##############################################################################
#
# Copyright (c) 2004 Zope Corporation and Contributors.
# All Rights Reserved.
#
# This software is subject to the provisions of the Zope Public License,
# Version 2.1 (ZPL). A copy of the ZPL should accompany this distribution.
# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
# FOR A PARTICULAR PURPOSE.
#
##############################################################################
"""
Filters
Child objects can be filtered out by certain criteria which are
defined by a filter. Writing your own filter should be very easy. All
you have to implement is the
:class:`zope.container.interfaces.IObjectFindFilter` interface.
Already existing filters for the find machinery may be used with
statictree just as well.
Since commonly needed, this module provides two filters that filter by
interface.
"""
from zope.interface import implementer
from zope.container.interfaces import IObjectFindFilter
[docs]@implementer(IObjectFindFilter)
class OnlyInterfacesFilter(object):
"""Only match objects that implement one of the given interfaces.
"""
only_interfaces = True
def __init__(self, *filterby):
self.ifaces = filterby
def matches(self, obj):
ifaces = self.ifaces
for iface in ifaces:
if iface.providedBy(obj):
return self.only_interfaces
return not self.only_interfaces
[docs]class AllButInterfacesFilter(OnlyInterfacesFilter):
"""Match only objects that do not implement one of the given
interfaces.
"""
only_interfaces = False