package util;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Phaser;
import java.util.concurrent.TimeUnit;

/**
 * Created by ldh on 2019年4月3日.
 */
public class PhaserTest {

 public static void main(String[] args) {
 MyPhaser phaser = new MyPhaser();

 int num = 5;
 StudentTask[] studentTask = new StudentTask[num];
 for (int i = 0; i < studentTask.length; i++) {
 studentTask[i] = new StudentTask(phaser);
 phaser.register();	//注册一次表示phaser维护的线程个数
 }

 ExecutorService executorService = Executors.newFixedThreadPool(num);
 for (int i = 0; i < studentTask.length; i++) {
 Thread thread = new Thread(studentTask[i], "Student "+i);
 executorService.submit(thread);
 }

 executorService.shutdown();
 System.out.println("Phaser has finished:"+phaser.isTerminated());
 }

 public static class StudentTask implements Runnable {
 private Phaser phaser;
 public StudentTask(Phaser phaser) {
 this.phaser = phaser;
 }

 @Override
 public void run() {
 System.out.println(Thread.currentThread().getName()+"到达考试");
 phaser.arriveAndAwaitAdvance();

 System.out.println(Thread.currentThread().getName()+"做第1题时间...");
 doExercise1();
 System.out.println(Thread.currentThread().getName()+"做第1题完成...");
 phaser.arriveAndAwaitAdvance();

 System.out.println(Thread.currentThread().getName()+"做第2题时间...");
 doExercise2();
 System.out.println(Thread.currentThread().getName()+"做第2题完成...");
 phaser.arriveAndAwaitAdvance();

 System.out.println(Thread.currentThread().getName()+"做第3题时间...");
 doExercise3();
 System.out.println(Thread.currentThread().getName()+"做第3题完成...");
 phaser.arriveAndAwaitAdvance();
 }

 private void doExercise1() {
 long duration = (long)(Math.random()*10);
 try {
 TimeUnit.SECONDS.sleep(duration);
 } catch (InterruptedException e) {
 e.printStackTrace();
 }
 }

 private void doExercise2() {
 long duration = (long)(Math.random()*10);
 try {
 TimeUnit.SECONDS.sleep(duration);
 } catch (InterruptedException e) {
 e.printStackTrace();
 }
 }

 private void doExercise3() {
 long duration = (long)(Math.random()*10);
 try {
 TimeUnit.SECONDS.sleep(duration);
 } catch (InterruptedException e) {
 e.printStackTrace();
 }
 }

 }

 public static class MyPhaser extends Phaser {

 @Override
 protected boolean onAdvance(int phase, int registeredParties) { //在每个阶段执行完成后回调的方法

 switch (phase) {
 case 0:
 return studentArrived();
 case 1:
 return finishFirstExercise();
 case 2:
 return finishSecondExercise();
 case 3:
 return finishExam();
 default:
 return true;
 }

 }

 private boolean studentArrived() {
 System.out.println(Thread.currentThread().getName()+ "学生准备好了,学生人数:" + getRegisteredParties());
 return false;
 }

 private boolean finishFirstExercise() {
 System.out.println(Thread.currentThread().getName()+ "第一题所有学生做完");
 return false;
 }

 private boolean finishSecondExercise() {
 System.out.println(Thread.currentThread().getName()+"第二题所有学生做完");
 return false;
 }

 private boolean finishExam() {
 System.out.println(Thread.currentThread().getName()+"第三题所有学生做完,结束考试");
 return true;
 }

 }
}