Java SortedSet

Overview

The SortedSet interface present in java.util package extends the Set interface present in the collection framework. It provides a total ordering of its elements. The elements are ordered using their natural ordering, or by a Comparator typically provided at sorted set creation time. This interface contains methods that extends from Set Interface.

In the above image, the navigable set extends the SortedSet interface. Since a Set doesn’t retain the insertion order, the navigable set interface provides the implementation to navigate through the Set. The class which implements the navigable set is a TreeSet which is an implementation of a self-balancing tree. Therefore, this interface provides us with a way to navigate through this tree.

Declaration

public interface SortedSet extends Set

Initialize SortedSet Objects

As SortedSet is an interface, objects cannot be created of the type SortedSet. We always need a class which extends this list in order to create an object. The type-safe can be defined as :

SortedSet<String> set = new TreeSet<String> ();

SortedSet Example

package com.techijournal.sets;

import java.util.Iterator;
import java.util.SortedSet;
import java.util.TreeSet;

public class SortedSetExample {
	public static void main(String[] args) {
		SortedSet<String> ts = new TreeSet<String>();

		// using add()
		ts.add("Sumanth");
		ts.add("Durgesh");
		ts.add("Ritesh");

		// Adding the duplicate element
		ts.add("Durgesh");
		System.out.println(ts);

		// Removing items from TreeSet
		ts.remove("Ritesh");
		System.out.println("Set after removing Reitesh is : " + ts);

		// Iterating over Tree set items
		System.out.println("Iterating over set : ");
		Iterator<String> i = ts.iterator();
		while (i.hasNext()) {
			System.out.println(i.next());
		}
	}
}

Output :
[Durgesh, Ritesh, Sumanth]
Set after removing Reitesh is : [Durgesh, Sumanth]
Iterating over set : 
Durgesh
Sumanth

SortedSet Methods

Various operations on SortedSet

All the elements of a SortedSet must implement the Comparable interface and all such elements must be mutually comparable. Mutually Comparable simply means that two objects accept each other as the argument to their compareTo method. The class which implements the SortedSet interface is TreeSet.

Adding Elements

In the examples we are using TreeSet as it implements SortedSet. It behaves like a simple set with the exception that it stores elements in a sorted format. TreeSet uses a tree data structure for storage. Let’s see how to create a sortedset object using this class.

package com.techijournal.sets;

import java.util.SortedSet;
import java.util.TreeSet;

public class SortedSetOperations {
	public static void main(String[] args) {
		SortedSet<String> ts = new TreeSet<String>();
		// Elements are added using add() method
		ts.add("Sumanth");
		ts.add("Durgesh");
		ts.add("Anjan");
		ts.add("Anil");
		System.out.println(ts);
	}
}

Output :
[Anil, Anjan, Durgesh, Sumanth]

Removing the Elements

The values can be removed from the SortedSet using the remove() method.

package com.techijournal.sets;

import java.util.SortedSet;
import java.util.TreeSet;

public class SortedSetOperations {
	public static void main(String[] args) {
		SortedSet<String> ts = new TreeSet<String>();
		// Elements are added using add() method
		ts.add("Sumanth");
		ts.add("Durgesh");
		ts.add("Anjan");
		ts.add("Anil");
		System.out.println("Initial TreeSet        " + ts);

		// Removing the element b
		ts.remove("Anjan");

		System.out.println("After removing element " + ts);
	}
}

Output : 
Initial TreeSet        [Anil, Anjan, Durgesh, Sumanth]
After removing element [Anil, Durgesh, Sumanth]

Iterating Elements

There are multiple ways to iterate through the SortedSet. One of the way is using enchanced for loop.

package com.techijournal.sets;

import java.util.SortedSet;
import java.util.TreeSet;

public class SortedSetOperations {
	public static void main(String[] args) {
		SortedSet<String> ts = new TreeSet<String>();
		// Elements are added using add() method
		ts.add("Sumanth");
		ts.add("Durgesh");
		ts.add("Anjan");
		ts.add("Anil");
		// Iterating though the SortedSet 
		for (String value : ts)
			System.out.print(value + ", ");
		System.out.println();
	}
}

Output : 
Anil, Anjan, Durgesh, Sumanth,

Conclusion

There is a lot more you can do with a SortedSet which will be discussed in further posts. A SortedSet is a Collection that cannot contain duplicate elements and implemented by other classes.

Thanks, Note

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