Hybrid Transformation Modeling Integrating a Declarative with an Imperative Model Transformation Language Pieter Van Gorp

2 Overview Case Study  Conceptual Model  Robustness Model Imperative Approach  Story Diagrams  Flexible  Too Low Level Declarative Approach  Triple Graph Grammars  Compact  Too Generic Hybrid Approach  Story Diagrams + TGG rules  Expressive and Compact Language Integration  Metamodel Merging  Metamodel Mapping

3 Case Study Conceptual Model Robustness Model

4 UML Profiled Models as Graphs

5 Sample Constraint (Informal Version) All classes from the conceptual model should correspond to entities in the robustness model. Their attributes and attribute types should correspond. Both internal types and library types should be supported.

6 Overview Case Study Imperative Approach - Story Diagrams Declarative Approach Hybrid Approach Language Integration

7 Imperative Approach: Story Diagrams Evaluate whether each class in the conceptual model traces to an entity in the robustness model 91 let eachClassTracesToAnEntity(): Boolean= 92 conceptualmodelTracesToRobustnessmodel() and -- ’rm’ not Undefined 93 allClassesFromModel(cm)->forAll(cmc| 94 allClassesFromModel(rm)->exists(rmc| 95 this.traceabilityLinks->select(oclIsKindOf(Class2Entity))->exists(l| 96 l.node->contains(cmc) and 97 l.node->contains(rmc) 98 ) 99 ) 100 ) Any interaction pattern can be implemented: setFocus chooseAlternative...

8 Story Pattern: “Is the Class related to an Entity?”

9 Can be abstracted by TGG rules.. Too low-level Recurring Patterns - Story diagram for creating elements - Story diagram for incremental update - Story diagram for manual resolution -... Problem

10 Overview Case Study Imperative Approach Declarative Approach - TGG Rules Hybrid Approach Language Integration

11 Classes to Entities

12 Handling Internal Attribute Types

13 Handling External Attribute Types

14 Problem Overlapping Applicability Need user decision to resolve

15 Overview Case Study Imperative Approach Declarative Approach Hybrid Approach Language Integration

16 Solution Adding a rule with higher preference - Application condition: situation (6) or (8) - Effects: user interaction delegate to appropriate TGG rule - Arbitrary user interaction and control flows story diagrams Resulting language: Hybrid - Declarative: TGG rules fully supported Staged: rules are ordered - Imperative: Calls & branches in rules

17 Making TGG rules Callable First State - Match nodes that are bound in the controlled TGG rule Second State - Call to the controlled TGG rule

18 Controlled Triple Graph Grammars

19 Language Integration Case Study Imperative Approach Declarative Approach Hybrid Approach Language Integration

20 Metamodel Merging VS Mapping Hybrid Language: TGGs merged with SDM Alternative: Strict mapping from TGGs to SDM - With traceability (=> bootstrap desirable?) - User interaction implemented by manually completing the generated story diagrams Discussion: - What adds most value to the QVT approach? - What is most readable? -... Either approach would make TGGs more attractive than QVT

21 Related Work ATL - Not bidirectional, which reduces the declarativeness of a called rule to... 0 QVT: - Also 2 layer language architecture - May not be possible to merge relational and operational Choosing a TGG tool to extend... - Darmstadt: advantage of JMI compliance Wait for all operational rule derivations? - Paderborn: advantage of completed incrementality Generate JMI wrappers? - Aachen: advantage of alternative approach to user interaction Standard Compliance? Why not share what is no contribution anymore?

22 Conclusions Hybrid Language reconciles: - Compactness of TGTSs with - Expressiveness of Story Diagrams Language Engineering: - Metamodel Merging: Advantage: no confusion about semantics of TGG rules Implementation: - Minimal modification to rule derivation strategy (add > nodes) - Metamodel Mapping: Advantage: no “details” on TGG level Implementation: - Rule derivation HOT needs to generate traceability links - No hard guidelines (yet)

23 Thanks for your Attention Questions?