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Fixed #17754 -- Refactored gis.measure

This refactoring does allow much easier MeasureBase subclassing.
Many thanks to Ricardo di Virgilio for the initial patch.
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commit 4d46106f8c233c5af283c903000ef8c6f1165393 1 parent fe873e2
Claude Paroz claudep authored
1  AUTHORS
View
@@ -161,6 +161,7 @@ answer newbie questions, and generally made Django that much better:
Rajesh Dhawan <rajesh.dhawan@gmail.com>
Sander Dijkhuis <sander.dijkhuis@gmail.com>
Jordan Dimov <s3x3y1@gmail.com>
+ Riccardo Di Virgilio
Nebojša Dorđević
dne@mayonnaise.net
dready <wil@mojipage.com>
313 django/contrib/gis/measure.py
View
@@ -30,7 +30,7 @@
Distance and Area objects to allow for sensible and convienient calculation
and conversions.
-Authors: Robert Coup, Justin Bronn
+Authors: Robert Coup, Justin Bronn, Riccardo Di Virgilio
Inspired by GeoPy (http://exogen.case.edu/projects/geopy/)
and Geoff Biggs' PhD work on dimensioned units for robotics.
@@ -40,13 +40,134 @@
from django.utils.functional import total_ordering
+NUMERIC_TYPES = (int, float, long, Decimal)
+AREA_PREFIX = "sq_"
+
+def pretty_name(obj):
+ return obj.__name__ if obj.__class__ == type else obj.__class__.__name__
+
+
+@total_ordering
class MeasureBase(object):
+ STANDARD_UNIT = None
+ ALIAS = {}
+ UNITS = {}
+ LALIAS = {}
+
+ def __init__(self, default_unit=None, **kwargs):
+ value, self._default_unit = self.default_units(kwargs)
+ setattr(self, self.STANDARD_UNIT, value)
+ if default_unit and isinstance(default_unit, basestring):
+ self._default_unit = default_unit
+
+ def _get_standard(self):
+ return getattr(self, self.STANDARD_UNIT)
+
+ def _set_standard(self, value):
+ setattr(self, self.STANDARD_UNIT, value)
+
+ standard = property(_get_standard, _set_standard)
+
+ def __getattr__(self, name):
+ if name in self.UNITS:
+ return self.standard / self.UNITS[name]
+ else:
+ raise AttributeError('Unknown unit type: %s' % name)
+
+ def __repr__(self):
+ return '%s(%s=%s)' % (pretty_name(self), self._default_unit,
+ getattr(self, self._default_unit))
+
+ def __str__(self):
+ return '%s %s' % (getattr(self, self._default_unit), self._default_unit)
+
+ # **** Comparison methods ****
+
+ def __eq__(self, other):
+ if isinstance(other, self.__class__):
+ return self.standard == other.standard
+ else:
+ return NotImplemented
+
+ def __lt__(self, other):
+ if isinstance(other, self.__class__):
+ return self.standard < other.standard
+ else:
+ return NotImplemented
+
+ # **** Operators methods ****
+
+ def __add__(self, other):
+ if isinstance(other, self.__class__):
+ return self.__class__(default_unit=self._default_unit,
+ **{self.STANDARD_UNIT: (self.standard + other.standard)})
+ else:
+ raise TypeError('%(class)s must be added with %(class)s' % {"class":pretty_name(self)})
+
+ def __iadd__(self, other):
+ if isinstance(other, self.__class__):
+ self.standard += other.standard
+ return self
+ else:
+ raise TypeError('%(class)s must be added with %(class)s' % {"class":pretty_name(self)})
+
+ def __sub__(self, other):
+ if isinstance(other, self.__class__):
+ return self.__class__(default_unit=self._default_unit,
+ **{self.STANDARD_UNIT: (self.standard - other.standard)})
+ else:
+ raise TypeError('%(class)s must be subtracted from %(class)s' % {"class":pretty_name(self)})
+
+ def __isub__(self, other):
+ if isinstance(other, self.__class__):
+ self.standard -= other.standard
+ return self
+ else:
+ raise TypeError('%(class)s must be subtracted from %(class)s' % {"class":pretty_name(self)})
+
+ def __mul__(self, other):
+ if isinstance(other, NUMERIC_TYPES):
+ return self.__class__(default_unit=self._default_unit,
+ **{self.STANDARD_UNIT: (self.standard * other)})
+ else:
+ raise TypeError('%(class)s must be multiplied with number' % {"class":pretty_name(self)})
+
+ def __imul__(self, other):
+ if isinstance(other, NUMERIC_TYPES):
+ self.standard *= float(other)
+ return self
+ else:
+ raise TypeError('%(class)s must be multiplied with number' % {"class":pretty_name(self)})
+
+ def __rmul__(self, other):
+ return self * other
+
+ def __div__(self, other):
+ if isinstance(other, self.__class__):
+ return self.standard / other.standard
+ if isinstance(other, NUMERIC_TYPES):
+ return self.__class__(default_unit=self._default_unit,
+ **{self.STANDARD_UNIT: (self.standard / other)})
+ else:
+ raise TypeError('%(class)s must be divided with number or %(class)s' % {"class":pretty_name(self)})
+
+ def __idiv__(self, other):
+ if isinstance(other, NUMERIC_TYPES):
+ self.standard /= float(other)
+ return self
+ else:
+ raise TypeError('%(class)s must be divided with number' % {"class":pretty_name(self)})
+
+ def __nonzero__(self):
+ return bool(self.standard)
+
def default_units(self, kwargs):
"""
Return the unit value and the default units specified
from the given keyword arguments dictionary.
