Java AtomicReferenceArray getAndSet()用法及代码示例

AtomicReferenceArray类的getAndSet()方法用于原子地将AtomicReferenceArray对象的索引i的值设置为newValue，该值作为参数传递并返回AtomicReferenceArray对象的旧值，具有由VarHandle.getAndSet(java.lang .Object…).VarHandle.getAndSet(java.lang.Object…)指定将变量作为设置的内存语义，就像将该变量声明为volatile一样。

用法:

public final E getAndSet(int i, E newValue)

参数：此方法接受：

i这是执行操作的AtomicReferenceArray的索引，
newValue 这是要设置的新值。

返回值：此方法返回索引i的旧值。

以下示例程序旨在说明getAndSet()方法：
程序1:

// Java program to demonstrate 
// AtomicReferenceArray.getAndSet() method 
  
import java.util.concurrent.atomic.*; 
  
public class GFG { 
    public static void main(String[] args) 
    { 
        // create an atomic reference object. 
        AtomicReferenceArray<Integer> ref 
            = new AtomicReferenceArray<Integer>(3); 
  
        // set some value 
        ref.set(0, 1234); 
        ref.set(1, 4322); 
  
        // apply getAndSet() 
        int oldV1 = ref.getAndSet(0, 8913); 
        int oldV2 = ref.getAndSet(1, 6543); 
  
        // print 
        System.out.println("Old value at index 0:"
                           + oldV1); 
        System.out.println("New value at index 0:"
                           + ref.get(0)); 
        System.out.println("Old value at index 1:"
                           + oldV2); 
        System.out.println("New value at index 1:"
                           + ref.get(1)); 
    } 
}

输出：

Old value at index 0:1234
New value at index 0:8913
Old value at index 1:4322
New value at index 1:6543

程序2:

// Java program to demonstrate 
// AtomicReferenceArray.getAndSet() method 
  
import java.util.concurrent.atomic.*; 
  
public class GFG { 
    public static void main(String[] args) 
    { 
        // create an atomic reference object. 
        AtomicReferenceArray<String> ref 
            = new AtomicReferenceArray<String>(3); 
  
        // set some value 
        ref.set(0, "GFG"); 
        ref.set(1, "JS"); 
  
        // apply getAndSet() 
        String oldV1 
            = ref.getAndSet(0, "GEEKS FOR GEEKS"); 
        String oldV2 
            = ref.getAndSet(1, "JAVA SCRIPT"); 
  
        // print 
        System.out.println( 
            "Old value at index 0:"
            + oldV1); 
        System.out.println( 
            "New value at index 0:"
            + ref.get(0)); 
        System.out.println( 
            "Old value at index 1:"
            + oldV2); 
        System.out.println( 
            "New value at index 1:"
            + ref.get(1)); 
    } 
}

输出：

Old value at index 0:GFG
New value at index 0:GEEKS FOR GEEKS
Old value at index 1:JS
New value at index 1:JAVA SCRIPT

参考文献： https://docs.oracle.com/javase/10/docs/api/java/util/concurrent/atomic/AtomicReferenceArray.html#getAndSet(int, E)

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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 AtomicReferenceArray getAndSet() 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。