##############################################################################
#
# Copyright (c) 2008 Zope Foundation 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.
#
##############################################################################
"""
"""
__docformat__ = "reStructuredText"
import zope.interface
import zope.schema
from zope.schema.interfaces import IField, ValidationError
from z3c.schema.optchoice import interfaces
[docs]@zope.interface.implementer(interfaces.IOptionalChoice)
class OptionalChoice(zope.schema.Choice):
"""Optional Choice field."""
def __init__(self, value_type, **kw):
super(OptionalChoice, self).__init__(**kw)
# whine if value_type is not a field
if value_type is not None and not IField.providedBy(value_type):
raise ValueError("'value_type' must be field instance.")
self.value_type = value_type
def _validate(self, value):
try:
super(OptionalChoice, self)._validate(value)
except ValidationError:
self.value_type._validate(value)
[docs] def fromUnicode(self, value):
try:
return super(OptionalChoice, self).fromUnicode(value)
except ValidationError:
return self.value_type.fromUnicode(value)