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
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