接下来，我们实现具体主题类ConcreteSubject和具体观察者类ConcreteObserver：
代码语言：javascript复制import java.util.ArrayList;
import java.util.List;
public class ConcreteSubject implements Subject {
private List<Observer> observers;
private float temperature;
private float humidity;
private float pressure;
public ConcreteSubject() {
observers = new ArrayList<>();
}
@Override
public void registerObserver(Observer observer) {
observers.add(observer);
}
@Override
public void removeObserver(Observer observer) {
observers.remove(observer);
}
@Override
public void notifyObservers() {
for (Observer observer : observers) {
observer.update(temperature, humidity, pressure);
}
}
public void setMeasurements(float temperature, float humidity, float pressure) {
this.temperature = temperature;
this.humidity = humidity;
this.pressure = pressure;
measurementsChanged();
}
public void measurementsChanged() {
notifyObservers();
}
}
public class ConcreteObserver implements Observer {
private float temperature;
private float humidity;
private float pressure;
@Override
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 degrees and " humidity "% humidity and " pressure "Pa");
}
}
