AttributeValidationMixin

class dtaianomaly.type_validation.AttributeValidationMixin

Mixin object to automatically validate class-attributes.

Mixin object to add functionality for validating the types of the attributes. By adding this class as parent to the new class, and defining the property attribute_validation, the defined attributes will always be verified when their value changes (upon construction and upon setting).

Attribute validation can also deal with using inheritance: only the parent class needs to add the AttributeValidationMixin as a base, and then in each class you can define the valid types in attribute_validation.

Note that defining attributes in the attribute_validation dictionary is completely optional. It is possible to exclude attributes from this dictionary. For such excluded attriutes, when there is a state change (e.g., construction or through the setter), the change will simply happen without any checks.

Attributes:

attribute_validationdict of (str, BaseAttributeValidation)

The validation for each attribute. The key is the name of the attribute to check, and the value is the related BaseAttributeValidation that will verify the correct state of the property.

Examples

>>> from dtaianomaly.type_validation import AttributeValidationMixin, IntegerAttribute
>>>
>>> class MyObject(AttributeValidationMixin):
...     positive_int: int
...     attribute_validation = {"positive_int": IntegerAttribute(minimum=0)}
...
...     def __init__(self, positive_int: int):
...         self.positive_int = positive_int
>>>
>>> MyObject("not-an-int")  # Constructing with invalid type
Traceback (most recent call last):
    ...
TypeError: Attribute 'positive_int' in class 'MyObject' must be of type int, but received 'not-an-int' of type <class 'str'>!
>>> MyObject(-1)  # Constructing with invalid value
Traceback (most recent call last):
    ...
ValueError: Attribute 'positive_int' in class 'MyObject' must be greater than or equal to 0, but received '-1'!
>>> my_object = MyObject(42)
>>> my_object.positive_int
42
>>> my_object.positive_int = "another-one"  # Setting to invalid type
Traceback (most recent call last):
    ...
TypeError: Attribute 'positive_int' in class 'MyObject' must be of type int, but received 'another-one' of type <class 'str'>!
>>> my_object.positive_int = -5  # Setting to invalid value
Traceback (most recent call last):
    ...
ValueError: Attribute 'positive_int' in class 'MyObject' must be greater than or equal to 0, but received '-5'!
>>> my_object.positive_int = 1
>>> my_object.positive_int
1