Angel Luis Rubio

Evolving XML schemas and documents using UML class diagrams

The widespread use of XML brings new challenges for its integration into general software development processes. In particular, it is necessary to keep the consistency between different software artifacts and XML documents when evolution tasks are carried out. In this paper we present an approach to evolve XML schemas and documents conceptually modeled by means of UML class diagrams. Evolution primitives are issued on the UML class diagram and are automatically propagated down to the XML schema. The XML documents are also automatically modified to conform to the new XML schema. In this way, the consistency between the different artifacts involved is kept. This goal is achieved by using an intermediate component which reflects how the UML diagrams are translated into the XML schemas.

MeDEA: A database evolution architecture with traceability

One of the most important challenges that software engineers (designers, developers) still have to face in their everyday work is the evolution of working database systems. As a step for the solution of this problem in this paper we propose MeDEA, which stands for Metamodel-based Database Evolution Architecture. MeDEA is a generic evolution architecture that allows us to maintain the traceability between the different artifacts involved in any database development process. MeDEA is generic in the sense that it is independent of the particular modeling techniques being used. In order to achieve this, a metamodeling approach has been followed for the development of MeDEA. The other basic characteristic of the architecture is the inclusion of a specific component devoted to storing the translation of conceptual schemas to logical ones. This component, which is one of the most noteworthy contributions of our approach, enables any modification (evolution) realized on a conceptual schema to be traced to the corresponding logical schema, without having to regenerate this schema from scratch, and furthermore to be propagated to the physical and extensional levels.

A systematic review of code generation proposals from state machine specifications

Context: Model Driven Development (MDD) encourages the use of models for developing complex software systems. Following a MDD approach, modelling languages are used to diagrammatically model the structure and behaviour of object-oriented software, among which state-based languages (including UML state machines, finite state machines and Harel statecharts) constitute the most widely used to specify the dynamic behaviour of a system. However, generating code from state machine models as part of the final system constitutes one of the most challenging tasks due to its dynamic nature and because many state machine concepts are not supported by the object-oriented programming languages. Therefore, it is not surprising that such code generation has received great attention over the years. Objective: The overall objective of this paper is to plot the landscape of published proposals in the field of object oriented code generation from state machine specifications, restricting the search neither to a specific context nor to a particular programming language. Method: We perform a systematic, accurate literature review of published studies focusing on the object oriented implementation of state machine specifications. Results: The systematic review is based on a comprehensive set of 53 resources in all, which we have classified into two groups: pattern-based and not pattern-based. For each proposal, we have analysed both the state machine specification elements they support and the means the authors propose for their implementation. Additionally, the review investigates which proposals take into account desirable features to be considered in software development such as maintenance or reusability. Conclusions: One of the conclusions drawn from the review is that most of the analysed works are based on a software design pattern. Another key finding is that many papers neither support several of the main components of the expressive richness of state machine specifications nor provide an implementation strategy that considers relevant qualitative aspects in software development.

Evolution of XML schemas and documents from stereotyped UML class models: A traceable approach

Context: UML and XML are two of the most commonly used languages in software engineering processes. One of the most critical of these processes is that of model evolution and maintenance. More specifically, when an XML schema is modified, the changes should be propagated to the corresponding XML documents, which must conform with the new, modified schema. Objective: The goal of this paper is to provide an evolution framework by which the XML schema and documents are incrementally updated according to the changes in the conceptual model (expressed as a UML class model). In this framework, we include the transformation and evolution of UML profiles specified in UML class models because they are widely used to capture domain specific semantics. Method: We have followed a metamodeling approach which allowed us to achieve a language independent framework, not tied to the specific case of UML-XML. Besides, our proposal considers a traceability setting as a key aspect of the transformation process which allows changes to be propagated from UML class models to both XML schemas and documents. Results: As a general framework, we propose a Generic Evolution Architecture (GEA) for the model-driven engineering context. Within this architecture and for the particular case of the UML-to-XML setting, our contribution is a UML-to-XML framework that, to our knowledge, is the only approach that incorporates the following four characteristics. Firstly, the evolution tasks are carried out in a conceptual model. Secondly, our approach includes the transformation to XML of UML profiles. Thirdly, the proposal allows stereotyped UML class models to be evolved, propagating changes to XML schemas and documents in such a way that the different elements are kept in synch. Finally, we propose a traceability setting that enables evolution tasks to be performed seamlessly. Conclusions: Generic frameworks such as that proposed in this paper help to reduce the work overload experienced by software engineers in keeping different software artifacts synchronized.

