Source code for hifis_surveyval.models.mixins.identifiable

# hifis-surveyval
# Framework to help developing analysis scripts for the HIFIS Software survey.
#
# SPDX-FileCopyrightText: 2021 HIFIS Software <support@hifis.net>
#
# SPDX-License-Identifier: GPL-3.0-or-later
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
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# This program is distributed in the hope that it will be useful,
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"""
This module contains the base class for all objects that carry a unique ID.

IDs are composed of multiple parts interjected by a hierarchy separator.
"""

from typing import Optional, Set


[docs]class Identifiable(object): """ This is the abstract superclass for all objects that carry an ID. The ID is expected to be a string (or be convertible into such and to be unique among all identifiable objects. IDs are separated by a HIERARCHY_SEPARATOR and the part after the last separator forms the so-called "short ID". If no hierarchical parent_id is given, the short ID and the full ID are the same. """ HIERARCHY_SEPARATOR: str = "/" known_ids: Set[str] = set()
[docs] def __init__(self, object_id: str, parent_id: Optional[str] = None): """ Create a new identifiable object with a given ID. The class will track all known IDs to prevent duplicates. A full ID is formed by merging the parent's full ID (if it exists) and the object's ID. Args: object_id: A string serving as an ID to the object. It must be neither None nor empty. parent_id: (Optional, Default=None) The full ID of another identifiable object that forms the hierarchical parent of this one. Used to generate the full ID. Raises: ValueError: Signals either a duplicate or invalid object_id """ if not object_id: raise ValueError( "ID of an identifiable object may neither be empty nor None" ) if object_id in Identifiable.known_ids: raise ValueError(f"Attempted to assign duplicate ID {object_id}") self._full_id: str = ( f"{parent_id}{Identifiable.HIERARCHY_SEPARATOR}{object_id}" if parent_id else object_id ) Identifiable.known_ids.add(self._full_id)
def __del__(self) -> None: """ Deconstruct an identifiable object. The used ID will be removed from the known IDs and can be re-used. """ try: Identifiable.known_ids.remove(self._full_id) # FIXME For some reason removing the full ID from the list of # known IDs fails due to them already being removed. But why? # This has been put into this little exception-catch box to not # spam the command line output, but I would prefer to understand # better what is going on here… except KeyError: pass @property def short_id(self) -> str: """ Get the short ID of this object (without parent_id IDs). Returns: The string identifying this object with respect to its siblings """ return self._full_id.split(Identifiable.HIERARCHY_SEPARATOR)[-1] # TODO: Decide whether to cache the short id @property def full_id(self) -> str: """ Get the full ID of the object (includes parent_id IDs). Returns: The string identifying the object with respect to any other Identifiable """ return self._full_id def __str__(self) -> str: """Return the full ID as representation of this identifiable object.""" return self.full_id