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。