A number of approaches have been proposed to achieve separation of concerns. Although all these approaches form suitable candidates for separating cross-cutting concerns in a system, one approach can be more suitable for implementing certain types of concerns as compared to the others. This paper proposes a hybrid approach to separation of concerns. The approach is based on using the most suitable approach for implementing each cross-cutting concern in a system. The discussion is based on using three different approaches: composition filters, adaptive programming and aspect-oriented programming to implement cross-cutting concerns in SADES, a customisable and extensible object database evolution system.

Previous taxonomies of software evolution have focused on the purpose of the change (i.e., the why) rather than the underlying mechanisms. This paper proposes a taxonomy of software evolution based on the characterizing mechanisms of change and the factors that influence these mechanisms. The taxonomy is organized into the following logical groupings: temporal properties, objects of change, system properties, and change support. The ultimate goal

This paper discusses two mechanisms for weaving aspects in persistent environments founded on object-oriented databases. The first mechanism is based on exploiting existing aspect languages and their associated weavers while the second mechanism is based on building weaving functionality into the database management system (DBMS). The first mechanism has been used to integrate AspectJ and its associated weaver with the Jasmine ODBMS. The second approach has been used to implement a weaver within the SADES object database evolution system.

This paper provides a comparative evaluation of two aspect-oriented features of the SADES object database evolution system with three other systems each representing a particular category of evolution systems. The evaluation is based on a case study involving a design correction scenario. The features compared include schema relationships and instance adaptation. The discussion demonstrates the cost-effectiveness and resilience of an aspectoriented approach in the face of unanticipated changes, customisations and extensions.

N-Version Mode expose a range of abstract methods that are concretised by the sub-aspects to customise the schema evolution approach.

Abstract. Object database management systems (ODBMSs) typically offer fixed approaches to evolve the schema of the database and adapt existing instances accordingly. Applications, however, have very specialised evolution requirements that can often not be met by the fixed approach offered by the ODBMS. In this paper, we discuss how aspect-oriented programming (AOP) has been employed in the AspOEv evolution framework, which supports flexible adaptation and introduction of evolution mechanisms – for dynamic evolution of the schema and adaptation of existing instances – governing an object database. We argue that aspects support flexibility in the framework by capturing crosscutting hot spots (customisation points in the framework) and establishing their causality relationships with the custom evolution approaches. Furthermore, aspects help in information hiding by screening the database programmer from the complexity of the hot spots manipulated by custom evolution mechanisms. They also make it possible to preserve architectural constraints and specify custom version polymorphism policies. 1.

In this paper we present a Model for Dynamic Hyperslices which uses a particular Aspect-Oriented (AO) approach – Hyperspaces – for decomposition and reflection as a means for composition of software modules. This model allows for structured, dynamic, incremental change introduction and rollback, thus, supporting run-time evolution yet preserving component modularity. The applicability of the model is illustrated through a schema adaptation scenario. 1.

Abstract. A software product line comprises a set of products implementing different configurations of features. The set of valid feature configurations within a product line can be described by a feature model. In some practical situations, a feature configuration needs to be derived in stages by creating a series of successive specializations of the initial feature model. In this paper, we consider the scenario where changes to the feature model due to, for example, the evolution of the product line, need to be propagated to its existing specializations and configurations. After discussing general dimensions of model synchronization, a solution to synchronizing cardinality-based feature models and their specializations and configurations is presented. 1

Abstract not found