Question

QUESTION 13

1. Implement in Python and test the classes shown in the UML below. The LibraryItem class shown in the UML, represents an item that the library issues to students. The partial Python code is provided and It has the following attributes. Test the program by creating a list of books and a list of DVDs and printing the details of each element in the list.

   Attribute	Description
   ID	The ID of the item.
   createdate	The date the item was created as dd/mm/yyyy
   title	The title of the item.

   class LibraryItem:
       def __init__(self,ID="",year=0,title=""):
           self.ID=ID
           self.year=year
           self.title=title
   
       def getLoanPeriod(self):
           return 0
   

   A) Implement the Book class. It inherits from LibraryItem. Furthermore, it has this additional attribute

   Attribute	Description
   author	The author of the book
   Electronic	This tells whether the book is available as an electronic book (e book)

   Implement the getLoanPeriod function in this way:

   - If the book was written before the year 2000, the loan period will be 14 days.

   - If the book was written after or in 2000, the loan period will be 7 days.

   B) Implement the DVD class. It inherits from LibraryItem. Furthermore, it has this additional attribute

   Attribute	Description
   length	The length of the DVD. Example: “2 hours: 30 minutes”
   HD	Whether the DVD is available in HD (High Definition) or not

   Implement the getLoanPeriod function in this way:

   - If the DVD is available in HD format, the loan period will be 3 days. Otherwise, the loan period will be 7 days.

Answer 1

Here is the Python code:

import datetime

class LibraryItem:
    def __init__ (self, ID=0, year = 2000, month = 1, day = 1, title = ""):
        self.ID = ID
        self.year = year
        self.createDate = datetime.datetime (year, month, day)
        self.title = title
        
    def getLoanPeriod (self):
        return 0

class Book (LibraryItem):
    def __init__ (self, ID=0, year = 2000, month = 1, day = 1, title = "", Author = "", Electronic = 1):
        self.Author = Author
        self.Electronic = Electronic
        LibraryItem.__init__ (self, ID, year, month, day, title)
        
    def getLoanPeriod (self):
        if self.year < 2000:
            return 14
        else:
            return 7

class DVD (LibraryItem):
    def __init__ (self, ID=0, year = 2000, month = 1, day = 1, title = "", length = "", HD = 1):
        self.length = length
        self.HD = HD
        LibraryItem.__init__ (self, ID, year, month, day, title)
        
    def getLoanPeriod (self):
        if self.HD == 1:
            return 3
        else:
            return 7

l1 = Book (1, 1998, 10, 20, "Book 1", "Auth 1", 1)
l2 = Book (2, 2018, 11, 21, "Book 2", "Auth 2", 0)
l3 = DVD (3, 2018, 12, 22, "DVD 1", "2 hours 30 mins", 1)
l4 = DVD (4, 2017, 3, 4, "DVD 2", "1 hours 25 mins", 0)

print (l1.createDate, l1.getLoanPeriod())
print (l2.Author, l2.getLoanPeriod())
print (l3.HD, l3.getLoanPeriod())
print (l4.length, l4.getLoanPeriod())