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

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

fromabcimportABC, abstractmethod


classModel(ABC):
@abstractmethod
def__iter__(self):
pass

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

@property
@abstractmethod
defitem_type(self):
pass


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(ABC):
@abstractmethod
defshow_item_list(self, item_type, item_list):
pass

@abstractmethod
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()"""
pass

@abstractmethod
defitem_not_found(self, item_type, item_name):
pass


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 {} "{}" does not exist in the records'.format(item_type, item_name))


classController:
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)


defmain():
"""
 >>> model = ProductModel()
 >>> view = ConsoleView()
 >>> controller = Controller(model, view)

 >>> controller.show_items()
 PRODUCT LIST:
 milk
 eggs
 cheese
 <BLANKLINE>

 >>> controller.show_item_information("cheese")
 PRODUCT INFORMATION:
 Name: cheese, Price: 2.00, Quantity: 10
 <BLANKLINE>

 >>> controller.show_item_information("eggs")
 PRODUCT INFORMATION:
 Name: eggs, Price: 0.20, Quantity: 100
 <BLANKLINE>

 >>> controller.show_item_information("milk")
 PRODUCT INFORMATION:
 Name: milk, Price: 1.50, Quantity: 10
 <BLANKLINE>

 >>> controller.show_item_information("arepas")
 That product "arepas" does not exist in the records
 """


if__name__=="__main__":
importdoctest

doctest.testmod()