Improving modularity of reflective middleware with aspect-oriented programming

Abstract

Reflective middleware has been proposed as an effective way to enhance adaptability of component-oriented middleware architectures. To be effectively adaptable, the implementation of reflective middleware needs to be modular. However, some recently emerged applications such as mobile, pervasive, and embedded applications have imposed more stringent modularity requirements to the middleware design. They require support for the conception of a minimal middleware while promoting finegrained modularity of reflective middleware features. The key problem is that fundamental mechanisms for decomposing reflective middleware implementations, such as object-oriented ones, suffer from not providing the proper means to achieve the required level of localizing reflection-specific concerns. This paper presents a systematic investigation on how aspect-oriented programming scales up to improve modularity of typical reflection-specific crosscutting concerns. We have quantitatively compared Java and AspectJ implementations of an OpenORBcompliant reflective middleware using separation of concerns metrics.

The AOSD Research Community in Brazil and Its Crosscutting Impact

“…The authors made both qualitative and quantitative assessments of 62 pair-wise compositions of patterns taken from 3 medium-sized systems implemented in Java and AspectJ programming languages. Cacho et al [60] assessed the use of AOP for improving the modularity of a reflective middleware. Kulesza et al [61] presented an empirical study in which they quantified the effects of AOP in the maintainability of a web-based information system.…”

Composing Structural Views in xADL

“…We should highlight that from our experience in previous case studies [18,25,33,10] the three relations and the composition seem to be recurrently demanding in architecture design processes. For instance, concerns such as error handling, distribution, and persistence, have been identified as crosscutting in the architecture of a Web-based information system [33,18], Eclipse CVS plugin [18,25], a reflective middleware system [10,9], and a traveller information system [18,25]. We have observed that in all these cases, advice-pointcut mechanisms, as supported by most AO ADLs, are not sufficient to cope with the separation and composition of such concerns.…”

Conquering Fine-Grained Blends of Design Patterns

“…Proxy (4) State (3) Strategy (2) Mediator ( Figure 1 shows a design slice of an OpenOrb-compliant reflective middleware system [7] in which 21 classical design patterns [10] are used and combined to achieve the middleware requirements of customizability and adaptability [6]. A number of methods and attributes were omitted for simplification reasons.…”

“…Different approaches have been proposed for documenting pattern blends: role composition [12,18], UML-based composition [21], temporal logic composition [16] and aspect-oriented composition [6,7,13,19].…”

“…Patterns often need to be documented as pair-wise blends of patterns' responsibilities rather than as individual and intact entities. This phenomenon has been recurrently identified in the design of product lines [8], middleware systems [6], and domain-specific frameworks [7]. Not surprisingly there is an increasing empirical evidence that a considerable proportion of code clones in real-world software projects are related to variants of pattern blends [2,14].…”