Java开发网 - 为何Main Thread没有被notify？

Topic: 为何Main Thread没有被notify？

1.为何Main Thread没有被notify？

Posted by: jfml
Posted on: 2003-06-03 16:15

程序如下：
public class ThreadTester
{
public static boolean flag = false;

public static void main(String[] args)
{
ThreadTester tt = new ThreadTester();

MonitorThread dpt = new MonitorThread();
WorkThread wpt = new WorkThread();

dpt.start();
wpt.start();

tt.pauseSelf();

tt.goOn();
}

public ThreadTester()
{
}

public void goOn()
{
for (int i = 0; i < 10; i++)
{
System.out.println("OKay!");
}
}

public synchronized void pauseSelf()
{
try
{
System.out.println(
"Main Thread " + Thread.currentThread() + " waiting...");
wait();
System.out.println("Main Thread " + Thread.currentThread() + " go on...");
}
catch (InterruptedException e)
{
e.printStackTrace();
}
}
}

class WorkThread extends Thread
{
public void run()
{
System.out.println(
"Work Thread "
+ Thread.currentThread()
+ " changed flag's value to true!");
ThreadTester.flag = true;
}
}

class MonitorThread extends Thread
{
public void run()
{
while (!ThreadTester.flag)
{
System.out.println(
"MonitorThread " + Thread.currentThread() + " watching the flag!");
}

synchronized (this)
{
System.out.println(
"Monitor Thread "
+ Thread.currentThread()
+ " waking every waited thread!");
notifyAll();
}
}

运行结果如下：
Main Thread Thread[main,5,main] waiting...
MonitorThread Thread[Thread-1,5,main] watching the flag!
MonitorThread Thread[Thread-1,5,main] watching the flag!
MonitorThread Thread[Thread-1,5,main] watching the flag!
MonitorThread Thread[Thread-1,5,main] watching the flag!
MonitorThread Thread[Thread-1,5,main] watching the flag!
MonitorThread Thread[Thread-1,5,main] watching the flag!
MonitorThread Thread[Thread-1,5,main] watching the flag!
MonitorThread Thread[Thread-1,5,main] watching the flag!
MonitorThread Thread[Thread-1,5,main] watching the flag!
MonitorThread Thread[Thread-1,5,main] watching the flag!
MonitorThread Thread[Thread-1,5,main] watching the flag!
MonitorThread Thread[Thread-1,5,main] watching the flag!
MonitorThread Thread[Thread-1,5,main] watching the flag!
Work Thread Thread[Thread-2,5,main] changed flag's value to true!
MonitorThread Thread[Thread-1,5,main] watching the flag!
Monitor Thread Thread[Thread-1,5,main] waking every waited thread!

最后Main Thread并未被notify，请问原因何在呢，该如何修改

谢谢

2.Re:为何Main Thread没有被notify？ [Re: CrazyJavar]

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Posted by: fengyifan
Posted on: 2003-06-05 21:06

synchronized (this)
{
System.out.println(
"Monitor Thread "
+ Thread.currentThread()
+ " waking every waited thread!");
notifyAll();
}

notify的是wpt自己的.
改变如下:
ThreadTester增加方法
public synchronized void resumeSelf()
{
notify();
}

-------------------------------------
synchronized (this)
{
System.out.println(
"Monitor Thread "
+ Thread.currentThread()
+ " waking every waited thread!");
notifyAll();
}

改为
tt.resumeSelf()
当然要把tt传入这个thread