so_magic.utils.command_factory_interface

Complexity

Total Complexity

5

Size/Duplication

Total Lines	37
Duplicated Lines	0 %

Importance

Changes

0

4 Methods

Rating	Name	Duplication	Size	Complexity
A	CommandFactoryType.create()	0	4	2
A	CommandFactoryType.register_as_subclass()	0	5	1
A	CommandFactoryType.__new__()	0	4	1
A	CommandFactoryInterface.construct()	0	8	1

"""This module is responsible to define an interface to construct Command objects (instances of the Command class)."""
from abc import ABC, abstractmethod
from .command_interface import CommandInterface


class CommandFactoryInterface(ABC):
    """Define a way to create objects of type Command.

    Classes implementing this interface define a way to construct (initialize) new Command objects (class instances).
    """
    @abstractmethod
    def construct(self, *args, **kwargs) -> CommandInterface:
        """Construct a new Command object (new class instance) that can be executed.

        Returns:
            Command: the command object (instance)
        """
        raise NotImplementedError


class CommandFactoryType(type):
    def __new__(mcs, *args, **kwargs):
        command_factory_type = super().__new__(mcs, *args, **kwargs)
        command_factory_type.subclasses = {}
        return command_factory_type

    def register_as_subclass(cls, factory_type):
        def wrapper(subclass):
            cls.subclasses[factory_type] = subclass
            return subclass
        return wrapper

    def create(cls, factory_type, *args, **kwargs):
        if factory_type not in cls.subclasses:
            raise ValueError('Bad "Factory type" \'{}\''.format(factory_type))
        return cls.subclasses[factory_type](*args, **kwargs)