Untitled

/**
 * A class that maintains information on a book.
 * This might form part of a larger application such
 * as a library system, for instance.
 *
 * @author (Insert your name here.)
 * @version (Insert today's date here.)
 */
class Book
{
    // The fields.
    private String author;
    private String title;
    private int pages;
    private String refNumber;

    /**
     * Set the author and title fields when this object
     * is constructed.
     */
    public Book(String bookAuthor, String bookTitle, int bookPages)
    {
        author = bookAuthor;
        title = bookTitle;
        pages = bookPages;
        refNumber = "";
    }
    
    public void setRefNumber(String ref) {
        if(ref.length() >= 3)
        refNumber = ref;
        
        else System.out.println("Error");
    }
    
    public String getRefNumber() {
        return refNumber;
    }

    // get Author
    public String getAuthor() {
        return author;
    }
    
    // get Title
    public String getTitle() {
        return title;
    }
    
    // get pages
    public int getPages() {
        return pages;
    }
    
    // Print Author
    public void printAuthor() {
        System.out.println(author);
    }
    
    //Print Title
    public void printTitle() {
        System.out.println(title);
    }
    
    // Print details
    public void printDetails() {
        System.out.println("The title of the book is " + title + ".");
        System.out.println("The author who wrote the book is " + author + ".");
        System.out.println("There is " + pages + " pages in the book");
        if(refNumber.length() > 0)
        System.out.println(refNumber);
        else System.out.println("ZZZ");
    }
}