Module astrapy.utils.str_enum
Expand source code
# Copyright DataStax, Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from __future__ import annotations
from enum import Enum, EnumMeta
from typing import TypeVar
T = TypeVar("T", bound="StrEnum")
class StrEnumMeta(EnumMeta):
def _name_lookup(cls, value: str) -> str | None:
"""Return a proper key in the enum if some matching logic works, or None."""
mmap = {k: v.value for k, v in cls._member_map_.items()}
# try exact key match
if value in mmap:
return value
# try case-insensitive key match
u_value = value.upper()
u_mmap = {k.upper(): k for k in mmap.keys()}
if u_value in u_mmap:
return u_mmap[u_value]
# try case-insensitive *value* match
v_mmap = {v.upper(): k for k, v in mmap.items()}
if u_value in v_mmap:
return v_mmap[u_value]
return None
def __contains__(cls, value: object) -> bool:
"""Return True if the provided string belongs to the enum."""
if isinstance(value, str):
return cls._name_lookup(value) is not None
return False
class StrEnum(Enum, metaclass=StrEnumMeta):
@classmethod
def coerce(cls: type[T], value: str | T) -> T:
"""
Accepts either a string or an instance of the Enum itself.
If a string is passed, it converts it to the corresponding
Enum value (case-insensitive).
If an Enum instance is passed, it returns it as-is.
Raises ValueError if the string does not match any enum member.
"""
if isinstance(value, cls):
return value
elif isinstance(value, str):
norm_value = cls._name_lookup(value)
if norm_value is not None:
return cls[norm_value]
# no matches
raise ValueError(
f"Invalid value '{value}' for {cls.__name__}. "
f"Allowed values are: {[e.value for e in cls]}"
)
raise ValueError(
f"Invalid value '{value}' for {cls.__name__}. "
f"Allowed values are: {[e.value for e in cls]}"
)
Classes
class StrEnum (*args, **kwds)
-
Create a collection of name/value pairs.
Example enumeration:
>>> class Color(Enum): ... RED = 1 ... BLUE = 2 ... GREEN = 3
Access them by:
- attribute access:
Color.RED
- value lookup:
Color(1)
- name lookup:
Color['RED']
Enumerations can be iterated over, and know how many members they have:
>>> len(Color) 3
>>> list(Color) [<Color.RED: 1>, <Color.BLUE: 2>, <Color.GREEN: 3>]
Methods can be added to enumerations, and members can have their own attributes – see the documentation for details.
Expand source code
class StrEnum(Enum, metaclass=StrEnumMeta): @classmethod def coerce(cls: type[T], value: str | T) -> T: """ Accepts either a string or an instance of the Enum itself. If a string is passed, it converts it to the corresponding Enum value (case-insensitive). If an Enum instance is passed, it returns it as-is. Raises ValueError if the string does not match any enum member. """ if isinstance(value, cls): return value elif isinstance(value, str): norm_value = cls._name_lookup(value) if norm_value is not None: return cls[norm_value] # no matches raise ValueError( f"Invalid value '{value}' for {cls.__name__}. " f"Allowed values are: {[e.value for e in cls]}" ) raise ValueError( f"Invalid value '{value}' for {cls.__name__}. " f"Allowed values are: {[e.value for e in cls]}" )
Ancestors
- enum.Enum
Subclasses
- MapEncodingMode
- ModelStatus
- TableIndexType
- ColumnType
- TableKeyValuedColumnType
- TablePassthroughColumnType
- TableUDTColumnType
- TableUnsupportedColumnType
- TableValuedColumnType
- TableVectorColumnType
Static methods
def coerce(value: str | T) ‑> ~T
-
Accepts either a string or an instance of the Enum itself. If a string is passed, it converts it to the corresponding Enum value (case-insensitive). If an Enum instance is passed, it returns it as-is. Raises ValueError if the string does not match any enum member.
Expand source code
@classmethod def coerce(cls: type[T], value: str | T) -> T: """ Accepts either a string or an instance of the Enum itself. If a string is passed, it converts it to the corresponding Enum value (case-insensitive). If an Enum instance is passed, it returns it as-is. Raises ValueError if the string does not match any enum member. """ if isinstance(value, cls): return value elif isinstance(value, str): norm_value = cls._name_lookup(value) if norm_value is not None: return cls[norm_value] # no matches raise ValueError( f"Invalid value '{value}' for {cls.__name__}. " f"Allowed values are: {[e.value for e in cls]}" ) raise ValueError( f"Invalid value '{value}' for {cls.__name__}. " f"Allowed values are: {[e.value for e in cls]}" )
class StrEnumMeta (*args, **kwargs)
-
Metaclass for Enum
Expand source code
class StrEnumMeta(EnumMeta): def _name_lookup(cls, value: str) -> str | None: """Return a proper key in the enum if some matching logic works, or None.""" mmap = {k: v.value for k, v in cls._member_map_.items()} # try exact key match if value in mmap: return value # try case-insensitive key match u_value = value.upper() u_mmap = {k.upper(): k for k in mmap.keys()} if u_value in u_mmap: return u_mmap[u_value] # try case-insensitive *value* match v_mmap = {v.upper(): k for k, v in mmap.items()} if u_value in v_mmap: return v_mmap[u_value] return None def __contains__(cls, value: object) -> bool: """Return True if the provided string belongs to the enum.""" if isinstance(value, str): return cls._name_lookup(value) is not None return False
Ancestors
- enum.EnumType
- builtins.type