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
