console.WriteLine("穿T恤");
        }
    }

    class Overalls : Finery
    {
        public override void Show()
        {
            base.Show();
            Console.WriteLine("工裝褲");
        }
    }
}