Coverage for python/lsst/daf/butler/_deferredDatasetHandle.py: 51%

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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/>. 

21 

22""" 

23Module containing classes used with deferring dataset loading 

24""" 

25from __future__ import annotations 

26 

27__all__ = ("DeferredDatasetHandle",) 

28 

29import dataclasses 

30from typing import TYPE_CHECKING, Any, Optional 

31 

32if TYPE_CHECKING: 32 ↛ 33line 32 didn't jump to line 33, because the condition on line 32 was never true

33 from ._limited_butler import LimitedButler 

34 from .core import DataCoordinate, DatasetRef 

35 

36 

37@dataclasses.dataclass(frozen=True) 

38class DeferredDatasetHandle: 

39 """Proxy class that provides deferred loading of datasets from a butler.""" 

40 

41 def get( 

42 self, *, component: Optional[str] = None, parameters: Optional[dict] = None, **kwargs: dict 

43 ) -> Any: 

44 """Retrieves the dataset pointed to by this handle 

45 

46 This handle may be used multiple times, possibly with different 

47 parameters. 

48 

49 Parameters 

50 ---------- 

51 component : `str` or None 

52 If the deferred object is a component dataset type, this parameter 

53 may specify the name of the component to use in the get operation. 

54 parameters : `dict` or None 

55 The parameters argument will be passed to the butler get method. 

56 It defaults to None. If the value is not None, this dict will 

57 be merged with the parameters dict used to construct the 

58 `DeferredDatasetHandle` class. 

59 **kwargs 

60 This argument is deprecated and only exists to support legacy 

61 gen2 butler code during migration. It is completely ignored 

62 and will be removed in the future. 

63 

64 Returns 

65 ------- 

66 return : `Object` 

67 The dataset pointed to by this handle 

68 """ 

69 if self.parameters is not None: 

70 mergedParameters = self.parameters.copy() 

71 if parameters is not None: 

72 mergedParameters.update(parameters) 

73 elif parameters is not None: 

74 mergedParameters = parameters 

75 else: 

76 mergedParameters = {} 

77 

78 ref = self.ref.makeComponentRef(component) if component is not None else self.ref 

79 return self.butler.getDirect(ref, parameters=mergedParameters) 

80 

81 @property 

82 def dataId(self) -> DataCoordinate: 

83 """The full data ID associated with the dataset 

84 (`DataCoordinate`). 

85 

86 Guaranteed to contain records. 

87 """ 

88 return self.ref.dataId 

89 

90 butler: LimitedButler 

91 """The butler that will be used to fetch the dataset (`LimitedButler`). 

92 """ 

93 

94 ref: DatasetRef 

95 """Reference to the dataset (`DatasetRef`). 

96 """ 

97 

98 parameters: Optional[dict] 

99 """Optional parameters that may be used to specify a subset of the dataset 

100 to be loaded (`dict` or `None`). 

101 """