Extractor
=========

A type of :doc:`Callable </Callables/Callable>` that performs data extraction. 

Definition
----------

Constructor
^^^^^^^^^^^

.. py:class:: controller.callable.extractor.Extractor(self, id: str, params: CallableParameters)

    An abstract subclass of :doc:`Callable </Callables/Callable>` where its implementations are Callables that perform data extraction.

    :param id: The unique identifier of this Callable. Also referred to as ``callable_id`` in documentations for specific Callables.
    :type id: str
    :param params: The parameters of this Callable. Refer to the documentation for a specific Callable for details.
    :type params: CallableParameters

Methods
^^^^^^^

.. py:method:: controller.callable.Callable.check_params(self, params: CallableParameters) -> boolean
    :abstractmethod:
    
    See :doc:`Callable </Callables/Callable>`.

.. py:method:: controller.callable.Callable.exec(self, data: pd.DataFrame, **kwargs) -> pd.DataFrame
    :abstractmethod:
    
    See :doc:`Callable </Callables/Callable>`.

Usage
-----

A concrete implementation of a Callable may inherit this class and override its ``check_params()`` and ``exec()`` methods.

Output conventions
------------------

Refer to :doc:`Callable </Callables/Callable>` for conventions on all Callable outputs.

- There are no further restrictions on the column names of a Extractor's output DataFrame.