336 lines
12 KiB
Python
336 lines
12 KiB
Python
#
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# Copyright (c) 2013 Helmut Merz helmutm@cy55.de
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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#
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"""
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Implementation of the utilities needed for the relations package.
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"""
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from logging import getLogger
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from BTrees.IOBTree import IOBTree
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from persistent import Persistent
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from persistent.interfaces import IPersistent
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from zope import component
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from zope.component import adapts
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from zope.interface import Interface, Attribute, implements
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from zope.app.catalog.catalog import Catalog, ResultSet
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from zope.app.catalog.field import FieldIndex
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from zope.intid.interfaces import IIntIds
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from zope.location.interfaces import ILocation
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from zope.event import notify
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from zope.component.interfaces import ObjectEvent
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from zope.security.proxy import removeSecurityProxy
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from zope.traversing.api import getName, getParent
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from interfaces import IRelationRegistry, IRelationInvalidatedEvent, IRelation
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logger = getLogger('cybertools.relation.registry')
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class DummyRelationRegistry(object):
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""" Dummy implementation for demonstration and test purposes.
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"""
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implements(IRelationRegistry)
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def __init__(self):
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self.relations = []
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self.objects = []
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def register(self, relation):
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if relation not in self.relations:
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self.relations.append(relation)
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if relation not in self.objects:
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self.objects.append(relation)
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for attr in ('first', 'second', 'third',):
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value = getattr(relation, attr, None)
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if value is not None:
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intids = component.queryUtility(IIntIds)
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if intids is not None:
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intids.register(value)
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elif value not in self.objects:
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self.objects.append(value)
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def unregister(self, relation):
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if relation in self.relations:
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self.relations.remove(relation)
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notify(RelationInvalidatedEvent(relation))
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def getUniqueIdForObject(self, obj):
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if obj == '*': # wild card
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return '*'
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intids = component.queryUtility(IIntIds)
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if intids is not None:
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return intids.register(obj)
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if obj not in self.objects:
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self.objects.append(obj)
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return self.objects.index(obj)
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def query(self, example=None, **kw):
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result = []
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criteria = {}
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if example is not None:
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for attr in ('first', 'second', 'third',):
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value = getattr(example, attr, None)
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if value is not None:
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criteria[attr] = value
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criteria['relationship'] = example
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criteria.update(kw)
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for r in self.relations:
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if r is None:
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continue
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hit = True
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for k in criteria:
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crit = criteria[k]
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if k == 'relationship':
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critpn = crit.getPredicateName()
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if critpn.endswith('*'):
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if not r.getPredicateName().startswith(critpn[:-1]):
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hit = False; break
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elif r.getPredicateName() != critpn:
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hit = False; break
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else:
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if not hasattr(r, k) or getattr(r, k) != crit:
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hit = False; break
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if hit:
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result.append(r)
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return result
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class RelationRegistry(Catalog):
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""" Local utility for registering (cataloguing) and searching relations.
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"""
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implements(IRelationRegistry)
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relations = None
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def __init__(self, *args, **kw):
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super(RelationRegistry, self).__init__(*args, **kw)
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self.relations = IOBTree()
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def setupIndexes(self):
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for idx in ('relationship', 'first', 'second', 'third'):
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if idx not in self:
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self[idx] = FieldIndex(idx, IIndexableRelation)
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def register(self, relation):
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if getattr(relation, '__parent__', None) is None:
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# Allow the IntIds utility to get a DB connection:
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relation.__parent__ = self
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uid = component.getUtility(IIntIds).register(relation)
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self.index_doc(uid, relation)
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if self.relations is not None:
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self.relations[uid] = relation
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#logger.info('added relation with uid %i.' % uid)
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def unregister(self, relation):
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uid = component.getUtility(IIntIds).getId(relation)
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self.unindex_doc(uid)
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if self.relations is not None and uid in self.relations:
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del self.relations[uid]
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#logger.info('removed relation with uid %i.' % uid)
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notify(RelationInvalidatedEvent(relation))
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def cleanupRelations(self):
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logger = getLogger('cybertools.relation.registry.cleanup')
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intids = component.getUtility(IIntIds)
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if self.relations is not None:
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logger.info('%i relations currently stored.' % len(self.relations))
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self.relations = IOBTree()
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result = self.apply(dict(relationship='*'))
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logger.info('%i relations found.' % len(result))
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for idx, uid in enumerate(result):
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relation = intids.getObject(uid)
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self.relations[uid] = relation
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pass
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def getUniqueIdForObject(self, obj):
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if obj == '*': # wild card
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return '*'
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return component.getUtility(IIntIds).queryId(obj)
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def apply(self, criteria):
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for k in criteria:
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# set min, max
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value = criteria[k]
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if k == 'relationship' and value.endswith('*'):
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criteria[k] = (value[:-1], value[:-1] + '\x7f')
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else:
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criteria[k] = (value, value)
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return super(RelationRegistry, self).apply(criteria)
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def query(self, example=None, **kw):
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intids = component.getUtility(IIntIds)
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criteria = {}
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if example is not None:
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for attr in ('first', 'second', 'third',):
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value = getattr(example, attr, None)
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if value is not None:
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criteria[attr] = intids.getId(value)
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pn = example.getPredicateName()
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if pn is not None:
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criteria['relationship'] = pn
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for k in kw:
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# overwrite example fields with explicit values
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if k == 'relationship':
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criteria[k] = kw[k].getPredicateName()
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else:
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criteria[k] = intids.getId(kw[k])
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results = self.apply(criteria)
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return ResultSet(results, intids)
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class IIndexableRelation(Interface):
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""" Provides the attributes needed for indexing relation objects in
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a catalog-based registry.
