import java.util.concurrent.Phaser;
public class StarPhaserDemo {
    public static void main(String args[]) {
        Phaser phsr = new NewlinePhaser(4,3);
        new StarThread(phsr);
        new StarThread(phsr);
        new StarThread(phsr);
        new StarThread(phsr);
    }
}
class NewlinePhaser extends Phaser {
   int numPhases;
   public NewlinePhaser(int numParties, int phases) {
       super(numParties);
       numPhases = phases;
   }
   public boolean onAdvance(int phase, int numParties) {
       System.out.println(); // print a newline
       return phase == numPhases-1; // stop after numPhases
    }
}
class StarThread implements Runnable {
   Phaser phsr;
   StarThread(Phaser p) {
      phsr = p;
      new Thread(this).start();
    }
    public void run() {
        while (!phsr.isTerminated()) {
            System.out.print('*');
            phsr.arriveAndAwaitAdvance();
         }
     }
}