题目:猫大叫一声,所有的老鼠都开始逃跑,主人被惊醒
要求:1。要有联动性,老鼠和主人的行为是被动的 2。考虑可扩展性,猫的叫声可能引起其他联动效应 两种方法
1 使用观察者模式 public interface Observer { void Response(); //观察者的响应,如是老鼠见到猫的反映 } public interface Subject { void AimAt(Observer obs); //针对哪些观察者,这里指猫的要扑捉的对象---老鼠 } public class Mouse : Observer { private string name; public Mouse(string name, Subject subj) { this.name = name; subj.AimAt(this); } public void Response() { Console.WriteLine(name + " attempt to escape!"); } } public class Master : Observer { public Master(Subject subj) { subj.AimAt(this); } public void Response() { Console.WriteLine("Host waken!"); } } public class Cat : Subject { private ArrayList observers; public Cat() { this.observers = new ArrayList(); } public void AimAt(Observer obs) { this.observers.Add(obs); } public void Cry() { Console.WriteLine("Cat cryed!"); foreach (Observer obs in this.observers) { obs.Response(); } } } class MainClass { static void Main(string[] args) { Cat cat = new Cat(); Mouse mouse1 = new Mouse("mouse1", cat); Mouse mouse2 = new Mouse("mouse2", cat); Master master = new Master(cat); cat.Cry(); } } 2 使用事件 public delegate void SubEventHandler(); public abstract class Subject { public event SubEventHandler SubEvent; protected void FireAway() { if (this.SubEvent != null) this.SubEvent(); } } public class Cat : Subject { public void Cry() { Console.WriteLine("cat cryed."); this.FireAway(); } } public abstract class Observer { public Observer(Subject sub) { sub.SubEvent += new SubEventHandler(Response); } public abstract void Response(); } public class Mouse : Observer { private string name; public Mouse(string name, Subject sub) : base(sub) { this.name = name; } public override void Response() { Console.WriteLine(name + " attempt to escape!"); } } public class Master : Observer { public Master(Subject sub) : base(sub){} public override void Response() { Console.WriteLine("host waken"); } } class Class1 { static void Main(string[] args) { Cat cat = new Cat(); Mouse mouse1 = new Mouse("mouse1", cat); Mouse mouse2 = new Mouse("mouse2", cat); Master master = new Master(cat); cat.Cry(); } } |
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