AtomicReferenceArray weakCompareAndSetAcquire() method in Java with Examples

The weakCompareAndSetAcquire() 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 at index i with memory ordering effects compatible with memory_order_acquire ordering. This method returns true if set a new value to AtomicRefrence is successful.

Syntax:

public final boolean
       weakCompareAndSetAcquire(
           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 set a new value to AtomicRefrence is successful.

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

// Java program to demonstrate
// weakCompareAndSetAcquire() method

import java.util.concurrent.atomic.*;

public class GFG {

    public static void main(String[] args)
    {

        // create an atomic reference object.
        AtomicReferenceArray<Integer> ref
            = new AtomicReferenceArray<Integer>(5);

        // set some value
        ref.set(0, 543);
        ref.set(1, 123);
        ref.set(2, 5443);

        // apply weakCompareAndSetAcquire()
        boolean result
            = ref.weakCompareAndSetAcquire(
                0,
                5443,
                234);

        // print value
        System.out.println(
            "Setting new value"
            + " is successful = "
            + result);

        System.out.println("Value of index 0 = "
                           + ref.get(0));
    }
}

Output:

Program 2:

// Java program to demonstrate
// weakCompareAndSetAcquire() method

public class GFG {

    public static void main(String[] args)
    {

        // create an atomic reference object.c
        AtomicReferenceArray<String> ref
            = new AtomicReferenceArray<String>(5);

        // set some value
        ref.set(0, "C");
        ref.set(1, "PYTHON");
        ref.set(2, "TS");
        ref.set(3, "C++");
        ref.set(4, "C");

        // apply weakCompareAndSetAcquire()
        boolean result
            = ref.weakCompareAndSetAcquire(
                4,
                "C",
                "JAVA");

        // print value
        System.out.println(
            "Setting new value"
            + " is successful = "
            + result);

        System.out.println(
            "Value of index 4 = "
            + ref.get(4));
    }
}

Output:

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