"""

This module holds simple classes used by GeoQuery.convert_values

to convert geospatial values from the database.

"""

from django.contrib.gis.db.backend import SpatialBackend

class BaseField(object):

    def get_internal_type(self):

        "Overloaded method so OracleQuery.convert_values doesn't balk."

        return None

if SpatialBackend.oracle: BaseField.empty_strings_allowed = False

class AreaField(BaseField):

    "Wrapper for Area values."

    def __init__(self, area_att):

        self.area_att = area_att

class DistanceField(BaseField):

    "Wrapper for Distance values."

    def __init__(self, distance_att):

        self.distance_att = distance_att

class GeomField(BaseField):

    """

    Wrapper for Geometry values.  It is a lightweight alternative to 

    using GeometryField (which requires a SQL query upon instantiation).

    """

    pass