第四天：创建型模式--原型模式

import copy
from collections import OrderedDict


class Book:
    def __init__(self, name, authors, price, **rest):
        '''rest的例子有：出版商、长度、标签、出版日期'''
        self.name = name
        self.authors = authors
        self.price = price
        self.__dict__.update(rest)

    def __str__(self):
        mylist = []
        ordered = OrderedDict(sorted(self.__dict__.items()))
        for i in ordered.keys():
            mylist.append('{}：{}'.format(i, ordered[i]))
            if i == 'price':
                mylist.append('$')
            mylist.append('\n')
        return ''.join(mylist)


class Prototype:
    def __init__(self):
        self.objects = dict()

    def register(self, identifiter, obj):
        self.objects[identifiter] = obj

    def unregister(self, identifier):
        del self.objects[identifier]

    def clone(self, identifier, **attr):
        found = self.objects.get(identifier)
        if not found:
            raise ValueError('Incorrect object identifier:{}'.format(identifier))
        obj = copy.deepcopy(found)
        obj.__dict__.update(attr)
        return obj


def main():
    b1 = Book('The Cprogramming Language', ('Brian W.Kernighan', 'Dennis M.Ritchie'), price=118,
              publisher='Prentice Hall', length=228, publication_date='1978-02-22',
              tags=('C', 'programming', 'algorithma', 'algorihma', 'data structures'))

    prototype = Prototype()
    cid = 'k&r-first'
    prototype.register(cid, b1)
    b2 = prototype.clone(cid, name='The CProgramming Language(ANSI)', price=48.99, length=274,
                         publication_date='1988-04-01', edition=2)
    for i in (b1, b2):
        print(i)
    print('ID b1:{}!= ID b2:{}'.format(id(b1), id(b2)))


if __name__ == '__main__':
    main()