The Memento design pattern provides a solution:
Define Originator and Memento objects
so that an originator saves/restores its internal state to/from a memento.
Describing the Memento design in more detail is the theme of the following sections.
See Applicability section for all problems Memento can solve.

• The key idea in this pattern is to make an object (originator) itself responsible for saving/restoring its internal state (to/from a memento). Only the originator that created a memento is permitted to access it.
• Define Originator and Memento objects:
  • Originator defines an operation for saving its internal state to a memento (createMemento(): return new Memento(state)) and for restoring to a previous state from a memento (restore(memento): state = memento.getState()).
  • Memento defines the required data structures to store an originator's internal state, and it is protected against access by objects other than the originator.
    This is usually achieved by implementing memento as inner class of originator and declaring all members of memento private (see Implementation and Sample Code).
• Clients (caretaker) that are responsible for saving/restoring an originator's internal state hold a list of mementos so that a memento can be passed back to the originator to restore to a previous state.
  But a caretaker isn't permitted to access a memento. Only the originator that created a memento is permitted to access it. This enables to save and restore originator's internal state without violating its encapsulation.