def _validate_length(self, new_length):
"""
Validate the new length for a proposed operation.
Parameters
----------
new_length : int
New length of the list.
Raises
------
TraitError
If the proposed new length would violate the length constraints
of the list.
"""
trait = getattr(self, "trait", None)
if trait is None:
return
if not trait.minlen <= new_length <= trait.maxlen:
raise TraitError(
"The '%s' trait of %s instance must be %s, "
"but you attempted to change its length to %d %s." % (
self.name,
class_of(self.object()),
self.trait.full_info(self.object(), self.name, Undefined),
new_length,
"element" if new_length == 1 else "elements",
))
def info ( self ):
aClass = self.aClass
if aClass is None:
result = 'path'
else:
if type( aClass ) is not str:
aClass = aClass.__name__
result = 'path to an instance of ' + class_of( aClass )
if self.or_none is None:
return result + ' or an empty string'
return result
def info(self):
aClass = self.aClass
if aClass is None:
result = "path"
else:
if type(aClass) is not str:
aClass = aClass.__name__
result = "path to an instance of " + class_of(aClass)
if self.or_none is None:
return result + " or an empty string"
return result
def validate(self, object, name, value):
""" Validates that a specified value is valid for this trait."""
if isinstance(value, (str, bytes)):
if not self.exists:
return value
if os.path.isdir(value):
return value
else:
raise TraitError(
args='The trait \'{}\' of {} instance is {}, but the path '
' \'{}\' does not exist.'.format(name, class_of(object),
self.info_text, value))
self.error(object, name, value)
def validate(self, object, name, value):
""" Validates that a specified value is valid for this trait."""
validated_value = super(File, self).validate(object, name, value)
if not self.exists:
return validated_value
elif os.path.isfile(value):
return validated_value
else:
raise TraitError(
args='The trait \'{}\' of {} instance is {}, but the path '
' \'{}\' does not exist.'.format(name, class_of(object),
self.info_text, value))
self.error(object, name, value)
def validate(self, object, name, value):
""" Validates that a specified value is valid for this trait."""
if isinstance(value, (str, bytes)):
if not self.exists:
return value
if os.path.isdir(value):
return value
else:
raise TraitError(
args='The trait \'{}\' of {} instance is {}, but the path '
' \'{}\' does not exist.'.format(name, class_of(object),
self.info_text, value))
self.error(object, name, value)
def validate(self, object, name, value):
""" Validates that a specified value is valid for this trait."""
validated_value = super(File, self).validate(object, name, value)
if not self.exists:
return validated_value
elif os.path.isfile(value):
return validated_value
else:
raise TraitError(
args='The trait \'{}\' of {} instance is {}, but the path '
' \'{}\' does not exist.'.format(name, class_of(object),
self.info_text, value))
self.error(object, name, value)