#
# Copyright (C) 2018 Satoru SATOH <ssato @ redhat.com>
# License: MIT
#
r"""Abstract processor module.

.. versionadded:: 0.9.5

   - Add to abstract processors such like Parsers (loaders and dumpers).
"""
from __future__ import absolute_import


class Processor(object):
    """
    Abstract processor class to provide basic implementation of some methods,
    interfaces and members.

    - _type: type indicates data types it can process
    - _priority: Priority to select it if there are others of same type
    - _extensions: File extensions of data type it can process

    .. note::
       This class ifself is not a singleton but its children classes should so
       in most cases, I think.
    """
    _cid = None
    _type = None
    _priority = 0   # 0 (lowest priority) .. 99  (highest priority)
    _extensions = []

    @classmethod
    def cid(cls):
        """Processor class ID
        """
        return repr(cls) if cls._cid is None else cls._cid

    @classmethod
    def type(cls):
        """Processors' type
        """
        return cls._type

    @classmethod
    def priority(cls):
        """Processors's priority
        """
        return cls._priority

    @classmethod
    def extensions(cls):
        """A list of file extensions of files which this process can process.
        """
        return cls._extensions

    def __eq__(self, other):
        return self.cid() == other.cid()

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