Component Based Development has emerged as economical, reusable, scalable way of developing enterprise as well as embedded software applications. Testing distributed component based systems is difficult when third party components are being used in the development. Many testing methodologies that have been proposed for testing object oriented programs in the literature are being imported into component domain directly or by tuning them. But testing components involves much manual work due to the lack of information of the component. Middleware architectures like, DCOM(Distributed COM), Jini and CORBA(Common Object Request Broker Architecture) are being used in developing the distributed component applications in different vertical domains. In this thesis, a language- Distributed Object Testing Language(DOTL) for specifying the testing process and generation of distributed testing environment for CORBA based applications has been proposed. The language captures required semantics for specifying dummy servers, clients, controlling the testing process, generation of test cases, activating and deactivating objects. Many existing testing techniques can be specified using the semantics provided by the language. Faults occurring in distributed object systems, in addition to the functional errors, can be identifiable using the tool. The language provides abstract types object, argument to specify variables in the testing environment, and operations dealing with these variables to conducts necessary tests. The DOTL has been implemented on MICO(Mico Is CORBA) orb on Linux OS, with mapping of DOTL to CORBA C++.

Currently, several mature and commercial component models (for e.g. EJB, .NET, COM+) exist on the market. These technologies were designed largely for applications with business-oriented non-functional requirements such as data persistence, confidentiality, and transactional support. They provide only limited support for the development of components and applications with non-functional properties (NFPs) like QoS (e.g. throughput, response time). The integration of QoS into component infrastructure requires among other things the support of components’ QoS contract specification, negotiation, adaptation, etc. This thesis focuses on contract negotiation. For applications in which the consideration of non-functional properties (NFPs) is essential (e.g. Video-on-Demand, eCommerce), a component-based solution demands the appropriate composition of the QoS contracts specified at the different ports of the collaborating components. The ports must be properly connected so that the QoS level required by one is matched by the QoS level provided by the other. Generally, QoS contracts of components depend on run-time resources (e.g. network bandwidth, CPU time) or quality attributes to be established dynamically and are usually specified in multiple QoS-Profiles. QoS contract negotiation enables the selection of appropriate concrete QoS contracts between collaborating components. In our approach, the component containers perform the contract negotiation at run-time. This thesis addresses the QoS contract negotiation problem by first modelling it as a constraint satisfaction optimization problem (CSOP). As a basis for this modelling, the provided and required QoS as well as resource demand are specified at the component level. The notion of utility is applied to select a good solution according to some negotiation goal (e.g. user’s satisfaction). We argue that performing QoS contract negotiation in multiple phases simplifies the negotiation process and makes it more efficient. Based on such classification, the thesis presents heuristic algorithms that comprise coarse-grained and fine-grained negotiations for collaborating components deployed in distributed nodes in the following scenarios: (i) single-client - single-server, (ii) multiple-clients, and (iii) multi-tier scenarios. To motivate the problem as well as to validate the proposed approach, we have examined three componentized distributed applications. These are: (i) video streaming, (ii) stock quote, and (iii) billing (to evaluate certain security properties). An experiment has been conducted to specify the QoS contracts of the collaborating components in one of the applications we studied. In a run-time system that implements our algorithm, we simulated different behaviors concerning: (i) user’s QoS requirements and preferences, (ii) resource availability conditions concerning the client, server, and network bandwidth, and (iii) the specified QoS-Profiles of the collaborating components. Under various conditions, the outcome of the negotiation confirms the claim we made with regard to obtaining a good solution.

In this thesis we present a novel approach to the analysis of dependency graphs of object-oriented programs, and we describe a tool that has been implemented for this purpose. A graph-theoretical clustering algorithm is used in order to compute the modular structure of programs. This can be used to assist software engineers to redraw component boundaries in software in order to improve the level of reuse and maintainability. The analysis of the dependency graph of an object-oriented program is useful for assessing the quality of software design. The dependency graph can be extracted from a program using various different methods, including source code, byte code, and dynamic (behavioral) analysis. The nodes in the dependency graph are classes, members, packages and other artifacts, while the edges represent uses and extends relationships between those artifacts. Once the dependency graph has been extracted, it can be analysed in order to quantify certain characteristics of the respective program. Examples include the detection of circular dependencies and measurements of the responsibility or independence of units based on their relationships. Tools like JDepend1 implementing these principles have become very popular in recent years. Our work includes grouping types in dependency graphs using di erent clustering methods: Grouping into namespaces; Grouping into clusters using graph clustering algorithms; Grouping into clusters using rules. The detected mismatches are candidates for refactoring. We have developed a tool for processing dependency graphs clustering and producing results where users can outline possible design violations.

The increasing complexity in the development of a configurable real-time system has emerged new principles of software techniques, such as aspect-oriented software development and component-based software development. These techniques allow encapsulation of the system's crosscutting concerns and increase the modularity of the software. The properties of a component that influences the systems performance or semantics are specified separately in entities called aspects, while basic functionality of the property still remains in the component. When building a real-time system, different sets of configurations of aspects and components can be combined, resulting in different configurations of the system. The temporal behavior of the system changes and a way to ensure the predictability of the system is needed. This thesis presents a tool for aspect-level worst-case execution time analysis, which gives a priori information about the temporal behavior of the system, before the process of composing aspects with components.

