BlockingDeque pollLast() method in Java with examples

The pollLast() method of BlockingDeque returns the last element in the Deque container, and deletes it. It returns null if the container is empty.

Syntax:

public E pollLast()

Parameters: This method does not accept any parameters.

Returns: This method returns last element in the Deque container if the container is not empty and deletes the element also. It returns null if the container is empty.

Note: The pollLast() method of BlockingDeque has been inherited from the LinkedBlockingDeque class in Java.

Below programs illustrate pollLast() method of BlockingDeque:

Program 1:

// Java Program Demonstrate pollLast()
// method of BlockingDeque

import java.util.concurrent.LinkedBlockingDeque;
import java.util.concurrent.BlockingDeque;
import java.util.*;

public class GFG {
    public static void main(String[] args)

    {

        // create object of BlockingDeque
        BlockingDeque<Integer> BD
            = new LinkedBlockingDeque<Integer>();

        // Add numbers to end of BlockingDeque
        BD.addFirst(7855642);
        BD.addFirst(35658786);
        BD.addFirst(5278367);
        BD.addFirst(74381793);

        // Print the queue
        System.out.println("Blocking Deque: " + BD);

        // prints and deletes the last element
        System.out.println("Front element in Deque: " + BD.pollLast());

        // prints the Deque after deletion of last element
        System.out.println("Blocking Deque: " + BD);
    }
}

Output:

Blocking Deque: [74381793, 5278367, 35658786, 7855642]
Front element in Deque: 7855642
Blocking Deque: [74381793, 5278367, 35658786]

Program 2:

// Java Program Demonstrate pollLast()
// method of BlockingDeque
// when Deque is empty

import java.util.concurrent.LinkedBlockingDeque;
import java.util.concurrent.BlockingDeque;
import java.util.*;

public class GFG {
    public static void main(String[] args)

    {

        // create object of BlockingDeque
        BlockingDeque<Integer> BD
            = new LinkedBlockingDeque<Integer>();

        // Add numbers to end of BlockingDeque
        BD.add(7855642);
        BD.add(35658786);
        BD.add(5278367);
        BD.add(74381793);

        // Print the queue
        System.out.println("Blocking Deque: " + BD);

        // empty deque
        BD.clear();

        System.out.println("Front element in Deque: " + BD.pollLast());
    }
}

Output:

Blocking Deque: [7855642, 35658786, 5278367, 74381793]
Front element in Deque: null

Reference: https://docs.oracle.com/javase/7/docs/api/java/util/concurrent/BlockingDeque.html#pollLast(long, %20java.util.concurrent.TimeUnit)