如果AtomicReference对象的当前值等于期望值,则使用AtomicReference类的compareAndSet()方法以原子方式将newValue的值设置为AtomicReference对象,如果操作成功,则返回true,否则返回false。此方法使用设置的内存语义更新值,就像将该变量声明为volatile一样。
用法:
public final V compareAndSet(V expectedValue, V newValue)
参数:该方法接受ExpectedValue(期望值)和newValue(新值)来设置新值。
返回值:此方法返回见证值,如果成功,它将与期望值相同。
以下示例程序旨在说明compareAndSet()方法:
程序1:
// Java program to demonstrate
// AtomicReference.compareAndSet() method
import java.util.concurrent.atomic.AtomicReference;
public class GFG {
public static void main(String[] args)
{
// create an atomic reference object.
AtomicReference<Long> ref
= new AtomicReference<Long>();
// set some value
ref.set(987654321L);
// apply compareAndSet()
boolean response
= ref.compareAndSet(1234L,
999999L);
// print value
System.out.println(" Value is set = "
+ response);
}
}
输出:
Value is set = false
程序2:
// Java program to demonstrate
// AtomicReference.compareAndSet() method
import java.util.concurrent.atomic.AtomicReference;
public class GFG {
public static void main(String[] args)
{
// create an atomic reference object.
AtomicReference<String> ref
= new AtomicReference<String>();
// set some value
ref.set("Geeks For Geeks");
// apply compareAndSet()
boolean response
= ref.compareAndSet(
"Geeks For Geeks",
"GFG");
// print value
System.out.println(" Value is set = "
+ response);
}
}
输出:
Value is set = true
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注:本文由纯净天空筛选整理自AmanSingh2210大神的英文原创作品 AtomicReference compareAndSet() method in Java with Examples。非经特殊声明,原始代码版权归原作者所有,本译文未经允许或授权,请勿转载或复制。