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java.lang.Object.wait(long timeout)方法实例

java.lang.Object.wait(long timeout) 导致当前线程等待,直到其他线程调用此对象的 notify() 方法或notifyAll()方法,或在指定已经过去的时间。

当前线程必须拥有该对象的监视器。

声明

以下是java.lang.Object.wait()方法的声明

public final void wait(long timeout)

参数

  • timeout -- 最大等待时间(毫秒)。

返回值

这个方法没有返回值。

异常

  • IllegalArgumentException --如果超时的值是负的。

  • IllegalMonitorStateException -- 如果当前线程不是对象监视器的拥有者。

  • InterruptedException -- 如果另一个线程中断了当前线程。当这种异常被抛出当前线程的中断状态被清除。

例子

下面的例子显示lang.Object.wait()方法的使用。

package com.yiibai;

import java.util.Collections;
import java.util.LinkedList;
import java.util.List;

public class ObjectDemo extends Object {

   private List synchedList;

   public ObjectDemo() {
      // create a new synchronized list to be used
      synchedList = Collections.synchronizedList(new LinkedList());
   }

   // method used to remove an element from the list
   public String removeElement() throws InterruptedException {
      synchronized (synchedList) {

         // while the list is empty, wait up to 10 seconds
         while (synchedList.isEmpty()) {
            System.out.println("List is empty...");
            synchedList.wait(10000);
            System.out.println("Waiting...");
         }
         String element = (String) synchedList.remove(0);

         return element;
      }
   }

   // method to add an element in the list
   public void addElement(String element) {
      System.out.println("Opening...");
      synchronized (synchedList) {

         // add an element and notify all that an element exists
         synchedList.add(element);
         System.out.println("New Element:'" + element + "'");

         synchedList.notifyAll();
         System.out.println("notifyAll called!");
      }
      System.out.println("Closing...");
   }

   public static void main(String[] args) {
      final ObjectDemo demo = new ObjectDemo();

      Runnable runA = new Runnable() {

         public void run() {
            try {
               String item = demo.removeElement();
               System.out.println("" + item);
            } catch (InterruptedException ix) {
               System.out.println("Interrupted Exception!");
            } catch (Exception x) {
               System.out.println("Exception thrown.");
            }
         }
      };

      Runnable runB = new Runnable() {

         // run adds an element in the list and starts the loop
         public void run() {
            demo.addElement("Hello!");
         }
      };

      try {
         Thread threadA1 = new Thread(runA, "A");
         threadA1.start();

         Thread.sleep(500);

         Thread threadA2 = new Thread(runA, "B");
         threadA2.start();

         Thread.sleep(500);

         Thread threadB = new Thread(runB, "C");
         threadB.start();

         Thread.sleep(1000);

         threadA1.interrupt();
         threadA2.interrupt();
      } catch (InterruptedException x) {
      }
   }
}

让我们来编译和运行上面的程序,这将产生以下结果:

List is empty...
List is empty...
Opening...
New Element:'Hello!'
notifyAll called!
Closing...
Waiting...
Hello!
Waiting...
List is empty...
Interrupted Exception!