Java AtomicBoolean类

java.util.concurrent.atomic.AtomicBoolean类提供了可以原子读取和写入的底层布尔值的操作，并且还包含高级原子操作。 AtomicBoolean支持基础布尔变量上的原子操作。 它具有获取和设置方法，如在volatile变量上的读取和写入。 也就是说，一个集合与同一变量上的任何后续get相关联。 原子compareAndSet方法也具有这些内存一致性功能。

1 AtomicBoolean类的方法

以下是AtomicBoolean类中可用的重要方法的列表。

2 AtomicBoolean类的案例

以下TestThread程序显示了基于线程的环境中AtomicBoolean变量的使用。

package com.yiidian;

/**
 * 一点教程网： http://www.yiidian.com
 */
import java.util.concurrent.atomic.AtomicBoolean;

public class TestThread {

   public static void main(final String[] arguments) throws InterruptedException {
      final AtomicBoolean atomicBoolean = new AtomicBoolean(false);
      new Thread("Thread 1") {
         public void run() {
            while(true){
               System.out.println(Thread.currentThread().getName() 
                  +" Waiting for Thread 2 to set Atomic variable to true. Current value is "
                  + atomicBoolean.get());
               if(atomicBoolean.compareAndSet(true, false)) {
                  System.out.println("Done!");
                  break;
               }
            }};
      }.start();

      new Thread("Thread 2") {
         public void run() {
            System.out.println(Thread.currentThread().getName() + ", Atomic Variable: " +atomicBoolean.get()); 
            System.out.println(Thread.currentThread().getName() +" is setting the variable to true ");
            atomicBoolean.set(true);
            System.out.println(Thread.currentThread().getName() + ", Atomic Variable: " +atomicBoolean.get()); 
         };
      }.start();
   }  
}

输出结果为：

Thread 1 Waiting for Thread 2 to set Atomic variable to true. Current value is false
Thread 1 Waiting for Thread 2 to set Atomic variable to true. Current value is false
Thread 1 Waiting for Thread 2 to set Atomic variable to true. Current value is false
Thread 2, Atomic Variable: false
Thread 1 Waiting for Thread 2 to set Atomic variable to true. Current value is false
Thread 2 is setting the variable to true
Thread 2, Atomic Variable: true
Thread 1 Waiting for Thread 2 to set Atomic variable to true. Current value is false
Done!