Towards an aspect weaving BPEL engine

This position paper proposes the use of dynamic aspects and the visitor design pattern to obtain a highly configurable and extensible BPEL engine. Using these two techniques, the core of this infrastructural software can be customised to meet new requirements and add features such as debugging, execution monitoring, or changing to another Web Service selection policy. Additionally, it can easily be extended to cope with customer-specific BPEL extensions. We propose the use of dynamic aspects not only on the engine itself but also on the workflow in order to tackle the problems of Web Service hot deployment and hot fixes to long running processes. In this way, composing aWeb Service "on-the-fly" means weaving its choreography interface into the workflow

A qualitative assessment of modularity in CaesarJ components based on implementations of design patterns

Tese de Mestrado em Engenharia InformáticaThe advent of the Aspect-Oriented Programming (AOP) paradigm brought new features and mechanisms to support the separation of crosscutting concerns, in order to develop programs with higher modularity and consequently, higher reuse. As the paradigm matures, various aspectoriented programming languages appeared that propose varying ways to realize the paradigm’s concepts. CaesarJ is one of those aspect-oriented languages. While the majority of practical studies on AOP languages focused on the AspectJ language, the characteristics of other languages such as CaesarJ remain to be explored. The lack of research on the utilization of CaesarJ in concrete cases leads to the existence of few case studies from which to draw considerations about their strengths and shortcomings. In the past, implementations of design patterns have been used for the demonstration of the characteristics of the programming languages used to implement them. This dissertation follows a similar approach to assess CaesarJ’s support for modularity and reuse by producing CaesarJ design patterns implementations and subjecting those implementations to a qualitative analysis. This dissertation presents CaesarJ implementations of eleven Gang-of-Four pattern that serve as the basis for a qualitative analysis of the modularity degree CaesarJ enables for each pattern. A distinction is made between four levels of module reuse that the implementations support, in order to differentiate between the several levels of reuse achieved. A comparison is drawn to analogue design pattern implementations in AspectJ. Finally, general guidelines for the implementation of CaesarJ components are described

A Domain Specific Graphical User Interface Framework

Since the early days of software development, there has been an ongoing trend towards higher-order or higher level abstractions in programming languages, software libraries and application frameworks. Some of the arguments for software development tools with higher levels of abstraction include simpler software development, improved portability and better maintainability. Higher level abstractions can however lead to reduced performance. This thesis presents an innovative graphical user interface software solution that mixes high-level and low-level approaches to achieve acceptable performance while retaining good maintainability. The solution is an extension to a graphical application framework called JavaFX. The scope of this thesis is defined by a software development project which goal is to create a graphical user interface framework. The framework is used in the creation of customer specific user interfaces for an accompanying intralogistics system. The resulting user interfaces must be able to visualize possibly thousands of objects moving on a factory floor. The views must simultaneously support user-initiated zooming, panning, and tilting of the two-dimensional view. Meeting these requirements while maintaining acceptable performance, requires an unconventional solution and a deviation from idiomatic JavaFX. The user interface framework in question is developed using a high-level graphical user interface application framework called JavaFX. JavaFX is the most recent graphical user interface toolkit included in the official Java Development Kit. It has many reactive traits and other modern high-level properties. Overcoming performance challenges with JavaFX when producing views with thousands of animated items was the key research challenge in this research. Some attention is also given to replacing JavaFX built-in dependency injection system with Spring framework to improve JavaFX suitability to the task at hand. This thesis presents a hybrid solution that overcomes JavaFX’s performance challenges in the problem domain, while retaining as much as possible of the usefulness of the high-level features present in the JavaFX framework. The key innovation is a mechanism that enables automated rendering of sprite-bitmaps from JavaFX scene-graph nodes. The solution includes a system that draws the automatically generated bitmaps to a lower-level JavaFX component called Canvas. The solution enables layered mixing of regular JavaFX views with the custom high-performance views, including seamless resizing and event handling between the two types of views. The solution enables the developers of customer specific user interfaces to choose an appropriate graphics rendering type, such that only objects that cause performance issues, typically items which number exceeds dozens, need to use the more complex high-performance system

An Empirical Assessment of the Software Design Pattern Concept

Context: The publication of the milestone textbook on design patterns by the ‘Gang of Four’ (GoF) in 1995, introduced a set of 23 design patterns that are largely concerned with improving the practices and products of software development. However, there has been no comprehensive assessment of the effectiveness of design patterns, nor is there any evidence about any claims and factors that are made for pattern reuse in software development. Aims: The aims of this thesis are to assess the design patterns systematically in a sequence of studies, and to identify the claims and factors to determine how well they reflect experiences of pattern reuse in practice. Method: This thesis describes four studies: a document survey to identify claims for patterns, a mapping study to identify empirical studies about patterns, an online survey, and a narrative synthesis. The mapping study and the online survey together provide quite comprehensive and thorough evidence for the narrative synthesis. In the narrative synthesis, we check whether there is any consistency or not in the evidence about specific patterns, and also to see how the claims and factors influence pattern reuse. Results: The mapping study found 20 primary studies, and the online survey had 206 usable responses. In the 20 primary study of the mapping study 17 design patterns were examined. In the online survey 175 respondents considered patterns were useful, and 155 respondents reported on patterns that they considered not to be useful. Conclusion: From the synthesis results, the specific patterns Composite and Observer are evaluated as being generally useful, but the Visitor and Singleton patterns, while useful, have possible negative aspects. And also four of the claims and the effect of one factor are demonstrated to be generally true. But the others are either unsupported or have no effect

