Latest Tutorials| Questions and Answers|Ask Questions?|Site Map



Home Java Jdk6 Navigable Map Example

Related Tutorials


 
 

Share on Google+Share on Google+

Navigable Map Example

Advertisement
In NavigableMap we use methods to return the key value pair like navMap.put(1, "January"); whereas in NavigableSet we use methods to return values. ConcurrentSkipListMap is the one of the class which implements NavigableMap.

Navigable Map Example

     

We already know that NavigableMap is similar to NavigableSet. In NavigableMap we use methods to return the key value pair like navMap.put(1, "January"); whereas in NavigableSet we use methods to return values. ConcurrentSkipListMap is the one of the class which implements NavigableMap. Lets have a look at the example.

Description of program:

The following program helps you in inserting, removing and retrieving the data from the NavigableMap. It uses the put() method to add the element. If you want to retrieve the data at first and last position from the NavigableMap, you use the firstEntry() and lastEntry() methods. The descendingMap() method represents all data to the NavigableMap in descending order. 

You can retrieve the nearest less than or equal to the given number and the greatest key strictly less than the given number floorEntry() and lowerEntry() methods. And you retrieve a key-value associated with the least key strictly greater than the given key, you use the higherEntry() method. The pollFirstEntry() method removes the first data from the NavigableMap and pollLastEntry() method also removes the data at the last position from the NavigableMap.

Here is the code of program:

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

public class NavigableMapExample{
  public static void main(String[] args) {
  System.out.println("Navigable Map Example!\n");
  NavigableMap <Integer, String>navMap = new 
  
ConcurrentSkipListMap<Integer, String>();
  navMap.put(1"January");
  navMap.put(2"February");
  navMap.put(3"March");
  navMap.put(4"April");
  navMap.put(5"May");
  navMap.put(6"June");
  navMap.put(7"July");
  navMap.put(8"August");
  navMap.put(9"September");
  navMap.put(10"October");
  navMap.put(11"November");
  navMap.put(12"December");
  //Displaying all data
  System.out.println("Data in the navigable map: " 
    navMap.descendingMap
()+"\n");
  //Retrieving first data
  System.out.print("First data: " + navMap.firstEntry()+"\n");
  //Retrieving last data
  System.out.print("Last data: " + navMap.lastEntry()+"\n\n");
  //Retrieving the nreatest less than or equal to the given key
  System.out.print("Nearest less than or equal to the given key: " 
 
+ navMap.floorEntry(5)+"\n");
  //Retrieving the greatest key strictly less than the given key
  System.out.println("Retrieving the greatest key strictly less than 
   the given key: " 
+ navMap.lowerEntry(3));
  //Retrieving a key-value associated with the least key 
  strictly greater than the given key

  System.out.println("Retriving data from navigable map greter than 
   the given key: " 
+ navMap.higherEntry(5)+"\n");
  //Removing first
  System.out.println("Removing First: " + navMap.pollFirstEntry());
  //Removing last
  System.out.println("Removing Last: " + navMap.pollLastEntry()+"\n");
  //Displaying all data
  System.out.println("Now data: " + navMap.descendingMap());
  }
}

Download this example.

Output of program:

C:\vinod\collection>javac NavigableMapExample.java

C:\vinod\collection>java NavigableMapExample
Navigable Map Example!

Data in the navigable map: {12=December, 11=November, 10=October, 9=September, 8
=August, 7=July, 6=June, 5=May, 4=April, 3=March, 2=February, 1=January}

First data: 1=January
Last data: 12=December

Nearest less than or equal to the given key: 5=May
Retrieving the greatest key strictly less than the given key: 2=February
Retriving data from navigable map greter than the given key: 6=June

Removing First: 1=January
Removing Last: 12=December

Now data: {11=November, 10=October, 9=September, 8=August, 7=July, 6=June, 5=May
, 4=April, 3=March, 2=February}

C:\vinod\collection>
Advertisement

If you enjoyed this post then why not add us on Google+? Add us to your Circles



Liked it!  Share this Tutorial


Follow us on Twitter, or add us on Facebook or Google Plus to keep you updated with the recent trends of Java and other open source platforms.

Posted on: June 22, 2007

Related Tutorials

Discuss: Navigable Map Example  

Post your Comment


Your Name (*) :
Your Email :
Subject (*):
Your Comment (*):
  Reload Image
 
 
Comments:1
Rajesh
March 30, 2012
compie time error of this program............

it is showing the compie time error .. in place of navigablemap we should use the concuurentskiplistmap class..check it once
DMCA.com