dep/django-selectable/selectable/registry.py

   1 from __future__ import unicode_literals
   2
   3 from django.utils.encoding import force_text
   4 from django.utils.module_loading import autodiscover_modules
   5
   6 from selectable.base import LookupBase
   7 from selectable.exceptions import (LookupAlreadyRegistered, LookupNotRegistered,
   8                                     LookupInvalid)
   9
  10
  11 class LookupRegistry(object):
  12
  13     def __init__(self):
  14         self._registry = {}
  15
  16     def validate(self, lookup):
  17         if not issubclass(lookup, LookupBase):
  18             raise LookupInvalid('Registered lookups must inherit from the LookupBase class')
  19
  20     def register(self, lookup):
  21         self.validate(lookup)
  22         name = force_text(lookup.name())
  23         if name in self._registry:
  24             raise LookupAlreadyRegistered('The name %s is already registered' % name)
  25         self._registry[name] = lookup
  26
  27     def unregister(self, lookup):
  28         self.validate(lookup)
  29         name = force_text(lookup.name())
  30         if name not in self._registry:
  31            raise LookupNotRegistered('The name %s is not registered' % name)
  32         del self._registry[name]
  33
  34     def get(self, key):
  35         return self._registry.get(key, None)
  36
  37
  38 registry = LookupRegistry()
  39
  40
  41 def autodiscover():
  42     # Attempt to import the app's lookups module.
  43     autodiscover_modules('lookups', register_to=registry)