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 AtomicReference 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

// 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

// 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)