Rising complexity in the development of real-time systems has made it crucial to have reusable components and a more flexible way of configuring these components into a coherent system. Aspect-oriented system development (AOSD) is a technique that allows one to put a system’s crosscutting concerns into"modules"that are called aspects. Applying AOSD in real-time and embedded system development one can expect reductions in the complexity of the system design and development. A problem with AOSD in its current form is that it does not support predictability in the time domain. Hence, in order to use AOSD in real-time system development, we need to provide ways of analyzing temporal behavior of aspects, components and resulting system (made from weaving aspects and components). Aspect analyzer is a tool that computes the worst-case execution time (WCET) for a set of components and aspects, thus, enabling support for predictability in the time domain of aspect-oriented real-time software. A limitation of the aspect analyzer, until now, were that no verification had been made whether the aspect analyzer would produce WCET values that were close to the measured or computed (with another WCET analysis technique) WCET of an aspect-oriented real-time system. Therefore, in this thesis we perform a verification of the correctness of the aspect analyzer using a number of different methods for WCET analysis. These investigations of the correctness of the output from the aspect analyzer gave confidence to the automated WCET analysis. In addition, performing this verification led to the identification of the steps necessary to compute the WCETs of a piece of program, when using a third party tool, which gives the ability to write accurate input files for the aspect analyzer.

During the last years the need for real-time database services has increased due to the growing number of data-intensive applications needing to enforce real-time constraints. The COMponent-based Embedded real-Time database (COMET) is a real-time database developed to meet these demands. COMET is developed using the AspeCtual COmponent-based Real-time system Development (ACCORD) design method, and consists of a number of components and aspects, which can be composed into a number of different configurations depending on system demands, e.g., Quality of Service (QoS) management can be used in unpredictable environments. In embedded systems with requirementson high up-time it may not be possible to temporarily shut down the system for reconfiguration. Instead it is desirable to enable dynamic reconfiguration of the system, exchanging components during run-time. This in turn sets demands on the feedback control of the system to adjust to these new conditions, since a new time variant system has been created. This thesis project implements improvements in COMET to create a more stable database suitable for further development. A mechanism for dynamic reconfiguration of COMET is implemented, thus, enabling components and aspects to be swapped during run-time. Adaptive feedback control algorithms are also implemented in order to better adjust to workload variations and database reconfiguration.

Game development presents more challenges as this type of software becomes more complex and detailed. As in the development of traditional software, this growth in scope incurs in a development process that costs more and has a longer production time, increasing the risks faced by companies that wish to enter or maintain themselves in the electronic game market. With this, it becomes increasingly desirable to search and implement tools that allow for the reduction of required resources to develop games. It is also noticeable that there is an increasing need to proved development teams with new tools that allow faster creation of prototypes, enabling them to test and evolve new game ideas in a nimbler and less expensive way. This work presents the project and implementation of a modular platform that aims to solve or lessen the aforementioned problems, offering a tool that allows for the development of games with reduced costs, in addition to simplifying the quick prototyping process. Through the use of a programming approach based on reusable software components written in different programming languages, this work aims to enable methodologies that are able to foster code reuse, to facilitate team work, to reduce development time and to improve the quality of the final product. / O desenvolvimento de jogos apresenta mais desafios à medida que softwares desse tipo tornam-se mais complexos e detalhados. Assim como no desenvolvimento de softwares tradicionais, esse crescimento do escopo incorre em custos maiores e prazos de produção mais longos, aumentando os riscos enfrentados por empresas do ramo que buscam situar-se ou manter-se no mercado de jogos eletrônicos. Com isso, torna-se cada vez mais desejável buscar e implementar formas de desenvolvimento que possibilitem a redução de recursos necessários para a produção desse tipo de software. Também se observa um aumento da necessidade de disponibilizar às equipes de desenvolvimento novas ferramentas que possibilitem a criação mais rápida de protótipos, permitindo testar e evoluir novas ideias de jogos de forma mais ágil e menos onerosa. Este trabalho trata do projeto e da implementação de uma plataforma modular que objetiva a resolução ou amenização dos problemas citados, oferecendo uma ferramenta que possibilite o desenvolvimento de jogos com custo reduzido, além de simplificar o processo de prototipação rápida. Através do uso de uma abordagem de programação baseada no uso de componentes de software reaproveitáveis escritos em diferentes linguagens de programação, este trabalho busca tornar possível metodologias que sejam capazes de incentivar o reuso de código, facilitar o trabalho em equipe, reduzir o tempo de desenvolvimento e melhorar a qualidade do produto final.

