package org.rui.thread.block; import java.util.Timer;
import java.util.TimerTask;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit; public class NotifyVsNotifyAll { public static void main(String[] args) throws InterruptedException {
ExecutorService exec = Executors.newCachedThreadPool();
for (int i = 0; i < 5; i++) {
exec.execute(new Task());
}
exec.execute(new Task2());
Timer timer = new Timer();
// 安排指定的任务在指定的延迟后開始进行反复的固定速率运行。
timer.scheduleAtFixedRate(new TimerTask() {
boolean prod = true; public void run() {
if (prod) {
System.out.println("\n notify() ");
Task.blocker.prod();//
prod = false;
} else {
System.out.println("\n notifyAll()");
Task.blocker.prodAll();
prod = true;
}
}
}, 400, 400);
TimeUnit.SECONDS.sleep(5);// run for a while...
timer.cancel();// 终止此计时器，
System.out.println("\n Timer canceled");
TimeUnit.MILLISECONDS.sleep(500);
System.out.println("Task.blocker.prodAll()");
Task2.blocker.prodAll();//唤醒task2 不包含不论什么在Task.blocker中的锁上等待的任务
TimeUnit.MILLISECONDS.sleep(500);
System.out.println("\nshutting down");
exec.shutdownNow(); }
} class Blocker {
synchronized void waitingCall() {
try {
while (!Thread.interrupted()) {
wait();
System.out.println(Thread.currentThread() + " ");
} } catch (InterruptedException e) {
// ok to exit this way
}
} synchronized void prod() {
notify();//在众多等候同一个锁的任务中。仅仅有一个会被唤醒，因此假设你希望使用nofify ，就必须保证被唤醒的是恰当的任务
} synchronized void prodAll() {
notifyAll();//仅仅有等待这个锁的任务才会被唤醒
}
} // ////////
class Task implements Runnable {
static Blocker blocker = new Blocker(); public void run() {
blocker.waitingCall();
} } // ////////
class Task2 implements Runnable {
// a separate blocker object 一个单独的拦截器对象
static Blocker blocker = new Blocker(); public void run() {
blocker.waitingCall();
//System.out.println(Thread.currentThread()+" : Task 不会被换醒Task2");
} }
/**
* output:
*
notify()
Thread[pool-1-thread-2,5,main] notifyAll()
Thread[pool-1-thread-2,5,main]
Thread[pool-1-thread-5,5,main]
Thread[pool-1-thread-4,5,main]
Thread[pool-1-thread-3,5,main]
Thread[pool-1-thread-1,5,main] notify()
Thread[pool-1-thread-2,5,main] notifyAll()
Thread[pool-1-thread-2,5,main]
Thread[pool-1-thread-1,5,main]
Thread[pool-1-thread-3,5,main]
Thread[pool-1-thread-4,5,main]
Thread[pool-1-thread-5,5,main] notify()
Thread[pool-1-thread-2,5,main] notifyAll()
Thread[pool-1-thread-2,5,main]
Thread[pool-1-thread-5,5,main]
Thread[pool-1-thread-4,5,main]
Thread[pool-1-thread-3,5,main]
Thread[pool-1-thread-1,5,main] notify()
Thread[pool-1-thread-2,5,main] notifyAll()
Thread[pool-1-thread-2,5,main]
Thread[pool-1-thread-1,5,main]
Thread[pool-1-thread-3,5,main]
Thread[pool-1-thread-4,5,main]
Thread[pool-1-thread-5,5,main] notify()
Thread[pool-1-thread-2,5,main] notifyAll()
Thread[pool-1-thread-2,5,main]
Thread[pool-1-thread-5,5,main]
Thread[pool-1-thread-4,5,main]
Thread[pool-1-thread-3,5,main]
Thread[pool-1-thread-1,5,main] notify()
Thread[pool-1-thread-2,5,main] notifyAll()
Thread[pool-1-thread-2,5,main]
Thread[pool-1-thread-1,5,main]
Thread[pool-1-thread-3,5,main]
Thread[pool-1-thread-4,5,main]
Thread[pool-1-thread-5,5,main] Timer canceled
Task.blocker.prodAll()
Thread[pool-1-thread-6,5,main] shutting down
*/