LinkedBlockingDeque descendingIterator() method in Java

Last Updated : 14 Sep, 2018

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()

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