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Developer Guide

• Acknowledgements
• Design
  • Architecture
  • Parser
  • Command
  • Storage
  • Library
  • Ui
• Implementation
  • Add Book Feature
  • Delete Book Feature
  • List Book Feature
  • List Members With Overdue Books Feature
  • Searching Feature
  • Undo Feature
  • Load
  • Save
  • Statistics Feature
• Appendix
  • Product Scope
  • Target User Profile
  • Value Proposition
  • User Stories
• Non-Functional Requirements
• Glossary
• Instructions for manual testing
  • Initial Launch
  • Adding a book
  • Deleting a book
  • Listing books
  • Borrowing a book
  • Returning a book
  • Listing overdue books
  • Listing borrowed books
  • Listing members with overdue books
  • Searching books
  • Viewing book quantity
  • Listing books on a shelf
  • Viewing library statistics
  • Undo last valid command
  • Exiting the application
  • Additional test cases
• Handling missing/corrupted data files

Acknowledgements

LeBook uses the following libraries:

1. JUnit - For writing and executing automated tests
2. Gradle - A build automation tool

Design

Architecture

Main Components of the architecture:

• Ui: The Ui of the system.
• Parser: Process User Input.
• Command: Executes instructions based on commandType.
• MemberManager: Library members.
• Storage: Reads data from, and writes data to, the hard disk. Data includes book details and borrower.
• Library: Manages global catalogue and shelves, as well as a UndoManager for undoing of a command.

Parser component

API: Parser.java

Shown below is a simplified class diagram of the Parser component:

The parser component is responsible for interpreting user input and calling the appropriate command object. It takes a string input from the user, determines the corresponding command type, and returns an instance of a subclass of Command.

How the parser component works:

1. Extracts the command keyword from the user input.
2. Matches the keyword to the relevant commands.
3. Parses and extracts the remaining arguments (if any).
4. Returns a corresponding Command object for execution.

Command component

Overview

• All commands extend the Command class, which is abstract and defines the execute() method.
• The execute() method in each command class contains the logic to perform a specific action.
• Each command interacts with Library (to manage catalogue and shelves), Ui (to print messages), and Storage (to save data to a file).

Storage component

API: Storage.java

1. Overview
   • The Storage class in LeBook is responsible for saving the data after the user exits LeBook. To load the data when the user launches LeBook, it reads data from a file and loads it into a list. When exiting the program, it writes the Books back into the file in a specific format.
2. Design
   • Each Book is stored in structured text using a | delimiter.
   • Each time the user exits the program, the file is overwritten, ensuring that the content is up to date.
   • If the file to save the data does not exist, an empty list is returned. Exceptions are caught and logged.
   • If the file is tampered with, the program is notified, and it automatically deletes all existing data written in the file.

Library component

API: Library.java

1. Overview

   • The Library class in LeBook handles the job of managing all book-related operations. It contains a BookManager called catalogueManager, a ShelvesManager to manage the books on shelves, as well as a UndoManager to facilitate undoing of past user interactions.
   • Whenever a book-operation comes e.g add, both the global catalogue of books and the shelves will be modified. (In this case, the book is added to the global catalogue and the relevant shelf based on its Genre).

2. Design

   • catalogueManager: manages the global catalogue (e.g adding / deleting).
   • ShelvesManager: manages shelves of different genres. The same book in the global catalogue is also stored in their respective shelves.
   • UndoManager: undo certain user commands like delete and add when prompted.

Class Diagram (Library):

BookManager

The BookManager class is responsible for managing the library’s global catalogue of books. Within the Library class, it is referenced as catalogueManager.

It handles core operations such as:

1. Adding a book to the catalogue
2. Deleting a book from the catalogue
3. Listing all books in the catalogue
4. Borrowing and returning books
5. Providing data for statistics and search functionalities.

Class Diagram (BookManager):

ShelvesManager

The ShelvesManager class is responsible for managing the Shelves. ShelvesManager contains sections, divided based on the genre of the book added. In each section, there are 5 Shelf objects, and each Shelf contains 100 Books.

