python-patterns/patterns/structural/mvc.py at master · Androidown/python-patterns · GitHub

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#!/usr/bin/env python
# -*- coding: utf-8 -*-

"""
*TL;DR
Separates data in GUIs from the ways it is presented, and accepted.
"""


classModel(object):
def__iter__(self):
raiseNotImplementedError

defget(self, item):
"""Returns an object with a .items() call method
 that iterates over key,value pairs of its information."""
raiseNotImplementedError

@property
defitem_type(self):
raiseNotImplementedError


classProductModel(Model):
classPrice(float):
"""A polymorphic way to pass a float with a particular
 __str__ functionality."""

def__str__(self):
return"{:.2f}".format(self)

products= {
'milk': {'price': Price(1.50), 'quantity': 10},
'eggs': {'price': Price(0.20), 'quantity': 100},
'cheese': {'price': Price(2.00), 'quantity': 10},
 }

item_type='product'

def__iter__(self):
foriteminself.products:
yielditem

defget(self, product):
try:
returnself.products[product]
exceptKeyErrorase:
raiseKeyError((str(e) +" not in the model's item list."))


classView(object):
defshow_item_list(self, item_type, item_list):
raiseNotImplementedError

defshow_item_information(self, item_type, item_name, item_info):
"""Will look for item information by iterating over key,value pairs
 yielded by item_info.items()"""
raiseNotImplementedError

defitem_not_found(self, item_type, item_name):
raiseNotImplementedError


classConsoleView(View):
defshow_item_list(self, item_type, item_list):
print(item_type.upper() +' LIST:')
foriteminitem_list:
print(item)
print('')

@staticmethod
defcapitalizer(string):
returnstring[0].upper() +string[1:].lower()

defshow_item_information(self, item_type, item_name, item_info):
print(item_type.upper() +' INFORMATION:')
printout='Name: %s'%item_name
forkey, valueinitem_info.items():
printout+=', '+self.capitalizer(str(key)) +': '+str(value)
printout+='\n'
print(printout)

defitem_not_found(self, item_type, item_name):
print('That %s "%s" does not exist in the records'% (item_type, item_name))


classController(object):
def__init__(self, model, view):
self.model=model
self.view=view

defshow_items(self):
items=list(self.model)
item_type=self.model.item_type
self.view.show_item_list(item_type, items)

defshow_item_information(self, item_name):
try:
item_info=self.model.get(item_name)
exceptException:
item_type=self.model.item_type
self.view.item_not_found(item_type, item_name)
else:
item_type=self.model.item_type
self.view.show_item_information(item_type, item_name, item_info)


if__name__=='__main__':

model=ProductModel()
view=ConsoleView()
controller=Controller(model, view)
controller.show_items()
controller.show_item_information('cheese')
controller.show_item_information('eggs')
controller.show_item_information('milk')
controller.show_item_information('arepas')


### OUTPUT ###
# PRODUCT LIST:
# cheese
# eggs
# milk
#
# PRODUCT INFORMATION:
# Name: Cheese, Price: 2.00, Quantity: 10
#
# PRODUCT INFORMATION:
# Name: Eggs, Price: 0.20, Quantity: 100
#
# PRODUCT INFORMATION:
# Name: Milk, Price: 1.50, Quantity: 10
#
# That product "arepas" does not exist in the records