For this lab, you will write a class that represents a book. The Book class will support the following hidden state:

title as a Java String

author$($s$)$ as an ArrayList of String

ISBN as a Java String

number of pages as an integer

retail price as a double

publisher as a Java String

Your Book class must support the following interface:

public Book$($String title, String isbn, int np$,$ double rp$,$ String publisher, String $...$ authors$)$

public String getTitle$()$

public String getIsbn$()$

public int getNumberOfPages$()$

public double getRetailPrice$()$

public String $[]$ getAuthors$()$

public String toString$()$

For example, the Java statement statements:

Book b $=$ new Book$("$Java How to Program",

$"978-0131016217",$

$1400,19\mathrm{.}97,$ "Prentice$-$Hall",

"Harvey M$.$ Deitel", "Paul J$.$ Deitel" $)$;

System.out.printf$("\%$s$\%$n$",$ b$)$;

should produce the following output:

That is$,$ the toString$()$ should produce a string that has the book object state in this order

title

authors $($comma separated with space after the comma inside $[]$

number of pages

retail price

publisher

ISBn

inside $<>.$

If the constructor receives a null value for any of the String state, that state should be set to "Unknown". If no authors are given, the ArrayList should contain a single string "Unknown".

For example, the Java statement:

Book b $=$ new Book$($null$,$ null, $5,20\mathrm{.}10,$ null$)$;

System.out.printf$("\%$s$\%$n$",$ b$)$;

should produce the output

import java.util.ArrayList;

import java.util.Arrays;

public class Book $\{$

$//$ Private fields for the book's state

private String title;

private String isbn;

private int numberOfPages;

private double retailPrice;

private String publisher;

private ArrayList authors;

$//$ Constructor

public Book$($String title, String isbn, int np$,$ double rp$,$ String publisher, String... authors$)\{$

this.title $=($title $!=$ null$)?$ title : "Unknown";

this.isbn $=($isbn $!=$ null$)?$ isbn : "Unknown";

this.numberOfPages $=$ np;

this.retailPrice $=$ rp;

this.publisher $=($publisher $!=$ null$)?$ publisher : "Unknown";

$//$ Handling authors, default to "Unknown" if no authors are provided

if $($authors $!=$ null && authors.length $>0)\{$

this.authors $=$ new ArrayList$<>($Arrays$.$asList$($authors$))$;

$\}$ else $\{$

this.authors $=$ new ArrayList$<>()$;

this.authors.add$("$Unknown$")$;

$\}$

$\}$

$//$ Getters

public String getTitle$()\{$

return title;

$\}$

public String getIsbn$()\{$

return isbn;

$\}$

public int getNumberOfPages$()\{$

return numberOfPages;

$\}$

public double getRetailPrice$()\{$

return retailPrice;

$\}$

public String$[]$ getAuthors$()\{$

return authors.toArray$($new String$[0])$;

$\}$

$//$ toString method

@Override

public String toString$()\{$

return String.format$("$