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.
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.
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.
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.