Java 中的 AtomicInteger compareAndSet()方法，带示例
原文:https://www . geeksforgeeks . org/atomicinteger-compareandset-method-in-Java-with-examples/
java . util . concurrent . atomic . atomicnteger . compareandset()是 Java 中的一个内置方法，如果当前值等于也在参数中传递的预期值，则将该值设置为参数中传递的值。该函数返回一个布尔值，它告诉我们更新是否完成。
语法:
公共最终布尔比较数据集(int expect，int val)
参数:该功能接受两个强制参数，如下所述:
- expect: 指定原子对象应该是的值。
- val: 指定原子整数等于期望值时要更新的值。
返回值:函数返回一个布尔值，成功则返回真，否则返回假。
下面的程序演示了该功能:
程序 1:
// Java Program to demonstrates
// the compareAndSet() function
import java.util.concurrent.atomic.AtomicInteger;
public class GFG {
public static void main(String args[])
{
// Initially value as 0
AtomicInteger val = new AtomicInteger(0);
// Prints the updated value
System.out.println("Previous value: "
+ val);
// Checks if previous value was 0
// and then updates it
boolean res = val.compareAndSet(0, 6);
// Checks if the value was updated.
if (res)
System.out.println("The value was"
+ " updated and it is "
+ val);
else
System.out.println("The value was "
+ "not updated");
}
}
输出:
Previous value: 0
The value was updated and it is 6
程序二:
// Java Program to demonstrates
// the compareAndSet() function
import java.util.concurrent.atomic.AtomicInteger;
public class GFG {
public static void main(String args[])
{
// Initially value as 0
AtomicInteger val
= new AtomicInteger(0);
// Prints the updated value
System.out.println("Previous value: "
+ val);
// Checks if previous value was 0
// and then updates it
boolean res = val.compareAndSet(10, 6);
// Checks if the value was updated.
if (res)
System.out.println("The value was"
+ " updated and it is "
+ val);
else
System.out.println("The value was "
+ "not updated");
}
}
输出:
Previous value: 0
The value was not updated
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