我正在尝试编写BookStore的库存清单，但我似乎无法让它通过Book类中的params

Question

- public class BookStore {
   private String storeName; 
   private Book[] inventory;  

   public BookStore(){
       inventory = new Book[1]; 

       inventory[0]  = new Book ((new Author(firstname,lastname,middle)), new Date(2015), "booktitle") ;


   }

public class Book {
   private static final String DEFAULT_TITLE = "Untitled";

   private Author author;
   private Date published;
   private String title;


   public Book(Author author, Date published, String title)
   {
       setAuthor(author);
       setDatePublished(published);
       setTitle(title);
   }

   }   {

   private String first;
   private String middle;
   private String last;