In dem Beitrag wird zunächst kurz die Funktionalität des Forschungsprototyps cofis.net, einem Informationssystem für Virtuelle Finanzdienstleister, vorgestellt und ein Einblick in seine Entwicklungsgeschichte gewährt. Anschließend wird ein Überblick über die Fachkomponenten des Informationssystems geben. Die Fachkomponenten von cofis.net wurden auf Basis des Memorandums zur Vereinheitlichung der Spezifikation von Fachkomponenten des Arbeitskreises 5.10.3: Komponentenorientierte betriebliche Anwendungssysteme der Gesellschaft für Informatik spezifiziert. Auszüge aus der erstellten Spezifikation werden vorgestellt. Darüber hinaus werden Erfahrungen, die bei der Spezifikation gemacht worden sind, sowie dabei identifizierte Problembe-reiche dargelegt. Abgerundet wird die Fallstudie durch Empfehlungen, die Hinweise zur Weiter-entwicklung des Memorandums beschreiben.

Currently, several mature and commercial component models (for e.g. EJB, .NET, COM+) exist on the market. These technologies were designed largely for applications with business-oriented non-functional requirements such as data persistence, confidentiality, and transactional support. They provide only limited support for the development of components and applications with non-functional properties (NFPs) like QoS (e.g. throughput, response time). The integration of QoS into component infrastructure requires among other things the support of components’ QoS contract specification, negotiation, adaptation, etc. This thesis focuses on contract negotiation. For applications in which the consideration of non-functional properties (NFPs) is essential (e.g. Video-on-Demand, eCommerce), a component-based solution demands the appropriate composition of the QoS contracts specified at the different ports of the collaborating components. The ports must be properly connected so that the QoS level required by one is matched by the QoS level provided by the other. Generally, QoS contracts of components depend on run-time resources (e.g. network bandwidth, CPU time) or quality attributes to be established dynamically and are usually specified in multiple QoS-Profiles. QoS contract negotiation enables the selection of appropriate concrete QoS contracts between collaborating components. In our approach, the component containers perform the contract negotiation at run-time. This thesis addresses the QoS contract negotiation problem by first modelling it as a constraint satisfaction optimization problem (CSOP). As a basis for this modelling, the provided and required QoS as well as resource demand are specified at the component level. The notion of utility is applied to select a good solution according to some negotiation goal (e.g. user’s satisfaction). We argue that performing QoS contract negotiation in multiple phases simplifies the negotiation process and makes it more efficient. Based on such classification, the thesis presents heuristic algorithms that comprise coarse-grained and fine-grained negotiations for collaborating components deployed in distributed nodes in the following scenarios: (i) single-client - single-server, (ii) multiple-clients, and (iii) multi-tier scenarios. To motivate the problem as well as to validate the proposed approach, we have examined three componentized distributed applications. These are: (i) video streaming, (ii) stock quote, and (iii) billing (to evaluate certain security properties). An experiment has been conducted to specify the QoS contracts of the collaborating components in one of the applications we studied. In a run-time system that implements our algorithm, we simulated different behaviors concerning: (i) user’s QoS requirements and preferences, (ii) resource availability conditions concerning the client, server, and network bandwidth, and (iii) the specified QoS-Profiles of the collaborating components. Under various conditions, the outcome of the negotiation confirms the claim we made with regard to obtaining a good solution.

Increasing complexity of real-time systems and demands for enabling their configurability and tailorability are strong motivations for applying new software engineering principles such as aspect-oriented and component-based software development. The integration of these two techniques into real-time systems development would enable: (i) efficient system configuration from the components in the component library based on the system requirements, (ii) easy tailoring of components and/or a system for a specific application by changing the behavior (code) of the component by aspect weaving, and (iii) enhanced flexibility of the real-time and embedded software through the notion of system configurability and component tailorability. In this thesis we focus on applying aspect-oriented and component-based software development to real-time system development. We propose a novel concept of aspectual component-based real-time system development (ACCORD). ACCORD introduces the following into real-time system development: (i) a design method that assumes the decomposition of the real-time system into a set of components and a set of aspects, (ii) a real-time component model denoted RTCOM that supports aspect weaving while enforcing information hiding, (iii) a method and a tool for performing worst-case execution time analysis of different configurations of aspects and components, and (iv) a new approach to modelling of real-time policies as aspects. We present a case study of the development of a configurable real-time database system, called COMET, using ACCORD principles. In the COMET example we show that applying ACCORD does have an impact on the real-time system development in providing efficient configuration of the real-time system. Thus, it could be a way for improved reusability and flexibility of real-time software, and modularization of crosscutting concerns. In connection with development of ACCORD, we identify criteria that a design method for component-based real-time systems needs to address. The criteria include a well-defined component model for real-time systems, aspect separation, support for system configuration, and analysis of the composed real-time system. Using the identified set of criteria we provide an evaluation of ACCORD. In comparison with other approaches, ACCORD provides a distinct classification of crosscutting concerns in the real-time domain into different types of aspects, and provides a real-time component model that supports weaving of aspects into the code of a component, as well as a tool for temporal analysis of the weaved system. / <p>Report code: LiU-TEK-LIC-2003:23.</p>