TreeMap ceilingEntry() and ceilingKey() methods in Java

There are two variants of ceilingEntry() in Java.util.TreeMap, both are discussed in this article.

1. ceilingEntry(K Key) : It is used to return a key-value mapping associated with the least key greater than or equal to the given key, or null if there is no such key.

Syntax : 
public Map.Entry ceilingEntry(K key)
Parameters : 
key : The key to be matched.
Return Value : 
It returns the entry with the least key greater than or equal to key, and null if 
there is no such key.
Exception : 
ClassCastException : It throws the exception if the specified key cannot be compared
with the keys currently in the map.
NullPointerException : It throws the exception if the specified key is null. 

filter_none

edit
close

play_arrow

link
brightness_4
code

// Java code to demonstrate the working of 
// ceilingEntry()
  
import java.io.*;
import java.util.*;
  
public class ceilingEntry1 {
      
  public static void main(String[] args) {
   
  // Declaring the tree map of Integer and String
  TreeMap<Integer, String> treemap = new TreeMap<Integer, String>();
       
  // assigning the values in the tree map
  // using put()
  treemap.put(2, "two");
  treemap.put(7, "seven");
  treemap.put(3, "three");
     
  // Use of ceilingEntry()
  // returns 7=seven ( next greater key-value)
  System.out.println("The next greater key-value of 5 is : " + treemap.ceilingEntry(5));
    
  // returns "null" as no value present
  // greater than or equal to number
  System.out.println("The next greater key-value of 8 is : " + treemap.ceilingEntry(8));
    
  }
}

chevron_right


Output:

The next greater key-value of 5 is : 7=seven
The next greater key-value of 8 is : null

2. ceilingKey(K key) : This has also the same work as that of the upper one but the only difference is that it does not contains the mapped-keys.It simply returns the least key greater or equal to the given key, else returns NULL.

Syntax : 
public K ceilingKey(K key)
Parameters : 
key : The key to be matched.
Return Value : 
It returns the entry with the least key greater than or equal to key, and null 
if there is no such key.
Exception:
ClassCastException : It throws the exception if the specified key cannot be compared
with the keys currently in the map.
NullPointerException : It throws the exception if the specified key is null. 

filter_none

edit
close

play_arrow

link
brightness_4
code

// Java code to demonstrate the working of 
// ceilingKey()
  
import java.io.*;
import java.util.*;
  
public class ceilingKey1 {
      
  public static void main(String[] args) {
   
  // Declaring the tree map of Integer and String
  TreeMap<Integer, String> treemap = new TreeMap<Integer, String>();
       
  // assigning the values in the tree map
  // using put()
  treemap.put(2, "two");
  treemap.put(7, "seven");
  treemap.put(3, "three");
     
  // Use of ceilingKey()
  // returns 7 ( next greater key)
  System.out.println("The next greater key of 5 is : " + treemap.ceilingKey(5));
    
  // returns "null" as no key present
  // greater than or equal to number
  System.out.println("The next greater key of 8 is : " + treemap.ceilingKey(8));
    
  }
}

chevron_right


Output:

The next greater key of 5 is : 7
The next greater key of 8 is : null

This article is contributed by Shambhavi Singh. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above.



My Personal Notes arrow_drop_up


Article Tags :
Practice Tags :


Be the First to upvote.


Please write to us at contribute@geeksforgeeks.org to report any issue with the above content.