Java AtomicReference weakCompareAndSetVolatile()用法及代碼示例

如果當前值等於作為參數傳遞的ExpectedValue，則使用AtomicReference類的weakCompareAndSetVolatile()方法為AtomicReference原子地將值設置為newValue。此方法使用VarHandle.weakCompareAndSet(java.lang.Object…)指定的具有 memory 效應的值來更新該值。如果成功將AtomicRefrence設置為新值，則此方法返回true。

用法:

public final boolean 
       weakCompareAndSetVolatile(V expectedValue,
                                 V newValue)

參數：該方法接受ExpectedValue(期望值)和newValue(新值)來設置新值。

返回值：如果成功，則此方法返回true。

以下示例程序旨在說明weakCompareAndSetVolatile()方法：
程序1:

// Java program to demonstrate 
// AtomicReference.weakCompareAndSetVolatile() method 
  
import java.util.concurrent.atomic.AtomicReference; 
  
public class GFG { 
    public static void main(String[] args) 
    { 
  
        // create an atomic reference object. 
        AtomicReference<Double> ref 
            = new AtomicReference<Double>(); 
  
        // set some value 
        ref.set(1234.00); 
  
        // apply weakCompareAndSetVolatile() 
        boolean result 
            = ref.weakCompareAndSetVolatile(124.00, 
                                            234.32); 
  
        // print value 
        System.out.println("Setting new value"
                           + " is successful = "
                           + result); 
  
        System.out.println("Value = " + ref.get()); 
    } 
}

輸出：

程序2:

// Java program to demonstrate 
// AtomicReference.weakCompareAndSetVolatile() method 
  
import java.util.concurrent.atomic.AtomicReference; 
  
public class GFG { 
    public static void main(String[] args) 
    { 
  
        // create an atomic reference object which stores String. 
        AtomicReference<String> ref = new AtomicReference<String>(); 
  
        // set some value 
        ref.set("GFG"); 
  
        // apply weakCompareAndSetVolatile() 
        boolean result 
            = ref.weakCompareAndSetVolatile( 
                "GFG", 
                "GEEKS FOR GEEKS"); 
  
        // print value 
        System.out.println("Setting new value"
                           + " is successful = "
                           + result); 
        System.out.println("Value  = " + ref.get()); 
    } 
}

輸出：

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

相關用法

注：本文由純淨天空篩選整理自AmanSingh2210大神的英文原創作品 AtomicReference weakCompareAndSetVolatile() 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。