Observer
Observer接口
public interface Observer {
//通知
void notice();
String getName();
}
Alarm
public class Alarm {
List<Observer> observers = new ArrayList<>();
public void addObserver(Observer o){
observers.add(o);
}
public void removeObserver(Observer o){
observers.remove(o);
}
public void notice(){
for (Observer observer:this.observers){
observer.notice();
}
}
}
Fighter
public class Fighter implements Observer{
private String name;
public Fighter() {
}
public Fighter(String name) {
this.name = name;
}
@Override
public void notice() {
System.out.println(name+"士兵向城外集合...");
}
@Override
public String getName() {
return this.name;
}
}
Worker
public class Worker implements Observer{
private String name;
public Worker() {
}
public Worker(String name) {
this.name = name;
}
@Override
public void notice() {
System.out.println(name+"工人向城内集合...");
}
@Override
public String getName() {
return this.name;
}
}
Main
public class Main {
public static void main(String[] args) {
Alarm alarm = new Alarm();
Fighter f1 = new Fighter("peter");
Fighter f2 = new Fighter("gus");
Worker w1 = new Worker("al");
Worker w2 = new Worker("patrick");
alarm.addObserver(f1);
alarm.addObserver(f2);
alarm.addObserver(w1);
alarm.addObserver(w2);
alarm.notice();
}
}