The compareAndSet() method of a AtomicReferenceArray class is used to atomically sets the value of index i of AtomicReferenceArray to newValue, if the current value at index i of AtomicReferenceArray object is equal to the expectedValue.This method will return true if update is successful.
Syntax:
public final boolean
compareAndSet(
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 and false return indicates that the actual value was not equal to the expected value.
Below programs illustrate the compareAndSet() method:
Program 1:
// Java program to demonstrate// compareAndSet() 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>(3); // set some value ref.set(0, 1234); ref.set(1, 4322); // apply compareAndSet() boolean op1 = ref.compareAndSet(0, 5434, 8913); boolean op2 = ref.compareAndSet(1, 3236, 6543); // print System.out.println("Operation at index 0: " + op1); System.out.println("Operation at index 0: " + op2); }} |
Output:
Operation at index 0: false Operation at index 0: false
Program 2:
// Java program to demonstrate// compareAndSet() method import java.util.concurrent.atomic.*; public class GFG { public static void main(String[] args) { // create an atomic reference object. AtomicReferenceArray<String> ref = new AtomicReferenceArray<String>(3); // set some value ref.set(0, "GFG"); ref.set(1, "JS"); // apply compareAndSet() boolean op1 = ref.compareAndSet( 0, "GFG", "GEEKS FOR GEEKS"); boolean op2 = ref.compareAndSet( 1, "JS", "JAVA SCRIPT"); // print System.out.println("Operation at index 0: " + op1); System.out.println("New value at index 0: " + ref.get(0)); System.out.println("Operation at index 1: " + op2); System.out.println("New value at index 1: " + ref.get(1)); }} |
Output:
Operation at index 0: true New value at index 0: GEEKS FOR GEEKS Operation at index 1: true New value at index 1: JAVA SCRIPT