"""
val = 0.0
+ default_unit = self.STANDARD_UNIT
for unit, value in kwargs.iteritems():
if not isinstance(value, float): value = float(value)
if unit in self.UNITS:
@@ -86,8 +207,8 @@ def unit_attname(cls, unit_str):
else:
raise Exception('Could not find a unit keyword associated with "%s"' % unit_str)
-@total_ordering
class Distance(MeasureBase):
+ STANDARD_UNIT = "m"
UNITS = {
'chain' : 20.1168,
'chain_benoit' : 20.116782,
@@ -163,189 +284,33 @@ class Distance(MeasureBase):
}
LALIAS = dict([(k.lower(), v) for k, v in ALIAS.items()])
- def __init__(self, default_unit=None, **kwargs):
- # The base unit is in meters.
- self.m, self._default_unit = self.default_units(kwargs)
- if default_unit and isinstance(default_unit, str):
- self._default_unit = default_unit
-
- def __getattr__(self, name):
- if name in self.UNITS:
- return self.m / self.UNITS[name]
- else:
- raise AttributeError('Unknown unit type: %s' % name)
-
- def __repr__(self):
- return 'Distance(%s=%s)' % (self._default_unit, getattr(self, self._default_unit))
-
- def __str__(self):
- return '%s %s' % (getattr(self, self._default_unit), self._default_unit)
-
- def __eq__(self, other):
- if isinstance(other, Distance):
- return self.m == other.m
- else:
- return NotImplemented
-
- def __lt__(self, other):
- if isinstance(other, Distance):
- return self.m < other.m
- else:
- return NotImplemented
-
- def __add__(self, other):
- if isinstance(other, Distance):
- return Distance(default_unit=self._default_unit, m=(self.m + other.m))
- else:
- raise TypeError('Distance must be added with Distance')
-
- def __iadd__(self, other):
- if isinstance(other, Distance):
- self.m += other.m
- return self
- else:
- raise TypeError('Distance must be added with Distance')
-
- def __sub__(self, other):
- if isinstance(other, Distance):
- return Distance(default_unit=self._default_unit, m=(self.m - other.m))
- else:
- raise TypeError('Distance must be subtracted from Distance')
-
- def __isub__(self, other):
- if isinstance(other, Distance):
- self.m -= other.m
- return self
- else:
- raise TypeError('Distance must be subtracted from Distance')
-
def __mul__(self, other):
- if isinstance(other, (int, float, long, Decimal)):
- return Distance(default_unit=self._default_unit, m=(self.m * float(other)))
- elif isinstance(other, Distance):
- return Area(default_unit='sq_' + self._default_unit, sq_m=(self.m * other.m))
+ if isinstance(other, self.__class__):
+ return Area(default_unit=AREA_PREFIX + self._default_unit,
+ **{AREA_PREFIX + self.STANDARD_UNIT: (self.standard * other.standard)})
+ elif isinstance(other, NUMERIC_TYPES):
+ return self.__class__(default_unit=self._default_unit,
+ **{self.STANDARD_UNIT: (self.standard * other)})
else:
- raise TypeError('Distance must be multiplied with number or Distance')
+ raise TypeError('%(distance)s must be multiplied with number or %(distance)s' % {
+ "distance" : pretty_name(self.__class__),
+ })
- def __imul__(self, other):
- if isinstance(other, (int, float, long, Decimal)):
- self.m *= float(other)
- return self
- else:
- raise TypeError('Distance must be multiplied with number')
- def __rmul__(self, other):
- return self * other
-
- def __div__(self, other):
- if isinstance(other, (int, float, long, Decimal)):
- return Distance(default_unit=self._default_unit, m=(self.m / float(other)))
- else:
- raise TypeError('Distance must be divided with number')
-
- def __idiv__(self, other):
- if isinstance(other, (int, float, long, Decimal)):
- self.m /= float(other)
- return self
- else:
- raise TypeError('Distance must be divided with number')
-
- def __nonzero__(self):
- return bool(self.m)
-
-@total_ordering
class Area(MeasureBase):
