Collection Examples,NavigableSet

Navigable Set Example

In the example below we have used NavigableSet method to sort the elements in ascending order, descending order, also to retrieve the element which is immediately greater than or equal to 35 etc. With the help of NavigableSet methods its just a method call to get the result. It is used to return the closest matches of elements for the given elements in the collection.

Description of program:

Inserting the data in the NavigableSet by the add() method. The NavigableSet provides the facility to getting the data in both orders: ascending and descending orders. The descendingSet() method returns the data from the NavigableSet in descending order. If you want to get the data in ascending order must be used an iterator. An iterator stores the data as a index and the hasNext() method returns 'true' until, the next() method returns the element in ascending order.

Here, you remove the element from the NavigableSet at first and last position, you use the pollFirst() and pollLast() methods. Sometimes, you want to get the less and greater than or equal to the given element by using the floor() and ceiling() methods. For getting the all elements of the NavigableSet that is greater than or equal to the given element by the tailSet() method and less than or equal to the given element of the NavigableSet by the headSet() method.

Here is the code of program:


import java.util.*;

import java.util.concurrent.*;



public class NavigableSetExample{

  public static void main(String[] args) {

    System.out.println("Navigable set Example!\n");

    NavigableSet <Integer>nSet = new ConcurrentSkipListSet<Integer>();

    nSet.add(10);

    nSet.add(20);

    nSet.add(50);

    nSet.add(30);

    nSet.add(100);

    nSet.add(80);

    // Returns an iterator over the elements in navigable set,

                  
 in ascending order.

    Iterator iterator = nSet.iterator();

    System.out.print("Ascending order navigable set: ");

    //Ascending order list

    while (iterator.hasNext()){

      System.out.print(iterator.next() + " ");

    }

    System.out.println();

    //Descending order list

    System.out.println("Descending order navigable set: " + 

                            
nSet.descendingSet() + "\n");

    //Greater than or equal to the given element

    System.out.println("Least element in Navigable set greater than 

                        
or equal to 35: " + nSet.ceiling(35));

    //Less than or equal to the given element

    System.out.println("Greatest element in Navigable set less than 

                        
or equal to 35: " + nSet.floor(35) + "\n");

    //Viewing the portion of navigable set whose elements are 

                         
strictly less than the given element

    System.out.println("Navigable set whose elements are strictly 

                        
less than '40': " + nSet.headSet(40));

    //Viewing the portion of navigable set whose elements are 

                 
greater than or equal to the given element

    System.out.println("Navigable set whose elements are greater 

               
than or equal to '40': " + nSet.tailSet(40) + "\n");

    //Removing first element from navigable set

    System.out.println("Remove element: "+nSet.pollFirst());

    //After removing the first element, now get navigable set

    System.out.println("Now navigable set: " + nSet.descendingSet() + "\n");

    //Removing last element from navigable set

    System.out.println("Remove element: " + nSet.pollLast());

    //After removing the last element, now get navigable set

    System.out.println("Now navigable set: " + nSet.descendingSet());

  }

}

Output of this program

C:\vinod\collection>javac NavigableSetExample.java

C:\vinod\collection>java NavigableSetExample
Navigable set Example!

Ascending order navigable set: 10 20 30 50 80 100
Descending order navigable set: [100, 80, 50, 30, 20, 10]

Least element in Navigable set greater than or equal to 35: 50
Greatest element in Navigable set less than or equal to 35: 30

Navigable set whose elements are strictly less than '40': [10, 20, 30]
Navigable set whose elements are greater than or equal to '40': [50, 80, 100]

Remove element: 10
Now navigable set: [100, 80, 50, 30, 20]

Remove element: 100
Now navigable set: [80, 50, 30, 20]

C:\vinod\collection>