Design Patterns 06 - 装饰模式

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

class ConcreteComponent : Component {
    public override void Operation() {
        // todo
    }
}

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 addedState;

    public override void Opertaion() {
        base.Operation();
        addedState = "New State";
        // todo
    }
}

class ConcreteDecoratorB : Decorator {
    public override void Operation() {
        base.Operation();
        AddedBehavior();
        // todo
    }

    private void AddedBehavior() {
        // todo
    }
}

public static void Main(string[] args) {
    ConcreteComponent concreteComponent = new ConcreteComponent();
    ConcreteDecoratorA concreteDecoratorA = new ConcreteDecoratorA(concreteComponent);
    ConcreteDecoratorB concreteDecoratorB = new ConcreteDecoratorB(concreteDecoratorA);
    concreteDecoratorB.Operation();
}