Monitoring extensions for component-based distributed software

This paper defines a generic class of monitoring extensions to component-based distributed enterprise software. Introducing a monitoring extension to a legacy application system can be very costly. In this paper, we identify the minimum support for application monitoring within the generic components of a distributed system, necessary for rapid development of new monitoring extensions. Furthermore, this paper offers an approach for design and implementation of monitoring extensions at reduced cost. A framework of basic facilities supporting the monitoring extensions is presented. These facilities handle different aspects critical to the monitoring process, such as ordering of the generated monitoring events, decoupling of the application components from the components of the monitoring extensions, delivery of the monitoring events to multiple consumers, etc.\ud The work presented in this paper is being validated in the prototype of a large distributed system, where a specific monitoring extension is built as a tool for debugging and testing the application behaviour.\u

Flexible programmable networking: A reflective, component-based approach

The need for programmability and adaptability in networking systems is becoming increasingly important. More specifically, the challenge is in the ability to add services rapidly, and be able to deploy, configure and reconfigure them as easily as possible. Such demand is creating a considerable shift in the way networks are expected to operate in the future. This is the main aim of programmable networking research community, and in our project we are investigating a component-based approach to the structuring of programmable networking software. Our intention is to apply the notion of components, component frameworks and reflection ubiquitously, thus accommodating all the different elements that comprise a programmable networking system

UM ESTUDO COMPARATIVO ENTRE SOLUÇÕES DE MIDDLEWARES REFLEXIVOS PARA APLICAÇÕES DE ALTA DINAMICIDADE: ESTADO DA ARTE E DESAFIOS DE PESQUISA

The monolithic characteristic of the first middleware platforms makes the self-adaptation impossible, since the middleware is not capable of access and change applications or their own internal structures. The inspection and dynamic adaptation capability may be achieved through the usage of more flexible middleware solutions based on reflexive computing. In this article, we aim to present the main solutions of reflexive middleware that provides the inspection and adaptation of applications with high level of dynamicity, and also identify the main research challenges of construction and usage of this middleware category.A característica monolítica das primeiras plataformas de middleware impossibilita a auto-adaptação, uma vez que o middleware não é capaz de acessar ou modificar sua própria estrutura interna ou das aplicações. A capacidade de inspeção e adaptação dinâmica pode ser conseguida através do uso de soluções de middlewares mais flexíveis, baseados em reflexão computacional. O objetivo deste artigo é apresentar as principais soluções de middlewares reflexivos que possibilitam a inspeção e a adaptação de aplicações com alto grau de dinamicidade, bem como identificar os principais desafios de pesquisa na construção e no uso desta categoria de middleware

A comparative analysis of adaptive middleware architectures based on computational reflection and aspect oriented programming to support mobile computing applications

Mobile computing applications are required to operate in environments in which the availability for resources and services may change significantly during system operation. As a result, mobile computing applications need to be capable of adapting to these changes to offer the best possible level of service to their users. However, traditional middleware is limited in its capability of adapting to environment changes and different users requirements. Computational Reflection and Aspect Oriented Programming paradigms have been used in the design and implementation of adaptive middleware architectures. In this paper, we propose two adaptive middleware architectures, one based on reflection and other based on aspects, which can be used to develop adaptive mobile applications. The reflection based architecture is compared to an aspect oriented based architecture from a quantitative perspective. The results suggest that middleware based on Aspect Oriented Programming can be used to build mobile adaptive applications that require less processor running time and more memory space than Computational Reflection while producing code that is easier to comprehend and modify.8th IFIP/IEEE International conference on Mobile and Wireless CommunicationRed de Universidades con Carreras en Informática (RedUNCI

Fine Grained Component Engineering of Adaptive Overlays: Experiences and Perspectives

