浅尝DesignPattern_Decorator

UML:

Component:定义一个对象接口,可以给这些对象动态的添加职责

ContreteComponent:定义了一个具体的对象,也可以给这个对象添加一些职责

Decorator:装饰抽象类,继承了Component,从外类来扩展Component类的功能,但对于Component来说,是无需知道Decrator的存在的

ContreteDecoratorA和ContreteDecoratorB都是具体的装饰对象,骑到给Component添加职责的功能

SAMPLE:

Component.cs

    abstract class Component
    {
        public abstract void Operation();
    }

ConcreteComponent.cs

    class ConcreteComponent:Component
    {
        public override void Operation()
        {
            Console.WriteLine("具体对象的操作");
        }
    }

Decorator.cs

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

ConcreteDecoratorA.cs

    class ConcreteDecoratorA : Decorator
    {
        private string addedState;
        public override void Operation()
        {
            base.Operation();
            addedState = "new state";
            Console.WriteLine("具体装饰对象A的操作");
        }
    }

ConcreteDecoratorB.cs

    class ConcreteDecoratorB:Decorator
    {
        public override void Operation()
        {
            base.Operation();
            addMethod();
            Console.WriteLine("具体装饰对象B的操作");
        }
        //用来区别A方法
        private void addMethod()
        { }
    }

Program.cs

            ConcreteComponent c = new ConcreteComponent();
            ConcreteDecoratorA d1 = new ConcreteDecoratorA();
            ConcreteDecoratorB d2 = new ConcreteDecoratorB();

            d1.setComponent(c);
            d2.setComponent(d2);
            d2.Operation();

装饰模式是利用setComponent来对付对象进行包装的.这样每个装饰独享的实现就和如何使用这个对象分离开了,每个装饰对象只关心自己的功能,不需要关心如何被添加到对象链当中.