| #!/usr/bin/python2.5 | |
| # Copyright (C) 2007 Google 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 gtfsfactoryuser import GtfsFactoryUser | |
| class GtfsObjectBase(GtfsFactoryUser): | |
| """Object with arbitrary attributes which may be added to a schedule. | |
| This class should be used as the base class for GTFS objects which may | |
| be stored in a Schedule. It defines some methods for reading and writing | |
| attributes. If self._schedule is None than the object is not in a Schedule. | |
| Subclasses must: | |
| * define an __init__ method which sets the _schedule member to None or a | |
| weakref to a Schedule | |
| * Set the _TABLE_NAME class variable to a name such as 'stops', 'agency', ... | |
| * define methods to validate objects of that type: | |
| * ValidateBeforeAdd, which is called before an object is added to a | |
| Schedule. With the default loader the object is added to the Schedule if | |
| this function returns True, and is not added if it returns False. | |
| * ValidateAfterAdd, which is called after an object is added to a Schedule. | |
| With the default Loader the return value, if any, is not used. | |
| """ | |
| def __getitem__(self, name): | |
| """Return a unicode or str representation of name or "" if not set.""" | |
| if name in self.__dict__ and self.__dict__[name] is not None: | |
| return "%s" % self.__dict__[name] | |
| else: | |
| return "" | |
| def __getattr__(self, name): | |
| """Return None or the default value if name is a known attribute. | |
| This method is only called when name is not found in __dict__. | |
| """ | |
| if name in self.__class__._FIELD_NAMES: | |
| return None | |
| else: | |
| raise AttributeError(name) | |
| def iteritems(self): | |
| """Return a iterable for (name, value) pairs of public attributes.""" | |
| for name, value in self.__dict__.iteritems(): | |
| if (not name) or name[0] == "_": | |
| continue | |
| yield name, value | |
| def __setattr__(self, name, value): | |
| """Set an attribute, adding name to the list of columns as needed.""" | |
| object.__setattr__(self, name, value) | |
| if name[0] != '_' and self._schedule: | |
| self._schedule.AddTableColumn(self.__class__._TABLE_NAME, name) | |
| def __eq__(self, other): | |
| """Return true iff self and other are equivalent""" | |
| if not other: | |
| return False | |
| if id(self) == id(other): | |
| return True | |
| for k in self.keys().union(other.keys()): | |
| # use __getitem__ which returns "" for missing columns values | |
| if self[k] != other[k]: | |
| return False | |
| return True | |
| def __ne__(self, other): | |
| return not self.__eq__(other) | |
| # TODO(Tom): According to | |
| # http://docs.python.org/reference/datamodel.html#object.__hash__ | |
| # this class should set '__hash__ = None' because it defines __eq__. This | |
| # can't be fixed until the merger is changed to not use a/b_merge_map. | |
| def __repr__(self): | |
| return "<%s %s>" % (self.__class__.__name__, sorted(self.iteritems())) | |
| def keys(self): | |
| """Return iterable of columns used by this object.""" | |
| columns = set() | |
| for name in vars(self): | |
| if (not name) or name[0] == "_": | |
| continue | |
| columns.add(name) | |
| return columns | |
| def _ColumnNames(self): | |
| return self.keys() | |