设计模式之观察者模式
来源:互联网 发布:四川大学软件学院二专 编辑:程序博客网 时间:2024/04/24 13:47
public interface Subject ...{
public void registerObserver(Observer o);
public void removeObserver(Observer o);
public void notifyObservers();
}
public interface Observer ...{
public void update(float temp, float humidity, float pressure);
}
public interface DisplayElement ...{
public void display();
}
public class WeatherData implements Subject ...{
private ArrayList observers;
private float temperature;
private float humidity;
private float pressure;
public WeatherData() ...{
observers = new ArrayList();
}
public void registerObserver(Observer o) ...{
observers.add(o);
}
public void removeObserver(Observer o) ...{
int i = observers.indexOf(o);
if (i >=0) ...{
observers.remove(i);
}
}
public void notifyObservers() ...{
for (int i=0; i<observers.size(); i++) ...{
Observer observer = (Observer)observers.get(i);
observer.update(temperature, humidity, pressure);
}
}
public void measurementsChanged() ...{
notifyObservers();
}
public void setMeasurements(float temperature, float humidity,
float pressure) ...{
this.temperature = temperature;
this.humidity = humidity;
this.pressure = pressure;
measurementsChanged();
}
//WeatherData的其他方法
}
public class CurrentConditionsDisplay implements Observer, DisplayElement ...{
private float temperature;
private float humidity;
private Subject weatherData;
public CurrentConditionsDisplay(Subject weatherData) ...{
this.weatherData = weatherData;
weatherData.registerObserver(this);
}
public void update(float temperature, float humidity, float pressure) ...{
this.temperature = temperature;
this.humidity = humidity;
this.pressure = pressure;
display();
}
public void display() ...{
System.out.println("Current conditions: " + temperature + "F degress and " +
humidity + "% humidity");
}
}
public class WeatherStation ...{
public static void main(String[] args) ...{
WeatherData weatherData = new WeatherData();
CurrentConditionsDisplay currentDisplay =
new CurrentConditionsDisplay(weatherData);
StatisticsDisplay statisticsDisplay = new StatisticsDisplay(weatherData);
ForecastDisplay forecastDisplay = new ForecastDisplay(weatherData);
weatherData.setMeasurements(80, 65, 30.4f);
weatherData.setMeasurements(82, 70, 29.2f);
weatherData.setMeasurements(78, 90, 29.2f);
}
}
==>
Current conditions: 80.0F degrees and 65.0% humidity
Avg/Max/Min temperature = 80.0/80.0/80.0
Forecast: Improving weather on the way!
……
利用内置的支持重做WorkStation
import java.util.Observable;
import java.util.Observer;
public class WeatherData extends Observable ...{
private float temperature;
private float humidity;
private float pressure;
public WeatherData() ...{
}
public void measurementsChanged() ...{
setChanged();
notifyObservers();
}
public void setMeasurements(float temperature, float humidity,
float pressure) ...{
this.temperature = temperature;
this.humidity = humidity;
this.pressure = pressure;
measurementsChanged();
}
public float getTemperature() ...{
return temperature;
}
public float getHumidity() ...{
return humidity;
}
public float getPressure() ...{
return pressure;
}
}
import java.util.Observable;
import java.util.Observer;
public class CurrentConditionsDisplay implements Observer, DisplayElement ...{
Observable observable;
private float temperature;
private float humidity;
public CurrentConditionsDisplay(Observable observable) ...{
this.observable = observable;
observable.addObserver(this);
}
public void update(Observable obs, Object arg) ...{
if (obs instanceof WeatherData) ...{
WeatherData weatherData = (WeatherData)obs;
this.temperature = weatherData.getTemperature();
this.humidity = weatherData.getHumidity();
display();
}
}
public void display() ...{
System.out.println("Current conditions: " + temperature + "F degress and " +
humidity + "% humidity");
}
}
==Swing==
public class SwingObserverExample ...{
JFrame frame;
public static void main(String[] args) ...{
SwingObserverExample example = new SwingObserverExample();
example.go();
}
public void go() ...{
frame = new JFrame();
JButton button = new JButton("Should I do it?");
button.addActionListener(new AngelListener());
button.addActionListener(new DevilListener());
frame.getContentPane().add(BorderLayout.CENTER, button);
//在这里设置frame属性
}
class AngelListener implements ActionListener ...{
public void actionPerformed(ActionEvent event) ...{
System.out.println("Don't do it, you might regret it!");
}
}
class DevilListener implements ActionListener ...{
public void actionPerformed(ActionEvent event) ...{
System.out.println("Come on, do it!");
}
}
}
public void registerObserver(Observer o);
public void removeObserver(Observer o);
public void notifyObservers();
}
public interface Observer ...{
