|xAlfa is the name of the notation used for creating composition models of Alfa's primitives. This notation is created as a visual language that is employed in the visual modeling tool for Alfa called ViSAC. Moreover, xAlfa itself is defined as a meta model for GME. It certainly can be defined consistently with UML 2.0. If you are interested in mapping the GME meta model of xAlfa to UML 2.0, please contact us.
xAlfa models created in ViSAC can be currently accessed using Java. An API for xAlfa supports access to styles and architectures created using ViSAC. xAlfa data structures are created by alfaac, a compiler and analyzer for Alfa, from xAlfa models. xAlfa models can be obtained from ViSAC as well as from xAlfa serialized pickle files.
JavaDoc for xAlfa is available, so is the class diagram describing the classes and relationships of this API.