Java LinkedBlockingDeque descendingIterator() method

The descendingIterator() method of LinkedBlockingDeque class returns an iterator over the elements of this queue. The elements are returned in the reverse sequential order.

Syntax:

Parameters:

Specified By:

The descendingIterator() method of LinkedBlockingDeque class is specified by descendingIterator() method of interface Deque<E>.

Return Value:

The descendingIterator() method returns an iterator across the elements of this deque in reverse order.

Example 1

import java.util.Iterator;
import java.util.concurrent.LinkedBlockingDeque;
public class LinkedBlockingDequeDescendingIteratorExample1 {
    public static void main(String[] args) {
        LinkedBlockingDeque<String> deque = new LinkedBlockingDeque<String>();
        deque.add("Reema");
        deque.add("Rahul");
        deque.add("Rita");
        deque.add("Ramesh");
        //returns an iterator over the elements in this deque in reverse sequential order
        Iterator it =  deque.descendingIterator();
        while (it.hasNext()) {
            System.out.println(it.next());
        }
    }
}

Test it Now

Output:

Ramesh
Rita
Rahul
Reema

Example 2

import java.util.Iterator;
import java.util.concurrent.LinkedBlockingDeque;
public class LinkedBlockingDequeDescendingIteratorExample2 {
    public static void main(String[] args) {
        LinkedBlockingDeque<Character> deque = new LinkedBlockingDeque<Character>();
       for (char c ='A';c<='Z';c++){
           deque.add(c);
       }
        System.out.println("Characters : ");
        System.out.print("[");
       for (Character ch : deque){
           System.out.print(ch +",");
       }
        System.out.println("]");
        System.out.println("After reversing the characters : ");
        //returns an iterator over the elements in this deque in reverse sequential order
        Iterator it =  deque.descendingIterator();
        System.out.print("[");
        while (it.hasNext()) {
            System.out.print(it.next()+",");
        }
        System.out.println("]");
    }
}

Test it Now

Output:

Characters : 
[A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z,]
After reversing the characters : 
[Z,Y,X,W,V,U,T,S,R,Q,P,O,N,M,L,K,J,I,H,G,F,E,D,C,B,A,]

Example 3

import java.util.Iterator;
import java.util.concurrent.LinkedBlockingDeque;
public class LinkedBlockingDequeDescendingIteratorExample3 {
    static int i=1;
    public static void main(String[] args) {
        LinkedBlockingDeque<Student> deque = new LinkedBlockingDeque<Student>();
    Student student1 = new Student("15cs1029", "MVN University", "Reema");
    Student student2 = new Student("15cs1010", "MVN University", "Geetanjali");
    Student student3 = new Student("17cs1029", "MR University", "Vineet");
        deque.add(student1);
        deque.add(student2);
        deque.add(student3);
    Iterator<Student> iterator = deque.descendingIterator();
    //Returns a descending iterator over the elements
        while (iterator.hasNext()) {
            System.out.println(i++ + "." + iterator.next());
        }
    }
}
class Student {
    static int i = 1;
    public String name;
    public String college;
    String rollNo;
    Student(String rollNo, String college, String name) {
        this.rollNo = rollNo;
        this.name = name;
        this.college = college;
    }
    public String toString() {
        return ".Roll No. =  " + this.rollNo + "\n  College =  " + this.college + "\n  Name = " + this.name + "\n";
    }
}

Test it Now

Output:

1..Roll No. =  17cs1029
  College =  MR University
  Name = Vineet

2..Roll No. =  15cs1010
  College =  MVN University
  Name = Geetanjali

3..Roll No. =  15cs1029
  College =  MVN University
  Name = Reema

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