wait, notify及线程通讯机制

1) wait(), notify() 方法被调用的时候，只要外面没有被synchronized()罩住，编译可过，但是跑起来一定发生异常--- current thread not owner

 

2) wait(), notify()的ref1一定要和synchronized(ref2)一致！两个ref必须是同一个东西，否则报错。

3) 处于wait()状态的Thread t1, 如果被别人调用了t1.interrupt(),立刻从wait()状态抛出interrupted异常，由此看来，线程通讯的另一种方法---wait(), interrupt()组合。当等待时间不确定的时候，只需要让某线程wait()在一个本地obj上(保证永远不会被别人notify()起来)，然后让外部线程通过interrupt()来唤醒。

 

public class ThreadTest

{

      /**

       * @param args

       * @throws InterruptedException

       */

      public static void main(String[] args) throws InterruptedException

      {

            ThreadWait t5 = new ThreadWait();

            t5.start();

            // Doing alot of staff, here, maybe takes around 100ms, have no idea how long it will take.

            Thread.sleep(1000);

            t5.interrupt();  

      }

}

 

class ThreadWait extends Thread

{

      public void run()

      {

            Object obj = new Object();

            synchronized (obj)

            {

                  for (int i = 1; i <= 3; i++)

                  {

                        System.out.println("ThreadSleep : " + i + ".    " + this.getName());

                  }

                  try

                  {

                        obj.wait();//永远没有机会被notify(),只有等待被interrupt,被interrupt之后，才会继续执行，

                        //因为我也不知道我要等待多长时间

                  }

                  catch (InterruptedException ignore){}

                  for (int i = 4; i <= 6; i++)

                  {

                        System.out.println("ThreadSleep : " + i + ".    " + this.getName());

                  }

            }

      }

}