Extending UML templates towards flexibility

UML templates are generic model elements that may be instantiated as domain specific solutions by means of parameterization. Some of the elements in a template definition are marked as parameters, implying that these must be sub-stituted by elements of the domain model, so to get a fully functional instance of the template. On parameter substitutions, UML enforces that the parame-tered element and its substitute must be of the same kind (both classes, both at-tributes, etc.). This paper shows that this constraint confines the applicability of templates and proposes an alternative that, by allowing substitutions among elements of different kinds, broadens that applicability. Cross-kind substitu-tions, however, require adequate semantics for the Binding relationship. Such semantics are proposed as model transformations that must complement the plain substitutions preconized by UML. Examples of such transformations are provided for activities in a template being expanded into a bound element.info:eu-repo/semantics/publishedVersio

Extending UML templates towards flexibility (extended version)

Extended version of a research paper submitted to the 2nd Flexible MDE Workshop, FlexMDE 2016 (www.di.univaq.it/flexmde/).UML templates are generic model elements that may be instantiated as domain specific solutions by means of parameterization. Some of the elements in a tem-plate definition are marked as parameters, which must be substituted by conform-ing elements in the domain model to get a fully functional instance of the tem-plate. The validation of parameter substitutions enforces that the parametered ele-ment and its substitute must be of the same kind (both classes, both attributes, etc.). This paper shows that such imperative restrains the applicability of tem-plates and proposes an alternative set of constraints that, by allowing substitu-tions among elements of different kinds, widens that applicability. Cross-kind substitutions, however, require adequate semantics for the Binding relationship. Such semantics are proposed as model transformations that must complement the plain substitutions preconized by UML and are exemplified w.r.t. the instantiation of activity diagrams

Transformation As Search

In model-driven engineering, model transformations are con- sidered a key element to generate and maintain consistency between re- lated models. Rule-based approaches have become a mature technology and are widely used in different application domains. However, in var- ious scenarios, these solutions still suffer from a number of limitations that stem from their injective and deterministic nature. This article pro- poses an original approach, based on non-deterministic constraint-based search engines, to define and execute bidirectional model transforma- tions and synchronizations from single specifications. Since these solely rely on basic existing modeling concepts, it does not require the intro- duction of a dedicated language. We first describe and formally define this model operation, called transformation as search, then describe a proof-of-concept implementation and discuss experiments on a reference use case in software engineering

Extending UML templates towards computability

UML templates allow the specification of generic model elements that can be reproduced in domain models by means of the Bind relationship. Binding to a template encompasses the substitution of that template’s parameters by compatible domain elements. The requirement of compatibility, however, is checked over by UML in a very permissive way. As a consequence, binding to a template can result in badly-formed models and non-computable expressions. Such option in the design of UML was certainly intentional and meant to allow for richer semantics for the Bind relationship, as the specialization of the concept is advised at several points of the standard. This paper proposes one such specialization. One that guarantees well-formedness and computability for elements bound to a template. This is achieved by introducing the concept of Functional Conformance, which is imposed between every template’s parameter and its application domain substitute. Functional conformance is defined in terms of well-formedness rules, expressed as OCL constraints on top of OMG’s UML metamodel.info:eu-repo/semantics/acceptedVersio

The pros and cons of using SDL for creation of distributed services

In a competitive market for the creation of complex distributed services, time to market, development cost, maintenance and flexibility are key issues. Optimizing the development process is very much a matter of optimizing the technologies used during service creation. This paper reports on the experience gained in the Service Creation projects SCREEN and TOSCA on use of the language SDL for efficient service creation

Pattern Reification as the Basis for Description-Driven Systems

One of the main factors driving object-oriented software development for information systems is the requirement for systems to be tolerant to change. To address this issue in designing systems, this paper proposes a pattern-based, object-oriented, description-driven system (DDS) architecture as an extension to the standard UML four-layer meta-model. A DDS architecture is proposed in which aspects of both static and dynamic systems behavior can be captured via descriptive models and meta-models. The proposed architecture embodies four main elements - firstly, the adoption of a multi-layered meta-modeling architecture and reflective meta-level architecture, secondly the identification of four data modeling relationships that can be made explicit such that they can be modified dynamically, thirdly the identification of five design patterns which have emerged from practice and have proved essential in providing reusable building blocks for data management, and fourthly the encoding of the structural properties of the five design patterns by means of one fundamental pattern, the Graph pattern. A practical example of this philosophy, the CRISTAL project, is used to demonstrate the use of description-driven data objects to handle system evolution.Comment: 20 pages, 10 figure