java.lang.Object.notifyAll()方法範例

java.lang.Object.notifyAll() 喚醒正在等待此物件的監視器上的所有執行緒。通過呼叫wait方法的物件的監視器上的一個執行緒等待。

該喚醒執行緒將不能繼續進行，直到當前執行緒放棄此物件的鎖。被喚醒的執行緒將完全可能積極在此物件上進行同步的任何其他執行緒通常的方式相爭; 例如，喚醒執行緒分享下一個執行緒鎖定的物件沒有可靠的特權或劣勢。

這個方法只能由一個執行緒是此物件監視器的所有者被呼叫。

宣告

以下是java.lang.Object.notifyAll()方法的宣告

public final void notifyAll()

引數

• NA

返回值

這個方法沒有返回值。

異常

• IllegalMonitorStateException --如果當前執行緒不是此物件監視器的擁有者。

例子

對於Class型別的物件，通過執行該類的同步靜態方法。

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
         while (synchedList.isEmpty()) {
            System.out.println("List is empty...");
            synchedList.wait();
            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) {
      }
   }
}

讓我們來編譯和執行上面的程式，這將產生以下結果：

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