Coverage for python/lsst/daf/butler/core/mappingFactory.py: 26%
60 statements
« prev ^ index » next coverage.py v7.2.7, created at 2023-08-12 09:20 +0000
« prev ^ index » next coverage.py v7.2.7, created at 2023-08-12 09:20 +0000
1# This file is part of daf_butler.
2#
3# Developed for the LSST Data Management System.
4# This product includes software developed by the LSST Project
5# (http://www.lsst.org).
6# See the COPYRIGHT file at the top-level directory of this distribution
7# for details of code ownership.
8#
9# This program is free software: you can redistribute it and/or modify
10# it under the terms of the GNU General Public License as published by
11# the Free Software Foundation, either version 3 of the License, or
12# (at your option) any later version.
13#
14# This program is distributed in the hope that it will be useful,
15# but WITHOUT ANY WARRANTY; without even the implied warranty of
16# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17# GNU General Public License for more details.
18#
19# You should have received a copy of the GNU General Public License
20# along with this program. If not, see <http://www.gnu.org/licenses/>.
22from __future__ import annotations
24__all__ = ("MappingFactory",)
26from collections.abc import Iterable
27from typing import Any
29from lsst.utils.introspection import get_class_of
31from .config import Config
32from .configSupport import LookupKey
35class MappingFactory:
36 """Register the mapping of some key to a python type and retrieve
37 instances.
39 Enables instances of these classes to be retrieved from the factory later.
40 The class can be specified as an object, class or string.
41 If the key is an object it is converted to a string by accessing
42 a ``name`` attribute.
44 Parameters
45 ----------
46 refType : `type`
47 Python reference `type` to use to ensure that items stored in the
48 registry create instance objects of the correct class. Subclasses
49 of this type are allowed. Using `None` disables the check.
51 """
53 def __init__(self, refType: type):
54 self._registry: dict[LookupKey, dict[str, Any]] = {}
55 self.refType = refType
57 def __contains__(self, key: Any) -> bool:
58 """Indicate whether the supplied key is present in the factory.
60 Parameters
61 ----------
62 key : `LookupKey`, `str` or objects with ``name`` attribute
63 Key to use to lookup whether a corresponding element exists
64 in this factory.
66 Returns
67 -------
68 in : `bool`
69 `True` if the supplied key is present in the factory.
70 """
71 key = self._getNameKey(key)
72 return key in self._registry
74 def getLookupKeys(self) -> set[LookupKey]:
75 """Retrieve the look up keys for all the registry entries.
77 Returns
78 -------
79 keys : `set` of `LookupKey`
80 The keys available for matching in the registry.
81 """
82 return set(self._registry)
84 def getClassFromRegistryWithMatch(
85 self, targetClasses: Iterable[Any]
86 ) -> tuple[LookupKey, type, dict[Any, Any]]:
87 """Get the class stored in the registry along with the matching key.
89 Parameters
90 ----------
91 targetClasses : `LookupKey`, `str` or objects with ``name`` attribute
92 Each item is tested in turn until a match is found in the registry.
93 Items with `None` value are skipped.
95 Returns
96 -------
97 matchKey : `LookupKey`
98 The key that resulted in the successful match.
99 cls : `type`
100 Class stored in registry associated with the first
101 matching target class.
102 kwargs: `dict`
103 Keyword arguments to be given to constructor.
105 Raises
106 ------
107 KeyError
108 Raised if none of the supplied target classes match an item in the
109 registry.
110 """
111 attempts: list[Any] = []
112 for t in targetClasses:
113 if t is None:
114 attempts.append(t)
115 else:
116 key = self._getNameKey(t)
117 attempts.append(key)
118 try:
119 entry = self._registry[key]
120 except KeyError:
121 pass
122 else:
123 return key, get_class_of(entry["type"]), entry["kwargs"]
125 # Convert list to a string for error reporting
126 msg = ", ".join(str(k) for k in attempts)
127 plural = "" if len(attempts) == 1 else "s"
128 raise KeyError(f"Unable to find item in registry with key{plural}: {msg}")
130 def getClassFromRegistry(self, targetClasses: Iterable[Any]) -> type:
131 """Get the matching class stored in the registry.
133 Parameters
134 ----------
135 targetClasses : `LookupKey`, `str` or objects with ``name`` attribute
136 Each item is tested in turn until a match is found in the registry.
137 Items with `None` value are skipped.
139 Returns
140 -------
141 cls : `type`
142 Class stored in registry associated with the first
143 matching target class.
