385 research outputs found
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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
Components and Aspects Composition Planning for Ubiquitous Adaptive Services
International audienceIn ubiquitous environments, resources limitations and fluctuations combined with device mobility requires the dynamic adaptation of mobile applications. This paper reports on an extension of the MUSIC adaptation middleware to support aspect-oriented programming in order to handle cross-cutting adaptations. Basically, this extension specifies an architectural model for defining applications as a composition of aspects and components. The dynamic adaptation of an application in a given context is realised by selecting the appropriate component and aspect implementations using utility functions as a mean of optimising the overall QoS. Our approach and middleware are implemented and tested on top of OSGi framework
An AOP Layer to Abstract Programming with Distributed Components
International audienceComponent models such as EJB or CCM are increasingly used to create complex and distributed systems and applications. Unless the details of the API and mechanisms used for programming with these models differ, the general features provided by the models share many characteristics. In this paper, we propose to capture these features in a common layer that can be used to develop model independant component programs. The layer is then mapped either onto EJB or CCM. This layer is defined with the AspectJ aspect-oriented programming language. We report on two samples applications that were developped with this layer: an application-level load balancing service and a contract enforcement service
A Framework for Evaluating Model-Driven Self-adaptive Software Systems
In the last few years, Model Driven Development (MDD), Component-based
Software Development (CBSD), and context-oriented software have become
interesting alternatives for the design and construction of self-adaptive
software systems. In general, the ultimate goal of these technologies is to be
able to reduce development costs and effort, while improving the modularity,
flexibility, adaptability, and reliability of software systems. An analysis of
these technologies shows them all to include the principle of the separation of
concerns, and their further integration is a key factor to obtaining
high-quality and self-adaptable software systems. Each technology identifies
different concerns and deals with them separately in order to specify the
design of the self-adaptive applications, and, at the same time, support
software with adaptability and context-awareness. This research studies the
development methodologies that employ the principles of model-driven
development in building self-adaptive software systems. To this aim, this
article proposes an evaluation framework for analysing and evaluating the
features of model-driven approaches and their ability to support software with
self-adaptability and dependability in highly dynamic contextual environment.
Such evaluation framework can facilitate the software developers on selecting a
development methodology that suits their software requirements and reduces the
development effort of building self-adaptive software systems. This study
highlights the major drawbacks of the propped model-driven approaches in the
related works, and emphasise on considering the volatile aspects of
self-adaptive software in the analysis, design and implementation phases of the
development methodologies. In addition, we argue that the development
methodologies should leave the selection of modelling languages and modelling
tools to the software developers.Comment: model-driven architecture, COP, AOP, component composition,
self-adaptive application, context oriented software developmen
Efficient Customizable Middleware
The rather large feature set of current Distributed Object Computing (DOC) middleware can be a liability for certain applications which have a need for only a certain subset of these features but have to suffer performance degradation and code bloat due to all the present features. To address this concern, a unique approach to building fully customizable middleware was undertaken in FACET, a CORBA event channel written using AspectJ. FACET consists of a small, essential core that represents the basic structure and functionality of an event channel into which additional features are woven using aspects so that the resulting event channel supports all of the features needed by a given embedded application. However, the use of CORBA as the underlying transport mechanism may make FACET unsuitable for use in small-scale embedded systems because of the considerable footprint of many ORBs. In this thesis, we describe how the use of CORBA in the event channel can be made an optional feature in building highly efficient middle-ware. We look at the challenges that arise in abstracting the method invocation layer, document design patterns discovered and present quantitative footprint, throughput performance data and analysis. We also examine the problem of integrating FACET, written in Java, into the Boeing Open Experimental Platform (OEP), written in C++, in order to serve as a replacement for the TAO Real-Time Event Channel (RTEC). We evaluate the available alternatives in building such an implementation for efficiency, describe our use of a native-code compiler for Java, gcj, and present data on the efficacy of this approach. Finally, we take preliminary look into the problem of efficiently testing middleware with a large number of highly granular features. Since the number of possible combinations grow exponentially, building and testing all possible combinations quickly becomes impractical. To address this, we examine the conditions under which features are non-interfering. Non-interfering features will only need to be tested in isolation removing the need to test features in combination thus reducing the intractability of the problem
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Whitepaper: The Value of Improving the Separation of Concerns
Microsoft's enterprise customers are demanding better ways to modularize their software systems. They look to the Java community, where these needs are being met with language enhancements, improved developer tools and middleware, and better runtime support. We present a business case for why Microsoft should give priority to supporting better modularization techniques, also known as advanced separation of concerns (ASOC), for the .NET platform, and we provide a roadmap for how to do so
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