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# Copyright DataStax, Inc.
#
# 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.
__all__ = ['Element', 'Vertex', 'Edge', 'VertexProperty', 'Path', 'T']
class Element(object):
element_type = None
_attrs = ('id', 'label', 'type', 'properties')
def __init__(self, id, label, type, properties):
if type != self.element_type:
raise TypeError("Attempted to create %s from %s element", (type, self.element_type))
self.id = id
self.label = label
self.type = type
self.properties = self._extract_properties(properties)
@staticmethod
def _extract_properties(properties):
return dict(properties)
def __eq__(self, other):
return all(getattr(self, attr) == getattr(other, attr) for attr in self._attrs)
def __str__(self):
return str(dict((k, getattr(self, k)) for k in self._attrs))
class Vertex(Element):
"""
Represents a Vertex element from a graph query.
Vertex ``properties`` are extracted into a ``dict`` of property names to list of :class:`~VertexProperty` (list
because they are always encoded that way, and sometimes have multiple cardinality; VertexProperty because sometimes
the properties themselves have property maps).
"""
element_type = 'vertex'
@staticmethod
def _extract_properties(properties):
# vertex properties are always encoded as a list, regardless of Cardinality
return dict((k, [VertexProperty(k, p['value'], p.get('properties')) for p in v]) for k, v in properties.items())
def __repr__(self):
properties = dict((name, [{'label': prop.label, 'value': prop.value, 'properties': prop.properties} for prop in prop_list])
for name, prop_list in self.properties.items())
return "%s(%r, %r, %r, %r)" % (self.__class__.__name__,
self.id, self.label,
self.type, properties)
class VertexProperty(object):
"""
Vertex properties have a top-level value and an optional ``dict`` of properties.
"""
label = None
"""
label of the property
"""
value = None
"""
Value of the property
"""
properties = None
"""
dict of properties attached to the property
"""
def __init__(self, label, value, properties=None):
self.label = label
self.value = value
self.properties = properties or {}
def __eq__(self, other):
return isinstance(other, VertexProperty) and self.label == other.label and self.value == other.value and self.properties == other.properties
def __repr__(self):
return "%s(%r, %r, %r)" % (self.__class__.__name__, self.label, self.value, self.properties)
class Edge(Element):
"""
Represents an Edge element from a graph query.
Attributes match initializer parameters.
"""
element_type = 'edge'
_attrs = Element._attrs + ('inV', 'inVLabel', 'outV', 'outVLabel')
def __init__(self, id, label, type, properties,
inV, inVLabel, outV, outVLabel):
super(Edge, self).__init__(id, label, type, properties)
self.inV = inV
self.inVLabel = inVLabel
self.outV = outV
self.outVLabel = outVLabel
def __repr__(self):
return "%s(%r, %r, %r, %r, %r, %r, %r, %r)" %\
(self.__class__.__name__,
self.id, self.label,
self.type, self.properties,
self.inV, self.inVLabel,
self.outV, self.outVLabel)
class Path(object):
"""
Represents a graph path.
Labels list is taken verbatim from the results.
Objects are either :class:`~.Result` or :class:`~.Vertex`/:class:`~.Edge` for recognized types
"""
labels = None
"""
List of labels in the path
"""
objects = None
"""
List of objects in the path
"""
def __init__(self, labels, objects):
# TODO fix next major
# The Path class should not do any deserialization by itself. To fix in the next major.
from cassandra.datastax.graph.query import _graph_object_sequence
self.labels = labels
self.objects = list(_graph_object_sequence(objects))
def __eq__(self, other):
return self.labels == other.labels and self.objects == other.objects
def __str__(self):
return str({'labels': self.labels, 'objects': self.objects})
def __repr__(self):
return "%s(%r, %r)" % (self.__class__.__name__, self.labels, [o.value for o in self.objects])
class T(object):
"""
Represents a collection of tokens for more concise Traversal definitions.
"""
name = None
val = None
# class attributes
id = None
"""
"""
key = None
"""
"""
label = None
"""
"""
value = None
"""
"""
def __init__(self, name, val):
self.name = name
self.val = val
def __str__(self):
return self.name
def __repr__(self):
return "T.%s" % (self.name, )
T.id = T("id", 1)
T.id_ = T("id_", 2)
T.key = T("key", 3)
T.label = T("label", 4)
T.value = T("value", 5)
T.name_to_value = {
'id': T.id,
'id_': T.id_,
'key': T.key,
'label': T.label,
'value': T.value
}
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