java.util.concurrent.atomic.AtomicReferenceArray类提供可以原子方式读取和写入的底层引用数组的操作,还包含高级原子操作. AtomicReferenceArray支持对底层引用数组变量的原子操作.它具有get和set方法,类似于对volatile变量的读写操作.也就是说,一个集合与之前的相关变量的任何后续获取具有先发生关系.原子compareAndSet方法也具有这些内存一致性功能.
AtomicReferenceArray方法
以下是AtomicReferenceArray类中可用的重要方法列表.
Sr.No. | 方法&说明 |
---|---|
1 | public boolean compareAndSet(int i,E expect,E update) 如果当前值==期望值,则以原子方式将位置i的元素设置为给定的更新值. |
2 | public E get(int i) 获取位置i的当前值. |
3 | public E getAndSet(int i ,E newValue) 以原子方式将位置i的元素设置为给定值并返回旧值. |
4 | public void lazySet(int i, E newValue) 最终将位置i的元素设置为给定值. |
5 | public int length() 返回数组的长度. |
6 | public void set(int i,E newValue) 将位置i的元素设置为给定值. |
7 | public String toString() 返回数组当前值的String表示. |
8 | 公共布尔值weakCompareAndSet(int i,E expect,E update) 原子如果当前值==期望值,则将位置i处的元素设置为给定的更新值. |
示例
以下TestThread程序显示在基于线程的环境中使用AtomicReferenceArray变量.
import java.util.concurrent.atomic.AtomicReferenceArray;public class TestThread { private static String[] source = new String[10]; private static AtomicReferenceArrayatomicReferenceArray = new AtomicReferenceArray (source); public static void main(final String[] arguments) throws InterruptedException { for (int i = 0; i 这将产生以下结果.
输出
Thread 9, index 0, value: item-2Thread 10, index 0, value: item-1Item swapped: falseThread 10, index 1, value: item-2Item swapped: trueThread 9, index 1, value: updated-item-2Thread 10, index 1, updated-item-2Thread 10, index 2, value: item-3Item swapped: falseThread 10, index 3, value: item-2Item swapped: trueThread 10, index 3, updated-item-2Thread 10, index 4, value: item-2Item swapped: trueThread 10, index 4, updated-item-2Thread 10, index 5, value: item-2Item swapped: trueThread 10, index 5, updated-item-2Thread 10, index 6, value: item-2Thread 9, index 2, value: item-2Item swapped: trueThread 9, index 3, value: updated-item-2Thread 10, index 6, updated-item-2Thread 10, index 7, value: item-2Thread 9, index 4, value: updated-item-2Item swapped: trueThread 9, index 5, value: updated-item-2Thread 10, index 7, updated-item-2Thread 9, index 6, value: updated-item-2Thread 10, index 8, value: item-2Thread 9, index 7, value: updated-item-2Item swapped: trueThread 9, index 8, value: updated-item-2Thread 10, index 8, updated-item-2Thread 9, index 9, value: item-2Thread 10, index 9, value: item-10Item swapped: false