Towards Approximate Model Transformations

As the size and complexity of models grow, there is a need to count on novel mechanisms and tools for transforming them. This is required, e.g., when model transformations need to provide target models without having access to the complete source models or in really short time—as it happens, e.g., with streaming models—or with very large models for which the transformation algorithms become too slow to be of practical use if the complete population of a model is investigated. In this paper we introduce Approximate Model Transformations, which aim at producing target models that are accurate enough to provide meaningful and useful results in an efficient way, but without having to be fully correct. So to speak, this kind of transformations treats accuracy for execution performance. In particular, we redefine the traditional OCL operators used to query models (e.g., allInstances, select, collect, etc.) by adopting sampling techniques and analyse the accuracy of approximate model transformations results.Universidad de Málaga, Campus de Excelencia Internacional Andalucía Tech. European Commission under the ICT Policy Support Programme (grant no. 317859). Research Project TIN2011-23795

A change propagating model transformation language

Model transformations are a key component in Model Driven Development, but most approaches only allow `one shot' transformations to be expressed. Change propagating model transformations are those which can make suitable updates to models after an initial transformation. In this paper I outline the challenges presented by change prop- agating model transformations, before presenting a new change propagating model transformation approach

Incremental Reconfiguration of Product Specific Use Case Models for Evolving Configuration Decisions

[Context and motivation] Product Line Engineering (PLE) is increasingly common practice in industry to develop complex systems for multiple customers with varying needs. In many business contexts, use cases are central development artifacts for requirements engineering and system testing. In such contexts, use case configurators can play a significant role to capture variable and common requirements in Product Line (PL) use case models and to generate Product Specific (PS) use case models for each new customer in a product family. [Question/Problem] Although considerable research has been devoted to use case configurators, little attention has been paid to supporting the incremental reconfiguration of use case models with evolving configuration decisions. [Principal ideas/results] We propose, apply, and assess an incremental reconfiguration approach to support evolving configuration decisions in PL use case models. PS use case models are incrementally reconfigured by focusing only on the changed decisions and their side effects. In our prior work, we proposed and applied Product line Use case modeling Method (PUM) to support variability modeling in PL use case diagrams and specifications. We also developed a use case configurator, PUMConf, which interactively collects configuration decisions from analysts to generate PS use case models from PL models. Our approach is built on top of PUM and PUMConf. [Contributions] We provide fully automated tool support for incremental configuration as an extension of PUMConf. Our approach has been evaluated in an industrial case study in the automotive domain, which provided evidence it is practical and beneficial

Automated inference of likely metamorphic relations for model transformations

Model transformations play a cornerstone role in Model-Driven Engineering (MDE) as they provide the essential mechanisms for manipulating and transforming models. Checking whether the output of a model transformation is correct is a manual and errorprone task, referred to as the oracle problem. Metamorphic testing alleviates the oracle problem by exploiting the relations among di erent inputs and outputs of the program under test, so-called metamorphic relations (MRs). One of the main challenges in metamorphic testing is the automated inference of likely MRs. This paper proposes an approach to automatically infer likely MRs for ATL model transformations, where the tester does not need to have any knowledge of the transformation. The inferred MRs aim at detecting faults in model transformations in three application scenarios, namely regression testing, incremental transformations and migrations among transformation languages. In the experiments performed, the inferred likely MRs have proved to be quite accurate, with a precision of 96.4% from a total of 4101 true positives out of 4254 MRs inferred. Furthermore, they have been useful for identifying mutants in regression testing scenarios, with a mutation score of 93.3%. Finally, our approach can be used in conjunction with current approaches for the automatic generation of test cases.Comisión Interministerial de Ciencia y Tecnología TIN2015-70560-RJunta de Andalucía P12-TIC-186

Change Impact Analysis for Evolving Configuration Decisions in Product Line Use Case Models

Product Line Engineering is becoming a key practice in many software development environments where complex systems are developed for multiple customers with varying needs. In many business contexts, use cases are the main artifacts for communicating requirements among stakeholders. In such contexts, Product Line (PL) use cases capture variable and common requirements while use case-driven configuration generates Product Specific (PS) use cases for each new customer in a product family. In this paper, we propose, apply, and assess a change impact analysis approach for evolving configuration decisions in PL use case models. Our approach includes: (1) automated support to identify the impact of decision changes on prior and subsequent decisions in PL use case diagrams and (2) automated incremental regeneration of PS use case models from PL use case models and evolving configuration decisions. Our tool support is integrated with IBM Doors. Our approach has been evaluated in an industrial case study, which provides evidence that it is practical and beneficial to analyze the impact of decision changes and to incrementally regenerate PS use case models in industrial settings

