content: package com.itbulls.learnit.javacore.oop.hw.books;
  
  import java.math.BigDecimal;
  import java.util.Arrays;
  
  public class Demo {
  
  	public static void main(String[] args) {
  		Book[] books = new Book[] {
  				new Book(1, "Book_1", new Author[] { new Author(1, "Jon", "Johnson") },
  						new Publisher(1, "Publisher_1"), 1990, 231,
  						BigDecimal.valueOf(24.99), CoverType.PAPERBACK),
  				new Book(2, "Book_2",
  						new Author[] { new Author(1, "Jon", "Johnson"),
  								new Author(2, "William", "Wilson") },
  						new Publisher(2, "Publisher_2"), 2000, 120,
  						BigDecimal.valueOf(14.99), CoverType.PAPERBACK),
  				new Book(3, "Book_3",
  						new Author[] { new Author(3, "Walter", "Peterson") },
  						new Publisher(1, "Publisher_1"), 1997, 350,
  						BigDecimal.valueOf(34.99), CoverType.HARDCOVER),
  				new Book(4, "Book_4", new Author[] { new Author(4, "Craig", "Gregory") },
  						new Publisher(3, "Publisher_3"), 1992, 185,
  						BigDecimal.valueOf(19.99), CoverType.PAPERBACK) };
  
  		BookService bookService = new BookService();
  		System.out.println(Arrays.toString(
  				bookService.filterBooksByAuthor(new Author(1, "Jon", "Johnson"), books)));
  		
  		System.out.println(Arrays.toString(
  				bookService.filterBooksByPublisher(new Publisher(3, "Publisher_3"), books)));
  		
  		System.out.println(Arrays.toString(
  				bookService.filterBooksAfterSpecifiedYear(1992, books)));
  	}
  }
  