Source code for treelib.node

#!/usr/bin/env python
# Copyright (C) 2011
# Brett Alistair Kromkamp -
# Copyright (C) 2012-2017
# Xiaming Chen -
# and other contributors.
# 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
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# See the License for the specific language governing permissions and
# limitations under the License.
Node structure in treelib.

A :class:`Node` object contains basic properties such as node identifier,
node tag, parent node, children nodes etc., and some operations for a node.
import uuid

from .exceptions import NodePropertyError

[docs]class Node(object): """ Nodes are elementary objects that are stored in the `_nodes` dictionary of a Tree. Use `data` attribute to store node-specific data. """ #: Mode constants for routine `update_fpointer()`. (ADD, DELETE, INSERT, REPLACE) = list(range(4)) def __init__(self, tag=None, identifier=None, expanded=True, data=None): """Create a new Node object to be placed inside a Tree object""" #: if given as a parameter, must be unique self._identifier = None self._set_identifier(identifier) #: None or something else #: if None, self._identifier will be set to the identifier's value. if tag is None: self._tag = self._identifier else: self._tag = tag #: boolean self.expanded = expanded #: identifier of the parent's node : self._bpointer = None #: identifier(s) of the soons' node(s) : self._fpointer = list() #: User payload associated with this node. = data def __lt__(self, other): return self.tag < other.tag def _set_identifier(self, nid): """Initialize self._set_identifier""" if nid is None: self._identifier = str(uuid.uuid1()) else: self._identifier = nid @property def bpointer(self): """ The parent ID of a node. This attribute can be accessed and modified with ``.`` and ``=`` operator respectively. """ return self._bpointer @bpointer.setter def bpointer(self, nid): """Set the value of `_bpointer`.""" if nid is not None: self._bpointer = nid else: # print("WARNING: the bpointer of node %s " \ # "is set to None" % self._identifier) self._bpointer = None @property def fpointer(self): """ With a getting operator, a list of IDs of node's children is obtained. With a setting operator, the value can be list, set, or dict. For list or set, it is converted to a list type by the package; for dict, the keys are treated as the node IDs. """ return self._fpointer @fpointer.setter def fpointer(self, value): """Set the value of `_fpointer`.""" if value is None: self._fpointer = list() elif isinstance(value, list): self._fpointer = value elif isinstance(value, dict): self._fpointer = list(value.keys()) elif isinstance(value, set): self._fpointer = list(value) else: # TODO: add deprecated routine pass @property def identifier(self): """ The unique ID of a node within the scope of a tree. This attribute can be accessed and modified with ``.`` and ``=`` operator respectively. """ return self._identifier @identifier.setter def identifier(self, value): """Set the value of `_identifier`.""" if value is None: print("WARNING: node ID can not be None") else: self._set_identifier(value)
[docs] def is_leaf(self): """Return true if current node has no children.""" if len(self.fpointer) == 0: return True else: return False
[docs] def is_root(self): """Return true if self has no parent, i.e. as root.""" return self._bpointer is None
@property def tag(self): """ The readable node name for human. This attribute can be accessed and modified with ``.`` and ``=`` operator respectively. """ return self._tag @tag.setter def tag(self, value): """Set the value of `_tag`.""" self._tag = value if value is not None else None
[docs] def update_bpointer(self, nid): """Set the parent (indicated by the ``nid`` parameter) of a node.""" self.bpointer = nid
[docs] def update_fpointer(self, nid, mode=ADD, replace=None): """ Update the children list with different modes: addition (Node.ADD or Node.INSERT) and deletion (Node.DELETE). """ if nid is None: return if mode is self.ADD: self._fpointer.append(nid) elif mode is self.DELETE: if nid in self._fpointer: self._fpointer.remove(nid) elif mode is self.INSERT: # deprecate to ADD mode print("WARNING: INSERT is deprecated to ADD mode") self.update_fpointer(nid) elif mode is self.REPLACE: if replace is None: raise NodePropertyError( 'Argument "repalce" should be provided when mode is {}'.format(mode) ) ind = self._fpointer.index(nid) self._fpointer[ind] = replace
def __repr__(self): name = self.__class__.__name__ kwargs = [ "tag={0}".format(self.tag), "identifier={0}".format(self.identifier), "data={0}".format(, ] return "%s(%s)" % (name, ", ".join(kwargs))