145 Raises
146 ------
147 KeyError
148 Raised if none of the supplied target classes match an item in the
149 registry.
150 """
151 _, cls, _ = self.getClassFromRegistryWithMatch(targetClasses)
152 return cls
154 def getFromRegistryWithMatch(
155 self, targetClasses: Iterable[Any], *args: Any, **kwargs: Any
156 ) -> tuple[LookupKey, Any]:
157 """Get a new instance of the registry object along with matching key.
159 Parameters
160 ----------
161 targetClasses : `LookupKey`, `str` or objects with ``name`` attribute
162 Each item is tested in turn until a match is found in the registry.
163 Items with `None` value are skipped.
164 args : `tuple`
165 Positional arguments to use pass to the object constructor.
166 **kwargs
167 Keyword arguments to pass to object constructor.
169 Returns
170 -------
171 matchKey : `LookupKey`
172 The key that resulted in the successful match.
173 instance : `object`
174 Instance of class stored in registry associated with the first
175 matching target class.
177 Raises
178 ------
179 KeyError
180 Raised if none of the supplied target classes match an item in the
181 registry.
182 """
183 key, cls, registry_kwargs = self.getClassFromRegistryWithMatch(targetClasses)
185 # Supplied keyword args must overwrite registry defaults
186 # We want this overwriting to happen recursively since we expect
187 # some of these keyword arguments to be dicts.
188 # Simplest to use Config for this
189 config_kwargs = Config(registry_kwargs)
190 config_kwargs.update(kwargs)
191 merged_kwargs = config_kwargs.toDict()
193 return key, cls(*args, **merged_kwargs)
195 def getFromRegistry(self, targetClasses: Iterable[Any], *args: Any, **kwargs: Any) -> Any:
196 """Get a new instance of the object stored in the registry.
198 Parameters
199 ----------
200 targetClasses : `LookupKey`, `str` or objects with ``name`` attribute
201 Each item is tested in turn until a match is found in the registry.
202 Items with `None` value are skipped.
203 args : `tuple`
204 Positional arguments to use pass to the object constructor.
205 **kwargs
206 Keyword arguments to pass to object constructor.
208 Returns
209 -------
210 instance : `object`
211 Instance of class stored in registry associated with the first
212 matching target class.
214 Raises
215 ------
216 KeyError
217 Raised if none of the supplied target classes match an item in the
218 registry.
219 """
220 _, instance = self.getFromRegistryWithMatch(targetClasses, *args, **kwargs)
221 return instance
223 def placeInRegistry(
224 self, registryKey: Any, typeName: str | type, overwrite: bool = False, **kwargs: Any
225 ) -> None:
226 """Register a class name with the associated type.
228 Parameters
229 ----------
230 registryKey : `LookupKey`, `str` or object with ``name`` attribute.
231 Item to associate with the provided type.
232 typeName : `str` or Python type
233 Identifies a class to associate with the provided key.
234 overwrite : `bool`, optional
235 If `True`, an existing entry will be overwritten. This option
236 is expected to be used to simplify test suites.
237 Default is `False`.
238 **kwargs
239 Keyword arguments to always pass to object constructor when
240 retrieved.
242 Raises
243 ------
244 KeyError
245 Raised if item is already registered and has different value and
246 ``overwrite`` is `False`.
247 """
248 key = self._getNameKey(registryKey)
249 if key in self._registry and not overwrite:
250 # Compare the class strings since dynamic classes can be the
251 # same thing but be different.
252 if str(self._registry[key]) == str(typeName):
253 return
255 raise KeyError(
256 "Item with key {} already registered with different value ({} != {})".format(
257 key, self._registry[key], typeName
258 )
259 )
261 self._registry[key] = {
262 "type": typeName,
263 "kwargs": dict(**kwargs),
264 }
266 @staticmethod
267 def _getNameKey(typeOrName: Any) -> LookupKey:
268 """Extract name of supplied object as entity suitable for key use.
270 Parameters
271 ----------
272 typeOrName : `LookupKey, `str` or object supporting ``name`` attribute.
273 Item from which to extract a name.
275 Returns
276 -------
277 name : `LookupKey`
278 Extracted name as a string or
279 """
280 if isinstance(typeOrName, LookupKey):
281 return typeOrName
283 if isinstance(typeOrName, str):
284 name = typeOrName
285 elif hasattr(typeOrName, "name"):
286 name = typeOrName.name
287 else:
288 raise ValueError("Cannot extract name from type")
290 return LookupKey(name=name)