Stateful

class openstef_core.mixins.stateful.Stateful

Bases: object

Mixin for objects that can save and restore their internal state.

Provides versioned serialization with automatic state migration. Objects can be pickled, saved to disk, transmitted over networks, or stored in databases, then restored to their previous state. Version tracking ensures backward compatibility when object structure changes.

Subclasses can override _migrate_state to handle state migrations between versions. Increment _VERSION when making incompatible changes to object structure.

__getstate__() → VersionedState

Serialize object state with version metadata.

Return type:

VersionedState

Returns:

Versioned state dictionary containing version number, class name, and the object’s internal state.

__setstate__(state: Any) → None

Restore object from serialized state.

Handles both versioned and legacy state formats. Automatically migrates state from older versions using _migrate_state. Warns when loading legacy objects or when current version is older than saved version.

Parameters:

• state (Any) – Serialized state, either VersionedState dict or legacy format.

• state

Return type:

None