+ STANDARD_UNIT = AREA_PREFIX + Distance.STANDARD_UNIT
# Getting the square units values and the alias dictionary.
- UNITS = dict([('sq_%s' % k, v ** 2) for k, v in Distance.UNITS.items()])
- ALIAS = dict([(k, 'sq_%s' % v) for k, v in Distance.ALIAS.items()])
+ UNITS = dict([('%s%s' % (AREA_PREFIX, k), v ** 2) for k, v in Distance.UNITS.items()])
+ ALIAS = dict([(k, '%s%s' % (AREA_PREFIX, v)) for k, v in Distance.ALIAS.items()])
LALIAS = dict([(k.lower(), v) for k, v in ALIAS.items()])
- def __init__(self, default_unit=None, **kwargs):
- self.sq_m, self._default_unit = self.default_units(kwargs)
- if default_unit and isinstance(default_unit, str):
- self._default_unit = default_unit
-
- def __getattr__(self, name):
- if name in self.UNITS:
- return self.sq_m / self.UNITS[name]
- else:
- raise AttributeError('Unknown unit type: ' + name)
-
- def __repr__(self):
- return 'Area(%s=%s)' % (self._default_unit, getattr(self, self._default_unit))
-
- def __str__(self):
- return '%s %s' % (getattr(self, self._default_unit), self._default_unit)
-
- def __eq__(self, other):
- if isinstance(other, Area):
- return self.sq_m == other.sq_m
- else:
- return NotImplemented
-
- def __lt__(self, other):
- if isinstance(other, Area):
- return self.sq_m < other.sq_m
- else:
- return NotImplemented
-
- def __add__(self, other):
- if isinstance(other, Area):
- return Area(default_unit=self._default_unit, sq_m=(self.sq_m + other.sq_m))
- else:
- raise TypeError('Area must be added with Area')
-
- def __iadd__(self, other):
- if isinstance(other, Area):
- self.sq_m += other.sq_m
- return self
- else:
- raise TypeError('Area must be added with Area')
-
- def __sub__(self, other):
- if isinstance(other, Area):
- return Area(default_unit=self._default_unit, sq_m=(self.sq_m - other.sq_m))
- else:
- raise TypeError('Area must be subtracted from Area')
-
- def __isub__(self, other):
- if isinstance(other, Area):
- self.sq_m -= other.sq_m
- return self
- else:
- raise TypeError('Area must be subtracted from Area')
-
- def __mul__(self, other):
- if isinstance(other, (int, float, long, Decimal)):
- return Area(default_unit=self._default_unit, sq_m=(self.sq_m * float(other)))
- else:
- raise TypeError('Area must be multiplied with number')
-
- def __imul__(self, other):
- if isinstance(other, (int, float, long, Decimal)):
- self.sq_m *= float(other)
- return self
- else:
- raise TypeError('Area must be multiplied with number')
-
- def __rmul__(self, other):
- return self * other
-
def __div__(self, other):
- if isinstance(other, (int, float, long, Decimal)):
- return Area(default_unit=self._default_unit, sq_m=(self.sq_m / float(other)))
+ if isinstance(other, NUMERIC_TYPES):
+ return self.__class__(default_unit=self._default_unit,
+ **{self.STANDARD_UNIT: (self.standard / other)})
else:
- raise TypeError('Area must be divided with number')
+ raise TypeError('%(class)s must be divided by a number' % {"class":pretty_name(self)})
- def __idiv__(self, other):
- if isinstance(other, (int, float, long, Decimal)):
- self.sq_m /= float(other)
- return self
- else:
- raise TypeError('Area must be divided with number')
-
- def __nonzero__(self):
- return bool(self.sq_m)
# Shortcuts
D = Distance
6 django/contrib/gis/tests/test_measure.py
View
@@ -93,6 +93,8 @@ def testMultiplication(self):
self.assertEqual(d4.m, 50)
d4 /= 5
self.assertEqual(d4.m, 10)
+ d5 = d1 / D(m=2)
+ self.assertEqual(d5, 50)
a5 = d1 * D(m=10)
self.assertTrue(isinstance(a5, Area))
@@ -103,10 +105,6 @@ def testMultiplication(self):
self.fail('Distance *= Distance should raise TypeError')
with self.assertRaises(TypeError):
- d5 = d1 / D(m=1)
- self.fail('Distance / Distance should raise TypeError')
-
- with self.assertRaises(TypeError):
d1 /= D(m=1)
self.fail('Distance /= Distance should raise TypeError')
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