Help with building a library system

[Pitr]

Hi all..

I'm trying to build a library system that will print the following:
Title: colour of Magic
Author: Terry Pratchett
Year published: 1983

I have written the following:

public class Library
{
    public static void main(String args[])
    {
        Catalogue usersCatalogue = new Catalogue();
        String title = "Colour of Magic";
        String author = "Terry Pratchett";
        int year = 1983;
        usersCatalogue.set(title, author, year);
        System.out.println(usersCatalogue);
    }
}

-------------------------------------------------------------------

public class Catalogue
{
    private String title;
    private String author;
    private int year;

    public String toString()
    {
	return ("Title: " + title + "\nAuthor: " + author + "\nYear published: " + year);
    }

    public void set(String newTitle, String newAuthor, int newYear)
    {
	title = newTitle;
	if (newYear <0)
	{
	    System.out.println("Error: Incorrect year or author");
	    System.exit(0);
	}
	else
	{
	    author = newAuthor;
	    year = newYear;
	}
    }

    public Catalogue(String initialTitle, String initialAuthor)
    {
	title = initialTitle;
	author = initialAuthor;
	year = 0;
    }

    public void setTitle(String newTitle)
    {
	title = newTitle;
    }

    public Catalogue(String initialAuthor)
    {
	title = "No title yet.";
	year = 0;
    }


    public Catalogue(int initialYear)
    {
	title = "No title yet";
	author = "No author yet";
	if (initialYear < 0)
	{
	    System.out.println("Error: Negative year.");
	    System.exit(0);
	}
	else
	    year = initialYear;
    }

    public void setYear(int newYear)
    {
	if (newYear <0)
	{
	    System.out.println("Error: negative year");
	    System.exit(0);
	}
	else
	    year = newYear;
    }

    public Catalogue()
    {
	title = "No title yet.";
	author = "No author yet.";
	year = 0;
    }

    public String getTitle()
    {
	return title;
    }

    public String getAuthor()
    {
	return author;
    }

    public int getYear()
    {
	return year;
    }
}

It works fine as far as I'm concerned.. The only thing I need is to be able to print more books using arrays..

Could someone please let me know of the best way of doing this?

Thanks,


Pitr.

[nspils]

Wouldn't a real card catalogue be a collection of book data? So why won't your catalogue contain Book (or Card) objects?

If you are ready for it, this would be a great project for using a map or a hash table or a skip list - the key being something derived from the title, (or the author), the entry being your Book (or Card) object for that book.

[Pitr]

What I was thinking was to have a class called book.java

In it, define variables title author and year, and call them from the driver library..

I can't think on how to do this..

Any ideas?

I'm thinking

Book[] author = new Book[2];
author[1] = "Terry Pratchett";
author[2] = "Jasper Fforde";
author[3] = "Michael Marshall Smith"

Would that work?
To do a title, should I just do the same, only instead of author do title?

[nspils]

How about a Book which has a title, an author, and a year published; the class would include getters and setters for each field. Perhaps a compareTo() method to make the class Comparable, and a toString() method.

The Catalogue can have a field which is an ArrayList<Book> or Book[] to hold the book objects, and methods to add a book to its data storage, sort the data, print out the data, etc.

[Phaelax]

I like nspils' first idea of using a HashMap, but if retrieving a specific book isn't that important and maybe only bringing up more general search results then the array in a Catalog idea sounds simple enough.

[nspils]

the nice thing with a map is that you can store the books in some structure, then when someone wants to choose by way of authors, you use a hash of the author's name to be the key and store the book, and if by title you hash the title and have a different structure. A problem with using a hash is that you do away with searching keys with only a partial title or partial name of the author. Could do a "look up" (author table, title table) which can be searched using a partial result, then click to choose the corresponding complete name/hash key to return the book.

[Pitr]

Hi All..

I've re-written the program.. It now looks like this:

public class Library
{
    public static void main(String args[])
    {


        Book[] booksArray = new Book[3];

        Catalogue catalogue0 = new Catalogue("The Colour of Magic", "Terry Pratchett", 1982);
        Book book0 = new Book(catalogue0);
        booksArray[0] = book0;

        Catalogue catalogue1 = new Catalogue("The Light Fantastic", "Terry Pratchett", 1986);
        Book book1 = new Book(catalogue1);
        booksArray[1] = book1;

        Catalogue catalogue2 = new Catalogue("Equality Rights", "Terry Pratchett", 1987);
        Book book2 = new Book(catalogue2);
        booksArray[2] = book2;





        for (int i=0; i<booksArray.length; i++)
        {
            System.out.println(booksArray[i]);
        }
    }
}

public class Catalogue
{
    private String bookTitle;

    private String bookAuthor;

    private int bookYear;




    public Catalogue(String bookTitle, String bookAuthor, int bookYear)
    {
        this.bookTitle = bookTitle;
        this.bookAuthor = bookAuthor;
        this.bookYear = bookYear;
    }

    public String toString()
    {
        return "Title: " + bookTitle + "\nAuthor: " + bookAuthor + "\nYear: " + bookYear;
    }

}

public class Book
{
    private Catalogue catalogue;


    public Book(Catalogue catalogue)
    {
        this.catalogue = catalogue;
    }

    public Catalogue getCatalogue()
    {
        return this.catalogue;
    }

    public String toString()
    {
        return catalogue.toString() + "\n";
    }
}

What I am trying to do and can't figure out why it doesn't work, is something like this:

In the catalogue.java

public String fillData()
{
    return printWelcome;
}

and on the Library.java

Catalogue welcomeString = new Catalogue();
welcomeString.fillData();

Should that work, or does it not work like that?

[nspils]

I think this is more direct and more simple:

public class Book
{
    private String bookTitle;
    private String bookAuthor;
    private int bookYear;

    public Book (String bookTitle, String bookAuthor, int bookYear)
    {
        this.bookTitle = bookTitle;
        this.bookAuthor = bookAuthor;
        this.bookYear = bookYear;
    }

    public String getTitle()
    {
         return bookTitle;
    }

    public String getAuthor()
    {
         return bookAuthor;
    }

    public int getYear()
    {
         return bookYear;
    }

    public String toString()
    {
        return "Title: " + bookTitle + "\nAuthor: " + bookAuthor + "\nYear: " + bookYear;
    }

}

and

public class Catalogue
{
    private Book[] bookArray = new Book[3];

    public static void main(String args[])
    {

        Book book0 = new Book("The Colour of Magic", "Terry Pratchett", 1982);
        booksArray[0] = book0;

        Book book1 = new Book ("The Light Fantastic", "Terry Pratchett", 1986);
        booksArray[1] = book1;

        Book book2 = new Catalogue("Equality Rights", "Terry Pratchett", 1987);
        booksArray[2] = book2;
    }

    public void printCatalogue()
    {
        for( Book b : bookArray)
        {
            System.out.println(b.toString());
        }
    }
}

What are you trying to do with the "printWelcome" method?