| using System;
using System.Collections;
namespace Templates.Observer {
// Delegate type:
public delegate void
WeatherNotification(float temp, float rain, float pres);
// An observer
public class TemperatureWatcher {
private float currentTemperature;
private WeatherCenter mySubject;
private string watcherName;
public TemperatureWatcher (WeatherCenter s, float initTemp, string name){
mySubject = s;
currentTemperature = initTemp;
watcherName = name;
}
public void TemperatureAlarm(float temp, float rain, float pres){
currentTemperature = temp;
Console.WriteLine(
"Temperature watcher {1}: the temperature is now {0}.",
currentTemperature, watcherName);
}
}
public class RainWatcher {
private float currentRainAmount;
private WeatherCenter mySubject;
private string watcherName;
public RainWatcher (WeatherCenter s, float initAmount, string name){
mySubject = s;
currentRainAmount = initAmount;
watcherName = name;
}
public void RainAlarm(float temp, float rain, float pres){
currentRainAmount = rain;
Console.WriteLine("Rain watcher {1}: Accumulated rain fall: {0}.",
currentRainAmount, watcherName);
}
}
// A subject
public class WeatherCenter {
private float temperature,
rainAmount,
airPressure;
public WeatherCenter(float temp, float rain, float pres){
temperature = temp;
rainAmount = rain;
airPressure = pres;
}
public void WeatherUpdate(float temp, float rain, float pres){
float oldTemperature = this.temperature,
oldRainAmount = this.rainAmount,
oldAirPressure = this.airPressure;
this.temperature = temp;
this.rainAmount += rain;
this.airPressure = pres;
if (Math.Abs(oldTemperature - this.temperature) > 2.0F ||
rain > 0.5F ||
Math.Abs(oldAirPressure - this.airPressure) > 3.0F)
this.Notify();
}
private event WeatherNotification weatherNotifier;
public void AddNotifier(WeatherNotification n){
weatherNotifier += n;
}
public void RemoveNotifier(WeatherNotification n){
weatherNotifier -= n;
}
public void Notify(){
weatherNotifier(temperature, rainAmount, airPressure);
}
}
} |