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.
// 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 ));
}
} |
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.
// 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 ));
}
} |
Output:
The next greater key of 5 is : 7 The next greater key of 8 is : null