Traceability of Requirements and Software Architecture for Change Management

At the present day, software systems get more and more complex. The requirements of software systems change continuously and new requirements emerge frequently. New and/or modified requirements are integrated with the existing ones, and adaptations to the architecture and source code of the system are made. The process of integration of the new/modified requirements and adaptations to the software system is called change management. The size and complexity of software systems make change management costly and time consuming. To reduce the cost of changes, it is important to apply change management as early as possible in the software development cycle. Requirements traceability is considered crucial in change management for establishing and maintaining consistency between software development artifacts. It is the ability to link requirements back to stakeholders’ rationales and forward to corresponding design artifacts, code, and test cases. When changes for the requirements of the software system are proposed, the impact of these changes on other requirements, design elements and source code should be traced in order to determine parts of the software system to be changed. Determining the impact of changes on the parts of development artifacts is called change impact analysis. Change impact analysis is applicable to many development artifacts like requirements documents, detailed design, source code and test cases. Our focus is change impact analysis in requirements and software architecture. The need for change impact analysis is observed in both requirements and software architecture. When a change is introduced to a requirement, the requirements engineer needs to find out if any other requirement related to the changed requirement is impacted. After determining the impacted requirements, the software architect needs to identify the impacted architectural elements by tracing the changed requirements to software architecture. It is hard, expensive and error prone to manually trace impacted requirements and architectural elements from the changed requirements. There are tools and approaches that automate change impact analysis like IBM Rational RequisitePro and DOORS. In most of these tools, traces are just simple relations and their semantics is not considered. Due to the lack of semantics of traces in these tools, all requirements and architectural elements directly or indirectly traced from the changed requirement are candidate impacted. The requirements engineer has to inspect all these candidate impacted requirements and architectural elements to identify changes if there are any. In this thesis we address the following problems which arise in performing change impact analysis for requirements and software architecture. Explosion of impacts in requirements after a change in requirements. In practice, requirements documents are often textual artifacts with implicit structure. Most of the relations among requirements are not given explicitly. There is a lack of precise definition of relations among requirements in most tools and approaches. Due to the lack of semantics of requirements relations, change impact analysis may produce high number of false positive and false negative impacted requirements. A requirements engineer may have to analyze all requirements in the requirements document for a single change. This may result in neglecting the actual impact of a change. Manual, expensive and error prone trace establishment. Considerable research has been devoted to relating requirements and design artifacts with source code. Less attention has been paid to relating Requirements (R) with Architecture (A) by using well-defined semantics of traces. Designing architecture based on requirements is a problem solving process that relies on human experience and creativity, and is mainly manual. The software architect may need to manually assign traces between R&A. Manual trace assignment is time-consuming, expensive and error prone. The assigned traces might be incomplete and invalid. Explosion of impacts in software architecture after a change in requirements. Due to the lack of semantics of traces between R&A, change impact analysis may produce high number of false positive and false negative impacted architectural elements. A software architect may have to analyze all architectural elements in the architecture for a single requirements change. In this thesis we propose an approach that reduces the explosion of impacts in R&A. The approach employs semantic information of traces and is supported by tools. We consider that every relation between software development artifacts or between elements in these artifacts can play the role of a trace for a certain traceability purpose like change impact analysis. We choose Model Driven Engineering (MDE) as a solution platform for our approach. MDE provides a uniform treatment of software artifacts (e.g. requirements documents, software design and test documents) as models. It also enables using different formalisms to reason about development artifacts described as models. To give an explicit structure to requirements documents and treat requirements, architecture and traces in a uniform way, we use metamodels and models with formally defined semantics. The thesis provides the following contributions: A modeling language for definition of requirements models with formal semantics. The language is defined according to the MDE principles by defining a metamodel. It is based on a survey about the most commonly found requirements types and relation types. With this language, the requirements engineer can explicitly specify the requirements and the relations among them. The semantics of these entities is given in First Order Logic (FOL) and allows two activities. First, new relations among requirements can be inferred from the initial set of relations. Second, requirements models can be automatically checked for consistency of the relations. Tool for Requirements Inferencing and Consistency Checking (TRIC) is developed to support both activities. The defined semantics is used in a technique for change impact analysis in requirements models. A change impact analysis technique for requirements using semantics of requirements relations and requirements change types. The technique aims at solving the problem of explosion of impacts in requirements when semantics of requirements relations is missing. The technique uses formal semantics of requirements relations and requirements change types. A classification of requirements changes based on the structure of a textual requirement is given and formalized. The semantics of requirements change types is based on FOL. We support three activities for impact analysis. First, the requirements engineer proposes changes according to the change classification before implementing the actual changes. Second, the requirements engineer indentifies the propagation of the changes to related requirements. The change alternatives in the propagation are determined based on the semantics of change types and requirements relations. Third, possible contradicting changes are identified. We extend TRIC with a support for these activities. The tool automatically determines the change propagation paths, checks the consistency of the changes, and suggests alternatives for implementing the change. A technique that provides trace establishment between R&A by using architecture verification and semantics of traces. It is hard, expensive and error prone to manually establish traces between R&A. We present an approach that provides trace establishment by using architecture verification together with semantics of requirements relations and traces. We use a trace metamodel with commonly used trace types. The semantics of traces is formalized in FOL. Software architectures are expressed in the Architecture Analysis and Design Language (AADL). AADL is provided with a formal semantics expressed in Maude. The Maude tool set allows simulation and verification of architectures. The first way to establish traces is to use architecture verification techniques. A given requirement is reformulated as a property in terms of the architecture. The architecture is executed and a state space is produced. This execution simulates the behavior of the system on the architectural level. The property derived from the requirement is checked by the Maude model checker. Traces are generated between the requirement and the architectural components used in the verification of the property. The second way to establish traces is to use the requirements relations together with the semantics of traces. Requirements relations are reflected in the connections among the traced architectural elements based on the semantics of traces. Therefore, new traces are inferred from existing traces by using requirements relations. We use semantics of requirements relations and traces to both generate/validate traces and generate/validate requirements relations. There is a tool support for our approach. The tool provides the following: (1) generation/validation of traces by using requirements relations and/or verification of architecture, (2) generation/validation of requirements relations by using traces. A change impact analysis technique for software architecture using architecture verification and semantics of traces between R&A. The software architect needs to identify the impacted architectural elements after requirements change. We present a change impact analysis technique for software architecture using architecture verification and semantics of traces. The technique is semi-automatic and requires participation of the software architect. Our technique has two parts. The first part is to identify the architectural elements that implement the system properties to which proposed requirements changes are introduced. By having the formal semantics of requirements relations and traces, we identify which parts of software architecture are impacted by a proposed change in requirements. We have extended TRIC for determining candidate impacted architectural elements. The second part of our technique is to propose possible changes for software architecture when the software architecture does not satisfy the new and/or changed requirements. The technique is based on architecture verification. The output of verification is a counter example if the requirements are not satisfied. The counter example is used with a classification of architectural changes in order to propose changes in the software architecture. These changes produce a new version of the architecture that possibly satisfies the new or the changed requirements

