AtomicLongArray getAndIncrement() method in Java with Examples

Last Updated : 08 Feb, 2019

The Java.util.concurrent.atomic.AtomicLongArray.getAndIncrement() is an inbuilt method in Java that atomically increments the value present at any index of an AtomicLongArray by one. The method takes the index value of the AtomicLongArray as the parameter, returns the value at that index before the increment and then increments the value at that index. The function getAndIncrement() is similar to the incrementAndGet() function but the former returns the value before the increment while the latter returns the value after the increment operation. Syntax:

public final long getAndIncrement(int i)

Parameters: The function accepts a single parameter i which is the index where increment by one operation is performed. Return value: The function returns the previous value at that index before the update which is in long. Below programs illustrate the above method: Program 1:

Java

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

import java.util.concurrent.atomic.AtomicLongArray;

public class GFG {
    public static void main(String args[])
    {
        // Initializing an array
        long a[] = { 11, 12, 13, 14, 15 };

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

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

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

        // Updating the value at
        // idx applying getAndIncrement
        // and storing the previous value
        long prev = arr.getAndIncrement(idx);

        // Previous value at idx before update
        System.out.println("Value at index " + idx
                           + " before the update is "
                           + prev);

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

Output:

The array : [11, 12, 13, 14, 15]
Value at index 0 before the update is 11
The array after update : [12, 12, 13, 14, 15]

Program 2:

Java

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

import java.util.concurrent.atomic.AtomicLongArray;

public class GFG {
    public static void main(String args[])
    {
        // Initializing an array
        long a[] = { 11, 12, 13, 14, 15 };

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

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

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

        // Updating the value at
        // idx applying getAndIncrement
        // and storing the previous value
        long prev = arr.getAndIncrement(idx);

        // Previous value at idx before update
        System.out.println("Value at index " + idx
                           + " before the update is "
                           + prev);

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

Output:

The array : [11, 12, 13, 14, 15]
Value at index 3 before the update is 14
The array after update : [11, 12, 13, 15, 15]

Note: The function getAndIncrement() is similar to incrementAndGet() but the latter function returns the updated value whereas the former returns previous value after the update. Reference:https://docs.oracle.com/javase/8/docs/api/java/util/concurrent/atomic/AtomicLongArray.html#getAndIncrement-int-