The SortedSet interface of the Java Collections framework is used to store elements with some order in a set. In order to use the functionalities of the SortedSet interface, we need to use the TreeSet class that implements it.
To use SortedSet, we must import the java.util.SortedSet package first.
// SortedSet implementation by TreeSet class
SortedSet<String> animals = new TreeSet<>();
The SortedSet interface includes all the methods of the Set interface. It's because Set is a super interface of SortedSet. Besides methods included in the Set interface, the SortedSet interface also includes these methods:
| Method Name | Description |
|---|---|
| comparator() | returns a comparator that can be used to order elements in the set. |
| first() | returns the first element of the set. |
| last() | returns the last element of the set. |
| headSet(element) | returns all the elements of the set before the specified element. |
| tailSet(element) | returns all the elements of the set after the specified element including the specified element. |
| subSet(element1, element2) | returns all the elements between the element1 and element2 including element1. |
import java.util.SortedSet;
import java.util.TreeSet;
public class SortedSetExample {
public static void main(String[] args) {
// Creating SortedSet using the TreeSet
SortedSet<Integer> numbers = new TreeSet<>();
// Insert elements to the set
numbers.add(1);
numbers.add(2);
numbers.add(3);
numbers.add(4);
System.out.println("SortedSet: " + numbers);
// Access the element
int firstNumber = numbers.first();
System.out.println("First Number: " + firstNumber);
int lastNumber = numbers.last();
System.out.println("Last Number: " + lastNumber);
// Remove elements
boolean result = numbers.remove(2);
System.out.println("Is the number 2 removed? " + result);
}
}