Source code for evalml.pipelines.components.component_base_meta

"""Metaclass that overrides creating a new component by wrapping methods with validators and setters."""
from functools import wraps

from evalml.exceptions import ComponentNotYetFittedError
from evalml.utils.base_meta import BaseMeta


class ComponentBaseMeta(BaseMeta):
    """Metaclass that overrides creating a new component by wrapping methods with validators and setters."""

    @classmethod
    def check_for_fit(cls, method):
        """`check_for_fit` wraps a method that validates if `self._is_fitted` is `True`.

        It raises an exception if `False` and calls and returns the wrapped method if `True`.

        Args:
            method (callable): Method to wrap.

        Returns:
            The wrapped method.

        Raises:
            ComponentNotYetFittedError: If component is not yet fitted.
        """

        @wraps(method)
        def _check_for_fit(self, X=None, y=None):
            klass = type(self).__name__
            if not self._is_fitted and self.needs_fitting:
                raise ComponentNotYetFittedError(
                    f"This {klass} is not fitted yet. You must fit {klass} before calling {method.__name__}.",
                )
            elif method.__name__ == "inverse_transform":
                # Since inverse transform only takes one argument, the y is actually "called" X in this piece of code.
                return method(self, X)
            elif X is None and y is None:
                return method(self)
            elif y is None:
                return method(self, X)
            else:
                return method(self, X, y)

        return _check_for_fit