17.11. OOP UML

17.11.1. Value

Type + instance = Value

Type instances create Values:

>>> class str:
...     ...
...
>>> 'Alice'
>>> 'Apricot'

17.11.2. Scalars

Value + Identifier = Scalar

>>> firstname = 'Alice'
>>> lastname = 'Apricot'

17.11.3. Structure

Scalar + Relation = Structure

>>> user = ['Alice', 'Apricot']

17.11.4. Data

Structures + Meaning = Data

>>> user = {
...     'firstname': 'Alice',
...     'lastname': 'Apricot',
... }

17.11.5. Information

Data + Behavior = Information

>>> class User:
...     firstname: str
...     lastname: str
...
...     def __init__(self, firstname, lastname):
...         self.firstname = firstname
...         self.lastname = lastname
...         self._authenticated = False
...
...     def login(self):
...         self._authenticated = True
...
...     def logout(self):
...         self._authenticated = False
>>>
>>>
>>> user = User('Alice', 'Apricot')
>>>
>>> user.login()
>>> user.logout()

17.11.6. Application

Information + Business Logic = Application

>>> class User:
...     firstname: str
...     lastname: str
...
...     def __init__(self, firstname, lastname):
...         self.firstname = firstname
...         self.lastname = lastname
...         self._authenticated = False
...
...     def login(self, username, password):
...         if not (username == 'alice' and password == 'secret'):
...             raise PermissionError('Invalid username and/or password')
...         self._authenticated = True
...
...     def logout(self):
...         self._authenticated = False
>>>
>>>
>>> user = User('Alice', 'Apricot')
>>>
>>> user.login('alice', 'secret')
>>> user.logout()

17.11.7. UML Class Diagram

Unified Modeling Language

>>> class Account:
...     def __init__(self):
...         self._authenticated = False
...
...     def login(self):
...         self._authenticated = True
...
...     def logout(self):
...         self._authenticated = False
>>>
>>>
>>> class User(Account):
...     def __init__(self, firstname, lastname, birthdate):
...         self.firstname = firstname
...         self.lastname = lastname
...         self.birthdate = birthdate
...
...     def get_name(self):
...         return f'{self.firstname} {self.lastname}'
...
...     def get_age(self):
...         return ...
>>>
>>>
>>> class Admin(Account):
...     def __init__(self):
...         self.is_active = True
...         self.is_staff = True
...         self.is_admin = True
...
...     def add_user(self):
...         ...
...
...     def edit_user(self):
...         ...
...
...     def delete_user(self):
...         ...

17.11.8. UML Sequence Diagram

Unified Modeling Language

17.11.9. Use Case - 1

from decimal import Decimal
from datetime import date, datetime


class Address:
    street: str
    city: str
    postcode: str
    country: str


class Bank:
    name: str
    bic: str
    swift: str
    address: Address
    def manages(self): ...
    def maintains(self): ...


class Customer:
    firstname: str
    lastname: str
    birthdate: date
    address: Address
    def login(self): ...
    def logout(self): ...


class Card:
    customer: Customer
    number: int
    cvv: int
    expiration: date
    pin: int
    def change_pin(self): ...
    def create_transaction(self): ...


class CreditCard(Card):
    limit: Decimal
    interest_rate: float


class DebitCard(Card):
    pass


class ATM:
    bank: Bank
    address: Address
    def check_balance(self): ...
    def withdraw(self): ...
    def create_transaction(self): ...


class Transaction:
    id: str
    date: datetime
    type: str
    amount: Decimal
    def create(self): ...
    def commit(self): ...
    def rollback(self): ...


class Account:
    number: int
    iban: str
    balance: Decimal
    def deposit(self): ...
    def create_transaction(self): ...


class CurrentAccount:
    def withdraw(self): ...
    def transfer(self): ...


class SavingAccount:
    interest_rate: float
    def yield_interest(self): ...