Adaptive object management for distributed systems

This thesis describes an architecture supporting the management of pluggable software components and evaluates it against the requirement for an enterprise integration platform for the manufacturing and petrochemical industries. In a distributed environment, we need mechanisms to manage objects and their interactions. At the least, we must be able to create objects in different processes on different nodes; we must be able to link them together so that they can pass messages to each other across the network; and we must deliver their messages in a timely and reliable manner. Object based environments which support these services already exist, for example ANSAware(ANSA, 1989), DEC's Objectbroker(ACA,1992), Iona's Orbix(Orbix,1994)Yet such environments provide limited support for composing applications from pluggable components. Pluggability is the ability to install and configure a component into an environment dynamically when the component is used, without specifying static dependencies between components when they are produced. Pluggability is supported to a degree by dynamic binding. Components may be programmed to import references to other components and to explore their interfaces at runtime, without using static type dependencies. Yet thus overloads the component with the responsibility to explore bindings. What is still generally missing is an efficient general-purpose binding model for managing bindings between independently produced components. In addition, existing environments provide no clear strategy for dealing with fine grained objects. The overhead of runtime binding and remote messaging will severely reduce performance where there are a lot of objects with complex patterns of interaction. We need an adaptive approach to managing configurations of pluggable components according to the needs and constraints of the environment. Management is made difficult by embedding bindings in component implementations and by relying on strong typing as the only means of verifying and validating bindings. To solve these problems we have built a set of configuration tools on top of an existing distributed support environment. Specification tools facilitate the construction of independent pluggable components. Visual composition tools facilitate the configuration of components into applications and the verification of composite behaviours. A configuration model is constructed which maintains the environmental state. Adaptive management is made possible by changing the management policy according to this state. Such policy changes affect the location of objects, their bindings, and the choice of messaging system

Advances in component-oriented programming

WCOP 2006 is the eleventh event in a series of highly successful workshops, which took place in conjunction with every ECOOP since 1996. Component oriented programming (COP) has been described as the natural extension of object-oriented programming to the realm of independently extensible systems. Several important approaches have emerged over the recent years, including component technology standards, such as CORBA/CCM, COM/COM+, J2EE/EJB, and .NET, but also the increasing appreciation of software architecture for component-based systems, and the consequent effects on organizational processes and structures as well as the software development business as a whole. COP aims at producing software components for a component market and for late composition. Composers are third parties, possibly the end users, who are not able or willing to change components. This requires standards to allow independently created components to interoperate, and specifications that put the composer into the position to decide what can be composed under which conditions. On these grounds, WCOP\u2796 led to the following definition: "A component is a unit of composition with contractually specified interfaces and explicit context dependencies only. Components can be deployed independently and are subject to composition by third parties." After WCOP\u2796 focused on the fundamental terminology of COP, the subsequent workshops expanded into the many related facets of component software. WCOP 2006 emphasizes reasons for using components beyond reuse. While considering software components as a technical means to increase software reuse, other reasons for investing into component technology tend to be overseen. For example, components play an important role in frameworks and product-lines to enable configurability (even if no component is reused). Another role of components beyond reuse is to increase the predictability of the properties of a system. The use of components as contractually specified building blocks restricts the degrees of freedom during software development compared to classic line-by-line programming. This restriction is beneficial for the predictability of system properties. For an engineering approach to software design, it is important to understand the implications of design decisions on a system\u27s properties. Therefore, approaches to evaluate and predict properties of systems by analyzing its components and its architecture are of high interest. To strengthen the relation between architectural descriptions of systems and components, a comprehensible mapping to component-oriented middleware platforms is important. Model-driven development with its use of generators can provide a suitable link between architectural views and technical component execution platforms. WCOP 2006 accepted 13 papers, which are organised according to the program below. The organisers are looking forward to an inspiring and thought provoking workshop. The organisers thank Jens Happe and Michael Kuperberg for preparing the proceedings volume

Component-based software engineering: a quantitative approach

Dissertação apresentada para a obtenção do Grau de Doutor em Informática pela Universidade Nova de Lisboa, Faculdade de Ciências e TecnologiaBackground: Often, claims in Component-Based Development (CBD) are only supported by qualitative expert opinion, rather than by quantitative data. This contrasts with the normal practice in other sciences, where a sound experimental validation of claims is standard practice. Experimental Software Engineering (ESE) aims to bridge this gap. Unfortunately, it is common to find experimental validation efforts that are hard to replicate and compare, to build up the body of knowledge in CBD. Objectives: In this dissertation our goals are (i) to contribute to evolution of ESE, in what concerns the replicability and comparability of experimental work, and (ii) to apply our proposals to CBD, thus contributing to its deeper and sounder understanding. Techniques: We propose a process model for ESE, aligned with current experimental best practices, and combine this model with a measurement technique called Ontology-Driven Measurement (ODM). ODM is aimed at improving the state of practice in metrics definition and collection, by making metrics definitions formal and executable,without sacrificing their usability. ODM uses standard technologies that can be well adapted to current integrated development environments. Results: Our contributions include the definition and preliminary validation of a process model for ESE and the proposal of ODM for supporting metrics definition and collection in the context of CBD. We use both the process model and ODM to perform a series experimental works in CBD, including the cross-validation of a component metrics set for JavaBeans, a case study on the influence of practitioners expertise in a sub-process of component development (component code inspections), and an observational study on reusability patterns of pluggable components (Eclipse plug-ins). These experimental works implied proposing, adapting, or selecting adequate ontologies, as well as the formal definition of metrics upon each of those ontologies. Limitations: Although our experimental work covers a variety of component models and, orthogonally, both process and product, the plethora of opportunities for using our quantitative approach to CBD is far from exhausted. Conclusions: The main contribution of this dissertation is the illustration, through practical examples, of how we can combine our experimental process model with ODM to support the experimental validation of claims in the context of CBD, in a repeatable and comparable way. In addition, the techniques proposed in this dissertation are generic and can be applied to other software development paradigms.Departamento de Informática of the Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa (FCT/UNL); Centro de Informática e Tecnologias da Informação of the FCT/UNL; Fundação para a Ciência e Tecnologia through the STACOS project(POSI/CHS/48875/2002); The Experimental Software Engineering Network (ESERNET);Association Internationale pour les Technologies Objets (AITO); Association forComputing Machinery (ACM

INForum 2017: Atas do Nono Simpósio de Informática

Este volume contém as atas da 9.a edição do Simpósio em Informática, INForum 2017, a qual decorreu no Pavilhão de Exposições de Aveiro, em Aveiro, conjuntamente com o TechDays 2017, nos dias 12 e 13 de outubro de 2017. (...