import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; import java.util.Scanner; // Interface defining book management operations interface LibraryOperations<T> { void addItem(T item) throws IllegalArgumentException; boolean removeItem(String id); T findItem(String id); List<T> getAllItems(); } // Abstract class for library items abstract class LibraryItem { protected String id; protected String title; protected boolean isCheckedOut; public LibraryItem(String id, String title) { this.id = id; this.title = title; this.isCheckedOut = false; } public String getId() { return id; } public String getTitle() { return title; } public boolean isCheckedOut() { return isCheckedOut; } public void setCheckedOut(boolean status) { this.isCheckedOut = status; } @Override public String toString() { return "ID: " + id + ", Title: " + title + ", Checked Out: " + isCheckedOut; } } // Concrete class for books class Book extends LibraryItem { private String author; private int publicationYear; public Book(String id, String title, String author, int publicationYear) { super(id, title); this.author = author; this.publicationYear = publicationYear; } public String getAuthor() { return author; } public int getPublicationYear() { return publicationYear; } @Override public String toString() { return super.toString() + ", Author: " + author + ", Year: " + publicationYear; } } // Library management class implementing the interface class LibraryManager implements LibraryOperations<Book> { private Map<String, Book> bookInventory; private static final int MAX_BOOKS = 100; public LibraryManager() { bookInventory = new HashMap<>(); } @Override public void addItem(Book book) throws IllegalArgumentException { if (book == null || book.getId() == null) { throw new IllegalArgumentException("Book or ID cannot be null"); } if (bookInventory.size() >= MAX_BOOKS) { throw new IllegalStateException("Library is at full capacity"); } bookInventory.put(book.getId(), book); } @Override public boolean removeItem(String id) { if (id != null && bookInventory.containsKey(id)) { bookInventory.remove(id); return true; } return false; } @Override public Book findItem(String id) { return bookInventory.getOrDefault(id, null); } @Override public List<Book> getAllItems() { return new ArrayList<>(bookInventory.values()); } public int getInventorySize() { return bookInventory.size(); } } // Main class to run the library system public class LibrarySystem { public static void main(String[] args) { LibraryManager library = new LibraryManager(); Scanner scanner = new Scanner(System.in); boolean running = true; while (running) { System.out.println("\nLibrary Management System"); System.out.println("1. Add a book"); System.out.println("2. Remove a book"); System.out.println("3. Find a book"); System.out.println("4. List all books"); System.out.println("5. Exit"); System.out.print("Enter your choice (1-5): "); int choice; try { choice = Integer.parseInt(scanner.nextLine()); } catch (NumberFormatException e) { System.out.println("Invalid input. Please enter a number."); continue; } switch (choice) { case 1: System.out.print("Enter book ID: "); String id = scanner.nextLine(); System.out.print("Enter book title: "); String title = scanner.nextLine(); System.out.print("Enter author name: "); String author = scanner.nextLine(); System.out.print("Enter publication year: "); int year; try { year = Integer.parseInt(scanner.nextLine()); } catch (NumberFormatException e) { System.out.println("Invalid year. Book not added."); break; } Book newBook = new Book(id, title, author, year); try { library.addItem(newBook); System.out.println("Book added successfully: " + newBook); } catch (IllegalArgumentException | IllegalStateException e) { System.out.println("Error: " + e.getMessage()); } break; case 2: System.out.print("Enter book ID to remove: "); String removeId = scanner.nextLine(); if (library.removeItem(removeId)) { System.out.println("Book removed successfully."); } else { System.out.println("Book not found or invalid ID."); } break; case 3: System.out.print("Enter book ID to find: "); String findId = scanner.nextLine(); Book foundBook = library.findItem(findId); if (foundBook != null) { System.out.println("Book found: " + foundBook); } else { System.out.println("Book not found."); } break; case 4: List<Book> books = library.getAllItems(); if (books.isEmpty()) { System.out.println("No books in the library."); } else { System.out.println("Library Inventory (" + library.getInventorySize() + " books):"); for (Book book : books) { System.out.println(book); } } break; case 5: running = false; System.out.println("Exiting Library System. Goodbye!"); break; default: System.out.println("Invalid choice. Please select 1-5."); break; } } scanner.close(); } }