AtomicReferenceArray weakCompareAndSetVolatile() method in Java with Examples

The weakCompareAndSetVolatile() method of a AtomicReferenceArray class is used to atomically sets the value of the element at index i to newValue to newValue for AtomicReferenceArray if the current value is equal to expectedValue passed as parameter. This method updates the value with memory effects as specified by VarHandle.weakCompareAndSet(java.lang.Object…).This method returns true if set a new value to AtomicRefrence is successful.

Syntax:

public final boolean
       weakCompareAndSetVolatile(int i,
                                 E expectedValue,
                                 E newValue)

Parameters: This method accepts i which is an index of AtomicReferenceArray to perform the operation, expectedValue which is the expected value and newValue which is the new value to set.

Return value: This method returns true if successful.

Below programs illustrate the weakCompareAndSetVolatile() method:
Program 1:

// Java program to demonstrate AtomicReferenceArray 
// weakCompareAndSetVolatile() method 
  
import java.util.concurrent.atomic.AtomicReferenceArray; 
  
public class GFG { 
    public static void main(String[] args) 
    { 
  
        // create an atomic reference object. 
        AtomicReferenceArray<Double> ref 
            = new AtomicReferenceArray<Double>(5); 
  
        // set some value 
        ref.set(1, 1234.00); 
        ref.set(0, 2234.00); 
        ref.set(2, 3234.00); 
  
        // apply weakCompareAndSetVolatile() 
        boolean result 
            = ref.weakCompareAndSetVolatile(1, 124.00, 
                                            234.32); 
  
        // print value 
        System.out.println("Setting new value"
                           + " is successful = "
                           + result); 
  
        System.out.println("Value of index 1 = "
                           + ref.get(1)); 
    } 
} 

Output:

Program 2:

// Java program to demonstrate AtomicReferenceArray 
// weakCompareAndSetVolatile() method 
  
import java.util.concurrent.atomic.AtomicReferenceArray; 
  
public class GFG { 
    public static void main(String[] args) 
    { 
  
        // create an atomic reference object. 
        AtomicReferenceArray<String> ref 
            = new AtomicReferenceArray<String>(5); 
  
        // set some value 
        ref.set(0, "AMANDIP"); 
        ref.set(1, "AMAN"); 
  
        // apply weakCompareAndSetVolatile() 
        boolean result 
            = ref.weakCompareAndSetVolatile( 
                0, 
                "AMARDIP", 
                "AMAR"); 
  
        // print value 
        System.out.println("Setting new value"
                           + " is successful = "
                           + result); 
  
        System.out.println("Value of index 0 = "
                           + ref.get(0)); 
    } 
} 

Output:

References: https://docs.oracle.com/javase/10/docs/api/java/util/concurrent/atomic/AtomicReferenceArray.html#weakCompareAndSetVolatile(V, V)

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