2.9. UML Class Diagram

2.9.1. Attributes

>>> class Astronaut:
...     firstname: str
...     lastname: str

```mermaid
classDiagram

class Astronaut {
    firstname: str
    lastname: str
}
```

2.9.2. Methods Without Parameters

>>> class Astronaut:
...     def say_hello(self):
...         pass

```mermaid
classDiagram

class Astronaut {
    say_hello()
}
```

2.9.3. Methods With Parameters

>>> class Astronaut:
...     def say_hello(self, firstname: str, lastname: str):
...         pass

```mermaid
classDiagram

class Astronaut {
    say_hello(firstname: str, lastname: str)
}
```

2.9.4. Method Return Type

>>> class Astronaut:
...     def say_hello(self) -> str:
...         pass

```mermaid
classDiagram

class Astronaut {
    say_hello() str
}
```

2.9.5. Abstract Methods

>>> from abc import ABC, abstractmethod
>>>
>>>
>>> class Astronaut(ABC):
...     @abstractmethod
...     def say_hello(self):
...         pass

```mermaid
classDiagram

class Astronaut {
    say_hello()*
}
```

2.9.6. Static Methods

>>> class Astronaut:
...     @staticmethod
...     def say_hello():
...         pass

```mermaid
classDiagram

class Astronaut {
    say_hello()$
}
```

2.9.7. Types

>>> class Astronaut:
...     firstname: str
...     lastname: str
...
...     def say_hello(self, name: str) -> str:
...         pass

```mermaid
classDiagram

class Astronaut {
    firstname: str
    lastname: str

    say_hello(name: str) str
}
```

2.9.8. Access Modifiers

• + - Public

• - - Private

• # - Protected

• ~ - Package/Internal

2.9.9. Access Modifiers - Public

>>> class Astronaut:
...     firstname: str
...     lastname: str
...
...     def say_hello(self) -> str:
...         pass

```mermaid
classDiagram

class Astronaut {
    +firstname: str
    +lastname: str
    +say_hello() str
}
```

2.9.10. Access Modifiers - Protected

>>> class Astronaut:
...     _firstname: str
...     _lastname: str
...
...     def _say_hello(self) -> str:
...         pass

```mermaid
classDiagram

class Astronaut {
    #firstname: str
    #lastname: str
    #say_hello() str
}
```

2.9.11. Access Modifiers - Private

>>> class Astronaut:
...     __firstname: str
...     __lastname: str
...
...     def __say_hello(self) -> str:
...         pass

```mermaid
classDiagram

class Astronaut {
    -firstname: str
    -lastname: str
    -say_hello() str
}
```

2.9.12. Boxes and Arrows

2.9.13. Rationale

2.9.14. Django

• GraphViz: https://graphviz.org/

• Dot: https://graphviz.org/doc/info/lang.html

• Django Extensions: https://django-extensions.readthedocs.io/en/latest/graph_models.html#example-usage

$ brew install graphviz
$ pip install pydotplus
$ pip install django-extensions

# Add 'django_extensions' to INSTALLED_APP

$ python manage.py graph_models -a -g -o all.png
$ python manage.py graph_models myapp -g -o myapp.png
$ python manage.py graph_models -a -I Contact,Address -o models.png
$ python manage.py graph_models -a --arrow-shape normal -o myproject.png

2.9.15. Generate from code

• sphinx.ext.graphviz (from sphinx) - https://www.sphinx-doc.org/en/master/usage/extensions/graphviz.html

• pyreverse (from pylint) - https://www.logilab.org/blogentry/6883

• GraphModels (from django-command-extensions) - https://django-extensions.readthedocs.io/en/latest/graph_models.html#example-usage

• epydoc - http://epydoc.sourceforge.net - http://epydoc.sourceforge.net/api/epydoc.apidoc.VariableDoc-class.html

• pynsource - http://pynsource.com/

• pyUML - https://sourceforge.net/projects/eclipse-pyuml/

• lumpy - http://www.greenteapress.com/thinkpython/swampy/lumpy.html

• ObjectDomain - http://www.objectdomain.com/products/od-features

• argouml-python - http://argouml-python.tigris.org/

• pywebuml - https://bitbucket.org/tzulberti/pywebuml

• uml-to-django - https://github.com/auvipy/uml-to-django

• Python Vipera - https://sourceforge.net/projects/pythonvipera/

• gaphor - https://github.com/gaphor/gaphor

• https://stackoverflow.com/questions/260165/whats-the-best-way-to-generate-a-uml-diagram-from-python-source-code

• https://modeling-languages.com/uml-tools/#python

$ pyreverse -o png -p mymodule .