[Java] wait, notify, notifyAll에 의한 실행순서 동기화

▶ wait, notify, notifyAll에 의한 실행순서의 동기화

class NewsPaper {

String todayNews;

boolean isTodayNews = false;

public void setTodayNew(String news) {

todayNews = news;

isTodayNews = true;

synchronized(this) {

notifyAll(); // 모두 깨운다.

}

}

public String getTodayNews() {

if(isTodayNews == false){

try{

synchronized(this) {

wait(); // 기다려라.

}

} catch(InterruptedException e) {

e.printStackTrace();

}

}

return todayNews;

}

}

class NewsWriter extends Thread {

NewsPaper paper;

public NewsWriter(NewsPaper paper) {

this.paper = paper;

}

public void run() {

paper.setTodayNew("자바의 열기가 뜨겁습니다.");

}

}

class NewsReader extends Thread {

NewsPaper paper;

public NewsReader(NewsPaper paper) {

this.paper = paper;

}

@Override

public void run() {

System.out.println("오늘의 뉴스 : " + paper.getTodayNews());

}

}

public class NewsPaperStory {

public static void main(String[] args) {

NewsPaper paper = new NewsPaper();

NewsReader reader1 = new NewsReader(paper);

NewsReader reader2 = new NewsReader(paper);

NewsWriter writer = new NewsWriter(paper);

try {

reader1.start();

reader2.start();

Thread.sleep(1000);

writer.start();

reader1.join();

reader2.join();

writer.join();

} catch(InterruptedException e) {

e.printStackTrace();

}

}

}