The former represents every type of user interaction object, the latter groups together elements that have a logical relationship.
According to its semantics an interactor belongs to one of the following subtypes: The different types of interactor-compositions are: MARIA allows describing not only the presentation aspects but also the interactive behaviour.
For this purpose it has various features: This set of new features allows having already at the abstract level a model of the user interface that is not tied to layout details, but it is complete enough for reasoning on how UI supports both the user interaction and the application back end.
A Concrete User Interface (CUI) in MARIA provides platform-dependent but implementation language-independent details of a UI.
The model definition can be exploited for creating (or deriving with a code generator) final implementations in different target languages.