Ph.D. Thesis - Business Informatics Group

Chapter 1 Introduction
tion code as the only integration description, it is hard to get an idea what really happens in
the transformation, e.g., which information is lost in the transformation. Information loss is
actually a problem when models are exported from tool A into tool B and then back from
tool B into tool A, which is a quite common tool integration scenario.
Requirements for the Metamodel Bridging Framework. First, for tackling the mentioned
problems, a framework should be developed for building reusable mapping operators
which are used to define so-called metamodel bridges. Such metamodel bridges allow
the automatic transformation of models. For this, a uniform formalism should be used
not only for representing the transformation logic together with the metamodels and the
models themselves, but also for executing the transformations.
Second, the proposed framework should be applied for defining a set of mapping operators
subsumed in a mapping language which is intended to resolve typical structural
heterogeneities occurring between the core concepts usually used to define metamodels as
provided by the OMG standard MOF [OMG04]. In case a problem is not directly solvable,
new mapping operators can be defined by the user or the operational semantics of existing
mapping operators can be tweaked.
Third, the defined metamodel bridges in terms of mapping operators, should allow the
engineering of roundtrip transformations. This kind of transformations is especially needed
for tool integration, namely if models are transformed from tool A to tool B and then back
again to tool A. In such scenarios it is important that no information is lost during the transformation.
However, practice shows that information loss often occurs in modeling tool
integration, because of the high possibility of missing correspondences in mapping models.
Therefore, mechanisms are needed that can support the user by developing roundtrip
transformation in a systematic way where mapping models play a crucial role.
1.2 Contribution of This Thesis
In regard of these crucial problems and requirements for Tool Adapters and the Metamodel
Bridging Framework, the contribution of this thesis is threefold.
Contribution 1. To ease the burden of developing tool adapters for each tool combination
again and again, we propose a mining pattern for metamodels and models which can
be used for implementing bridges on the M3-layer between two different meta-languages.
With the term mining, we are not referring to stochastic methods such as used in the area
of data mining [HK00], instead, we use the term mining as a name for the process of generating
model-based representations out of text-based descriptions. In particular, we have
implemented this mining pattern in the DTD2Ecore framework, a framework for producing
Ecore-based metamodels out of Document Type Definitions (DTD). Therefore, we present a
semi-automatic process how a language definition described in a language with limited expressiveness,
e.g., DTD, is transformed into a language definition described in a language
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