Franciscus Sanen

Support for distributed adaptations in aspect-oriented middleware

Many aspect-oriented middleware platforms support run-time aspect weaving, but do not support coordinating distributed changes to a set of aspects at run-time. A distributed change entails weaving or unweaving multiple inter-dependent aspects that are logically or physically distributed. Coordinating such multiple weavings inside the application layer is a complex and difficult task for the application developer, because global state consistency, structural integrity and other safety properties have to be preserved. In this paper, we present the DyReS framework that offers the required coordination support on top of existing aspect-oriented middleware platforms. The framework is customizable towards application-specific requirements to achieve improved performance and reconfiguration semantics. We have validated our approach by delivering and examining two implementations of the DyReS framework: one on top of JBoss AOP and a second one for Spring AOP.

Managing concern interactions in middleware

In this paper, we define a conceptual model that describes the relevant information about interactions between concerns that needs to be captured. We have developed a prototype system that, starting from this model, can automatically generate a set of rules that enables software developers to improve their understanding of concerns in middleware and their interactions. This rule-base is the basis for an expert system that can be queried about particular concern interactions and a software engineering tool to support an application development team.

Adding dynamic reconfiguration support to JBoss AOP

The majority of aspect-oriented middlewares supporting dynamic aspect weaving fail to preserve important safety properties while weaving or unweaving a distributed aspect at runtime. This position paper looks in particular at the safety properties of structural integrity and global state consistency. Preserving these two safety properties in the presence of dynamic change has already been extensively addressed in the space of dynamic reconfiguration of component-based distributed systems. As will be argued in this position paper, existing coordination protocols developed in this space can be largely reused for distributed aspect weaving provided that some small adaptations are made to account for the aspect-oriented composition mechanisms. To demonstrate results and as a proof-of-concept, we describe how we have ported the NeCoMan dynamic reconfiguration support on top of the JBoss AOP framework. As a result, system-wide consistency can be preserved in JBoss when weaving or unweaving a distributed aspect at runtime.

Aspects, Dependencies and Interactions

For Aspect-Oriented Software Development (AOSD) the topic of Aspects, Dependencies and Interactions is of high importance across the whole range of development activities - from requirements engineering through to language design. Aspect interactions must be adequately addressed all across the software lifecycle if AOSD is to succeed as a paradigm. Thus, this topic must be tackled by the AOSD community as a whole. This first workshop, initiated by AOSD-Europe project, aimed to establish a dedicated forum for discussion of this vital topic and to attract both researchers and practitioners currently engaged with related issues. The workshop has succeeded in initiating a broad community-wide discussion of this topic and has provided an initial overview of perspectives on the state of the art as well as of outstanding issues in this area.

Mapping problem-space to solution-space features: a feature interaction approach

Mapping problem-space features into solution-space features is a fundamental configuration problem in software product line engineering. A configuration problem is defined as generating the most optimal combination of software features given a requirements specification and given a set of configuration rules. Current approaches however provide little support for expressing complex configuration rules between problem and solution space that support incomplete requirements specifications. In this paper, we propose an approach to model complex configuration rules based on a generalization of the concept of problem-solution feature interactions. These are interactions between solution-space features that only arise in specific problem contexts. The use of an existing tool to support our approach is also discussed: we use the DLV answer set solver to express a particular configuration problem as a logic program whose answer set corresponds to the optimal combinations of solution-space features. We motivate and illustrate our approach with a case study in the field of managing dynamic adaptations in distributed software, where the goal is to generate an optimal protocol for accommodating a given adaptation.