Java中的 AtomicIntegerArray getAndSet() 方法及示例

Java.util.concurrent.atomic.AtomicIntegerArray.getAndSet()是Java中的一个内置方法，它以原子方式在 AtomicIntegerArray 的任何给定位置设置给定值。该方法将 AtomicIntegerArray 的索引值和要设置的值作为参数。它在给定索引处设置新值之前返回给定索引处的值。 getAndSet()函数类似于set()函数，但前者返回值，而后者不返回任何值。

句法：

public final int getAndSet(int i, int newValue)

参数：该函数接受两个参数：

• i – 要进行更新的索引。
• newValue – 在索引i处设置的值

返回值：该函数返回更新前给定索引处的值，该值位于Integer中。

下面的程序说明了上述方法：

方案一：

// Java program that demonstrates
// the getAndSet() function
  
import java.util.concurrent.atomic.AtomicIntegerArray;
  
public class GFG {
    public static void main(String args[])
    {
        // Initializing an array
        int a[] = { 11, 12, 13, 14, 15 };
  
        // Initializing an AtomicIntegerArray with array a
        AtomicIntegerArray arr = new AtomicIntegerArray(a);
  
        // Displaying the AtomicIntegerArray
        System.out.println("The array : " + arr);
  
        // Index where operation is performed
        int idx = 0;
  
        // New value to set at idx
        int val = 100;
  
        // Updating the value at
        // idx applying getAndSet
        // and store previous value
        int prev = arr.getAndSet(idx, val);
  
        // Previous value at idx before update
        System.out.println("Value at index " + idx
                           + " before the update is "
                           + prev);
  
        // Displaying the AtomicIntegerArray
        System.out.println("The array after update : "
                           + arr);
    }
}

输出：

The array : [11, 12, 13, 14, 15]
Value at index 0 before the update is 11
The array after update : [100, 12, 13, 14, 15]

方案二：

// Java program that demonstrates
// the getAndSet() function
  
import java.util.concurrent.atomic.AtomicIntegerArray;
  
public class GFG {
    public static void main(String args[])
    {
        // Initializing an array
        int a[] = { 11, 12, 13, 14, 15 };
  
        // Initializing an AtomicIntegerArray with array a
        AtomicIntegerArray arr = new AtomicIntegerArray(a);
  
        // Displaying the AtomicIntegerArray
        System.out.println("The array : " + arr);
  
        // Index where operation is performed
        int idx = 3;
  
        // New value to set at idx
        int val = 10;
  
        // Updating the value at
        // idx applying getAndSet
        // and store previous value
        int prev = arr.getAndSet(idx, val);
  
        // Previous value at idx before update
        System.out.println("Value at index " + idx
                           + " before the update is "
                           + prev);
  
        // Displaying the AtomicIntegerArray
        System.out.println("The array after update : "
                           + arr);
    }
}

输出：

The array : [11, 12, 13, 14, 15]
Value at index 3 before the update is 14
The array after update : [11, 12, 13, 10, 15]

参考： https: Java/util/concurrent/atomic/AtomicIntegerArray.html#getAndSet(int, %20int)