Source code for gremlin_python.structure.graph

'''
Licensed to the Apache Software Foundation (ASF) under one
or more contributor license agreements.  See the NOTICE file
distributed with this work for additional information
regarding copyright ownership.  The ASF licenses this file
to you 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.
'''

__author__ = 'Marko A. Rodriguez (http://markorodriguez.com)'

from gremlin_python.process.graph_traversal import GraphTraversalSource
from gremlin_python.process.traversal import TraversalStrategies


class Graph(object):
    def __init__(self):
        if self.__class__ not in TraversalStrategies.global_cache:
            TraversalStrategies.global_cache[self.__class__] = TraversalStrategies()

    def traversal(self, traversal_source_class=None):
        if not traversal_source_class:
            traversal_source_class = GraphTraversalSource
        return traversal_source_class(self, TraversalStrategies.global_cache[self.__class__])

    def __repr__(self):
        return "graph[empty]"


class Element(object):
    def __init__(self, id, label):
        self.id = id
        self.label = label

    def __eq__(self, other):
        return isinstance(other, self.__class__) and self.id == other.id

    def __hash__(self):
        return hash(self.id)


class Vertex(Element):
    def __init__(self, id, label="vertex"):
        Element.__init__(self, id, label)

    def __repr__(self):
        return "v[" + str(self.id) + "]"


class Edge(Element):
    def __init__(self, id, outV, label, inV):
        Element.__init__(self, id, label)
        self.outV = outV
        self.inV = inV

    def __repr__(self):
        return "e[" + str(self.id) + "][" + str(self.outV.id) + "-" + self.label + "->" + str(self.inV.id) + "]"


class VertexProperty(Element):
    def __init__(self, id, label, value, vertex):
        Element.__init__(self, id, label)
        self.value = value
        self.key = self.label
        self.vertex = vertex

    def __repr__(self):
        return "vp[" + str(self.label) + "->" + str(self.value)[0:20] + "]"


class Property(object):
    def __init__(self, key, value, element):
        self.key = key
        self.value = value
        self.element = element

    def __repr__(self):
        return "p[" + str(self.key) + "->" + str(self.value)[0:20] + "]"

    def __eq__(self, other):
        return isinstance(other, self.__class__) and \
               self.key == other.key and \
               self.value == other.value and \
               self.element == other.element

    def __hash__(self):
        return hash(self.key) + hash(self.value)


class Path(object):
    def __init__(self, labels, objects):
        self.labels = labels
        self.objects = objects

    def __repr__(self):
        return str(self.objects)

    def __eq__(self, other):
        return isinstance(other, self.__class__) and self.objects == other.objects and self.labels == other.labels

    def __hash__(self):
        return hash(str(self.objects)) + hash(str(self.labels))

    def __getitem__(self, key):
        if isinstance(key, str):
            objects = []
            for i, labels in enumerate(self.labels):
                if key in labels:
                    objects.append(self.objects[i])
            if 0 == len(objects):
                raise KeyError("The step with label " + key + " does not exist")
            return objects if len(objects) > 1 else objects[0]
        elif isinstance(key, int):
            return self.objects[key]
        else:
            raise TypeError("The path access key must be either a string label or integer index")

    def __len__(self):
        return len(self.objects)