lsst.daf.persistence  13.0-30-gd2bda26+1
 All Classes Namespaces Files Functions Variables Typedefs Friends Macros
genericAssembler.py
Go to the documentation of this file.
1 #!/usr/bin/env python
2 
3 #
4 # LSST Data Management System
5 # Copyright 2016 LSST Corporation.
6 #
7 # This product includes software developed by the
8 # LSST Project (http://www.lsst.org/).
9 #
10 # This program is free software: you can redistribute it and/or modify
11 # it under the terms of the GNU General Public License as published by
12 # the Free Software Foundation, either version 3 of the License, or
13 # (at your option) any later version.
14 #
15 # This program is distributed in the hope that it will be useful,
16 # but WITHOUT ANY WARRANTY; without even the implied warranty of
17 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 # GNU General Public License for more details.
19 #
20 # You should have received a copy of the LSST License Statement and
21 # the GNU General Public License along with this program. If not,
22 # see <http://www.lsstcorp.org/LegalNotices/>.
23 #
24 
25 import inspect
26 
27 def genericAssembler(dataId, componentInfo, cls):
28  """A generic assembler for butler composite datasets, that can be used when the component names match the
29  argument names in the __init__ signature, or the setter name for component objects is specified or can be
30  inferred by component name.
31 
32  When determining setter names: If the setter name is specified by the policy then the genericAssembler
33  will use that to set the component into the python object. If the policy does not specify setter names the
34  genericAssembler will see if the __init__ func input argument names match the policy argument names. If
35  that does not work, and the python object has setter names that match the component name of all the object
36  then the setter name can be inferred; it will first try 'set' + <componentName>, and if that does not
37  exist it will try 'set' + <componentName>.capitalize (e.g. for component name 'foo', it will try setfoo
38  and then setFoo.) If no setter can be found for a component object, it will raise a runtime error.
39  """
40  initArgs = {k: v.obj for k, v in componentInfo.items()}
41  try:
42  obj = cls(**initArgs)
43  except TypeError:
44  obj = None
45 
46  if not obj:
47  obj = cls()
48  for componentName, componentInfo in componentInfo.items():
49  if componentInfo.setter is not None:
50  setter = getattr(obj, componentInfo.setter)
51  elif hasattr(obj, 'set_' + componentName):
52  setter = getattr(obj, 'set_' + componentName)
53  elif hasattr(obj, 'set' + componentName.capitalize()):
54  setter = getattr(obj, 'set' + componentName.capitalize())
55  else:
56  raise RuntimeError("No setter for datasetType:%s class:%s" %
57  (componentInfo.datasetType, cls))
58  setter(componentInfo.obj)
59  return obj
60 
61 
62 def genericDisassembler(obj, dataId, componentInfo):
63  """A generic disassembler for butler composite datasets, that can be used when the getter name for
64  component objects is specified or can be inferred by component name.
65 
66  When determining getter names: If the getter name is specified by the policy then the genericAssembler
67  will use that to get the component from the python object. If the policy does not specify getter names and
68  the python object has getter names that match the component name of all the object then the getter name
69  can be inferred; it will first try 'get' + <componentName>, and if that does not exist it will try 'get' +
70  <componentName>.capitalize (e.g. for component name 'foo', it will try getfoo and then getFoo.) If no
71  getter can be found for a component object, it will raise a runtime error.
72  """
73  for componentName, componentInfo in componentInfo.items():
74  if componentInfo.getter is not None:
75  getter = getattr(obj, componentInfo.getter)
76  elif hasattr(obj, 'get_' + componentName):
77  getter = getattr(obj, 'get_' + componentName)
78  elif hasattr(obj, 'get' + componentName.capitalize()):
79  getter = getattr(obj, 'get' + componentName.capitalize())
80  else:
81  raise RuntimeError("No getter for componentName:%s" % componentName)
82  componentInfo.obj = getter()