Recent years have seen significant research being carried out into peer-to-peer (P2P) systems. This work has focused on the styles and applications of P2P computing, from grid computation to content distribution; however, little investigation has been performed into how these systems are built. Component based engineering is an approach that has seen successful deployment in the field of middleware development; functionality is encapsulated in ‘building blocks’ that can be dynamically plugged together to form complete systems. This allows efficient, flexible and adaptable systems to be built with lower overhead and development complexity. This paper presents an investigation into the potential of using component based engineering in the design and construction of peer-to-peer overlays. It is highlighted that the quality of these properties is dictated by the component architecture used to implement the system. Three reusable decomposition architectures are designed and evaluated using Chord and Pastry case studies. These demonstrate that significant improvements can be made over traditional design approaches resulting in much more reusable, (re)configurable and extensible systems

GRIDKIT: Pluggable overlay networks for Grid computing

A `second generation' approach to the provision of Grid middleware is now emerging which is built on service-oriented architecture and web services standards and technologies. However, advanced Grid applications have significant demands that are not addressed by present-day web services platforms. As one prime example, current platforms do not support the rich diversity of communication `interaction types' that are demanded by advanced applications (e.g. publish-subscribe, media streaming, peer-to-peer interaction). In the paper we describe the Gridkit middleware which augments the basic service-oriented architecture to address this particular deficiency. We particularly focus on the communications infrastructure support required to support multiple interaction types in a unified, principled and extensible manner-which we present in terms of the novel concept of pluggable overlay networks

Towards Adaptable and Adaptive Policy-Free Middleware

We believe that to fully support adaptive distributed applications, middleware must itself be adaptable, adaptive and policy-free. In this paper we present a new language-independent adaptable and adaptive policy framework suitable for integration in a wide variety of middleware systems. This framework facilitates the construction of adaptive distributed applications. The framework addresses adaptability through its ability to represent a wide range of specific middleware policies. Adaptiveness is supported by a rich contextual model, through which an application programmer may control precisely how policies should be selected for any particular interaction with the middleware. A contextual pattern mechanism facilitates the succinct expression of both coarse- and fine-grain policy contexts. Policies may be specified and altered dynamically, and may themselves take account of dynamic conditions. The framework contains no hard-wired policies; instead, all policies can be configured.Comment: Submitted to Dependable and Adaptive Distributed Systems Track, ACM SAC 200

Reconfigurations dynamiques de services dans un intergiciel à composants CORBA CCM

International audienceToday, component oriented middlewares are used to design, develop and deploy easily distributed applications, by ensuring the heterogeneity, interoperability, and reuse of the software modules, and the separation between the business code encapsulated in the components and the system code managed by the containers. Several standards answer this definition such as: CCM (CORBA Component Model), EJB (Enterprise Java Beans) and .Net. However these standards offer a limited and fixed number of system services, removing any possibility to add system services or to reconfigure dynamically the middleware. Our works propose mechanisms to add and to adapt dynamically the system services, based on a reconfiguration language which is dynamically adaptable to the need of the reconfiguration, and on a tool of dynamic reconfiguration, a prototype was achieved for the OpenCCM platform, that is an implementation of the CCM specification. This work was partially financed by the european project IST-COACH (2001-34445).De nos jours, les intergiciels à composants sont utilisés pour concevoir, développer, et déployer facilement les applications réparties, et assurer l'hétérogénéité, et l'interopérabilité, ainsi que la réutilisation des modules logiciels, et la séparation entre le code métier encapsulé dans des composants et le code système géré par les conteneurs. De nombreux standards répondent à cette définition tels: CCM (CORBA Component Model), EJB (Entreprise Java Beans) et .NET. Cependant ces standards offrent un nombre limité et figé de services systèmes, supprimant ainsi toute possibilité d'ajout de services systèmes ou de reconfiguration dynamiques de l'intergiciel. Nos travaux proposent des mécanismes d'ajout et d'adaptation dynamique des services systèmes, basés sur un langage de reconfiguration adaptable dynamiquement aux besoins de la reconfiguration et sur un outil de reconfiguration dynamique. Un prototype a été réalisé pour la plateforme OpenCCM, qui est une implémentation de la spécification CCM de l'OMG. Ce travail a été partiellement financé par le projet européen IST-COACH (2001-34445)