Source code for traits.trait_errors
#------------------------------------------------------------------------------
#
# Copyright (c) 2005, Enthought, Inc.
# All rights reserved.
#
# This software is provided without warranty under the terms of the BSD
# license included in enthought/LICENSE.txt and may be redistributed only
# under the conditions described in the aforementioned license. The license
# is also available online at http://www.enthought.com/licenses/BSD.txt
#
# Thanks for using Enthought open source!
#
# Author: David C. Morrill
# Date: 06/21/2002
#
#------------------------------------------------------------------------------
""" Defines the standard exceptions raised by the Traits package.
"""
#-------------------------------------------------------------------------------
# Imports:
#-------------------------------------------------------------------------------
from __future__ import absolute_import
import sys
from .trait_base import class_of
from . import _py2to3
#-------------------------------------------------------------------------------
# Utilities
#-------------------------------------------------------------------------------
[docs]def repr_type(obj):
""" Return a string representation of a value and its type for readable
error messages.
"""
the_type = _py2to3.type_w_old_style(obj)
msg = '%r %r' % (obj, the_type)
return msg
#-------------------------------------------------------------------------------
# 'TraitError' class:
#-------------------------------------------------------------------------------
[docs]class TraitError ( Exception ):
def __init__ ( self, args = None, name = None, info = None, value = None ):
if name is None:
# If the given args is not a tuple then assume that the user intended
# it to be the single item in a one-element tuple.
if not isinstance(args, tuple):
args = args,
self.args = args
else:
# Save the information, in case the 'args' object is not the correct
# one, and we need to regenerate the message later:
self.name = name
self.info = info
self.value = value
self.desc = None
self.prefix = 'The'
self.set_desc( None, args )
def set_desc ( self, desc, object = None ):
if hasattr( self, 'desc' ):
if desc is not None:
self.desc = desc
if object is not None:
self.object = object
self.set_args()
def set_prefix ( self, prefix ):
if hasattr( self, 'prefix' ):
self.prefix = prefix
self.set_args()
def set_args ( self ):
if self.desc is None:
extra = ''
else:
extra = ' specifies %s and' % self.desc
obj = getattr( self, 'object', None )
# Note: self.args must be a tuple so be sure to leave the trailing
# commas.
the_type = _py2to3.type_w_old_style(self.value)
if obj is not None:
self.args = ("%s '%s' trait of %s instance%s must be %s, "
"but a value of %s was specified." % (
self.prefix, self.name, class_of(obj), extra,
self.info, repr_type(self.value))),
else:
self.args = ("%s '%s' trait%s must be %s, but a value of %s was "
"specified." % (self.prefix, self.name, extra,
self.info, repr_type(self.value))),
#-------------------------------------------------------------------------------
# 'TraitNotificationError' class:
#-------------------------------------------------------------------------------
[docs]class TraitNotificationError ( Exception ):
pass
#-------------------------------------------------------------------------------
# 'DelegationError' class:
#-------------------------------------------------------------------------------
[docs]class DelegationError ( TraitError ):
def __init__ ( self, args ):
# .args must be a tuple.
self.args = args,
#-------------------------------------------------------------------------------
# Export the defined exceptions to the C-base traits module:
#-------------------------------------------------------------------------------
from . import ctraits
ctraits._exceptions( TraitError, DelegationError )