Indicates that an object belongs to the UI/application layer, and is intended to be used as a view model.
Objects that are part of the domain object layer should instead implement RecreatableDomainObject .
Obtain a memento of the view model.
Typically this will be the identifier of a backing domain entity, but it could also be an arbitrary string, for example a bunch of JSON.
This method is called by the framework in order that the view model may be recreated subsequently through #viewModelInit(String) .