bluechips/model/types.py

   1 """
   2 Define special types used in BlueChips
   3 """
   4
   5 import sqlalchemy as sa
   6 from bluechips.lib.subclass import SmartSubclass
   7
   8 class Currency(object):
   9     __metaclass__ = SmartSubclass(int)
  10     def __init__(self, value):
  11         if isinstance(value, str):
  12             self.value = int(float(value) * 100)
  13         else:
  14             self.value = int(value)
  15
  16     def __int__(self):
  17         return self.value
  18     def __float__(self):
  19         return float(self.value)
  20     def __long__(self):
  21         return long(self.value)
  22
  23     def __cmp__(self, other):
  24         try:
  25             return self.value.__cmp__(int(other))
  26         except:
  27             return self.value.__cmp__(0)
  28
  29     def __mul__(self, other):
  30         return Currency(self.value * other)
  31     def __rmul__(self, other):
  32         return self.__mul__(other)
  33
  34     def __str_no_dollar__(self):
  35         return str(self)[1:]
  36
  37     def __repr__(self):
  38         return '%s("%s")' % (self.__class__.__name__, str(self))
  39     def __str__(self):
  40         sign = '-' if self.value < 0 else ''
  41         cents = abs(self.value) % 100
  42         dollars = (abs(self.value) - cents) / 100
  43         return '$%s%s.%.02d' % (sign, dollars, cents)
  44
  45 class DBCurrency(sa.types.TypeDecorator):
  46     """
  47     A type which represents monetary amounts internally as integers.
  48
  49     This avoids binary/decimal float conversion issues
  50     """
  51
  52     impl = sa.types.Integer
  53
  54     def process_bind_param(self, value, engine):
  55         return int(value)
  56
  57     def convert_result_value(self, value, engine):
  58         return Currency(value)