Java AtomicReference getAndAccumulate()用法及代碼示例

AtomicReference類的getAndAccumulate()方法用於原子地更新AtomicReference的當前值，並將給定的accumulatorFunction應用於當前值和給定值，並返回先前的值。 accumulatorFunction應該沒有副作用，因為當嘗試更新由於線程之間的爭用而失敗時，可能會重新應用accumulatorFunction。應用該函數時，將當前值作為其第一個參數，並將給定的update作為第二個參數。

用法:

public final E getAndAccumulate(E x,
     BinaryOperator<E> accumulatorFunction)

參數：此方法接受：

x這是更新的值，
accumulatorFunction這是兩個參數的無副作用函數。

返回值：此方法返回prevoius值。

以下示例程序旨在說明getAndAccumulate()方法：
程序1:

// Java program to demonstrate 
// AtomicReference.getAndAccumulate() method 
  
import java.util.concurrent.atomic.*; 
import java.util.function.BinaryOperator; 
  
public class GFG { 
    public static void main(String args[]) 
    { 
  
        // AtomicReference with value 
        AtomicReference<Integer> ref 
            = new AtomicReference<>(3456); 
  
        // Value to apply getAndAccumulate 
        int x = 45654; 
  
        // Declaring the accumulatorFunction 
        // applying function to add value as string 
        BinaryOperator add 
            = (u, v) -> u.toString() + v.toString(); 
  
        // apply getAndAccumulate() 
        int value = ref.getAndAccumulate(x, add); 
  
        // print AtomicReference 
        System.out.println( 
            "The AtomicReference previous value:"
            + value); 
        System.out.println( 
            "The AtomicReference new value:"
            + ref.get()); 
    } 
}

輸出：

程序2:

// Java program to demonstrate 
// AtomicReference.getAndAccumulate() method 
  
import java.util.concurrent.atomic.*; 
import java.util.function.BinaryOperator; 
  
public class GFG { 
    public static void main(String args[]) 
    { 
        // AtomicReference with value 
        AtomicReference<String> ref 
            = new AtomicReference<String>("GFG "); 
  
        // Value to apply getAndAccumulate 
        String x = "Welcome"; 
  
        // Declaring the accumulatorFunction 
        // applying function to add value as string 
        BinaryOperator add 
            = (u, v) -> v + " to " + u; 
  
        // apply getAndAccumulate() 
        String previousValue 
            = ref.getAndAccumulate(x, add); 
  
        // print AtomicReference 
        System.out.println( 
            "The AtomicReference previous value:"
            + previousValue); 
    } 
}

輸出：

參考文獻： https://docs.oracle.com/javase/10/docs/api/java/util/concurrent/atomic/AtomicReference.html#getAndAccumulate(V, java.util.function.BinaryOperator)

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注：本文由純淨天空篩選整理自AmanSingh2210大神的英文原創作品 AtomicReference getAndAccumulate() method in Java with Examples。非經特殊聲明，原始代碼版權歸原作者所有，本譯文未經允許或授權，請勿轉載或複製。