old_contents: # Copyright 2013 Red Hat, Inc.
  # All Rights Reserved.
  #
  #    Licensed under the Apache License, Version 2.0 (the "License"); you may
  #    not use this file except in compliance with the License. You may obtain
  #    a copy of the License at
  #
  #         http://www.apache.org/licenses/LICENSE-2.0
  #
  #    Unless required by applicable law or agreed to in writing, software
  #    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
  #    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
  #    License for the specific language governing permissions and limitations
  #    under the License.
  
  from ironic import api
  from ironic.api.controllers import base
  from ironic.api.controllers import link
  from ironic.api import types as atypes
  
  
  class Collection(base.Base):
  
      next = str
      """A link to retrieve the next subset of the collection"""
  
      @property
      def collection(self):
          return getattr(self, self._type)
  
      @classmethod
      def get_key_field(cls):
          return 'uuid'
  
      def has_next(self, limit):
          """Return whether collection has more items."""
          return len(self.collection) and len(self.collection) == limit
  
      def get_next(self, limit, url=None, **kwargs):
          """Return a link to the next subset of the collection."""
          if not self.has_next(limit):
              return atypes.Unset
  
          resource_url = url or self._type
          fields = kwargs.pop('fields', None)
          # NOTE(saga): If fields argument is present in kwargs and not None. It
          # is a list so convert it into a comma seperated string.
          if fields:
              kwargs['fields'] = ','.join(fields)
          q_args = ''.join(['%s=%s&' % (key, kwargs[key]) for key in kwargs])
          next_args = '?%(args)slimit=%(limit)d&marker=%(marker)s' % {
              'args': q_args, 'limit': limit,
              'marker': getattr(self.collection[-1], self.get_key_field())}
  
          return link.make_link('next', api.request.public_url,
                                resource_url, next_args)['href']
  
new_contents: # Copyright 2013 Red Hat, Inc.
  # All Rights Reserved.
  #
  #    Licensed under the Apache License, Version 2.0 (the "License"); you may
  #    not use this file except in compliance with the License. You may obtain
  #    a copy of the License at
  #
  #         http://www.apache.org/licenses/LICENSE-2.0
  #
  #    Unless required by applicable law or agreed to in writing, software
  #    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
  #    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
  #    License for the specific language governing permissions and limitations
  #    under the License.
  
  from ironic import api
  from ironic.api.controllers import base
  from ironic.api.controllers import link
  from ironic.api import types as atypes
  
  
  def has_next(collection, limit):
      """Return whether collection has more items."""
      return len(collection) and len(collection) == limit
  
  
  def get_next(collection, limit, url=None, key_field='uuid', **kwargs):
      """Return a link to the next subset of the collection."""
      if not has_next(collection, limit):
          return None
  
      fields = kwargs.pop('fields', None)
      # NOTE(saga): If fields argument is present in kwargs and not None. It
      # is a list so convert it into a comma seperated string.
      if fields:
          kwargs['fields'] = ','.join(fields)
      q_args = ''.join(['%s=%s&' % (key, kwargs[key]) for key in kwargs])
  
      last_item = collection[-1]
      # handle items which are either objects or dicts
      if hasattr(last_item, key_field):
          marker = getattr(last_item, key_field)
      else:
          marker = last_item.get(key_field)
  
      next_args = '?%(args)slimit=%(limit)d&marker=%(marker)s' % {
          'args': q_args, 'limit': limit,
          'marker': marker}
  
      return link.make_link('next', api.request.public_url,
                            url, next_args)['href']
  
  
  class Collection(base.Base):
  
      next = str
      """A link to retrieve the next subset of the collection"""
  
      @property
      def collection(self):
          return getattr(self, self._type)
  
      @classmethod
      def get_key_field(cls):
          return 'uuid'
  
      def has_next(self, limit):
          """Return whether collection has more items."""
          return has_next(self.collection, limit)
  
      def get_next(self, limit, url=None, **kwargs):
          """Return a link to the next subset of the collection."""
          resource_url = url or self._type
          the_next = get_next(self.collection, limit, url=resource_url,
                              key_field=self.get_key_field(), **kwargs)
          if the_next is None:
              return atypes.Unset
          return the_next
  
subject: Break out collection functions for json usage