A survey of UML models to XML schemas transformations

UML is being increasing used for the analysis and design of Web Information Systems. At the same time, many XML-based languages are cornerstones in the development of this kind of system. As a consequence of the predominance of these languages, there are many works in the literature devoted to exploring the relationships between UML and XML. In this paper we present a survey of current approaches to the transformation of UML models into XML schemas. The study is focused on the case of transformation of UML class diagrams to XML schemas, since we have not found any proposal regarding other kinds of UML diagrams.

Modeling issues: a survival guide for a non-expert modeler

While developing an integral security model to be used in a Service Oriented Architecture (SOA) context, we find a lot of ambiguities and inaccuracies when authors speak of models, metamodels, profiles and so on. This led us to study a great number of references in a search for precise definitions to help us to address our research. Our study and discussions were so extensive that we are convinced they will be a valuable contribution to the community. In particular, in this paper we present several Reference Concept Maps that depict graphically a large number of definitions with their associated bibliographical references. Nevertheless, we truly believe that there are still a lot of concepts to be clarified and that this clarification is essential so that basic modeling concepts can be best used by non-expert modelers.

Dynamic Semantics of UML State Machines: A Metamodeling Perspective

A clear understanding of the dynamic semantics of UML State Machines is essential for a large and varied audience such as final users of the language, CASE tool builders or method engineers. Our proposal aims at achieving such an understanding by suggesting a different metamodeling approach. This approach is based on a two-layer architecture which puts forward the explicit distinction between the generic behavior represented in a dynamic model (Base Layer) and the behavior represented in relation to a particular situation (Snapshot Layer). Using this architecture as a starting point, a metamodel of UML State Machines is proposed, which consists basically of two UML class diagrams (one diagram for each layer of the architecture) and two maps. These maps represent, respectively, the determination of the initial status and the process performed by a run-to-completion step as defined in the UML semantics.

Occurrence-Oriented Design Strategy for Developing Business Process Monitoring Systems

In a competitive market, business process improvement is a requirement for any organization. This improvement can only be achieved with the support of comprehensive systems that fully monitor business processes. We propose an occurrence - based approach to business process monitoring that provides a holistic perspective of system dynamics, lending support to evolution aspects. More specifically, we present a three-dimensional artifact, called Occurrence, in which structure, behavior, and guidance are considered simultaneously. Based on this, we define more complex structures, namely Occurrence Base and Occurrence Management System, which serve as scaffolding to develop business process monitoring systems. We also present a specific occurrence-based design strategy that, using an MDE approach, has been applied by our research group for the development of successful monitoring applications.

Model---Driven, View---Based Evolution of Relational Databases

Among other issues, database evolution includes the necessity of propagating the changes inside and between abstraction levels. There exist several mechanisms in order to carry out propagations from one level to another, that are distinguished on the basis of when and how the changes are performed. The strict mechanism, which implies the immediate realization of modifications, is a time---consuming process. In this paper we propose a solution that is closer to the lazy and logical mechanisms, in which changes are delayed or not finally realized, respectively. This solution makes use of the notion of view. The use of views allows the data not to be changed if it is not necessary and facilitates carrying out changes when required.

Model-driven development based transformation of stereotyped class diagrams to XML schemas in a healthcare context

The health sector uses clinical guidelines as instruments for helping decision making. We are interested in the development of a ubiquitous decision support system (UDSS) for clinical guidelines in order to help the medical staff in their decisions and in order to record a trace of the application of the guidelines. For the development of such a system in a Model-Driven Development (MDD) setting, we propose the use of class diagrams of the Unified Modeling Language (UML) with stereotypes and eXtensible Markup Language (XML) schemas. When both languages, UML and XML, have to share a common modelling space, the necessity of transforming UML models into XML schemas arises. However, to our knowledge, previous transformation proposals do not consider the case in which some profiles have been applied to the UML model. For this reason, in this paper we propose a set of rules for translating stereotyped UML class diagrams into XML schemas, storing a trace of the application of the guideline.