Question

I need help with converting the java class into a python class. this is what i have so far :

class Library:
  
def __init__(self):
  
def addAuthor(self, Author):
  
def addPublisher(self, Publisher):
  
def addBook(self, Book):
  

Here is the original java class:

import java.util.ArrayList;
import java.util.List;

public class Library {

private List<Book> books;
private List<Author> authors;
private List<Publisher> publishers;

public Library(){
this.books=new ArrayList<>();
this.authors=new ArrayList<>();
this.publishers=new ArrayList<>();
}

public void addAuthor(String name){
authors.add(new Author(name));
}

public void addPublisher(String name, String address){
publishers.add( new Publisher(name,address));
}

public void addBook(String title,String location, int yearPub, String authorName, String publisherName ) throws AuthorNotFoundException, PublisherNotFoundException {
//Find Author
Author author=null;
for (Author a:authors){
if (a.getName().equals(authorName)){
author = a;
break;
}
}
if (author==null) {
throw new AuthorNotFoundException("Author is not in the system");
}

//Find Publisher
Publisher publisher=null;
for (Publisher p:publishers){
if (p.getName().equals(publisherName)){
publisher=p;
break;
}
}
if (publisher==null){
throw new PublisherNotFoundException("Publisher is not in the system");
}

books.add(new Book(title, location,yearPub,author,publisher));
}

public List<Book> getBooks(){return books;}
public List<Author> getAuthors(){return authors;}
public List<Publisher> getPublishers(){return publishers;}

}

Answer 1

class Author:
    def __init__(self, name):
        self._name = name

    def get_name(self):
        return self._name

    def set_name(self, name):
        self._name = name


class Publisher:
    def __init__(self, name, address='unknown'):
        self._name = name
        self._address = address

    def get_name(self):
        return self._name

    def get_address(self):
        return self._address

    def set_name(self, name):
        self._name = name

    def set_address(self, address):
        self._address = address

    def __str__(self):
        return "Publisher '%s' at '%s'" % (self._name, self._address)


class Book:
    def __init__(self, title, locationCode, yearPub, author=None, publisher=None):
        self._title = title
        self._locationCode = locationCode
        self._yearPub = yearPub
        self._author = author
        self._publisher = publisher

    def get_title(self):
        return self._title

    def get_locationCode(self):
        return self._locationCode

    def get_yearPub(self):
        return self._yearPub

    def get_author(self):
        return self._author

    def get_publisher(self):
        return self._publisher

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

    def set_locationCode(self, locationCode):
        self._locationCode = locationCode

    def set_yearPub(self, yearPub):
        self._yearPub = yearPub

    def __str__(self):
        return "A book called '%s' written by '%s' and published in %d by '%s'" % (
            self._title, self._author.get_name(), self.get_yearPub(), self._publisher.get_name())


class AuthorNotFoundException(Exception):
    pass


class PublisherNotFoundException(Exception):
    pass


class Library:
    def __init__(self):
        self.books = []
        self.authors = []
        self.publishers = []

    def add_author(self, author):
        self.authors.append(author)

    def add_publisher(self, name, address):
        p = Publisher(name, address)
        self.publishers.append(p)

    def add_book(self, title, location, yearPub, authorName, publisherName):
        author = None
        for a in self.authors:
            if a.get_name() == authorName:
                author = a
                break
        if author is None:
            raise AuthorNotFoundException("Author is not in the system")

        publisher = None
        for p in self.publishers:
            if p.get_name() == publisherName:
                publisher = p
                break
        if publisher is None:
            raise PublisherNotFoundException("Publisher is not in the system")
        b = Book(title, location, yearPub, author, publisher)
        self.books.append(b)

    def get_books(self):
        return self.books

    def get_authors(self):
        return self.authors

    def get_publishers(self):
        return self.publishers