If this reference is not set then EObjectActionProvider creates a new Action using AppFactory in newAction() method. If this reference is set and is Action then a copy of the action is created and returned. Otherwise the reference value it is adapted to ActionProvider which is used to create an action. This allows to merge actions and chain action generation. E.g. generate Ecore model documentation and merge it into the Engineering documentation.
Principles can be nested. E.g. Architectural Principles may contain Data Architecture principles.
If element’s URI is not set then its default value is derived from the container URI and containment reference. This is a logical URI and it can be used for cross-referencing of elements in a resource-independent fashion.