cybertools/cybertools/knowledge/element.py

51 lines
1.3 KiB
Python

# cybertools.knowledge.element
""" Represent knowledge elements and their interrelations.
"""
from zope.interface import implementer
from cybertools.knowledge.interfaces import IKnowledgeElement
@implementer(IKnowledgeElement)
class KnowledgeElement(object):
def __init__(self):
self._parent = None
self._dependencies = {}
# backlinks:
self._children = set()
self._dependents = set()
self._knowers = set()
self._providers = set()
def setParent(self, obj):
old = self._parent
if old is not None and old != obj:
del old._children[self]
if obj is not None and old != obj:
obj._children.add(self)
self._parent = obj
def getParent(self): return self._parent
parent = property(getParent, setParent)
def getDependencies(self):
return self._dependencies
def dependsOn(self, obj):
self._dependencies[obj] = True
obj._dependents.add(self)
def removeDependency(self, obj):
del self._dependencies[obj]
del obj._dependents[self]
def getDependents(self):
return self._dependents
def getKnowers(self):
return self._knowers
def getProviders(self):
return tuple(self._providers)