bc4a012b4f
git-svn-id: svn://svn.cy55.de/Zope3/src/cybertools/trunk@677 fd906abe-77d9-0310-91a1-e0d9ade77398
131 lines
4 KiB
Python
131 lines
4 KiB
Python
#
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# Copyright (c) 2005 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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interface definitions for the Relations utility and relation objects.
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$Id$
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"""
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from zope.interface import Interface, Attribute
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from zope.app.event.interfaces import IObjectEvent
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# relation interfaces
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class IRelation(Interface):
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""" Base interface for relations.
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"""
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def getPredicateName():
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""" Return the predicate of this relation as a string that may be
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used for indexing.
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"""
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def validate(registry=None):
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""" Return True if this relation is valid.
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If the registry argument is provided the check should be done
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with respect to this relation registry, e.g. to
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"""
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class IMonadicRelation(IRelation):
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""" Relation with just one object.
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While a monadic relation could be easily represented by an attribute
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or an annotation, monadic relations are e.g. useful when working with
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an ontology-driven higher-level relation framework.
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"""
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first = Attribute('First and only object that belongs to the relation.')
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class IDyadicRelation(IRelation):
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""" Relation connecting two objects.
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"""
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first = Attribute('First object that belongs to the relation.')
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second = Attribute('Second object that belongs to the relation.')
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class ITriadicRelation(IDyadicRelation):
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""" Relation connecting three objects.
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"""
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third = Attribute('Third object that belongs to the relation.')
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class IPredicate(Interface):
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""" A predicate signifies a relationship. This may be implemented
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directly as a relation class, or the relation object may
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hold the predicate as an attribute.
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"""
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def getPredicateName():
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""" Return this predicate as a string that may be used for indexing.
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"""
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# event interfaces
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class IRelationInvalidatedEvent(IObjectEvent):
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""" This event fires when a relation is invalidated, typically because
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an object that is involved in the relation is removed.
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"""
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# relations registry interfaces
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class IRelationsRegistryUpdate(Interface):
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""" Interface for registering and unregistering relations with a
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relations registry.
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"""
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def register(relation):
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""" Register the relation given with this registry.
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"""
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def unregister(relation):
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""" Remove the relation given from this registry.
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"""
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class IRelationsRegistryQuery(Interface):
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""" Interface for querying a relations registry.
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"""
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def query(relation=None, **kw):
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""" Return a sequence of relations that fulfill the criteria given.
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You may provide a relation object as an example that specifies the
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search criteria, i.e. its predicate and first, second or third
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attribute will be used for searching, or explicit criteria
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via keyword arguments.
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Example for using keyword criteria:
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rr.queryRelations(first=someObject, second=anotherObject,
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relationship=SomeRelationClass)
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"""
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class IRelationsRegistry(IRelationsRegistryUpdate, IRelationsRegistryQuery):
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""" A registry for registering and searching relations typically
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implemented as a local utility .
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"""
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