static void Main(string[] args)
{
WeatherData weatherData = new WeatherData();
CurrentConditionsDisplay ccd = new CurrentConditionsDisplay(weatherData);
ForecastDisplay fd = new ForecastDisplay(weatherData);
StatisticsDisplay sd = new StatisticsDisplay(weatherData);
ThirdPartyDisplay tpd = new ThirdPartyDisplay(weatherData);
weatherData.SetMeasurements(15, 75, 30);
weatherData.SetMeasurements(18, 80, 31.2);
weatherData.SetMeasurements(18, 75, 32.8);
Console.ReadKey(true);
}
static void Main()
{
WeatherData wd = new WeatherData();
CurrentConditionsDisplay ccd = new CurrentConditionsDisplay(wd);
StatisticsDisplay sd = new StatisticsDisplay(wd);
HeatIndexDisplay hid = new HeatIndexDisplay(wd);
wd.SetMeasurements(78, 90, 29.2f);
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
Application.Run(new Form1());
}
static void Main()
{
// First example
ConcreteSubject s = new ConcreteSubject();
s.Attach(new ConcreteObserver(s, "x"));
s.Attach(new ConcreteObserver(s, "y"));
s.Attach(new ConcreteObserver(s, "z"));
s.SubjectState = "abc";
s.Notify();
IBM ibm = new IBM("IBM", 120.00);
ibm.Attach(new Investor("Sorros"));
ibm.Attach(new Investor("Berkshire"));
ibm.Price = 120.10;
ibm.Price = 121.00;
ibm.Price = 120.50;
ibm.Price = 120.75;
ibm.Notify();
// Second example
BaggageHandler provider = new BaggageHandler();
ArrivalsMonitor observer1 = new ArrivalsMonitor("BaggageClaimMonitor1");
ArrivalsMonitor observer2 = new ArrivalsMonitor("SecurityExit");
provider.BaggageStatus(712, "Detroit", 3);
observer1.Subscribe(provider);
provider.BaggageStatus(712, "Kalamazoo", 3);
provider.BaggageStatus(400, "New York-Kennedy", 1);
provider.BaggageStatus(712, "Detroit", 3);
observer2.Subscribe(provider);
provider.BaggageStatus(511, "San Francisco", 2);
provider.BaggageStatus(712);
observer2.Unsubscribe();
provider.BaggageStatus(400);
provider.LastBaggageClaimed();
// Third example
var weatherData = new WeatherData();
var forecastDisplay = new ForecastDisplay(weatherData);
var heatIndexDisplay = new HeatIndexDisplay(weatherData);
weatherData.setMeasurements(80, 65, 30.4f);
}
static void Main(string[] args)
{
var weather = new WeatherData();
var observer = new CurrentConditionsDisplay(weather);
//其他观察者
//
weather.setMeasurements(3, 4, 6);
Console.ReadKey();
}
public ComputerDevice(WeatherData weatherdata)
{
this.weatherdata = weatherdata;
this.weatherdata.AddObserver(this);
}
public StatisticsDisplay(WeatherData weatherData) //pull observer
{
this.weatherData = weatherData;
}
public ForecastDisplay(WeatherData weatherData)
{
this.weatherData = weatherData;
currentPressure = 29.2f;
weatherData.registerObserver(this);
}
public HeatIndexDisplay(WeatherData weatherData)
{
this.weatherData = weatherData;
heatIndex = 0.0f;
weatherData.registerObserver(this);
}
static void Main(string[] args)
{
/*
* The Observer Pattern
*
* Example:
* A publisher creates a new magazine and begins publishing issues.
* You subscribve and receive issues as along as you stay subscribed.
* You can unsubscribe at any time.
* Others can also subscribe.
* Other can also unsubscribe.
* If Publisher ceases business, you stop receiving issues.
*
* Allows:
* -Subjests and Observers are "loosely coupled"
* -Strive for loosely coupled designs between objects that interact. (Design Principle #4)
*
* Implementation (Push):
*
* We define 3 interfaces:
* -ISubject (implemented by publisher, stores the list of subscribers, notifies on updates)
* -IObserver (implemented by subscriber, update method)
* -IDisplayElement (implemented by subscriber, display method)
*
* We define main class WatherData:
* -WatherData that implements ISubject
* -Notifies observers(subscribers) though method Update()
* -This doesn't know anything about observers
* -Subject doesn't care it keeps doing its job
*
* We define subscriber classes:
* -Each implements interfaces IObserver and IDisplayElement just to display info
* -Each receives Subject(Publisher) in constructor, subscribes itself to it, and keeps it in private field
* -To become an observer it needs to implement IObserver
*
*/
//create concrete subject(publisher)
WeatherData weatherData = new WeatherData();
//create Observer(subscriber) and register with Subject(publisher)
CurrentConditionsDisplay currentConditions = new CurrentConditionsDisplay(weatherData); //subscribe in constructor of observer(subscriber), PUSH subscription
//create more Observers(subscribers)
weatherData.RegisterObserver(new StatisticsDisplay(weatherData)); //subscribe in method of subject(publisher), PULL subscription
ForecastDisplay forecastDisplay = new ForecastDisplay(weatherData);
//refresh data at Subject(publisher), simulate new data from sensors
weatherData.SetMeasurements(new Data()
{
Temp = 80,
Humidity = 65,
Pressure = 29.2
});
weatherData.SetMeasurements(new Data()
{
Temp = 82,
Humidity = 70,
Pressure = 30.4
});
weatherData.SetMeasurements(new Data()
{
Temp = 78,
Humidity = 90,
Pressure = 29.4
});
Console.ReadLine();
}
public Forecast(WeatherData newWeatherData)
{
this.weatherData = newWeatherData;
this.weatherData.ChangeEvent += new WeatherData.ChangeHandler(Update);
}
public Statistics(WeatherData newWeatherData)
{
this.weatherData = newWeatherData;
this.weatherData.ChangeEvent += new WeatherData.ChangeHandler(Update);
}
public Piano(WeatherData newWeatherData)
{
this.weatherData = newWeatherData;
this.weatherData.ChangeEvent += new WeatherData.ChangeHandler(Update);
}
public CurrentConditions(WeatherData newWeatherData)
{
this.weatherData = newWeatherData;
this.weatherData.ChangeEvent += new WeatherData.ChangeHandler(Update);
}
public MobileDevice(WeatherData weatherdata)
{
this.weatherdata = weatherdata;
this.weatherdata.AddObserver(this);
}
public SomeAnotherDevice(WeatherData weatherdata)
{
this.weatherdata = weatherdata;
this.weatherdata.AddObserver(this);
}
public StatisticsDisplay(WeatherData weatherData)
{
this._weatherData = weatherData;
weatherData.RegisterObserver(this);
}
public ForecastDisplay(WeatherData weatherData)
{
this.weatherData = weatherData;
weatherData.registerObserver(this);
}
public void setWeatherData(WeatherData weatherData)
{
this.weatherData = weatherData;
}
