设计模式笔记之 观察者模式

 

代码：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ObserverPattern
{
    class Program
    {
        static Subject subject=new Subject();//一个被观察者


        static void Main(string[] args)
        {
            ObserverDispalyInfor oneObserverDisplayInfor = new ObserverDispalyInfor();
            ObserverForecast oneObserverForecast = new ObserverForecast();

            subject.RegisterObserver(oneObserverDisplayInfor);//布告观察者注册
            subject.RegisterObserver(oneObserverForecast);//天气预报观察者注册

            subject.GetChange(12, 23, 34);

            subject.RemoveRegisterObserver(oneObserverDisplayInfor);//布告观察者离开了

            subject.GetChange(12, 23, 666);

           

        }
    }

    /// <summary>
    /// 被观察者接口
    /// </summary>
    public interface ISubject
    {
        void RegisterObserver(IObserver observer);
        void RemoveRegisterObserver(IObserver observer);
        void Notify();
    }

    /// <summary>
    /// 观察者接口
    /// </summary>
    public interface IObserver
    {
        void Updata(int temperature,int humidity,int pressure);
    }

    /// <summary>
    /// 布告板的显示动作接口
    /// </summary>
    public interface IDisplay
    {
        void DisPlay();
    }

    
    /// <summary>
    /// 被观察者类
    /// </summary>
    public class Subject
    {
        List<IObserver> observerList;

        private int temperature;
        private int humidity;
        private int pressure;

        
        public Subject()
        {
            this.observerList = new List<IObserver>(); 
        }

        /// <summary>
        /// 注册一个观察者
        /// </summary>
        /// <param name="observer"></param>
        public void RegisterObserver(IObserver observer)
        {
            this.observerList.Add(observer);
            Console.Write(observer.ToString() + "注册了,热烈欢迎\r\n");
            Console.Read();
            Console.Read();
        }

        /// <summary>
        /// 去掉一个注册者
        /// </summary>
        /// <param name="observer"></param>
        public void RemoveRegisterObserver(IObserver observer)
        {
            foreach (IObserver oneObserver in this.observerList)
            {
                if (oneObserver == observer)
                {
                    this.observerList.Remove(observer);
                    Console.Write(observer.ToString() + "走了，希望以后还有合作的机会\r\n");
                    Console.Read();
                    Console.Read();
                    break;
                }
            }
        }

        /// <summary>
        /// 通知观察者方法
        /// </summary>
        public void Notify()
        {
            Console.Write("参数发生了变化，我要通知给观察者\r\n");
            Console.Read();
            Console.Read();

            foreach (IObserver oneObserver in this.observerList)
            {
                oneObserver.Updata(this.temperature,this.humidity,this.pressure);
            }
        }

        /// <summary>
        /// 改变状态
        /// </summary>
        public void GetChange(int temperature,int humidity,int pressure)
        {
            this.temperature = temperature;
            this.humidity = humidity;
            this.pressure = pressure;

            
            this.Notify();//通知观察者
        }

        
    }

    /// <summary>
    /// 布告观察者
    /// </summary>
    public class ObserverDispalyInfor:IObserver,IDisplay
    {
        private int temperature;
        private int humidity;
        private int pressrue;

        private DateTime notifyTime;

        public ObserverDispalyInfor()
        {
            this.notifyTime = new DateTime();
        }



        public void Updata(int temperature, int humidity, int pressure)
        {
            this.temperature = temperature;
            this.humidity = humidity;
            this.pressrue = pressure;

            this.notifyTime = DateTime.Now;

            this.DisPlay();
        }

        public void DisPlay()
        {
            Console.Write("----" + this.ToString() + "接受到了新消息-----\r\n");

            System.Console.Write("气象部门" + this.notifyTime.ToString() + "发布的消息\r\n"
                                  +"温度："+this.temperature.ToString()
                                  +"\r\n湿度："+this.humidity.ToString()
                                  +"\r\n压力:"+this.pressrue.ToString());

            Console.Read();
            Console.Read();

        }
    }

    /// <summary>
    /// 天气预报观察者
    /// </summary>
    public class ObserverForecast : IObserver, IDisplay
    {
        private int temperature;
        private int humidity;
        private int pressrue;
        private bool rain;
        



        public void Updata(int temperature, int humidity, int pressure)
        {
            this.temperature = temperature;
            this.humidity = humidity;
            this.pressrue = pressure;

            this.DisPlay();

        }

        /// <summary>
        /// 天气预报观察者利用被观察者通知得到的信息计算出是不是要下雨
        /// </summary>
        private void Calculate()
        {
            if (this.temperature + this.humidity + this.pressrue > 100)
            {
                this.rain = true;
            }
            else
            {
                this.rain = false;
            }
        }

        public void DisPlay()
        {
            this.Calculate();

            string temp = string.Empty;
            if (this.rain)
            {
                temp = "下雨了，打雷收衣服啊\r\n";
            }
            else
            {
                temp = "今天天气不错，风和日丽的\r\n";
            }
            Console.Write("----"+this.ToString() + "接受到了新消息-----\r\n");
            System.Console.Write(temp);
            Console.Read();
            Console.Read();

        }
    }
}

 

运行后：