Admin Interface

Let's expand your Library Management System with an Admin Interface! A real library needs administrative capabilities—adding new books to the collection, removing outdated ones, and registering new members. You'll create an interface that defines these administrative operations and implement them in a dedicated admin class.

You'll continue building on your existing code across five files:

• Book.java: Keep your Book class with all existing functionality—isbn, title, author, isAvailable, borrowedBy, getDetails(), and the appropriate getters/setters.
• User.java: Keep your User class unchanged with id, name, the borrowedBooks ArrayList, borrowBook(), returnBook(), getBorrowedCount(), and toString().
• Library.java: Keep your Library class with all existing methods. Add a new method removeBook(String isbn) that finds and removes a book from the collection by its ISBN. The method should return true if the book was found and removed, false otherwise. A book can only be removed if it's currently available (not borrowed).
• LibraryAdmin.java: Create an interface called LibraryAdmin that defines the contract for administrative operations. Your interface should declare three methods:
  • addBook(String isbn, String title, String author) - returns a boolean indicating success
  • removeBook(String isbn) - returns a boolean indicating success
  • registerUser(String id, String name) - returns a boolean indicating success

  Then create a class called AdminService that implements this interface. The AdminService should hold a reference to a Library (passed through its constructor) and implement all three methods by delegating to the Library while adding appropriate feedback. When adding a book, create a new Book and add it to the library. When registering a user, create a new User and register them.

• Main.java: Demonstrate your admin system! You'll receive a series of admin commands as a single comma-separated string. Each command follows one of these formats:
  • ADD_BOOK:isbn:title:author
  • REMOVE_BOOK:isbn
  • REGISTER_USER:id:name
  • BORROW:userId:isbn

  Create a Library and an AdminService. Process each command and print the result:

  • For ADD_BOOK: print Added: [title] on success
  • For REMOVE_BOOK: print Removed: [isbn] on success, or Cannot remove: [isbn] if the book doesn't exist or is borrowed
  • For REGISTER_USER: print Registered: [name]
  • For BORROW: use the existing library borrow functionality

  After processing all commands, print Library status: followed by each book's details and availability status in the format [details] - [Available/Borrowed].

You will receive one input: a comma-separated string of commands.

For example, with input REGISTER_USER:U001:Alice,ADD_BOOK:ISBN-001:Clean Code:Robert Martin,ADD_BOOK:ISBN-002:Design Patterns:Gang of Four,BORROW:U001:ISBN-001,REMOVE_BOOK:ISBN-001,REMOVE_BOOK:ISBN-002, your output would be:

Registered: Alice
Added: Clean Code
Added: Design Patterns
Alice borrowed Clean Code
Cannot remove: ISBN-001
Removed: ISBN-002
Library status:
[ISBN-001] Clean Code by Robert Martin - Borrowed

Notice how the admin interface provides a clean contract for administrative operations, while the AdminService implementation handles the actual logic. The system correctly prevents removing a borrowed book while allowing removal of available ones. This separation of interface and implementation is a key OOP principle that makes your code more maintainable and testable!