python/google/appengine/tools/value_mixin.py

   1 #!/usr/bin/env python
   2 #
   3 # Copyright 2007 Google Inc.
   4 #
   5 # Licensed under the Apache License, Version 2.0 (the "License");
   6 # you may not use this file except in compliance with the License.
   7 # You may obtain a copy of the License at
   8 #
   9 #     http://www.apache.org/licenses/LICENSE-2.0
  10 #
  11 # Unless required by applicable law or agreed to in writing, software
  12 # distributed under the License is distributed on an "AS IS" BASIS,
  13 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  14 # See the License for the specific language governing permissions and
  15 # limitations under the License.
  16 #
  17 """Provides ValueMixin.
  18
  19 ValueMixin provides comparison (including equality) methods and hashing
  20 based on the values of fields.
  21 """
  22
  23
  24 class ValueMixin(object):
  25   def __cmp__(self, other):
  26
  27
  28
  29
  30
  31
  32     if hasattr(other, '__dict__'):
  33       return self.__dict__.__cmp__(other.__dict__)
  34     else:
  35       return 1
  36
  37   def __hash__(self):
  38     return hash(frozenset(self.__dict__.items()))
  39
  40   def __repr__(self):
  41
  42     d = self.__dict__
  43     attrs = ['%s=%r' % (key, d[key]) for key in sorted(d)]
  44     return '%s(%s)' % (self.__class__.__name__, ', '.join(attrs))