The Restrictions of XIG

 

Due to the beta status of the GXL format and the used UML case tool ArgoUML(tm) while the development of XIG, the final version 1.0 of XIG is restricted in some way. But not only the beta stati caused some limitations; also for clarity and an easier use of the translator, the features have some restrictions.

These restrictions are listed in the following:

 

Composite associations are translated as edges. The translation of composite associations was not yet implemented in the used version of the GXL definition.
The ordering of incidences is not translated correctly. This problem is not caused by XIG - the ordering of incidences is completely supported by the translator. But at the moment ArgoUMLŠ is not able to store the information correctly.
Invisible objects are translated by XIG. XIG is not able to distinguish visible and non visible object in the XMI code - the cause might be a wrong storing method for invisible objects in the XMI code.
The XLink namespace is not used in the produced GXL code. Due to problems with current XSLT processors, the prefix xlink is left out in all type-elements. If the problems are solved, the prefix can simply be inserted in the XSLT code of XIG (all elements, which have to be changed, are marked as such).
Nodes get IDs, but edges do not. While the development of XIG this point was not already defined yet.
Hypergraphs are not supported. Even now, the implementation of hypergraphs in GXL is under discussion yet and therefore not supported by XIG.
Attributed edges have to be constructed as <<edge>> stereotyped classes. This is caused by the limitations of ArgoUMLŠ - see the instruction of GXL for further information.
Edges between edge elements and/or relation elements respectively between edge elements and node elements are not supported yet. This is another restriction, caused by ArgoUMLŠ - see the introduction of GXL for further information again.
Only the atomic value types and the locator value type are translated at the moment. All other value types had not been completely specified as XIG had been developed.
If a graph element does not possess a name, the XMI ID is set as the name attribute in the GXL code. This is not really a restriction - this has been implemented to simplify the use of XIG.
Relation tentacles are only accepted, if they are whether directed or undirected. All other tentacles are not correct and therefore not supported by XIG. This limitation provides problems during the transformation.
In the case of edges, which are visualized as associations, only the following navigability types are allowed: "--->", "<---", "----". All other navigability is not correct and therefore not supported by XIG. This limitation provides problems during the transformation.
In the case of edges, which are visualized as classes with two adjacent associations, only the following navigability types are allowed: "--->[]--->", "<---[]<---", "----[]----". All other navigability is not correct and therefore not supported by XIG. This limitation provides problems during the transformation.