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"""
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class IndexableRelationAdapter(object):
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""" Adapter for providing the attributes needed for indexing
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relation objects.
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"""
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implements(IIndexableRelation)
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adapts(IRelation)
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def __init__(self, context):
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self.context = context
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def getRelationship(self):
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return self.context.getPredicateName()
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relationship = property(getRelationship)
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def __getattr__(self, attr):
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value = getattr(self.context, attr)
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if IPersistent.providedBy(value):
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return component.getUtility(IIntIds).getId(value)
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else:
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return value
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# convenience functions:
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def getRelations(first=None, second=None, third=None, relationships=None):
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""" Return a sequence of relations matching the query specified by the
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parameters.
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The relationships parameter expects a sequence of relationships
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(relation classes or predicate objects).
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"""
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registry = component.getUtility(IRelationRegistry)
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query = {}
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if first is not None: query['first'] = first
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if second is not None: query['second'] = second
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if third is not None: query['third'] = third
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if not relationships:
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return registry.query(**query)
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else:
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predicates = []
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for r in relationships:
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if hasattr(r, 'predicate'):
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predicates.append(r.predicate)
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r.predicate = None
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else:
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predicates.append(r.getPredicateName())
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result = registry.query(**query)
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if predicates:
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return [r for r in result
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if r.ident in predicates or r.fallback in predicates]
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return result
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def getRelationSingle(obj=None, relationship=None, forSecond=True):
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""" Returns the one and only relation for first having relationship
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or None if there is none.
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Raise an error if there is more than one hit.
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"""
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if forSecond:
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rels = getRelations(second=obj, relationships=[relationship])
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else:
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rels = getRelations(first=obj, relationships=[relationship])
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if len(rels) == 0:
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return None
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if len(rels) > 1:
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raise ValueError('Multiple hits when only one relation expected: '
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'%s, relationship: %s' % (getName(obj),
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relationship.getPredicateName()))
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return list(rels)[0]
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def setRelationSingle(relation, forSecond=True):
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""" Register the relation given, unregistering already existing
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relations for first and relationship. After this operation there
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will be only one relation for first with the relationship given.
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"""
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first = relation.first
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second = relation.second
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registry = component.getUtility(IRelationRegistry)
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if forSecond:
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rels = list(registry.query(second=second, relationship=relation))
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else:
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rels = list(registry.query(first=first, relationship=relation))
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for oldRel in rels:
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registry.unregister(oldRel)
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registry.register(relation)
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# events and handlers
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class RelationInvalidatedEvent(ObjectEvent):
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implements(IRelationInvalidatedEvent)
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def invalidateRelations(context, event):
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""" Handles IObjectRemoved event: unregisters
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all relations the object to be removed is involved in.
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"""
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# TODO: check marker interface of object:
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# if not IRelatable.providedBy(event.object):
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# return
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relations = []
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registries = component.getAllUtilitiesRegisteredFor(IRelationRegistry)
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for registry in registries:
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for attr in ('first', 'second', 'third'):
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try:
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relations = registry.query(**{attr: context})
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for relation in relations:
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registry.unregister(relation)
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except KeyError:
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pass
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def removeRelation(context, event):
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""" Handles IRelationInvalidatedEvent by removing the relation
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(that should be already unregistered from the relation registry)
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from its container (if appropriate) and the IntIds utility.
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"""
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if ILocation.providedBy(context):
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parent = getParent(context)
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if parent is not None:
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del parent[context]
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intids = component.getUtility(IIntIds)
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intids.unregister(context)
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def setupIndexes(context, event):
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""" Handles IObjectAdded event for the RelationRegistry utility
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and creates the indexes needed.
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"""
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if isinstance(context, RelationRegistry):
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context.setupIndexes()
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