Files
common/python37/packages/bigtree/node/dagnode.py

571 lines
17 KiB
Python

import copy
from typing import Any, Dict, Iterable, List
from bigtree.utils.exceptions import LoopError, TreeError
from bigtree.utils.iterators import preorder_iter
class DAGNode:
"""
Base DAGNode extends any Python class to a DAG node, for DAG implementation.
In DAG implementation, a node can have multiple parents.
Parents and children cannot be reassigned once assigned, as Nodes are allowed to have multiple parents and children.
If each node only has one parent, use `Node` class.
DAGNodes can have attributes if they are initialized from `DAGNode` or dictionary.
DAGNode can be linked to each other with `parents` and `children` setter methods,
or using bitshift operator with the convention `parent_node >> child_node` or `child_node << parent_node`.
>>> from bigtree import DAGNode
>>> a = DAGNode("a")
>>> b = DAGNode("b")
>>> c = DAGNode("c")
>>> d = DAGNode("d")
>>> c.parents = [a, b]
>>> c.children = [d]
>>> from bigtree import DAGNode
>>> a = DAGNode("a")
>>> b = DAGNode("b")
>>> c = DAGNode("c")
>>> d = DAGNode("d")
>>> a >> c
>>> b >> c
>>> d << c
Directly passing `parents` argument.
>>> from bigtree import DAGNode
>>> a = DAGNode("a")
>>> b = DAGNode("b")
>>> c = DAGNode("c", parents=[a, b])
>>> d = DAGNode("d", parents=[c])
Directly passing `children` argument.
>>> from bigtree import DAGNode
>>> d = DAGNode("d")
>>> c = DAGNode("c", children=[d])
>>> b = DAGNode("b", children=[c])
>>> a = DAGNode("a", children=[c])
**DAGNode Creation**
Node can be created by instantiating a `DAGNode` class or by using a *dictionary*.
If node is created with dictionary, all keys of dictionary will be stored as class attributes.
>>> from bigtree import DAGNode
>>> a = DAGNode.from_dict({"name": "a", "age": 90})
**DAGNode Attributes**
These are node attributes that have getter and/or setter methods.
Get and set other `DAGNode`
1. ``parents``: Get/set parent nodes
2. ``children``: Get/set child nodes
Get other `DAGNode`
1. ``ancestors``: Get ancestors of node excluding self, iterator
2. ``descendants``: Get descendants of node excluding self, iterator
3. ``siblings``: Get siblings of self
Get `DAGNode` configuration
1. ``node_name``: Get node name, without accessing `name` directly
2. ``is_root``: Get indicator if self is root node
3. ``is_leaf``: Get indicator if self is leaf node
**DAGNode Methods**
These are methods available to be performed on `DAGNode`.
Constructor methods
1. ``from_dict()``: Create DAGNode from dictionary
`DAGNode` methods
1. ``describe()``: Get node information sorted by attributes, returns list of tuples
2. ``get_attr(attr_name: str)``: Get value of node attribute
3. ``set_attrs(attrs: dict)``: Set node attribute name(s) and value(s)
4. ``go_to(node: BaseNode)``: Get a path from own node to another node from same DAG
5. ``copy()``: Deep copy DAGNode
----
"""
def __init__(
self, name: str = "", parents: List = None, children: List = None, **kwargs
):
self.name = name
self.__parents = []
self.__children = []
if parents is None:
parents = []
if children is None:
children = []
self.parents = parents
self.children = children
if "parent" in kwargs:
raise ValueError(
"Attempting to set `parent` attribute, do you mean `parents`?"
)
self.__dict__.update(**kwargs)
@property
def parent(self) -> None:
"""Do not allow `parent` attribute to be accessed"""
raise ValueError(
"Attempting to access `parent` attribute, do you mean `parents`?"
)
@parent.setter
def parent(self, new_parent):
"""Do not allow `parent` attribute to be set
Args:
new_parent (Self): parent node
"""
raise ValueError("Attempting to set `parent` attribute, do you mean `parents`?")