It handles core operations such as:

1. Adding a book to the Shelf
2. Deleting a book from the Shelf
3. Listing a specific Shelf

Class Diagram(ShelvesManager):

Ui component

API: Ui.java

1. Overview

   • The Uiclass in LeBook is responsible for all user interaction in the Command Line Interface (CLI).
   • Ui handles:
     • Displaying welcome, help and exit messages.
     • Reading user input and returning the raw command string.
     • Printing success and error messages in a standardized and formated way.
     • Displaying book lists in formatted layout.
   • Ui class is designed as a Singleton to ensure only one instance manages all user interaction throughout application’s cycle.

2. Design

   • Singleton pattern: Ui provides static instance via Ui.getUiInstance() and uses private constructor to prevent multiple instances.
   • readCommand() -> Reads user input from terminal.
   • printWelcomeMessage(), printHelp(), printExitMessage() -> Prints standardized success messages.
   • printSuccess(String message) -> Prints standardized success message.
   • printError(String message) -> Prints standardized error messages.
   • printWithSeparator(String message) -> Prints message surrounded by separators.
   • showBookList(List<Book> books) -> Displays formated list of books with their details.

Implementation

Add Book Feature

The add book feature allows librarians to add a book to the catalogue. When the librarian wishes to add a book, the book is added to the global catalogue in BookManager, and also concurrently added to the shelf in ShelvesManager.

The feature is facilitated by the following components:

• AddCommand: A command object that encapsulates the logic for adding the book to the catalogue and shelf.
• Library: Responsible for managing the BookManager as well as the ShelvesManager.
• ShelvesManager: Responsible for sorting the books into the correct genre.
• Shelves: Responsible for checking the appropriate shelf to add the book to.

Key Methods

• getSuitableIndex() in Shelf:
  • Iterates through all the slots in the shelf.
  • Check for a suitable spot on the shelf. The spot is suitable if:
    1. A book that was in that spot and previously deleted.
    2. The spot was never occupied.

Execution Flow

1. The librarian enters a string input add <Book Details>.
2. The Parser class parses the input and creates a AddCommand.
3. The execute method in AddCommand class calls Library’s addNewBookToCatalogue(<Book Details>) and addNewBookToShelf(<Book Details>) method.
4. The ShelfManager iterates through its shelf indexes, checks for open slots.
5. The result is passed to the Ui, which displays it to the user.

Sequence Diagram

Note: The Book Details consists of the Title, Author Name, as well as the genre.

Delete Book Feature

The delete book feature allows librarians to delete irrelevant books from the library using their bookID, their unique title and author or their bookIndex.

Each delete command also supports undo, restoring the last deleted book into the system.

Key Methods

1. deleteBook(int bookIndex) in Library

   Deletes a book based on its index in the global catalog list.

   • Input by user: delete num / 0
   • Retrieves the book ID using the bookIndex
   • Delete book from global catalog using bookIndex
   • Removes book from its corresponding shelf using the book ID (replaces with a dummy book).
   • Returns a String to indicate book deletion.

2. deleteBook(String bookTitle, String author) in Library

   Deletes a book based on its title and author in the global catalog list.

   • Input by user: delete bk / The Hobbit / J.R.R. Tolkien
   • Retrieves bookIndex and bookID using title and author
   • Delete book from global catalog using bookIndex
   • Removes book from its corresponding shelf using book ID(replaces with a dummy book).
   • Returns a String to indicate book deletion.

3. deleteBook(String bookID) in Library

   Deletes a book based on its book ID.

   • Input by user: delete id / AC-0-1
   • Refer to here for information about the formatting of book ID.
   • Retrieves bookIndex using book ID
   • Delete book from global catalog using bookIndex
   • Removes book from its corresponding shelf using book ID(replaces with a dummy book).
   • Returns a String to indicate book deletion.

Execution Flow

Given below is an example usage scenario and how the delete mechanism behaves at each step.

Assuming the initial state of the library is that there’s one book titled Book1 by AuthorA.

