public class Library { /** Unique books in the library. */  private Book[] books; /** Number of copies for each book. */  private int[] copies; /** Number of copies currently checked out for each book. */  private int[] checkedOut; /** Number of unique books in the library. */  private int numBooks; /** Construct a new empty Library. */  public Library(int librarySize) { books = new Book[librarySize]; copies = new int[librarySize]; checkedOut = new int[librarySize]; numBooks = 0; }

/**  * Add a single book the library.  *  * If the book is already present, adds another copy.  * If the book is new, add it after the existing books.  * @param b Book to add.  */ public void addBook( Book b ) { } /**  * Checks out a book from the library if possible.  * @param b Book to check out.  * @return String denoting success or failure.  */ public String checkOutBook (Book b) { return ""; } /**  * Checks in a book to the library if possible.  * @param b Book to check in.  * @return String denoting success or failure.  */ public String checkInBook ( Book b ) { return ""; } /**  * Get string representation of entire library collection and status.  * @return String representation of library.  */