ValueObject field

Field descriptor for embedding value objects within aggregates or entities.

Bases: Field

Represents a field that holds a value object.

This field is used to embed a value object within an entity. It provides functionality to handle the value object's fields and their values.

PARAMETER	DESCRIPTION
value_object_cls	The class of the value object to be embedded. TYPE: class

ATTRIBUTE	DESCRIPTION
embedded_fields	A dictionary that holds the embedded fields of the value object. TYPE: dict

Source code in src/protean/fields/embedded.py

def __init__(self, value_object_cls, *args, **kwargs):
    super().__init__(*args, **kwargs)

    if not isinstance(value_object_cls, str):
        # Validate the class being passed is a subclass of BaseValueObject
        self._validate_value_object_cls(value_object_cls)

    self._value_object_cls = value_object_cls

    self._embedded_fields = {}

embedded_fields cached property

embedded_fields

Property to retrieve embedded fields

get_shadow_fields

get_shadow_fields()

Return shadow field Primarily used during Entity initialization to register shadow field

Source code in src/protean/fields/embedded.py

def get_shadow_fields(self):
    """Return shadow field
    Primarily used during Entity initialization to register shadow field"""
    shadow_fields = []
    for field in self.embedded_fields.values():
        shadow_fields.append((field.attribute_name, field))
    return shadow_fields

as_dict

as_dict(value)

Return JSON-compatible value of self

Source code in src/protean/fields/embedded.py

def as_dict(self, value):
    """Return JSON-compatible value of self"""
    return (
        {
            field_name: shadow_field_obj.field_obj.as_dict(
                getattr(value, field_name, None)
            )
            for field_name, shadow_field_obj in self.embedded_fields.items()
        }
        if value
        else None
    )

__set__

__set__(instance, value)

Override __set__ to coordinate between value object and its embedded fields

Source code in src/protean/fields/embedded.py

def __set__(self, instance, value):
    """Override `__set__` to coordinate between value object and its embedded fields"""
    value = self._load(value)

    if value:
        # Check if the reference object has been saved. Otherwise, throw ValueError
        self._set_own_value(instance, value)
        self._set_embedded_values(instance, value)
    else:
        self._reset_values(instance)

    # Mark Entity as Dirty
    if hasattr(instance, "state_"):
        instance.state_.mark_changed()