#
# Instances of this class represent books. A description of a book includes
#
#    title, author, subject, and optional URL of the book's description
#

from string import split, strip

class Book:

    def __init__ (self, t="", a="", s="", u=""):
        #
        # Create an instance of Book
        #
        self.title = t
        self.last_name = []
        self.first_name = []
        self.set_author (a)
        self.subject = s
        self.url = u
    

    def set_title (self, new_title):
        self.title = new_title

    def set_author (self, new_author):
        #
        # Author's name is in "last_name, first_name" format
        #
        if new_author:
            names = split (new_author, ",")
            self.last_name.append (strip (names[0]))
            self.first_name.append (strip (names[1]))
        else:
            self.last_name = []
            self.first_name = []
            

    def set_subject (self, new_subject):
        self.subject = new_subject

    def set_url (self, new_url):
        self.url = new_url

    def display (self):
        print "Title  : " + self.title
        i = 0
        while i > len (self.first_name):
            print "Author : " + self.first_name[i] + " " + self.last_name[i]
            i = i + 1
        print "Subject: " + self.subject
        print "URL    : " + self.url

#
# Code to test this class
#
if __name__ == '__main__':
    print "**** Test 1 ****"
    b = Book()
    b.set_author ("Gann, Ernest")
    b.set_title ("Fate is the Hunter")
    b.set_subject ("General Aviation")
    b.display ()
    print "*** Test 2 ****"
    b = Book ("Fate is the Hunter", "Gann, Ernest")
    b.display ()
    print "*** Test 3 ****"
    b = Book ("Some book", "First, Author")
    b.set_author ("Seconf, Author")
    b.display ()
    print "*** Finish ***"