@property
def parents(self) -> Iterable:
"""Get parent nodes
Returns:
(Iterable[Self])
"""
return tuple(self.__parents)
@staticmethod
def __check_parent_type(new_parents: List):
"""Check parent type
Args:
new_parents (List[Self]): parent nodes
"""
if not isinstance(new_parents, list):
raise TypeError(
f"Parents input should be list type, received input type {type(new_parents)}"
)
def __check_parent_loop(self, new_parents: List):
"""Check parent type
Args:
new_parents (List[Self]): parent nodes
"""
seen_parent = []
for new_parent in new_parents:
# Check type
if not isinstance(new_parent, DAGNode):
raise TypeError(
f"Expect input to be DAGNode type, received input type {type(new_parent)}"
)
# Check for loop and tree structure
if new_parent is self:
raise LoopError("Error setting parent: Node cannot be parent of itself")
if new_parent.ancestors:
if any(ancestor is self for ancestor in new_parent.ancestors):
raise LoopError(
"Error setting parent: Node cannot be ancestor of itself"
)
# Check for duplicate children
if id(new_parent) in seen_parent:
raise TreeError(
"Error setting parent: Node cannot be added multiple times as a parent"
)
else:
seen_parent.append(id(new_parent))
@parents.setter
def parents(self, new_parents: List):
"""Set parent node
Args:
new_parents (List[Self]): parent nodes
"""
self.__check_parent_type(new_parents)
self.__check_parent_loop(new_parents)
current_parents = self.__parents.copy()
# Assign new parents - rollback if error
self.__pre_assign_parents(new_parents)
try:
# Assign self to new parent
for new_parent in new_parents:
if new_parent not in self.__parents:
self.__parents.append(new_parent)
new_parent.__children.append(self)
self.__post_assign_parents(new_parents)
except Exception as exc_info:
# Remove self from new parent
for new_parent in new_parents:
if new_parent not in current_parents:
self.__parents.remove(new_parent)
new_parent.__children.remove(self)
raise TreeError(
f"{exc_info}, current parents {current_parents}, new parents {new_parents}"
)
def __pre_assign_parents(self, new_parents: List):
"""Custom method to check before attaching parent
Can be overriden with `_DAGNode__pre_assign_parent()`
Args:
new_parents (List): new parents to be added
"""
pass
def __post_assign_parents(self, new_parents: List):
"""Custom method to check after attaching parent
Can be overriden with `_DAGNode__post_assign_parent()`
Args:
new_parents (List): new parents to be added
"""
pass
@property
def children(self) -> Iterable:
"""Get child nodes
Returns:
(Iterable[Self])
"""
return tuple(self.__children)
def __check_children_type(self, new_children: List):
"""Check child type
Args:
new_children (List[Self]): child node
"""
if not isinstance(new_children, list):
raise TypeError(
f"Children input should be list type, received input type {type(new_children)}"
)
def __check_children_loop(self, new_children: List):
"""Check child loop
Args:
new_children (List[Self]): child node
"""
seen_children = []
for new_child in new_children:
# Check type
if not isinstance(new_child, DAGNode):
raise TypeError(
f"Expect input to be DAGNode type, received input type {type(new_child)}"
)
# Check for loop and tree structure
if new_child is self:
raise LoopError("Error setting child: Node cannot be child of itself")
if any(child is new_child for child in self.ancestors):
raise LoopError(
"Error setting child: Node cannot be ancestors of itself"
)
# Check for duplicate children
if id(new_child) in seen_children:
raise TreeError(
"Error setting child: Node cannot be added multiple times as a child"
)
else:
seen_children.append(id(new_child))
@children.setter
def children(self, new_children: List):
"""Set child nodes
Args:
new_children (List[Self]): child node
"""
self.__check_children_type(new_children)
self.__check_children_loop(new_children)
current_children = list(self.children)
# Assign new children - rollback if error
self.__pre_assign_children(new_children)
try:
# Assign new children to self
for new_child in new_children:
if self not in new_child.__parents:
new_child.__parents.append(self)
self.__children.append(new_child)
self.__post_assign_children(new_children)
except Exception as exc_info:
# Reassign old children to self
for new_child in new_children:
if new_child not in current_children:
new_child.__parents.remove(self)
self.__children.remove(new_child)
raise TreeError(exc_info)
def __pre_assign_children(self, new_children: List):
"""Custom method to check before attaching children
Can be overriden with `_DAGNode__pre_assign_children()`
Args:
new_children (List[Self]): new children to be added
"""
pass
def __post_assign_children(self, new_children: List):
"""Custom method to check after attaching children
Can be overriden with `_DAGNode__post_assign_children()`
Args:
new_children (List[Self]): new children to be added
"""
pass
@property
def ancestors(self) -> Iterable:
"""Get iterator to yield all ancestors of self, does not include self
