如果观察者数量有许多，有人需要接受下雨通知，有人需要下雪，有人需要晴天，该如何来设计，肯定不能在目标借口写逻辑了
如果观察者数量有许多，有人需要接受下雨通知，有人需要下雪，有人需要晴天，该如何来设计，肯定不能在目标借口写逻辑了，
6 回答
观察者：
com.lone.watcherlombok.lombok.java.util.function.BiConsumerWeatherObserver Observer {
String BiConsumer<WeatherSubjectWeatherObserver> (Subject subject) {
(!(subject WeatherSubject)) {
IllegalArgumentException()}
.accept((WeatherSubject) subject)}
}测试：
com.lone.watchercom.lone.watcher.WeatherSubject.Statelombok.extern.slf4j.Main {
(String[] args) {
Observer girlfriend = WeatherObserver((subjectobserver) -> {
State state = subject.getSubjectState()(State.== state) {
.info(observer.getName()subject.getContent())}
})Observer mother = WeatherObserver((subjectobserver) -> {
State state = subject.getSubjectState()(State.== state || State.== state) {
.info(observer.getName()subject.getContent())}
})WeatherSubject subject = WeatherSubject()subject.attach(girlfriend)
.attach(mother)subject.setSubjectState(State.)subject.setContent()}
}可否这样写，用户自定义自己的行为，Subject的广播仍然存在，但在用户端过滤了。
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 | public class WheatherSubject { private List<WheatherObserver> mObservers = new ArrayList<>(); private String wheather; public final static String SNOW = "下雪"; public final static String RAIN = "下雨"; public final static String SUNNY = "晴"; public String getWheather() { return wheather; } public void setWheather(String wheather) { this.wheather = wheather; notifyObservers(wheather); } public void attach(WheatherObserver observer) { mObservers.add(observer); } public void detach(WheatherObserver observer) { mObservers.remove(observer); } public void notifyObservers(String wheather) { for (WheatherObserver observer : mObservers) { if (observer.getWheathers().size() < 1 || observer.getWheathers().contains(wheather)) { observer.update(wheather); } } }} |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 | public class WheatherObserver { private ArrayList<String> mWheathers; public WheatherObserver(String... wheathers) { mWheathers = new ArrayList<>(); mWheathers.addAll(Arrays.asList(wheathers)); } public ArrayList<String> getWheathers() { return mWheathers; } public void setWheathers(ArrayList<String> wheathers) { if (mWheathers != null) { mWheathers.clear(); mWheathers.addAll(wheathers); } } public void update(String wheather){ System.out.print(wheather); Log.i("fy",wheather); }} |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 | public class WheaterClint { public static void main(String[] args){ WheatherSubject subject = new WheatherSubject(); WheatherObserver observerAll = new WheatherObserver(); WheatherObserver observerSnow = new WheatherObserver(WheatherSubject.SNOW); WheatherObserver observerSnowAndRain = new WheatherObserver(WheatherSubject.SNOW,WheatherSubject.RAIN); subject.attach(observerAll); subject.attach(observerSnow); subject.attach(observerSnowAndRain); subject.setWheather(WheatherSubject.RAIN); }} |
举报
0/150
提交
取消
