from . import registry
from .i18n import _
[docs]class MachineMixin:
"""This mixing allows a model to automatically instantiate and assign an
``StateMachine``.
"""
state_field_name: str = "state"
"""The model's state field name that will hold the state value."""
state_machine_name: "str | None" = None
"""A fully qualified name of the class, where it can be imported."""
state_machine_attr: str = "statemachine"
"""Name of the model's attribute that will hold the machine instance."""
bind_events_as_methods: bool = False
"""If ``True`` the state machine events triggers will be bound to the model as methods."""
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
if not self.state_machine_name:
raise ValueError(
_("{!r} is not a valid state machine name.").format(self.state_machine_name)
)
machine_cls = registry.get_machine_cls(self.state_machine_name)
sm = machine_cls(self, state_field=self.state_field_name)
setattr(
self,
self.state_machine_attr,
sm,
)
if self.bind_events_as_methods:
sm.bind_events_to(self)