Java Set Interface

What is Set Interface in Java: The Basics

• add()
• remove()
• contains()

Set set = new HashSet<>();
set.add("Red");
set.add("Blue");
set.add("Green");
set.clear();

Core Features of Java Set Interface

Set numbers = new HashSet<>();
numbers.add(1);
numbers.add(2);
numbers.add(3);
numbers.add(1);
System.out.println(numbers);

Exploring Set Interface Methods in Java

Key Functions and Uses of Set Interface Methods in Java

• add(E e)
• remove(Object o)
• contains(Object o)
• size()
• isEmpty()
• iterator()
• clear()

Set cities = new HashSet<>();
boolean isAdded = cities.add("London");
if(!isAdded) {
    System.out.println("Element already exists in the set.");
}

Java Set Interface Example: Practical Insight

import java.util.*;
public class SetExample {
    public static void main(String[] args) {
        Set namesSet = new HashSet<>();
        Scanner sc = new Scanner(System.in);
        String name = "";

        while(!name.equals("STOP")) {  
            System.out.println("Enter a name or type 'STOP' to finish:");
            name = sc.nextLine();
            boolean isAdded = namesSet.add(name);
            if(!isAdded) {
                System.out.println("The name already exists in the list.");
            }
        }
        sc.close();

        System.out.println("List of unique names:");
        for(String s : namesSet) {
            System.out.println(s);
        }
    }
}

Distinguishing List and Set Interface in Java

Comparing Characteristics: List vs Java Set Interface

List list = new ArrayList<>();
list.add("Java");
list.add("Java");

Set set = new HashSet<>();
set.add("Java");
set.add("Java");

System.out.println(list.size()); // Prints 2
System.out.println(set.size()); // Prints 1

Making the Most of List and Set Interface in Java: Practical Tips

Implementing Set Interface in Java Collections

Mastering the Implementation of Set Interface in Java Collections

• HashSet: It's the most frequently used Set Interface implementation. However, it doesn't guarantee any order of elements. Especially suited for quick search operations, its computational complexity for fundamental operations such as add, remove, and contains is approximately \(O(1)\).
• TreeSet: To keep elements in a sorted order, TreeSet is used. It implements the NavigableSet Interface, which extends the SortedSet Interface. It's less preferred for operations that require time efficiency due to \(O(\log(n))\) time complexity. Nonetheless, it ensures the elements stay sorted, which might be necessary in certain circumstances.
• LinkedHashSet: This strikes a balance between HashSet's performance benefits and the ordered nature of the TreeSet. It maintains a LinkedList of the entries providing predictable iteration order, which is typically the insertion order. While it's slightly slower than HashSet due to linkage maintenance, it still offers considerably good performance.

import java.util.HashSet;

HashSet set = new HashSet<>();

set.add("Apple");
set.add("Banana");
set.add("Cherry");
System.out.println(set.contains("Banana")); // Prints true

Examples of Java Collections Using Set Interface

import java.util.HashSet;

class Book {
    String isbn;
    String title;
    
    // constructors, getters and setters omitted for brevity
}

HashSet library = new HashSet<>();

library.add(new Book("978-0201633610", "Design Patterns"));
library.add(new Book("978-0590353403", "Harry Potter and the Sorcerer's Stone"));
library.add(new Book("978-0201633610", "Design Patterns"));

System.out.println(library.size()); // Prints 2

import java.util.LinkedHashSet;

LinkedHashSet registrationQueue = new LinkedHashSet<>();

registrationQueue.add("Alice");
registrationQueue.add("Bob");
registrationQueue.add("Charlie");
registrationQueue.add("Alice");

System.out.println(registrationQueue.toString()); // Prints [Alice, Bob, Charlie]

How Does Java Set Interface Work: Unravelling the Process

Developing Understanding: How does Java Set Interface Function

• Uniqueness of Elements: Being a set, this interface inherently rejects duplicate values. Think of it as a bundle of unique items, much like unique ISBNs of books or individual ID numbers. The interface employs a method named .equals() to verify if an object is a duplicate.
• Regular Methods: The Set Interface features the same methods as the Collection interface, including add, remove, clear, contains, and size. Each is used for manipulation and retrieval of items.
• Static Methods: Since Java 8, four new static methods have been added: copyOf, of, sorted, and unordered. Notably, the of() and copyOf() methods were added in Java 9 and are used for creating an unmodifiable set in an efficient way.
• Null Element: The Set Interface generally allows a null element. However, in the case of class implementations like TreeSet, null values are not permitted.

Practical Demonstration: Operational Mechanism of Java Set Interface

import java.util.*;

public class Main {
    public static void main(String[] args) {
        Set set1 = new HashSet<>();
        Set set2 = new TreeSet<>();
        Set set3 = new LinkedHashSet<>();

        for (String fruit : new String[]{"Apple", "Banana", "Cherry", "Apple"}) {
            set1.add(fruit);
            set2.add(fruit);
            set3.add(fruit);
        }

        System.out.println(set1); // [Banana, Apple, Cherry]
        System.out.println(set2); // [Apple, Banana, Cherry]
        System.out.println(set3); // [Apple, Banana, Cherry]
    }
}