Interface for accumulator state. This should be implemented by the persistence layer that stores the accumulator members. It is advised to update the state when elements are added or removed from the accumulator.
Takes an element not in the domain and adds it.
Check if element is a member of the state.
Whether this element is in the domain (could be a member or not)
Interface for accumulator state. This should be implemented by the persistence layer that stores the accumulator members. It is advised to update the state when elements are added or removed from the accumulator.