#485: Drop Query use of Dataset object

gcloud/datastore/query.py

@@ -19,11 +19,10 @@
 from gcloud.datastore import _implicit_environ
 from gcloud.datastore import datastore_v1_pb2 as datastore_pb
 from gcloud.datastore import helpers
-from gcloud.datastore.dataset import Dataset
 from gcloud.datastore.key import Key
 
 
-class Query(_implicit_environ._DatastoreBase):
+class Query(object):
  """A Query against the Cloud Datastore.
 
  This class serves as an abstraction for creating a query over data
@@ -32,8 +31,9 @@ class Query(_implicit_environ._DatastoreBase):
  :type kind: string.
  :param kind: The kind to query.
 
- :type dataset: :class:`gcloud.datastore.dataset.Dataset`.
- :param dataset: The dataset to query.
+ :type dataset_id: str
+ :param dataset_id: The ID of the dataset to query. If not passed,
+ uses the implicit default.
 
  :type namespace: string or None.
  :param namespace: The namespace to which to restrict results.
@@ -54,6 +54,9 @@ class Query(_implicit_environ._DatastoreBase):
 
  :type group_by: sequence_of_string.
  :param group_by: field names used to group query results.
+
+ :raises: ValueError if ``dataset_id`` is not passed and no implicit
+ default is set.
  """
 
  OPERATORS = {
@@ -66,15 +69,22 @@ class Query(_implicit_environ._DatastoreBase):
  """Mapping of operator strings and their protobuf equivalents."""
 
  def __init__(self,
+ dataset_id=None,
  kind=None,
- dataset=None,
  namespace=None,
  ancestor=None,
  filters=(),
  projection=(),
  order=(),
  group_by=()):
- super(Query, self).__init__(dataset=dataset)
+
+ if dataset_id is None:
+ dataset_id = _implicit_environ.DATASET_ID
+
+ if dataset_id is None:
+ raise ValueError("No dataset ID supplied, and no default set.")
+
+ self._dataset_id = dataset_id
  self._kind = kind
  self._namespace = namespace
  self._ancestor = ancestor
@@ -84,26 +94,12 @@ def __init__(self,
  self._group_by = list(group_by)
 
  @property
- def dataset(self):
- """Get the dataset for this Query.
-
- The dataset against which the Query will be run.
-
- :rtype: :class:`gcloud.datastore.dataset.Dataset` or None,
- :returns: the current dataset.
- """
- return self._dataset
-
- @dataset.setter
- def dataset(self, value):
- """Set the dataset for the query
+ def dataset_id(self):
+ """Get the dataset ID for this Query.
 
- :type value: class:`gcloud.datastore.dataset.Dataset`
- :param value: the new dataset
+ :rtype: str
  """
- if not isinstance(value, Dataset):
- raise ValueError("Dataset must be a Dataset")
- self._dataset = value
+ return self._dataset_id
 
  @property
  def namespace(self):
@@ -294,34 +290,49 @@ def group_by(self, value):
  value = [value]
  self._group_by[:] = value
 
- def fetch(self, limit=0, offset=0, start_cursor=None, end_cursor=None):
+ def fetch(self, limit=None, offset=0, start_cursor=None, end_cursor=None,
+ connection=None):
  """Execute the Query; return an iterator for the matching entities.
 
  For example::
 
- >>> from gcloud import datastore
- >>> dataset = datastore.get_dataset('dataset-id')
- >>> query = dataset.query('Person').filter('name', '=', 'Sally')
+ >>> from gcloud.datastore.query import Query
+ >>> query = Query('dataset-id', 'Person')
+ >>> query.add_filter('name', '=', 'Sally')
  >>> list(query.fetch())
  [<Entity object>, <Entity object>, ...]
  >>> list(query.fetch(1))
  [<Entity object>]
 
- :type limit: integer
+ :type limit: integer or None
  :param limit: An optional limit passed through to the iterator.
 
- :type limit: offset
- :param limit: An optional offset passed through to the iterator.
+ :type offset: integer
+ :param offset: An optional offset passed through to the iterator.
 
- :type start_cursor: offset
+ :type start_cursor: bytes
  :param start_cursor: An optional cursor passed through to the iterator.
 
- :type end_cursor: offset
+ :type end_cursor: bytes
  :param end_cursor: An optional cursor passed through to the iterator.
 
+ :type connection: :class:`gcloud.datastore.connection.Connection`
+ :param connection: An optional cursor passed through to the iterator.
+ If not supplied, uses the implicit default.
+
+
  :rtype: :class:`Iterator`
+ :raises: ValueError if ``connection`` is not passed and no implicit
+ default has been set.
  """
- return Iterator(self, limit, offset, start_cursor, end_cursor)
+ if connection is None:
+ connection = _implicit_environ.CONNECTION
+
+ if connection is None:
+ raise ValueError("No connection passed, and no default set")
+
+ return Iterator(
+ self, connection, limit, offset, start_cursor, end_cursor)
 
 
 class Iterator(object):
@@ -334,9 +345,10 @@ class Iterator(object):
  datastore_pb.QueryResultBatch.MORE_RESULTS_AFTER_LIMIT,
  )
 
- def __init__(self, query, limit=None, offset=0,
+ def __init__(self, query, connection, limit=None, offset=0,
  start_cursor=None, end_cursor=None):
  self._query = query
+ self._connection = connection
  self._limit = limit
  self._offset = offset
  self._start_cursor = start_cursor
@@ -366,9 +378,9 @@ def next_page(self):
 
  pb.offset = self._offset
 
- query_results = self._query.dataset.connection().run_query(
+ query_results = self._connection.run_query(
  query_pb=pb,
- dataset_id=self._query.dataset.id(),
+ dataset_id=self._query.dataset_id,
  namespace=self._query.namespace,
  )
  # NOTE: `query_results` contains an extra value that we don't use,