Returns:
(Iterable[Self])
"""
if not len(list(self.parents)):
return ()
def recursive_parent(node):
for _node in node.parents:
yield from recursive_parent(_node)
yield _node
ancestors = list(recursive_parent(self))
return list(dict.fromkeys(ancestors))
@property
def descendants(self) -> Iterable:
"""Get iterator to yield all descendants of self, does not include self
Returns:
(Iterable[Self])
"""
descendants = list(
preorder_iter(self, filter_condition=lambda _node: _node != self)
)
return list(dict.fromkeys(descendants))
@property
def siblings(self) -> Iterable:
"""Get siblings of self
Returns:
(Iterable[Self])
"""
if self.is_root:
return ()
return tuple(
child
for parent in self.parents
for child in parent.children
if child is not self
)
@property
def node_name(self) -> str:
"""Get node name
Returns:
(str)
"""
return self.name
@property
def is_root(self) -> bool:
"""Get indicator if self is root node
Returns:
(bool)
"""
return not len(list(self.parents))
@property
def is_leaf(self) -> bool:
"""Get indicator if self is leaf node
Returns:
(bool)
"""
return not len(list(self.children))
@classmethod
def from_dict(cls, input_dict: Dict[str, Any]):
"""Construct node from dictionary, all keys of dictionary will be stored as class attributes
Input dictionary must have key `name` if not `Node` will not have any name
>>> from bigtree import DAGNode
>>> a = DAGNode.from_dict({"name": "a", "age": 90})
Args:
input_dict (Dict[str, Any]): dictionary with node information, key: attribute name, value: attribute value
Returns:
(Self)
"""
return cls(**input_dict)
def describe(self, exclude_attributes: List[str] = [], exclude_prefix: str = ""):
"""Get node information sorted by attribute name, returns list of tuples
Args:
exclude_attributes (List[str]): list of attributes to exclude
exclude_prefix (str): prefix of attributes to exclude
Returns:
(List[str])
"""
return [
item
for item in sorted(self.__dict__.items(), key=lambda item: item[0])
if (item[0] not in exclude_attributes)
and (not len(exclude_prefix) or not item[0].startswith(exclude_prefix))
]
def get_attr(self, attr_name: str) -> Any:
"""Get value of node attribute
Returns None if attribute name does not exist
Args:
attr_name (str): attribute name
Returns:
(Any)
"""
try:
return self.__getattribute__(attr_name)
except AttributeError:
return None
def set_attrs(self, attrs: Dict[str, Any]):
"""Set node attributes
>>> from bigtree.node.dagnode import DAGNode
>>> a = DAGNode('a')
>>> a.set_attrs({"age": 90})
>>> a
DAGNode(a, age=90)
Args:
attrs (Dict[str, Any]): attribute dictionary,
key: attribute name, value: attribute value
"""
self.__dict__.update(attrs)
def go_to(self, node) -> Iterable[Iterable]:
"""Get list of possible paths from current node to specified node from same tree
>>> from bigtree import DAGNode
>>> a = DAGNode("a")
>>> b = DAGNode("b")
>>> c = DAGNode("c")
>>> d = DAGNode("d")
>>> a >> c
>>> b >> c
>>> c >> d
>>> a >> d
>>> a.go_to(c)
[[DAGNode(a, ), DAGNode(c, )]]
>>> a.go_to(d)
[[DAGNode(a, ), DAGNode(c, ), DAGNode(d, )], [DAGNode(a, ), DAGNode(d, )]]
>>> a.go_to(b)
Traceback (most recent call last):
...
bigtree.utils.exceptions.TreeError: It is not possible to go to DAGNode(b, )
Args:
node (Self): node to travel to from current node, inclusive of start and end node
Returns:
(Iterable[Iterable])
"""
if not isinstance(node, DAGNode):
raise TypeError(
f"Expect node to be DAGNode type, received input type {type(node)}"
)
if self == node:
return [self]
if node not in self.descendants:
raise TreeError(f"It is not possible to go to {node}")
self.__path = []
def recursive_path(_node, _path, _ans):
if _node: # pragma: no cover
_path.append(_node)
if _node == node:
return _path
for _child in _node.children:
ans = recursive_path(_child, _path.copy(), _ans)
if ans:
self.__path.append(ans)
recursive_path(self, [], [])
return self.__path
def copy(self):
"""Deep copy self; clone DAGNode
>>> from bigtree.node.dagnode import DAGNode
>>> a = DAGNode('a')
>>> a_copy = a.copy()
Returns:
(Self)
"""
return copy.deepcopy(self)
def __copy__(self):
"""Shallow copy self
>>> import copy
>>> from bigtree.node.dagnode import DAGNode
>>> a = DAGNode('a')
>>> a_copy = copy.deepcopy(a)
Returns:
(Self)
"""
obj = type(self).__new__(self.__class__)
obj.__dict__.update(self.__dict__)
return obj
def __rshift__(self, other):
"""Set children using >> bitshift operator for self >> other
Args:
other (Self): other node, children
"""
other.parents = [self]
def __lshift__(self, other):
"""Set parent using << bitshift operator for self << other
Args:
other (Self): other node, parent
"""
self.parents = [other]
def __repr__(self):
class_name = self.__class__.__name__
node_dict = self.describe(exclude_attributes=["name"])
node_description = ", ".join(
[f"{k}={v}" for k, v in node_dict if not k.startswith("_")]
)
return f"{class_name}({self.node_name}, {node_description})"