public void update(float temp, float humidity, float pressure);
}
public interface DisplayElement ...{
public void display();
}
public class WeatherData implements Subject ...{
private ArrayList observers;
private float temperature;
private float humidity;
private float pressure;
public WeatherData() ...{
observers = new ArrayList();
}
public void registerObserver(Observer o) ...{
observers.add(o);
}
public void removeObserver(Observer o) ...{
int i = observers.indexOf(o);
if (i >=0) ...{
observers.remove(i);
}
}
public void notifyObservers() ...{
for (int i=0; i<observers.size(); i++) ...{
Observer observer = (Observer)observers.get(i);
observer.update(temperature, humidity, pressure);
}
}
public void measurementsChanged() ...{
notifyObservers();
}
public void setMeasurements(float temperature, float humidity,
float pressure) ...{
this.temperature = temperature;
this.humidity = humidity;
this.pressure = pressure;
measurementsChanged();
}
//WeatherData的其他方法
}
public class CurrentConditionsDisplay implements Observer, DisplayElement ...{
private float temperature;
private float humidity;
private Subject weatherData;
public CurrentConditionsDisplay(Subject weatherData) ...{
this.weatherData = weatherData;
weatherData.registerObserver(this);
}
public void update(float temperature, float humidity, float pressure) ...{
this.temperature = temperature;
this.humidity = humidity;
this.pressure = pressure;
display();
}
public void display() ...{
System.out.println("Current conditions: " + temperature + "F degress and " +
humidity + "% humidity");
}
}
public class WeatherStation ...{
public static void main(String[] args) ...{
WeatherData weatherData = new WeatherData();
CurrentConditionsDisplay currentDisplay =
new CurrentConditionsDisplay(weatherData);
StatisticsDisplay statisticsDisplay = new StatisticsDisplay(weatherData);
ForecastDisplay forecastDisplay = new ForecastDisplay(weatherData);
weatherData.setMeasurements(80, 65, 30.4f);
weatherData.setMeasurements(82, 70, 29.2f);
weatherData.setMeasurements(78, 90, 29.2f);
}
}
==>
Current conditions: 80.0F degrees and 65.0% humidity
Avg/Max/Min temperature = 80.0/80.0/80.0
Forecast: Improving weather on the way!
……
利用内置的支持重做WorkStation
import java.util.Observable;
import java.util.Observer;
public class WeatherData extends Observable ...{
private float temperature;
private float humidity;
private float pressure;
public WeatherData() ...{
}
public void measurementsChanged() ...{
setChanged();
notifyObservers();
}
public void setMeasurements(float temperature, float humidity,
float pressure) ...{
this.temperature = temperature;
this.humidity = humidity;
this.pressure = pressure;
measurementsChanged();
}
public float getTemperature() ...{
return temperature;
}
public float getHumidity() ...{
return humidity;
}
public float getPressure() ...{
return pressure;
}
}
import java.util.Observable;
import java.util.Observer;
public class CurrentConditionsDisplay implements Observer, DisplayElement ...{
Observable observable;
private float temperature;
private float humidity;
public CurrentConditionsDisplay(Observable observable) ...{
this.observable = observable;
observable.addObserver(this);
}
public void update(Observable obs, Object arg) ...{
if (obs instanceof WeatherData) ...{
WeatherData weatherData = (WeatherData)obs;
this.temperature = weatherData.getTemperature();
this.humidity = weatherData.getHumidity();
display();
}
}
public void display() ...{
System.out.println("Current conditions: " + temperature + "F degress and " +
humidity + "% humidity");
}
}
==Swing==
public class SwingObserverExample ...{
JFrame frame;
public static void main(String[] args) ...{
SwingObserverExample example = new SwingObserverExample();
example.go();
}
public void go() ...{
frame = new JFrame();
JButton button = new JButton("Should I do it?");
button.addActionListener(new AngelListener());
button.addActionListener(new DevilListener());
frame.getContentPane().add(BorderLayout.CENTER, button);
//在这里设置frame属性
}
class AngelListener implements ActionListener ...{
public void actionPerformed(ActionEvent event) ...{
System.out.println("Don't do it, you might regret it!");
}
}
class DevilListener implements ActionListener ...{
public void actionPerformed(ActionEvent event) ...{
System.out.println("Come on, do it!");
}
}
}
- 设计模式之-观察者
- 设计模式之观察者
- 设计模式之观察者
- 设计模式之观察者
- 设计模式之观察者
- 设计模式之观察者
- 设计模式之观察者
- 设计模式之观察者
- 设计模式之观察者
- 设计模式之观察者
- 设计模式之观察者
- 设计模式之观察者模式
- 设计模式之观察者模式
- 设计模式之观察者模式
- 设计模式之观察者模式
- 设计模式之观察者模式
- 设计模式之观察者模式
- 设计模式之观察者模式
- DVDRegionFree.exe
- 理解矩阵(二)
- ASP.NET随机码生成示例
- 理解矩阵(三)
- 批量添加远程桌面.vbs
- 设计模式之观察者模式
- dvldr32.exe
- Serv-U,Imail,DNS注册表相关备份及恢复
- 无题
- Spring开发风格
- 照片编辑软件PhotoTool 1.0.0.1发布
- dvremind.exe
- dvzmsgr.exe
- dw.exe