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:mod:`altgraph.ObjectGraph` --- Graphs of objecs with an identifier
===================================================================
.. module:: altgraph.ObjectGraph
:synopsis: A graph of objects that have a "graphident" attribute.
.. class:: ObjectGraph([graph[, debug]])
A graph of objects that have a "graphident" attribute. The
value of this attribute is the key for the object in the
graph.
The optional *graph* is a previously constructed
:class:`Graph <altgraph.Graph.Graph>`.
The optional *debug* level controls the amount of debug output
(see :meth:`msg`, :meth:`msgin` and :meth:`msgout`).
.. note:: the altgraph library does not generate output, the
debug attribute and message methods are present for use
by subclasses.
.. data:: ObjectGraph.graph
An :class:`Graph <altgraph.Graph.Graph>` object that contains
the graph data.
.. method:: ObjectGraph.addNode(node)
Adds a *node* to the graph.
.. note:: re-adding a node that was previously removed
using :meth:`removeNode` will reinstate the previously
removed node.
.. method:: ObjectGraph.createNode(self, cls, name, \*args, \**kwds)
Creates a new node using ``cls(*args, **kwds)`` and adds that
node using :meth:`addNode`.
Returns the newly created node.
.. method:: ObjectGraph.removeNode(node)
Removes a *node* from the graph when it exists. The *node* argument
is either a node object, or the graphident of a node.
.. method:: ObjectGraph.createReferences(fromnode, tonode[, edge_data])
Creates a reference from *fromnode* to *tonode*. The optional
*edge_data* is associated with the edge.
*Fromnode* and *tonode* can either be node objects or the graphident
values for nodes.
.. method:: removeReference(fromnode, tonode)
Removes the reference from *fromnode* to *tonode* if it exists.
.. method:: ObjectGraph.getRawIdent(node)
Returns the *graphident* attribute of *node*, or the graph itself
when *node* is :data:`None`.
.. method:: getIdent(node)
Same as :meth:`getRawIdent`, but only if the node is part
of the graph.
*Node* can either be an actual node object or the graphident of
a node.
.. method:: ObjectGraph.findNode(node)
Returns a given node in the graph, or :data:`Node` when it cannot
be found.
*Node* is either an object with a *graphident* attribute or
the *graphident* attribute itself.
.. method:: ObjectGraph.__contains__(node)
Returns True if *node* is a member of the graph. *Node* is either an
object with a *graphident* attribute or the *graphident* attribute itself.
.. method:: ObjectGraph.flatten([condition[, start]])
Yield all nodes that are entirely reachable by *condition*
starting fromt he given *start* node or the graph root.
.. note:: objects are only reachable from the graph root
when there is a reference from the root to the node
(either directly or through another node)
.. method:: ObjectGraph.nodes()
Yield all nodes in the graph.
.. method:: ObjectGraph.get_edges(node)
Returns two iterators that yield the nodes reaching by
outgoing and incoming edges.
.. method:: ObjectGraph.filterStack(filters)
Filter the ObjectGraph in-place by removing all edges to nodes that
do not match every filter in the given filter list
Returns a tuple containing the number of:
(*nodes_visited*, *nodes_removed*, *nodes_orphaned*)
.. method:: ObjectGraph.edgeData(fromNode, toNode):
Return the edge data associated with the edge from *fromNode*
to *toNode*. Raises :exc:`KeyError` when no such edge exists.
.. versionadded: 0.12
.. method:: ObjectGraph.updateEdgeData(fromNode, toNode, edgeData)
Replace the data associated with the edge from *fromNode* to
*toNode* by *edgeData*.
Raises :exc:`KeyError` when the edge does not exist.
Debug output
------------
.. data:: ObjectGraph.debug
The current debug level.
.. method:: ObjectGraph.msg(level, text, \*args)
Print a debug message at the current indentation level when the current
debug level is *level* or less.
.. method:: ObjectGraph.msgin(level, text, \*args)
Print a debug message when the current debug level is *level* or less,
and increase the indentation level.
.. method:: ObjectGraph.msgout(level, text, \*args)
Decrease the indentation level and print a debug message when the
current debug level is *level* or less.