Analysis of support for modularity in object teams based on design patterns

Dissertação de Mestrado em Engenharia InformáticaThe paradigm of Aspect-Oriented Programming is currently being studied and matured. Many aspectoriented languages have been proposed, including Object Teams for Java (OT/J). However, to date few studies were carried out to assess the contribution of the various languages available and compare their relative advantages and disadvantages. The aim of this dissertation is to contribute to fill this gap. In the past, implementations of design patterns in Java and AspectJ were successfully used as case studies to derive conclusions on the relative advantages and disadvantages of the language under consideration. This dissertation follows this approach, with the development of a suitable collection of examples based on the well-known Gang-of-Four design patterns. Two repositories of implementations in OT/J of the complete collection of 23 Gang-of-Four design patterns have been developed, to be used as a basis for subsequent analysis. The scenarios used for the examples are based on Java repositories by independent authors, freely available on the Web. Based on the repositories developed, an analysis of the modularizations obtained with OT/J is presented and compared with the results obtained using Java and AspectJ. OT/J provides direct language support for 3 of the patterns. 20 patterns yielded separate modules for the patterns, of which 10 modules proved to be reusable. Only in 1 of the patterns, no significant differences between Java and OT/J were obtained

DATA ACCESS ARCHITECTURE IN OBJECT-ORIENTED APPLICATIONS USING DESIGN PATTERNS

This paper is describing data access architecture in a modern object-oriented application. Complex application solutions have multiple, parallel data sources. Each data source has specific properties and ways to access data. This architecture, by using already tried solutions, ensures a simple and flexible way to access different data sources. It’s also describing singleton, data access object and abstract factory patterns and their interaction in achieving flexible and scalable data access architecture

Assessment of Octave’s OO features based on GoF patterns

This thesis aims to evaluate the object-oriented (OO) features of the Octave programming language, through the implementation of the popular Gang-of-Four (GoF) design patterns. The study explores the fundamental principles of OO, including modularity, inheritance, encapsulation, polymorphism, and abstraction, and investigates how these concepts are supported by Octave. This research is conducted through the implementation of two complete collections of the GoF patterns originally coded in Java and the subsequent analysis of the quality of the implementations thus derived. This evaluation is based on comparisons with their Java counterparts as regards modularity and flexible module composition. To our knowledge, no study of this nature has been made on Octave. This thesis is intended to contribute to a better understanding of Octave’s current OO capabilities and limitations as well as its potential as a tool for developing complex software systems.Esta tese visa avaliar as características orientadas a objetos (OO) da linguagem de programação Octave, através da implementação dos populares design patterns dos Gang-of-Four (GoF). O estudo explora alguns princípios fundamentais de OO, incluindo modularidade, herança, encapsulamento, polimorfismo e abstração, e investiga o suporte de Octave a estes conceitos. Esta investigação é conduzida através da implementação de duas coleções completas dos padrões GoF originalmente desenvolvidos em Java e da análise subsequente à qualidade das implementações assim derivadas. Esta avaliação é baseada em comparações com os seus equivalentes Java no que diz respeito à modularidade e composição de módulos flexível. Segundo a nossa pesquisa, ainda não foi feito qualquer estudo desta natureza em Octave. Esta tese destina-se a contribuir para uma melhor compreensão das atuais capacidades e limitações do paradigma OO em Octave, bem como do seu potencial como ferramenta para o desenvolvimento de sistemas de software complexos

Scenario-based software architecture for designing connectors framework in distributed system

Software connectors is one of key word in enterprise information system. In recent years, software developers have facing more challenges of connectors which are used to connect distributed components. Design of connectors in an existing system encounters many issues such as choosing the connectors based on scenario quality, matching these connectors with design pattern, and implementing them. Especially, we concentrate on identifying the attributes that interest an observer, identifying the functions where these connectors could be applied, and keeping all applications clean after adding new connectors. Each problem is described by a scenario to design architecture, especially to design a connector based on architecture attributes. In this paper, we develop a software framework to design connectors between components and solution of these issues. A case study is done to maintain high level of independency between components and to illustrate this independency. This case study uses Aspect-Oriented Programming (AOP) and AspectJ, Design Pattern to and Program Slicing to solve main problems of design of connectors. A conclusion is given at the end of this paper

Quantitative assessment of modularity of caesarJ components

Dissertação apresentada no âmbito do Mestrado em Engenharia Informática para obtenção do grau de Mestre em Engenharia InformáticaOs defensores do paradigma de programação orientada a aspectos afirmam que este paradigma oferece melhor modularidade que a programação orientada a objectos, assim como um melhor suporte para separação de facetas transversais. Embora o AspectJ seja a linguagem de AOP mais conhecida, e alvo de mais estudos, surgiram novas linguagens de programação que propõem diferentes formas de instanciar este paradigma. O CaesarJ é uma destas linguagens. Possui abstracções e mecanismos que o diferenciam do AspectJ, tais como classes virtuais, polimorfismo de família e uma maneira diferente de representar um aspecto. Qualquer alegação de uma linguagem ser melhor, à luz de um critério bem definido (neste caso, a modularidade), tem que ser apoiada por avaliações rigorosas de implementações feitas nessa linguagem. Este trabalho pretende fazer isso com um estudo comparativo entre as duas linguagens em termos da modularidade que se obtém em software por elas implementado. Em particular, vai-se estudar uma faceta da modularidade: a coesão. Este estudo utiliza da estrutura padrão de relatórios experimentais em Engenharia de Software, assim como todos os testes estatísticos apropriados. Para este fim, foi desenvolvida uma métrica de coesão que foi usada, juntamente com várias métricas de tamanho para avaliar 51 exemplos de implementações de padrões de concepção. No contexto desta dissertação a ferramenta de recolha automática de métricas MuLATo foi adaptada para suportar esta nova métrica de coesão. Os resultados do estudo efectuado sugerem que o CaesarJ é mais verboso que Java mas contem componentes menos complexos e mais coesos