Java/com/study/demo3/Library.java

package com.study.demo3;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.ArrayList;

public class Library {
   
    private Map<String, Book> books;

    public Library() {
        this.books = new HashMap<>();
    }

   
   
    public void addBook(Book b) {
        String isbn = b.getIsbn();

       
        if (books.containsKey(isbn)) {
            System.out.println("The book already exists, adding it failed.");
        } else {
            books.put(isbn, b);
            System.out.println("Book added successfully: " + b.getTitle());
        }
    }

   
   
    public List<Book> searchAvailableBooks() {
        List<Book> availableBooks = new ArrayList<>();
        
       
        for (Book book : books.values()) {
            if (book.isAvailable()) {
                availableBooks.add(book);
            }
        }
        return availableBooks;
    }
}