Designing a Change-Driven Language for Model Consistency Repair Routines

Ein Software-System kann während der Entwicklung durch verschiedene Modelle beschrieben werden, um unterschiedliche Teile oder Abstraktionen des Systems darzustellen. Diese Modelle können voneinander abhängige oder sogar redundante Informationen enthalten. Wenn ein Softwareentwickler an solchen Modellen Änderungen vornimmt ohne diese Abhängigkeiten zu beachten, können die Modelle inkonsistent werden. Ein Entwickler ist kaum in der Lage einen Überblick über alle Modelle eines Entwicklungsprozesses und deren Abhängigkeiten zu behalten. Daher sind automatisierte Verfahren zur Wiederherstellung von Konsistenz nach Modelländerungen notwendig. Existierende Methoden erlauben die deklarative Spezifikation von Abhängigkeiten zwischen Modellen, aus denen automatisiert Mechanismen zur Konsistenzerhaltung abgeleitet werden. Diese Ansätze sind in ihrer Ausdrucksmächtigkeit beschränkt und bieten nur eingeschränkten Einfluss auf die Art und Weise in der Konsistenz wiederhergestellt wird. Sie legen automatisiert eine Art der Wiederherstellung der Konsistenz fest, obwohl es verschiedene Möglichkeiten dafür gäbe. In dieser Arbeit stellen wir die änderungsgetriebene Response-Sprache für die Konsistenzerhaltung von Modellen vor. Sie erlaubt es, die Art und Weise der Wiederherstellung von Konsistenz explizit in imperativen Programmen festzulegen, welche als Reaktion auf festgelegte Änderungen ausgeführt werden. Zusätzlich bietet sie Sprachkonstrukte an, die wiederkehrende Reaktionen kapseln und wiederverwendbar machen. Wir führen einen Konsistenzbegriff mit dem Fokus auf Verständlichkeit ein und stellen eine Kategorisierung von möglichen Modelländerungen vor. Die Sprache ist entsprechend einer allgemeingültigen Struktur für die änderungsgetriebene Wiederherstellung von Konsistenz aufgebaut, welche wir aus unserem Konsistenzbegriff herleiten. Wir stellen eine Evaluation unseres Ansatzes anhand einer Fallstudie zur Konsistenzerhaltung von Architekturbeschreibungen und deren Implementierung in objektorientiertem Code vor. Die Evaluation zeigt die Anwendbarkeit der vorgestellten Sprache für die Sicherstellung von Modellkonsistenz in diesem konkreten Fall und verdeutlicht einige Vorteile gegenüber einer manuellen Implementierung der Mechanismen zur Konsistenzerhaltung

