Observer\u3068\u306f\u76e3\u8996\u8005\u3068\u3044\u3046\u610f\u5473\u3067\u3001\u4f55\u3089\u304b\u306e\u30a4\u30d9\u30f3\u30c8\u3092\u76e3\u8996\u3057\u3066\u5b9f\u884c\u3055\u305b\u308b\u30d1\u30bf\u30fc\u30f3\u3067\u3059\u3002<\/p>\n\n\n\n
package com.example.observer;
public interface Observer {
public void update(Event event);
}<\/pre>\n\n\n\npackage com.example.observer;
public class ConcreteObserver implements Observer {
@Override
public void update(Event event) {
}
}<\/pre>\n\n\n\npackage com.example.observer;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
public abstract class Event {
private List<Observer> observerList = new ArrayList<>();
public void addObserver(Observer observer) {
observerList.add(observer);
}
public void deleteObserver(Observer observer) {
observerList.remove(observer);
}
public void notifyObserver() {
Iterator it = observerList.iterator();
while(it.hasNext()) {
Observer observer = (Observer)it.next();
observer.update(this);
}
}
public abstract void execute();
}<\/pre>\n\n\n\npackage com.example.observer;
public class ConcreteEvent extends Event {
@Override
public void execute() {
notifyObserver();
}
}<\/pre>\n\n\n\npackage com.example.observer;
public class Main {
public static void main(String[] args) {
Observer observer1 = new ConcreteObserver();
Observer observer2 = new ConcreteObserver();
Event event = new ConcreteEvent();
event.addObserver(observer1);
event.addObserver(observer2);
event.execute();
}
}<\/pre>\n\n\n\nObserver\u3092\u5b9f\u88c5\u3057\u305f\u30af\u30e9\u30b9\u3092\u30a4\u30f3\u30b9\u30bf\u30f3\u30b9\u5316\u3057\u3066Event\u306b\u8ffd\u52a0\u3057\u3001\u5f8c\u307b\u3069Event\u306eexecute()\u3092\u5b9f\u884c\u3059\u308b\u3053\u3068\u3067update()\u306e\u51e6\u7406\u304c\u5b9f\u884c\u3055\u308c\u307e\u3059\u3002<\/p>\n\n\n\n
\u307e\u3041\u3001Observer\u306fexecute()\u306e\u51e6\u7406\u5b9f\u884c\u3092\u76e3\u8996\u3057\u3066\u3044\u308b\u30a4\u30e1\u30fc\u30b8\u3067\u3059\u3002<\/p>\n\n\n\n
<\/p>\n","protected":false},"excerpt":{"rendered":"
Observer\u3068\u306f\u76e3\u8996\u8005\u3068\u3044\u3046\u610f\u5473\u3067\u3001\u4f55\u3089\u304b\u306e\u30a4\u30d9\u30f3\u30c8\u3092\u76e3\u8996\u3057\u3066\u5b9f\u884c\u3055\u305b\u308b\u30d1\u30bf\u30fc\u30f3\u3067\u3059\u3002 package com.example.observer;public interface Observer { public … \u7d9a\u304d\u3092\u8aad\u3080 \u3010\u30c7\u30b6\u30a4\u30f3\u30d1\u30bf\u30fc\u30f3\u3011Observer\u30d1\u30bf\u30fc\u30f3<\/span>