Step 1. The user types in the string input delete num / 1 to delete the 1st book in the catalogue (in this case, it’s Book1).

Step 2. The Parser class parses the input and creates a DeleteByIndexCommand.

Step 3. The execute method in this command class calls library’s deleteBook(Int bookIndex) method.

Step 4. library calls upon catalogueManager deleteBook(bookIndex) to delete the book from the catalogue. The response containing information about the bookDeletion is stored in response.

Step 5. library calls retrieves the bookID using the bookIndex and passes it to shelvesManager which deletes the book from the relevant shelf.

Step 6. Book deletion is complete. The response is finally returned back to DeleteByIndexCommand which calls Ui to print out the response. Storage is also updated.

Sequence Diagram (of this example)

List Book Feature

The list book feature allows librarians to see the basic information of the catalogue in their system. This includes the BookTitle, Author, BookID and the DueDate if the book was borrowed.

Key Methods

1. listBooks() in BookManager
   • List all books in the global catalogue with their respective information including their status, title, author, bookID and due date.
   • Input by user: list

Execution Flow

Given below is an example usage scenario and how the list mechanism behaves at each step:

Assuming the initial state of the library is that there’s one book titled Book1 by AuthorA.

Step 1. The user types in the string input list to list all books in the catalogue.

Step 2. The Parser class parses the input and creates a ListCommand.

Step 3. The execute method in this command class calls library’s listBooks() method.

Step 4. library calls upon catalogueManager’s listBooks() method, stores the response.

Step 5. The response is returned to the command class and printed out by Ui.

List Members with Overdue Books Feature

The list members with overdue books feature allows librarians to view a list of members who currently have overdue books. It retrieves data from the MemberManager class, which maintains a list of all members and their borrowed books, and checks the overdue status of each book.

The feature is facilitated by the following components:

• ListOverdueUsersCommand: A command object that encapsulates the logic for listing members with overdue books.
• MemberManager: Responsible for managing all members and their borrowed books.
• Member: Represents an individual member and provides methods to retrieve their overdue books.
• Ui: Displays the formatted list of members with overdue books to the librarian.

Key Methods

• listMembersWithOverdueBooks() in MemberManager class:
  • Iterates through all members.
  • Checks each member’s borrowed books for overdue status.
  • Returns a formatted string listing members with overdue books.
• getOverdueBooks() in Member class:
  • Returns a list of overdue books for a specific member.

Execution Flow

1. The librarian enters a string input list overdue users.
2. The Parser class parses the input and creates a ListOverdueUsersCommand.
3. The execute method in ListOverdueUsersCommand class calls MemberManager’s listMembersWithOverdueBooks() method.
4. The MemberManager iterates through its list of members, checks for overdue books, and builds a formatted string containing the results.
5. The result is passed to the Ui, which displays it to the user.

Sequence Diagram

Searching Feature

The search functionality is encapsulated within the BookFinder utility class and initiated by specific SearchBy…Command objects (SearchByTitleCommand, SearchByAuthorCommand, SearchByGenreCommand, SearchByIDCommand). Delegation: Search logic is intentionally separated from BookManager into BookFinder. This promotes Separation of Concerns, making BookManager focused on catalogue management and BookFinder specialized in searching.

Commands & Behavior

1. SearchByTitleCommand
   • Searches for books where the title contains the specified query (case-insensitive).
     Input: find title <title_query> (e.g., find title Lord of the Rings)
   • Retrieves book list from BookManager via Library
   • Uses BookFinder.findBooksByTitle(titleQuery)
   • Displays matching books via Ui
2. SearchByAuthorCommand
   • Searches for books where the author’s name contains the specified query (case-insensitive).
     Input: find author <author_query> (e.g., find author Tolkien)
   • Retrieves book list from BookManager via Library
   • Uses BookFinder.findBooksByAuthor(authorQuery)
   • Displays matching books via Ui
3. SearchByGenreCommand
   • Searches for books matching the specified genre exactly (case-insensitive).
     Input: find genre <genre_query> (e.g., find genre adventure)
   • Retrieves book list from BookManager via Library
   • Uses BookFinder.findBooksByGenre(genreQuery)
   • Displays matching books via Ui
4. SearchByIDCommand
   • Searches for a book using the unique Book ID (case-insensitive).
     Input: find id <book_id> (e.g., find id AD-0-0)
   • Retrieves book list from BookManager via Library
   • Uses BookFinder.findBooksByShelfId(bookId)
   • Displays result via Ui

Execution flow:

1. The user enters a find command (e.g., find title Lord of the Rings or find id AD-0-0).
2. The Parser interprets this and creates the appropriate SearchBy…Command object (e.g., SearchByTitleCommand with the search term).
3. During execution (execute method), the SearchCommand:
4. Retrieves the BookManager instance via the Library.
5. Gets the current List<Book> from BookManager.
6. Creates a new BookFinder instance, passing the bookList to its constructor.
7. Calls the relevant search method on the BookFinder instance (e.g., finder.findBooksByTitle(searchTerm) or finder.findBooksByShelfId(searchTerm)).
8. BookFinder iterates through the provided bookList (using Java Streams and filtering) to find matching books. Searches are generally case-insensitive for user-friendliness.
9. The SearchCommand receives the list of results from BookFinder.
10. It then uses the Ui component to display the findings or a “not found” message to the user.

BookFinder provides specific methods for each search criterion (findBooksByTitle, findBooksByAuthor, findBooksByGenre, findBooksByShelfId). The user interacts with these via the find command using criteria: title, author, genre, or id.

Shown below is a simplified class diagram of Searching:

Simplified Sequence Diagram SearchByTitleCommand: This diagram illustrates the typical flow when a user performs a title search. (This remains unchanged as the core search flow is the same).

Design considerations:

Separate BookFinder class. (Current Choice)

1. Pros: Adheres to the Single Responsibility Principle. BookManager stays focused on catalogue state, while BookFinder handles search algorithms. BookFinder can be tested independently. Easy to add new search types without modifying BookManager.

2. Cons: Requires passing the book list reference from BookManager to BookFinder upon creation. Introduces a small amount of indirection.

Implement search methods directly in BookManager

1. Pros: Reduces the number of classes. Search methods have direct access to the internal books list.

2. Cons: Bloats the BookManager class, mixing management and query responsibilities. Makes BookManager harder to test and potentially violates SRP.

Design considerations:

Separate BookFinder class. (Current Choice)

1. Pros: Adheres to the Single Responsibility Principle. BookManager stays focused on catalogue state, while BookFinder handles search algorithms. BookFinder can be tested independently. Easy to add new search types without modifying BookManager.

2. Cons: Requires passing the book list reference from BookManager to BookFinder upon creation. Introduces a small amount of indirection.

Implement search methods directly in BookManager

1. Pros: Reduces the number of classes. Search methods have direct access to the internal books list.

2. Cons: Bloats the BookManager class, mixing management and query responsibilities. Makes BookManager harder to test and potentially violates SRP.

Undo Feature

The Undo feature allows users to revert the effects of previous commands that modified the library’s state (add, delete, borrow, return). It retrieves the command history from the UndoManager class which maintains a stack of executed commands and calls undo() method of the most recent undoable command.

The feature is facilitated by the following components:

• UndoCommand: Command object encapsulating logic for performing undo operation.
• UndoManager: Responsible for storing and managing history of executed commands.
• Command: Abstract class that defines undo() method of all commands.
• Ui: Displays SUCCESS or ERROR messages after an undo operation is made.

Key Methods

• undoCommands() in UndoManager:
  • Pops and undoes the specified number of undoable commands from the history stack.
  • Displays error message in the event there are no undoable commands.
• undo() in Command:
  • Reverts changes made by command.
  • Implemented by undoable commands, empty for non-undoable commands.
• confirmUndo() in Ui:
  • Prompts user for confirmation before undoing. Accepts only y, Y, n, N as inputs.
• execute() in Command:
  • Returns boolean to indicate whether a command has been executed successfully.
  • Only successful commands are pushed onto the undo stack.

Execution Flow

1. User inputs string input undo.
2. Parser class parses input and creates UndoCommand instance.
3. Execute method in UndoCommand calls Library’s getUndoManager() method.
4. UndoManager invokes undoCommands() and checks command history.
5. undo() method called for each undoable command to revert operation.
6. Ui displays success message if command was undone successfully or error message if no commands to undo.

Sequence Diagram

Load Book from File Feature

The Load Book from File Feature allows the user to keep and store the catalogue of books that are already present in the library. It achieves this by scanning the LeBook_data.txt file.

Key Methods

• handleCorruptedFile() in Storage:
  • When a file is tampered with, Storage will call handleCorruptedFile(), which will clear out the text file through a method called clearFile().
  • It then displays an error message stating that the file is tampered with.
  • Further, it displays that the file is cleared.

Execution Flow

1. User runs the program.
2. The library gets populated with books through the use of loadFileContents().
3. The corresponding Shelf gets populated in the process as well.

Sequence Diagram

Save Book to File Feature

The Save Book from File Feature is the counterpart to the Load Book from File. It allows the user to write to a text file as he/she executes commands.

Key Methods

• toFileFormat in Book:
  • Converts the Book object to a suitable String format to be saved as.
• writeToFile() in Storage:
  • Write to the .txt file for future use.

Execution Flow

1. User inputs a command.
2. The Command object calls the writeToFile() method in Storage.
3. The writeToFile() method calls a method in the Book class to convert the object into an appropriate format to be saved.

Sequence Diagram

Here, the newCommand() invocation represents a new command that the user has input to the system.

Statistics Feature

The Statistics feature allows librarians to get a quick overview of the library’s current status.

Statistics includes:

• Total number of books copies
• Total number of unique titles
• Total number of borrowed books
• Total number of books overdue
• List of unique book titles

The feature is facilitated by the following components:

• StatisticsCommand: Command object encapsulating the logic for computing and displaying statistics.
• BookManager: Provides access to the full list of books and contains helper methods to compute statistics.
• Ui: Displays formatted statistics in a user-friendly format.

Key Methods

• getStatistics() in BookManager class:
  • Calculates total book copies, number of unique titles and number of borrowed and overdue books.
  • Returns a formatted string with all statistics included.
• getUniqueTitleSize() and getUniqueTitles() in BookManager class:
  • Compute count and set of unique book titles.

Execution Flow

1. User inputs the command statistics.
2. Parser parses the input and creates a StatisticsCommand instance.
3. execute() in StatisticsCommand calls library.getBookManager().getStatistics().
4. BookManager computes and returns the formatted statistics string.
5. Ui prints the statistics for the user to view.

Sequence Diagram

Appendix

Product scope

LeBook is a comprehensive library management system that allows librarians to easily catalogue borrowed and returned books, streamlining inventory management and tracking book availabilities.

Target user profile

Library staff who wish to efficiently manage book collections.

Value proposition

Enables efficient cataloging, borrowing, and returning of books through a command-line interface, allowing librarians to manage inventory and track book availability quickly compared to a typical mouse/GUI driven app.

User Stories

Version	As a …	I want to …	So that I can …
v1.0	librarian	add new books to the system	keep track of the new arrivals.
v1.0	librarian	delete a book	remove outdated or lost books.
v1.0	librarian	see the list of all my books	see what books I have in the library.
v1.0	librarian	record when members borrow a book	keep track when a book is borrowed.
v1.0	librarian	record when members return a book	update its availability.
v1.0	librarian	set due dates for my books	so that I can monitor when books will be returned and keep track of books that have yet to been returned.
v1.0	librarian	save the book details	keep track of book statuses when using the system again.
v1.0	librarian	enter the command as one long string	enter the input without caring about different parts of the input.
v1.0	librarian	see what happens whenever I perform a command	confirm that my inputs have been added correctly.
v2.0	librarian	view the list of all available commands	know what commands are available in the system.
v2.0	librarian	know the genre of a book	better organise the catalogue.
v2.0	librarian	keep track of what shelf a book is on	easily locate the book.
v2.0	librarian	view the catalogue of a specific shelf	view available/missing/borrowed books on the shelf.
v2.0	librarian	view a list of overdue books	follow up with contacting the appropriate member.
v2.0	librarian	search for a book through keywords	find the appropriate book.
v2.0	librarian	see the overall statistics of the library	know the total number of books, overdue books and borrowed books.
v2.0	librarian	undo the last command	correct my actions if it was a wrong command.

Non-Functional Requirements

1. Should work on any mainstream OS that has installed Java 17 or above.
2. Built to support only a single user.

Glossary

• Member - A person who visits the library to borrow or return a book(s).
• Mainstream OS - Windows, Linux, Unix, macOS.

Instructions for manual testing

Initial Launch

1. Download the LeBook JAR file and copy it into an empty folder.
2. Start the application by using java -jar LeBook.jar in the terminal.

Adding a book

Adding a book while the library is empty

1. Prerequisites: List all books using the list command. No books in the list.
2. Test case: add The Great Gatsby / F. Scott Fitzgerald / romance
   • Expected: Book is added to the library and the relevant shelf. Details of the added book shown in the status message. Library now contains 1 book.
3. Test case: add (without title, author and genre)
   • Expected: No book is added. Error details shown in the status message. Library remains empty.
4. Other incorrect add commands to try:
   • add TITLE
   • add / AUTHOR
   • add TITLE / AUTHOR (missing genre)
   • add TITLE / AUTHOR / (missing genre value)
   • Expected: Similar to previous.

Deleting a book

Deleting a book while multiple books are listed

1. Prerequisites: List all books using the list command. Multiple books in the list.
2. Test case: delete num / 1
   • Expected: First book is deleted from the list. Details of the deleted book shown in the status message. Library now contains fewer books.
3. Test case: delete num / 0
   • Expected: No book is deleted. Error details shown in the status message. Library remains unchanged.
4. Test case: delete bk / Harry Potter / J.K. Rowling (assuming this book does not exist in the library)
   • Expected: No book is deleted. Message shows that no such book is found.
5. Test case: delete id / R-0-0 (assuming there’s a book with this bookID)
   • Expected: Book is deleted from the list. Details of the deleted book shown in the status message. Library now contains fewer books.
6. Other incorrect delete commands to try:
   • delete
   • delete bk / (missing title)
   • delete bk / TITLE (missing author)

Listing books

Listing books when the library is empty and when it contains multiple books

1. Prerequisites: List all books using the list command. Initially, no books in the list.
2. Test case: list (with no books)
   • Expected: Message indicating that the library is empty.
3. Test case: list (after adding multiple books)
   • Expected: List displays all books with their status and details.

Borrowing a book

Borrowing a book when it is available

1. Prerequisites: List all books using the list command. At least one available book in the list.
2. Test case: borrow 1 / Alice
   • Expected: Book is marked as borrowed. Status message indicates that the book has been borrowed. Book status changes to [X].
   • Return due date is set to 2 weeks from the date of borrowing.
3. Test case: borrow 0 / Alice
   • Expected: No book is borrowed. Error details shown in the status message. Book status remains unchanged.
4. Other incorrect borrow commands to try:
   • borrow
   • borrow 1 / (missing borrower name)
   • Expected: Similar to previous.

Returning a book

Returning a borrowed book

1. Prerequisites: List all books using the list command. At least one borrowed book in the list.
2. Test case: return 1
   • Expected: Book is marked as returned. Status message indicates that the book has been returned. Book status changes to [ ].
   • Return due date is reset and set to null.
3. Test case: return 0
   • Expected: No book is returned. Error details shown in the status message. Book status remains unchanged.
4. Other incorrect return commands to try:
   • return
   • return x (where x is larger than the list size or the book is not borrowed)
   • Expected: Similar to previous.

Listing overdue books

Listing books whose return due date has been surpassed by the current date

1. Prerequisites: List all overdue books using the list overdue command. Initially, no books are overdue.
2. Test case: list overdue (with no overdue books)
   • Expected: Message indicating that there are currently no overdue books.
3. Test case: list overdue (after multiple books have surpassed overdue date)
   • Expected: List displays all overdue books with their status and details.

Listing borrowed books

Listing books that are currently borrowed

1. Prerequisites: List all borrowed books using the list borrowed command. Initially, no books are borrowed.
2. Test case: list borrowed (with no borrowed books)
   • Expected: Message indicating that there are currently no borrowed books.
3. Test case: list borrowed (after multiple books have been borrowed)
   • Expected: List displays all borrowed books with their status and details.

Listing members with overdue books

Listing members who have overdue books, where the book title and author are also displayed

1. Prerequisites: List all members with overdue books using the list overdue users command. Initially, no members have overdue books.
2. Test case: list overdue users (with no members having overdue books)
   • Expected: Message indicating that there are currently no members with overdue books.
3. Test case: list overdue users (after multiple members have overdue books)
   • Expected: List displays all members with overdue books.

Searching books

Searching books by various criteria (title, author, genre, bookID)

1. Test case: find title lord
   • Expected: List displays books with titles containing “lord”.
2. Test case: find author Tolkien
   • Expected: List displays books by authors containing “Tolkien”.
3. Test case: find genre adventure
   • Expected: List displays books with the genre “adventure”.
4. Test case: find id AD-0-0
   • Expected: List displays the book with the specified ID.
5. Other incorrect find commands to try:
   • find
   • find title (missing term)
   • find genre (missing term)
   • Expected: Similar to previous.

Viewing book quantity

Viewing the quantity of a specific book

1. Test case: quantity / Harry Potter / J.K. Rowling
   • Expected: Displays the quantity of the specified book.
2. Test case: quantity / (missing title and author)
   • Expected: Error details shown in the status message.
3. Other incorrect quantity commands to try:
   • quantity
   • quantity / TITLE (missing author)
   • Expected: Similar to previous.

Listing books on a shelf

Listing books on a specific shelf

1. Test case: shelf / romance / 1
   • Expected: List displays books on the specified shelf.
2. Test case: shelf (missing genre and shelf number)
   • Expected: Error details shown in the status message.
3. Other incorrect shelf commands to try:
   • shelf / GENRE
   • shelf / SHELF_NUMBER
   • Expected: Similar to previous.

Viewing library statistics

Viewing the total number of book copies, unique titles, borrowed and overdue books, as well as the list of unique book titles

1. Test case: statistics
   • Expected: Displays library statistics.

Undo last valid command

Undoing the last command

1. Prerequisites: There was a command executed previously.
2. Test case: undo (when the previous command was add, delete, borrow, return)
   • Expected: Last command is undone. Library state reverts to before the last command.
3. Test case: undo (other commands)
   • Expected: No command is undone. Error details shown in the status message.

Help command

Displays a help menu listing commands for the user to refer to.

1. Test case: help
   • Expected: Help menu of available commands is shown.

Exiting the application

Exiting the application

1. Prerequisites: Application is running.
2. Test case: bye
   • Expected: Application closes with a goodbye message.

Additional test cases

• Invalid commands: Test various invalid commands (e.g., borrow, return, delete without specifying a book number) to ensure that the application responds correctly with error messages.
• Edge cases: Test edge cases such as deleting books when the library is empty, borrowing or returning books that are not available or already borrowed, etc.

Handling missing/corrupted data files

To simulate a missing or corrupted data file:

1. Delete or rename the data file used by LeBook.
2. Run LeBook and attempt to perform operations.

BookID

A variable tied to a Book and is unique to every new Book added.

Format

[GENRE_CODE]-[SHELF_INDEX]-[SLOT_NUM] 
Example: R-0-1
- R refers to 'Romance'
- '0' refers to Shelf 0
- '1' refers to Book 2

Expected behavior:

• LeBook should handle the absence or corruption of the data file gracefully.
• It should either create a new data file or display an error message indicating the problem.