Simulation of a distributed CORBA-based SCP

This paper examines load balancing issues relating to a distributed CORBA-based Service Control Point. Two types of load balancing strategies are explored through simulation studies: (i) a novel ant-based load balancing algorithm, which has been devised specically for this type of system. This algorithm is compared to more traditional algorithms, (ii) a method for optimal distribution of the computational objects composing the service programs. This is based on mathematically minimising the expected communication ows between network nodes and message-level processing costs. The simulation model has been based on the recently adopted OMG IN/CORBA Interworking specication and the TINA Service Session computational object model

Systematic composition of distributed objects: Processes and sessions

We consider a system with the infrastructure for the creation and interconnection of large numbers of distributed persistent objects. This system is exemplified by the Internet: potentially, every appliance and document on the Internet has both persistent state and the ability to interact with large numbers of other appliances and documents on the Internet. This paper elucidates the characteristics of such a system, and proposes the compositional requirements of its corresponding infrastructure. We explore the problems of specifying, composing, reasoning about and implementing applications in such a system. A specific concern of our research is developing the infrastructure to support structuring distributed applications by using sequential, choice and parallel composition, in the anarchic environment where application compositions may be unforeseeable and interactions may be unknown prior to actually occurring. The structuring concepts discussed are relevant to a wide range of distributed applications; our implementation is illustrated with collaborative Java processes interacting over the Internet, but the methodology provided can be applied independent of specific platforms

Component technologies: Java Beans, COM, CORBA, RMI, EJB and the CORBA component model

This one-day tutorial is aimed at software engineering practitioners and researchers, who are familiar with objectoriented analysis, design and programming and want to obtain an overview of the technologies that are enabling component-based development. We introduce the idea of component-based development by defining the concept and providing its economic rationale. We describe how object-oriented programming evolved into local component models, such as Java Beans and distributed object technologies, such as the Common Object Request Broker Architecture (CORBA), Java Remote Method Invocation (RMI) and the Component Object Model (COM). We then address how these technologies matured into distributed component models, in partiuclar Enterprise Java Beans (EJB) and the CORBA Component Model (CCM). We give an assessment of the maturity of each of these technologies and sketch how they are used to build distributed architectures

A Generic Deployment Framework for Grid Computing and Distributed Applications

Deployment of distributed applications on large systems, and especially on grid infrastructures, becomes a more and more complex task. Grid users spend a lot of time to prepare, install and configure middleware and application binaries on nodes, and eventually start their applications. The problem is that the deployment process is composed of many heterogeneous tasks that have to be orchestrated in a specific correct order. As a consequence, the automatization of the deployment process is currently very difficult to reach. To address this problem, we propose in this paper a generic deployment framework allowing to automatize the execution of heterogeneous tasks composing the whole deployment process. Our approach is based on a reification as software components of all required deployment mechanisms or existing tools. Grid users only have to describe the configuration to deploy in a simple natural language instead of programming or scripting how the deployment process is executed. As a toy example, this framework is used to deploy CORBA component-based applications and OpenCCM middleware on one thousand nodes of the French Grid5000 infrastructure.Comment: The original publication is available at http://www.springerlink.co

Component technologies: Java Beans, COM, CORBA, RMI, EJB and the CORBA component model

This one-day tutorial is aimed at software engineering practitioners and researchers, who are familiar with objectoriented analysis, design and programming and want to obtain an overview of the technologies that are enabling component-based development. We introduce the idea of component-based development by dening the concept and providing its economic rationale. We describe how objectoriented programming evolved into local component models, such as Java Beans and distributed object technologies, such as the Common Object Request Broker Architecture (CORBA), Java Remote Method Invocation (RMI) and the Component Object Model (COM). We then address how these technologies matured into distributed component models, in partiuclar Enterprise Java Beans (EJB) and the CORBA Component Model (CCM). We give an assessment of the maturity of each of these technologies and sketch how they are used to build distributed architectures

QoS Provisioning in CORBA by Introducing a Reflective Aspect-Oriented Transport Layer

Commercially available middleware systems today offer best-effort Quality-of-Service (QoS) to the application programs. Due to the natural limitation of resources and the differences between the priorities and demands of applications, middleware systems must have the capability to offer varying degrees of QoS. The QoS requirements of middleware applications can be monitored and fulfilled by configuring the middleware. This could be implemented, for example, by encapsulating the specific QoS concerns of middleware within the components and by installing the most suitable component on a particular QoS demand. Unfortunately, not all the QoS concerns of a distributed system can be defined and encapsulated by the interfaces of components. So-called crosscutting aspects hinder the adaptation of middleware systems since the implementations of QoS support techniques cannot be restricted to the implementations of components. We propose a reflective and aspect-oriented technique based on the principle of Composition-Filters to address this problem

Platform-independent Dynamic Reconfiguration of Distributed Applications

The aim of dynamic reconfiguration is to allow a system to evolve incrementally from one configuration to another at run-time, without restarting it or taking it offline. In recent years, support for transparent dynamic reconfiguration has been added to middleware platforms, shifting the complexity required to enable dynamic reconfiguration to the supporting infrastructure. These approaches to dynamic reconfiguration are mostly platform-specific and depend on particular implementation approaches suitable for particular platforms. In this paper, we propose an approach to dynamic reconfiguration of distributed applications that is suitable for application implemented on top of different platforms. This approach supports a platform-independent view of an application that profits from reconfiguration transparency. In this view, requirements on the ability to reconfigure components are expressed in an abstract manner. These requirements are then satisfied by platform-specific realizations

Aspect-Oriented Programming using Composition-Filters

Software engineers may experience problems in modeling certain aspects while applying object-oriented techniques [4, 10, 11]. Composition-Filters are capable of expressing various different kinds of aspects in a uniform manner. These aspects are, for example, inheritance and delegation [1] and atomic delegation [2], multiple views, dynamic inheritance and queries on objects [3], coordinated behavior and inter-object constraints [5], real-time [6] and composing real-time and synchronization together [9], synchronization [8] and distributed synchronization [7], and client-server architectures [10]

Modular and composable extensions to smalltalk using composition filters

Current and future trends in computer science require extensions to Smalltalk. Rather than arguing for particular language mechanisms to deal with specific requirements, in this position paper we want to make a case for two requirements that Smalltalk extensions should fulfill. The first is that the extensions must be integrated with Smalltalk without violating its basic object model. The second requirement is that extensions should allow for defining objects that are still adaptable, extensible and reusable, and in particular do not cause inheritance anomalies. We propose the composition filters model as a framework for language extensions that fulfills these criteria. Its applicability to solving various modeling problems is briefly illustrated