The getAndAccumulate() method of a AtomicReferenceArray class is used to atomically updates the element at index i of AtomicReferenceArray with the results of applying the given accumulatorFunction to the current and given values and returns the previous value. The accumulatorFunction should be side-effect-free, since it may be re-applied when attempted updates fail due to contention among threads. The function is applied with the current value at index i as its first argument, and the given update as the second argument.
Syntax:
public final E getAndAccumulate(int i, E x,
BinaryOperator<E> accumulatorFunction)
Parameters: This method accepts:
- i which is an index of AtomicReferenceArray to perform the operation accepts,
- x which is the updated value and
- accumulatorFunction which is a side-effect-free function of two arguments.
Return value: This method returns the previous value.
Below programs illustrate the getAndAccumulate() method:
Program 1:
// Java program to demonstrate// getAndAccumulate() method import java.util.concurrent.atomic.*;import java.util.function.BinaryOperator; public class GFG { public static void main(String args[]) { // an array Integer a[] = { 123, 1232, 1433, 134, 13415, 1343 }; // AtomicReferenceArray with array AtomicReferenceArray<Integer> array = new AtomicReferenceArray<>(a); // Print AtomicReferenceArray System.out.println( "The AtomicReferenceArray before update: " + array); // Index and Value to apply getAndAccumulate int index = 2; int E = 3; // Declaring the accumulatorFunction // applying function BinaryOperator add = (u, v) -> Integer.parseInt( u.toString()) * Integer .parseInt( v.toString()); // apply getAndAccumulate() int value = array.getAndAccumulate(index, E, add); // print AtomicReferenceArray System.out.println( "previous value of index 2:" + value); System.out.println( "The AtomicReferenceArray after update: " + array); }} |
Output:
Program 2:
// Java program to demonstrate// getAndAccumulate() method import java.util.concurrent.atomic.*;import java.util.function.BinaryOperator; public class GFG { public static void main(String args[]) { // an array String a[] = { "GFG", "JS" }; // AtomicReferenceArray with array AtomicReferenceArray<String> array = new AtomicReferenceArray<>(a); // Print AtomicReferenceArray System.out.println( "The AtomicReferenceArray before update : " + array); // Index and Value to apply getAndAccumulate int index = 1; String E = " PYTHON"; // Declaring the accumulatorFunction // applying function to add value as string BinaryOperator add = (u, v) -> u.toString() + " and " + v.toString(); // apply getAndAccumulate() String value = array.getAndAccumulate(index, E, add); // print AtomicReferenceArray System.out.println( "previous value of index 1:" + value); System.out.println( "The AtomicReferenceArray after update: " + array); }} |
Output:
