Thread: Can anyone give me help/advice on this java library program?

Hey everyone and thanks for taking the time to read my 1st post. Quite new to java and would appreciate if anyone could help me out with the following problems in my program. I am designing a program for a small classroom library. The code is below. The main application menu class, a loanBook class and a pupil helper class. Whats confusing me is trying to create and link up the the menu options of display available books, borrow book, and loan book. I have included the code and hope that some of you can give me any advice to help me. Thanks in advance.

public class bookArray
{
    static Scanner keyboard = new Scanner(System.in);
 
    loanBook [] bookArray = new loanBook[5];
    static String title, author, status;
 
    public void addBook ()
    {
        for (int count=0; count<bookArray.length; count++)
        {
            System.out.println("Please enter the book title :\t");
            title = keyboard.nextLine();
            System.out.println("Please enter the book author :\t");
            author = keyboard.nextLine();
            status = "Available";
 
            bookArray[count] = new loanBook(title, author);
        }
    }
 
    public void displayAvailableBooks ()
    {
 
    }
 
    public void displayBooksOnLoan ()
    {
 
    }
 
    public void borrowBook ()
    {
 
    }
 
    public void returnBook ()
    {
 
    }
 
    static void displayMenu ()
    {
        int menuChoice;
 
        System.out.println("Welcome to the Class Library System\n");
        System.out.println("1.\tAdd Book\n");
        System.out.println("2.\tDisplay available books\n");
        System.out.println("3.\tDisplay books currently on loan\n");
        System.out.println("4.\tBorrow Book\n");
        System.out.println("5.\tReturn Book\n");
        System.out.println("6.\tWrite book details to file\n");
        System.out.println("7.\tExit\n");
 
        // Prompt user to choose an option
 
        System.out.println("Please choose one of the above options: ");
 
        // Store users' choice as a variable
 
        menuChoice = keyboard.nextInt();
 
        switch (menuChoice)..............

loanBook class

public class loanBook
{
    String title, author, status;
    private int bookId;
    static int count=1;
    private pupil pupil;
 
    public loanBook (String title, String author)
    {
        this.title = title;
        this.author = author;
        this.status = "Available";
        this.bookId = count;
        count ++;
    }
}

pupil class

public class pupil
{
    private String firstname, surname;
    private Scanner keyboard = new Scanner(System.in);
 
    public pupil (String firstname, String surname)
    {
        this.firstname = firstname;
        this.surname = surname;
    }
 
    public String toString()
    {
        return (firstname + surname);
    }
 
    public void getPupil()
    {
        System.out.println("Please enter pupils first name : ");
        firstname = keyboard.nextLine();
        System.out.println("Please enter pupils surname : ");
        surname = keyboard.nextLine();
 
    }
}

Hi aussiemcgr.
Yea i created a status so that the following can happen. When a new book is added the status is 'available'. If the book is taken on loan then it should change to 'borrowed'. Just not sure on how to about this.

Class names begin with capital letters.

i followed your advice but how do i check the status. im thinking along the lines of the following but what condition do i use in the if statement?

public String displayAvailableBooks ()
    {
        for (int i=0; i < bookArray.length; i++)
        {
            if (?????????)
 
                return (LoanBook.class.toString());
 
            else
                System.out.println ("There are currently no books available");
 
        }
 
    }

Ok iv done this but i know im missing something here as the word status in the if statement is highlighted in red?

public class BookArray
{
    static Scanner keyboard = new Scanner(System.in);
 
    LoanBook [] bookArray = new LoanBook[5];
    static String title, author;
 
 
    public enum bookStatus
    {
        AVAILABLE, BORROWED
 
    }
 
    public void addBook ()
    {
        for (int count=0; count<bookArray.length; count++)
        {
            System.out.println("Please enter the book title :\t");
            title = keyboard.nextLine();
            System.out.println("Please enter the book author :\t");
            author = keyboard.nextLine();
            bookStatus status = bookStatus.AVAILABLE;
 
            bookArray[count] = new LoanBook(title, author);
        }
    }
 
 
    public String displayAvailableBooks ()
    {
        for (int i=0; i < bookArray.length; i++)
        {
            if (bookArray[i].status==bookStatus.AVAILABLE)
 
                return (LoanBook.class.toString());
            else
 
                System.out.println("There are currently no books available");
        }
 
    }

it says 'cannot resolve symbol status'. it also says (in the addBook option) 'the variable status is never used'

public class LoanBook
{
    String title, author;
 
    int bookId;
    static int count=1;
    private Pupil pupil;
 
    public LoanBook (String title, String author)
    {
        this.title = title;
        this.author = author;
        this.bookId = count;
 
        count ++;
    }
 
    public String toString ()
    {
        return ("Title :\t" +this.title+ "\nAuthor :\t" +this.author);
    }
 
 
}

Thanks its looking good now. Il give the rest a go now

Ok here's what i have ended up with. Still doesn't seem right to me so any suggestions would be appreciated. Should i have 2 more arrays for fiction and non-fiction?

public class MainMenu
{
    public static void displayMenu ()
    {
        //variables
        int menuChoice;
        Scanner keyboard = new Scanner(System.in);
 
        System.out.println("Welcome to the Class Library System\n");
        System.out.println("1.\tAdd Book\n");
        System.out.println("2.\tDisplay available books\n");
        System.out.println("3.\tDisplay books currently on loan\n");
        System.out.println("4.\tBorrow Book\n");
        System.out.println("5.\tReturn Book\n");
        System.out.println("6.\tWrite book details to file\n");
        System.out.println("7.\tExit\n");
 
        // Prompt user to choose an option
 
        System.out.println("Please choose one of the above options: ");
 
        // Store users' choice as a variable
 
        menuChoice = keyboard.nextInt();
 
        switch (menuChoice)
        {   // switch
 
            // If option 1 is selected
            case 1:     LoanBook.addBook();
 
                break;
 
            // If option 2 is selected
            case 2:      System.out.println("The following books are available\n");
                         LoanBook.displayAvailableBooks();
 
                break;
 
            // If option 3 is selected
            case 3:      System.out.println("The following books are on loan\n");
                         LoanBook.displayBooksOnLoan();
 
                break;
 
            // If option 4 is selected
            case 4:     LoanBook.borrowBook();
 
                break;
 
            // If option 5 is selected
            case 5:     LoanBook.returnBook();
 
                break;
 
            // If option 6 is selected
            case 6:     LoanBook.writeToFile();
 
                break;
 
            // If option 7 is selected exit program
            case 7:     System.out.println("Thank you for using the program....Goodbye!");
                break;
 
            // If option is not recognised display output
            default:    System.out.println(" Choice not recognised....Access denied!!!!");
 
        }   // switch
 
    } // displayMenu
 
    public static void main (String[]args)
    {
        displayMenu();
    }
}

LoanBook class

public class LoanBook
{
    //class variable
    private static int nextBookId=1;
 
    private static Scanner keyboard = new Scanner(System.in);
    private static int temp;
    private static boolean choice = false;
 
    static LoanBook [] books = new LoanBook[10];
    bookStatus status;
    //instance variables
    private String title, author;
    //title and author of book
    private int bookId;
    //unique ID number for book
 
    public LoanBook (String title, String author)
    {
        this.title = title;
        this.author = author;
        this.bookId = nextBookId;
 
        nextBookId ++;
    }//constructor
 
    public String toString()
    {
        return ("\nBook ID :\t" +this.bookId+ "\nTitle :\t" +this.title+ "\nAuthor :\t" +this.author+ "\n");
    }
 
    public enum bookStatus //declare values of bookStatus
    {
        AVAILABLE, BORROWED
 
    }
 
    //method to add book
    public static void addBook ()
    {
        for (int i=0; i < books.length; i++ )
        {
            System.out.println("Please enter the book title :\t");
            books[i].title = keyboard.nextLine();
            System.out.println("Please enter the book author :\t");
            books[i].author = keyboard.nextLine();
            books[i].status = bookStatus.AVAILABLE;
            do
            {
                System.out.println("Please select book type by entering the corresponding number");
                System.out.println("1: Fiction");
                System.out.println("2: Non-Fiction\n");
                temp = keyboard.nextInt();
                if (temp==1)
                {
                    LoanFiction.getGenre();
                    choice = true;
                }
                else if (temp==2)
                {
                    LoanNonFiction.getTopic();
                    choice = true;
                }
                else
                    System.out.println("Incorrect option. Please try again");
 
            } while (!choice);
        }
    } //addBook
 
    //method to display available books
    public static String displayAvailableBooks ()
    {
        for (int i=0; i < books.length; i++)
        {
            if (books[i].status==bookStatus.AVAILABLE)
            {
                return (books[i].toString());
            }
 
            else
            {
                System.out.println("There are currently no books available");
            }
 
        }
 
        return null;
    }
 
    //method to display books on loan
    public static String displayBooksOnLoan ()
    {
        for (int i=0; i < books.length; i++)
        {
            if (books[i].status==bookStatus.BORROWED)
            {
                return (books[i].toString()+" currently on loan to " +Pupil.class.toString());
            }
 
            else
            {
                System.out.println("There are currently no books on loan");
            }
 
        }
 
        return null;
    }
 
    //method to borrow book
    public static String borrowBook ()
    {
        int i, in;
        System.out.println("The following books are available to borrow\n");
 
        displayAvailableBooks();
 
        do
        {
            System.out.println("Please enter the Book Id that you would like to borrow : ");
            in = keyboard.nextInt();
 
 
 
            for (i=0; i < books.length; i++)
            {
                if ((books[i].status==bookStatus.AVAILABLE)&&(in==books[i].bookId))
                {
                    Pupil.getPupil();
                    System.out.println("You have successfully borrowed the following book :\n ");
                    return (books[i].toString());
                    books[i].status=bookStatus.BORROWED;
                }
                else
                {
                    System.out.println("Invalid book id: Please try again!");
                }
            }
        }   while (in!=books[i].bookId);
 
        return null;
    } //borrowBook
 
    //method to return book
    public static String returnBook ()
    {
        int i, in;
        System.out.println("The following books are on loan\n");
        displayBooksOnLoan();
 
        do
        {
            System.out.println("Please enter the book id of the book being returned : ");
            in = keyboard.nextInt();
 
            for (i=0; i < books.length; i++)
            {
                if ((books[i].status==bookStatus.BORROWED)&&(in==books[i].bookId))
                {
                    System.out.println("You have successfully returned the following book :\n ");
                    return (books[i].toString());
                    books[i].status=bookStatus.AVAILABLE;
                }
                else
                {
                    System.out.println("Invalid book id: Please try again!");
                }
            }
        }   while (in!=books[i].bookId);
        return null;
    } //returnBook
 
    public static void writeToFile()
    {
        String myFileName = "output.txt";
        boolean open = false;
        PrintWriter myOutFile;
 
        try
        {
            myOutFile = new PrintWriter(myFileName);
            open = true;
 
        }
        catch (FileNotFoundException ex)
        {
            System.out.println("Error opening the file");
            open = false;
 
            return;
        }
 
        try
        {
            if (open)
            {
                myOutFile.print(books.toString());
                myOutFile.close();
                open = false;
 
                System.out.println("Successfully written to file and closed");
            }
 
        }
 
        catch (Exception ex)
        {
            System.out.println("Exception "+ex.getMessage()+" caught");
        }
 
    }
}

public class LoanFiction extends LoanBook
{
    static Scanner keyboard = new Scanner(System.in);
    static int temp;
    static boolean option = false;
    static String genre;
 
    public LoanFiction (int topic, String title, String author)
    {
        super(title, author);
        this.genre = genre;
 
    }//constructor
 
    public static void getGenre()
    {
        do
        {
            System.out.println("Please choose the genre by entering the corresponding number");
            System.out.println("1: Comedy");
            System.out.println("2: Adventure");
            temp = keyboard.nextInt();
            if (temp ==1)
            {
                genre = "Comedy";
 
                option = true;
            }
            else if (temp ==2)
            {
                genre = "Adventure";
                option = true;
            }
            else
                System.out.println("Incorrect option. Please try again");
 
        }   while (!option);
    }
 
    public String toString()
    {
        return (super.toString()+"Fiction Genre : \t"+genre+"\n");
    }
}

public class LoanNonFiction extends LoanBook
{
    static int temp;
    static Scanner keyboard = new Scanner(System.in);
    static String topic;
    static boolean option = false;
 
    public LoanNonFiction (String title, String author)
    {
        super(title, author);
        this.topic = topic;
    }//constructor
 
    public static void getTopic ()
    {
        do
        {
 
            System.out.println("Please choose the topic by entering the corresponding number");
            System.out.println("1: History");
            System.out.println("2: Reference");
            temp = keyboard.nextInt();
            if (temp ==1)
            {
                topic = "History";
 
                option = true;
            }
            else if (temp ==2)
            {
                topic = "Reference";
                option = true;
            }
            else
                System.out.println("Incorrect option. Please try again");
 
        }   while (!option);
    }
 
    public String toString()
    {
        return ("Non-Fiction Topic : \t"+topic+"\n");
    }
}

public class Pupil
{
    private static String firstName, surname;
    private static Scanner keyboard = new Scanner(System.in);
 
    //contructor
    public Pupil (String firstName, String surname)
    {
        this.firstName = firstName;
        this.surname = surname;
    }
 
    public String toString()
    {
        return (firstName + surname);
    }
 
    public static void getPupil()
    {
        System.out.println("Please enter pupils first name : ");
        firstName = keyboard.nextLine();
        System.out.println("Please enter pupils surname : ");
        surname = keyboard.nextLine();
 
    }
}

Data about the books is not kept in arrays. Data about the books is kept in the LoanBook class (I think that's' the class that describes each book, but there are no comments that describes the purpose of each class is).

Notice the class names "LoanBook", "LoanFiction," and "LoanNonFiction" are actions. Classes are things or objects. Classes ARE things. Methods perform actions. Methods DO things. The class "LoanBook" should be called Book or maybe LibraryBook or BookToLoan. The class Book should have a fiction/nonfiction attribute. I see no reason for the classes LoanFiction and LoanNonFiction to exist or for them to extend LoanBook, though they might make good Library methods.

The classes I think your project should have are (at a minimum): Library, Book, and Customer. Library can either be the class with the main() method or there might be another class that presents the library's menu. If you had plans to evolve this program to a GUI, then the latter option would be preferred.

Thanks Greg. Yea normally that's the way i would have went about this but it's an assignment and we've been given instructions to have a main application class, a loanBook class, a Fiction and nonFiction subclass. Im now thinking that i should just have 2 arrays called fiction and nonfiction. Iv had my head stuck in this for too long and keep leaving it and coming back to it which doesnt help.

I'm sorry. Assignments don't always make sense, and those subclasses, as you've explained them, are inexplicable. What I could see for academic exercise purposes is:

Book - a super class, maybe abstract
FictionBook - extends Book
NonFictionBook - extends Book

Yea my thoughts exactly are that loanBook should ideally be a method to loan a book and this is the part creating most of the problems. Well its due to be handed in today so i will make a few last minute tweaks and just go with it. I'll update the post when i receive feedback on it. Many thanks to everyone who took the time to help.