LinkedBlockingDeque descendingIterator() method in Java

The descendingIterator() method of LinkedBlockingDeque returns an iterator over the elements in this deque in a reverse sequential order. The elements will be returned in order from last(tail) to first(head). The returned iterator is a “weakly consistent” iterator.

Syntax:

public Iterator descendingIterator()

Parameters: This method does not accept any parameter.

Returns: This method returns an iterator over the elements in this deque in a reverse sequential order.

Below programs illustrate descendingIterator() method of LinkedBlockingDeque:

Program 1:

// Java Program Demonstrate descendingIterator()
// method of LinkedBlockingDeque

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

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

    {

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

        // Add numbers to front of LinkedBlockingDeque
        LBD.addFirst(7855642);
        LBD.addFirst(35658786);
        LBD.addFirst(5278367);
        LBD.addFirst(74381793);

        // Call descendingIterator() method of LinkedBlockingDeque
        Iterator iteratorVals = LBD.descendingIterator();

        // Print elements of iterator
        // created from PriorityBlockingQueue
        System.out.println("The iterator values"
                           + " of LinkedBlockingDeque are:");

        // prints the elements using an iterator
        while (iteratorVals.hasNext()) {
            System.out.println(iteratorVals.next());
        }
    }
}

Output:

The iterator values of LinkedBlockingDeque are:
7855642
35658786
5278367
74381793

Program 2:

// Java Program Demonstrate descendingIterator()
// method of LinkedBlockingDeque
// when list is of strings

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

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

    {

        // create object of LinkedBlockingDeque
        LinkedBlockingDeque<String> LBD
            = new LinkedBlockingDeque<String>();

        // Add numbers to front of LinkedBlockingDeque
        LBD.add("Geeks");
        LBD.add("forGeeks");
        LBD.add("A");
        LBD.add("Computer");
        LBD.add("Portal");

        // Call iterator() method of LinkedBlockingDeque
        Iterator iteratorVals = LBD.descendingIterator();

        // Print elements of iterator
        // created from PriorityBlockingQueue
        System.out.println("The iterator values"
                           + " of LinkedBlockingDeque are:");

        // prints the elements using an iterator
        while (iteratorVals.hasNext()) {
            System.out.println(iteratorVals.next());
        }
    }
}

Output:

The iterator values of LinkedBlockingDeque are:
Portal
Computer
A
forGeeks
Geeks

Reference: https://docs.oracle.com/javase/7/docs/api/java/util/concurrent/LinkedBlockingDeque.html#descendingIterator()