pattern-memento

The Memento pattern captures and restores object state snapshots to support undo history without breaking encapsulation. It separates state management into Originator, Memento, and Caretaker roles, ensuring immutable snapshots and clear encapsulation boundaries for safe rollback.

The Memento pattern is a behavioral design technique that captures an object's private state into an immutable snapshot for later restoration. Use it when building undo/redo features, draft/publish workflows, audit trails, or any system needing to restore complex domain objects to a prior state.

Set up state history by defining an immutable Memento value object to store state and an Originator to create snapshots. Keep history management in a separate Caretaker role so snapshots can be replayed or reverted safely without violating the domain object's encapsulation.

Yes, the Memento pattern supports safe rollback by capturing entity state snapshots before applying risky updates. It maintains immutable states and clear encapsulation boundaries across the Originator and Caretaker roles, ensuring safe restoration during complex rollback operations.

A key limitation of the Memento pattern for state history is potential memory overhead from storing multiple immutable snapshots of complex domain objects. It requires careful Caretaker management to ensure history does not consume excessive resources during frequent state capture.