Question

Programming language: Java

Design an application that has three classes. The first one, named Book describes book object and has title and number of pages instance variables, constructor to initialize their values, getter methods to get their values, method to String to provide String representation of book object, and method is Long that returns true if book has over 300 pages, and returns false othewise. Provide also method char firstChard) that returns first cahracter of the book's title. The second class, named Library has bookShelf variable that is of ArrayList<Book> type, and has no other data. It has constructor in which you will assign bookShelf = new ArrayList<Book>0; Next, add five books of your choice to bookshelt In addition, implement the following methods for class Library: • String allBooks () // Method returns string representation of all books from the bookShelf // String has one book per line. This method does not print anything. • Book shortestBook () // Method returns shortest book object in the bookShelf. This method does not // print anything. • void printBookSelection (int num, char character) //Method prints books with // number of pages above num and title starting with given character. • ArrayList. <Book> longBooks 1) // Method returns ArrayList<Book> consisting of all long books Il in the bookShelf. This method does not print anything. If none // of the books is long. return empty ArrayList<Book>. The third class, named Tester has main method in it. It instantiates an object from class Library and it invokes and tests the above four methods. Each method invocation should be preceded or_acompanied by apropriate explanation what the result means or what the method does and should be printed to user. In order to test method printBookSelection ask user to provide num and character parameters. Invoke it at least once so that result has at two or more books, and at least once so that result is an empty ArrayList<Book>

Answer 1

CODE IN JAVA:

Book.java file:

public class Book {
   String title ;
   int numOfPages ;
   public Book(String title, int numOfPages) {
      
       this.title = title;
       this.numOfPages = numOfPages;
   }
   public String getTitle() {
       return title;
   }
   public int getNumOfPages() {
       return numOfPages;
   }
   public boolean isLong() {
       return numOfPages > 300 ;
   }
   public char firstChar() {
       return title.charAt(0);
   }
   @Override
   public String toString() {
       return "Book [title=" + title + ", numOfPages=" + numOfPages + "]";
   }
  
  
}

Library.java file:

import java.util.ArrayList;

public class Library {
   ArrayList<Book> bookShelf ;
   Library(){
       bookShelf = new ArrayList<Book>();
       bookShelf.add(new Book("Amrutham Kurisina ratri", 240));
       bookShelf.add(new Book("Rich dad poo dad", 400));
       bookShelf.add(new Book("Half girl friend", 320));
       bookShelf.add(new Book("Fountain head", 180));
       bookShelf.add(new Book("Amaravathi kathalu", 640));
   }
   String allBooks() {
       StringBuffer str = new StringBuffer("");
       for(Book b : bookShelf) {
           str.append(b);
           str.append("\n");
       }
       return str.toString() ;
   }
   Book shortestBook() {
       Book shortBook = bookShelf.get(0);
       for(Book b : bookShelf) {
           if(b.getNumOfPages() < shortBook.getNumOfPages())
               shortBook = b ;
       }
       return shortBook ;
   }
   void printBookSelection(int num, char character) {
       for(Book b : bookShelf) {
           if(b.getNumOfPages() > num && b.getTitle().charAt(0) == character) {
               System.out.println(b);
           }
       }
   }
   ArrayList<Book> longBooks(){
       ArrayList<Book> resultList = new ArrayList<Book>();
       for(Book b : bookShelf) {
           if(b.isLong())
               resultList.add(b);
       }
       return resultList ;
   }
  
}

Tester.java file:

import java.util.ArrayList;
import java.util.Scanner ;
public class Tester {

   public static void main(String[] args) {
      
       Scanner sc = new Scanner(System.in);
       Library library = new Library();
       System.out.println("Below are the all books of library : ");
       System.out.println(library.allBooks());
       System.out.println("\nShortest book : " + library.shortestBook());
       int num;
       char c ;
       System.out.print("Enter the number :");
       num = sc.nextInt();
       System.out.print("Enter the character:");
       c = sc.next().charAt(0);
       System.out.println("Below are the books having pages greater than number and title starting with your character : ");
       library.printBookSelection(num, c);
       ArrayList<Book> longBooks = library.longBooks();
       System.out.println("Below are the long books: ");
       for(Book b : longBooks)
           System.out.println(b);

   }

}

OUTPUT:

Console X <terminated > Tester (Java Application) C:\Program Files\ava\jdk-13.0.1\bin\javaw.exe (19-Apr-2020, 9:15:08 pm) Below are the all books of library : Book [title=Amrutham Kurisina ratri, numOfPages=240] Book [title=Rich dad poo dad, numOfPages=400] Book [title=Half girl friend, numOfPages=320] Book [title=Fountain head, numOfPages=180] Book [title=Amaravathi kathalu, numOfPages=640] Shortest book : Book [title=Fountain head, numOfPages=180] Enter the number :300 Enter the character:H Below are the books having pages greater than number and title starting with your character : Book [title=Half girl friend, numOfPages=320] Below are the long books: Book [title=Rich dad poo dad, numOfPages=400] Book [title=Half girl friend, numOfPages=320] Book [title=Amaravathi kathalu, numOfPages=640]