Extending a UML and OCL Tool for Multi-Levels: Applications towards Model Quality Assessment

Abstract

-Currently, meta- and multi-level modelling is gaining more and more attention. A natural, upcoming question is, how to extend existing two-level approaches to cover multi-levels. In this contribution, we extend the UML and OCL tool USE in order to describe multi-level models. We also apply the extension to demonstrate the usefulness of multi-level modelling for model querying and model quality assessment.

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In this contribution we show how to upgrade a twolevel modeling tool to three levels of modeling by adding the OMG (Object Management Group) UML meta-model to the topmost level. In addition to this tool extension, we discuss reflective model querying as it plays an essential role. Therefore, we also present a reflective model querying approach using OCL for the meta-model. We apply metamodel queries for model quality evaluation. Developers can use an appropriate method to evaluate their model and find drawbacks and problems on it.

II. META-MODELING IN TOOL USE

In the current contribution, we introduce an approach, in which the MOF architecture is integrated into USE for multilevel modelling. Roughly speaking, we now make the third OMG layer M2 explictily available, and an instance of the M2-model corresponding to the user model is added to the M1-layer. Fig. 1 shows the general schema for the three-level modeling in the new version of USE.

M2

UML Meta model <<instanceOf>>

Meta model instances M1 M0 <<viewOf>> <<viewOf>>

UML User model

<<instanceOf>>

Run-time instances Fig. 1. General schema for the three-level modeling.

III. APPLICATION: MODEL QUALITY ASSESSMENT Model quality assessment helps modelers to detect errors or mistakes on their models. These assessment properties might include design properties, respecting naming conventions or metrics properties [ 2 ]. We introduce a proposal that employs OCL utilizing the three-level modeling approach as presented before. Thus, we can automatically evaluate quality properties of a user model. Fig. 2 shows the workflow of our proposal for model quality evaluation, which uses reflective OCL constraints as a major ingredient.

IV. CONCLUSION

This contribution has proposed an extension of the tool USE that supports three-level modelling where the middle level can be seen at the same time as an object diagram, i.e., the instantiation of the meta model, and as a class diagram, i.e., the type model for the lower level. Based on these ideas, we present approaches for model quality assessment.

References

[1] Gogolla , M. , Büttner , F. , Richters , M.: USE: A UML-based Specification Environment for Validating UML and OCL . Sci. Comput . Program. 69 ( 1-3 ), 27 - 34 ( 2007 )

[2] López-Fernández , J.J. , Guerra , E., de Lara , J.: Assessing the Quality of Meta Models . In: Proc. 11th Workshop MoDeVVa@MODELS 2014 . pp. 3 - 12 ( 2014 )