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.
import java.io.*;
import java.util.*;
public class ceilingEntry1 {
public static void main(String[] args) {
TreeMap<Integer, String> treemap = new TreeMap<Integer, String>();
treemap.put( 2 , "two" );
treemap.put( 7 , "seven" );
treemap.put( 3 , "three" );
System.out.println( "The next greater key-value of 5 is : " + treemap.ceilingEntry( 5 ));
System.out.println( "The next greater key-value of 8 is : " + treemap.ceilingEntry( 8 ));
}
}
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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.
import java.io.*;
import java.util.*;
public class ceilingKey1 {
public static void main(String[] args) {
TreeMap<Integer, String> treemap = new TreeMap<Integer, String>();
treemap.put( 2 , "two" );
treemap.put( 7 , "seven" );
treemap.put( 3 , "three" );
System.out.println( "The next greater key of 5 is : " + treemap.ceilingKey( 5 ));
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
Last Updated :
18 Sep, 2023
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