Incremental Model Synchronization

Changing artifacts is intrinsic to the development and maintenance of software projects. The changes made to one artifact, however, do not come about in isolation. Software models are often vastly entangled. As such, a minuscule modification in one ripples in- consistency through several others. The primary goal of the this thesis is to investigate techniques and processes for the synchronization of artifacts in model driven development environments in which projects comprise manifold interdependent models, each being a live document that is continuously altered and evolved. The co-evolution of these artifacts demands an efficient mechanism to keep them consistent in such dynamic environments. To achieve this consistency, we intend to explore methods and algorithms for impact anal- ysis and the propagation of modifications across heterogenous interdependent models. In particular, we consider large scale models that are generated from other models by complex artifact generators. After creation, both the generated artifacts, and also the ones they are generated from, are subject to evolutionary changes throughout which their mutual consistency should be maintained. In such situations, the model transformation is the pri- mary benchmark of consistency rules between source and target models. But the rules are often implanted inside the implementation of artifact generators and hence unavailable. Trivially, the artifacts can be synchronized by regeneration. More often than not however, regeneration of such artifacts from scratch tends to be unwieldy due to their massive size. This thesis is a summary of research on effective change management methodologies in the context of model driven development. In particular, it presents two methods of in- crementally synchronizing software models related by existing model transformations, so that the synchronization time is proportional to the magnitude of change and not to the size of models. The first approach treats model transformations as black-boxes and adds to it incremental synchronization by a technique called conceptualization. The black-box is distinguished from other undertakings in that it does not require the extraction, re- engineering and re-implementation of consistency rules embedded inside transformations. The second approach is a white-box approach that uses static analysis to automatically transform the source code of the transformation into an incremental one. In particular it uses partial evaluation to derive a specialized, incremental transformation from the exist- ing one. These two approaches are complementary and together support a comprehensive range of model transformations

Incremental Model-to-Text Transformation

Model-driven engineering (MDE) promotes the use of abstractions to simplify the development of complex software systems. Through several model management tasks (e.g., model verification, re-factoring, model transformation), many software development tasks can be automated. For example, model-to-text transformations (M2T) are used to realize textual development artefacts (e.g., documentation, configuration scripts, code, etc.) from underlying source models. Despite the importance of M2T transformation, contemporary M2T languages lack support for developing transformations that scale. As MDE is applied to systems of increasing size and complexity, a lack of scalable M2T transformations and other model management tasks hinders industrial adoption. This is largely due to the fact that model management tools do not support efficient propagation of changes from models to other development artefacts. As such, the re-synchronisation of generated textual artefacts with underlying system models can take considerably large amount of time to execute due to redundant re-computations. This thesis investigates scalability in the context of M2T transformation, and proposes two novel techniques that enable efficient incremental change propagation from models to generated textual artefacts. In contrast to existing incremental M2T transformation technique, which relies on model differencing, our techniques employ fundamentally different approaches to incremental change propagation: they use a form of runtime analysis that identifies the impact of source model changes on generated textual artefacts. The structures produced by this runtime analysis, are used to perform efficient incremental transformations (scalable transformations). This claim is supported by the results of empirical evaluation which shows that the techniques proposed in this thesis can be used to attain an average reduction of 60% in transformation execution time compared to non-incremental (batch) transformation