AtomicIntegerArray decrementAndGet() method in Java with Examples

The Java.util.concurrent.atomic.AtomicIntegerArray.decrementAndGet() is an inbuilt method in Java that atomically decrements by one the element at a given index. This method takes the index value and the value to be added as the parameters and returns the updated value at this index. 

Syntax:

public final int decrementAndGet(int i)

Parameters: The function accepts a single parameter i which is the index where decrement by one operation is performed.

Return value: The function returns the updated value which is in Integer.

Below programs illustrate the above method: 

Program 1:

Java

// Java program that demonstrates
// the decrementAndGet() function

import java.util.concurrent.atomic.AtomicIntegerArray;

public class GFG {
    public static void main(String args[])
    {
        // Initializing an array
        int a[] = { 1, 2, 3, 4, 5 };

        // Initializing an AtomicIntegerArray with array a
        AtomicIntegerArray arr = new AtomicIntegerArray(a);

        // Displaying the AtomicIntegerArray
        System.out.println("The array : " + arr);

        // Index where operation is performed
        int idx = 3;

        // Updating the value at
        // idx applying decrementAndGet
        arr.decrementAndGet(idx);

        // Displaying the AtomicIntegerArray
        System.out.println("The array after update : "
                           + arr);
    }
}

Output:

The array : [1, 2, 3, 4, 5]
The array after update : [1, 2, 3, 3, 5]

Program 2:

Java

// Java program that demonstrates
// the decrementAndGet() function

import java.util.concurrent.atomic.AtomicIntegerArray;

public class GFG {
    public static void main(String args[])
    {
        // Initializing an array
        int a[] = { 1, 2, 3, 4, 5 };

        // Initializing an AtomicIntegerArray with array a
        AtomicIntegerArray arr = new AtomicIntegerArray(a);

        // Displaying the AtomicIntegerArray
        System.out.println("The array : " + arr);

        // Index where operation is performed
        int idx = 0;

        // Updating the value at
        // idx applying decrementAndGet
        arr.decrementAndGet(idx);

        // Displaying the AtomicIntegerArray
        System.out.println("The array after update : "
                           + arr);
    }
}

Output:

The array : [1, 2, 3, 4, 5]
The array after update : [0, 2, 3, 4, 5]

Reference: https://docs.oracle.com/javase/7/docs/api/java/util/concurrent/atomic/AtomicIntegerArray.html#decrementAndGet(int)