Design Patterns 24 - 职责链模式

abstract class Handler {
    protected Handler successor;

    public void SetSuccessor(Handler successor) {
        this.successor = successor;
    }

    public abstract void HandlerRequest(int request);
}

class ConcreteHandler1 : Handler {
    public override void HandlerRequest(int request) {
        if(request >= 0 && request < 10) {
            // todo
        }
        else if(successor != null) {
            successor.HandlerRequest(request);
        }
    }
}

class ConcreteHandler2 : Handler {
    public override void HandlerRequest(int request) {
        if(request >= 10 && request < 20) {
            // todo
        }
        else if(successor != null) {
            successor.HandlerRequest(request);
        }
    }
}

public void Main(string[] agrs) {
    Handler handler1 = new ConcreteHandler1();
    Handler handler2 = new ConcreteHandler2();
    handler1.SetSuccessor(handler2);

    int[] requests = {2, 5, 14, 19};

    foreach(int request in requests) {
        handler1.HandlerRequest(request);
    }
}