Phaser

书上的小例子，用婚礼流程比较形象的演示了phaser的使用。

Phaser 是一个类，继承这个类重写onAdvance(int phase, int registeredParties)

参数：两个参数分别是第几个阶段和到达这个阶段的线程数。

返回值：返回ture表示这个phaser结束了，因此只有最后一个阶段返回ture，其他阶段返回false。

phase.bulkRegister(7);//注册总线程数。

{

static MyPhase phase = new MyPhase();

public static void main(String[] args){

// 参数婚礼的总人数为7

phase.bulkRegister(7);

// 5个参加婚礼的客人

for (int i = 0;i<5;i++){

new Thread(new Person("P"+i)).start();

}

// 新郎和新娘

new Thread(new Person("新郎")).start();

new Thread(new Person("新娘")).start();

}

/**

* 参加婚礼的人，含新郎新娘

*/

static class Person implements Runnable{

private String name;

public Person(String name) {

this.name = name;

}

public void arrived() {

try {

TimeUnit.MILLISECONDS.sleep(new Random().nextInt(1000));

System.out.printf("%s is arrived! \n",name);

phase.arriveAndAwaitAdvance();

} catch (InterruptedException e) {

e.printStackTrace();

}

}

public void eat() {

try {

TimeUnit.MILLISECONDS.sleep(new Random().nextInt(1000));

System.out.printf("%s is eated! \n",name);

phase.arriveAndAwaitAdvance();

} catch (InterruptedException e) {

e.printStackTrace();

}

}

public void leave() {

try {

TimeUnit.MILLISECONDS.sleep(new Random().nextInt(1000));

System.out.printf("%s is leave! \n",name);

phase.arriveAndAwaitAdvance();

} catch (InterruptedException e) {

e.printStackTrace();

}

}

public void xx() {

try {

if(name.equals("新郎")|| name.equals("新娘")) {

TimeUnit.MILLISECONDS.sleep(new Random().nextInt(1000));

System.out.printf("%s is xx! \n",name);

phase.arriveAndAwaitAdvance();

}else {

// 客人不参与XX 到达这个阶段就直接撤销。

phase.arriveAndDeregister();

}

} catch (InterruptedException e) {

e.printStackTrace();

}

}

@Override

public void run() {

// 每个人需要依次执行到达，吃饭，离席，XX(客人就不要参加了)

arrived();

eat();

leave();

xx();

}

}

static class MyPhase extends Phaser{

@Override

protected boolean onAdvance(int phase, int registeredParties) {

switch (phase){

case 0:{

System.out.println("所有人到齐了，人数为："+registeredParties);

return false;

}

case 1:{

System.out.println("所有人开始吃饭 !!人数为："+registeredParties);

return false;

}

case 2:{

System.out.println("所有人吃完了，离席!!!人数为："+registeredParties);

return false;

}

case 3:{

System.out.println("xx的人数为："+registeredParties);

return true;

}

default:{

return true;

}

}

}

}

}

测试结果为：

P0 is arrived!

P3 is arrived!

新郎 is arrived!

P1 is arrived!

P4 is arrived!

P2 is arrived!

新娘 is arrived!

所有人到齐了，人数为：7

P1 is eated!

P2 is eated!

P0 is eated!

新郎 is eated!

P4 is eated!

新娘 is eated!

P3 is eated!

所有人开始吃饭 !!人数为：7

P2 is leave!

新娘 is leave!

P0 is leave!

P3 is leave!

P1 is leave!

新郎 is leave!

P4 is leave!

所有人吃完了，离席!!!人数为：7

新娘 is xx!

新郎 is xx!

xx的人数为：2