Aspect-oriented programming

Abstract: Aspect] is a simple and practical aspect-oriented extension to Java With just a few new constructs, AspectJ provides support for modular implementation of a range of crosscutting concerns. In AspectJ's dynamic join point model, join points are well-defined points in the execution of the program; pointcuts are collections of join points; advice are special method-like constructs that can be attached to pointcuts; and aspects are modular units of crosscutting implementation, comprising pointcuts, advice, and ordinary Java member declarations. AspectJ code is compiled into standard Java bytecode. Simple extensions to existing Java development environments make it possible to browse the crosscutting structure of aspects in the same kind of way as one browses the inheritance structure of classes. Several examples show that AspectJ is powerful, and that programs written using it are easy to understand.

Abstract: AspectJ implementations of the GoF design patterns show modularity improvements in 17 of 23 cases. These improvements are manifested in terms of better code locality, reusability, composability, and (un)pluggability.The degree of improvement in implementation modularity varies, with the greatest improvement coming when the pattern solution structure involves crosscutting of some form, including one object playing multiple roles, many objects playing one role, or an object playing roles in multiple pattern instances.

Abstract: Software product lines (SPLs) enable modular, large-scale reuse through a software architecture addressing multiple core and varying features. To reap the benefits of SPLs, their designs need to be stable. Design stability encompasses the sustenance of the product line's modularity properties in the presence of changes to both the core and varying features. It is usually assumed that aspect-oriented programming promotes better modularity and changeability of product lines than conventional variability mechanisms, such as conditional compilation. However, there is no empirical evidence on its efficacy to prolong design stability of SPLs through realistic development scenarios. This paper reports a quantitative study that evolves two SPLs to assess various design stability facets of their aspect-oriented implementations. Our investigation focused upon a multi-perspective analysis of the evolving product lines in terms of modularity, change propagation, and feature dependency. We have identified a number of scenarios which positively or negatively affect the architecture stability of aspectual SPLs.

Abstract: Design patterns offer flexible solutions to common problems in software development. Recent studies have shown that several design patterns involve crosscutting concerns. Unfortunately, object-oriented (OO) abstractions are often not able to modularize those crosscutting concerns, which in turn decrease the system reusability and maintainability. Hence, it is important verifying whether aspect-oriented approaches support improved modularization of crosscutting concerns relative to design patterns. Ideally, quantitative studies should be performed to compare OO and aspect-oriented implementations of classical patterns with respect to important software engineering attributes, such as coupling and cohesion. This paper presents a quantitative study that compares aspect-based and OO solutions for the 23 Gang-of-Four patterns. We have used stringent software engineering attributes as the assessment criteria. We have found that most aspect-oriented solutions improve separation of pattern-related concerns, although only 4 aspect-oriented implementations have exhibited significant reuse.