| Information & Knowledge Technologies Business Unit |
| Distributed Systems Technology Group Papers |
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The Aspect-Oriented Interceptors’ Pattern for Crosscutting and Separation of Concerns using Conventional Object Oriented Programming Languages
Citation: John Zinky, Richard Shapiro. The Second AOSD Workshop on Aspects, Components, and Patterns for Infrastructure Software (ACP4IS), part of International Conference on Aspect-Oriented Software Development, Boston, March 17, 2003.
Formats: PDF Word Powerpoint
Abstract With disciplined use of the aspect-oriented interceptors’ pattern [10], limited but effective crosscutting techniques can be used with conventional programming languages such as Java and C++. We have developed this pattern for use in Cougaar [7], a comprehensive infrastructure for supporting distributed agents. Cougaar can adapt to changes in the runtime environment, supporting such dynamic features as performance tuning, security, dependability, and agent mobility. Adaptation in this context affects not what the system does, but how it does it. Adaptive features, developed by various programming teams, must be dynamically enabled at runtime based on policy assertions and resource constraints. Adaptive features touch every part of the system, hence they are said to crosscut the dominant decomposition (which is based on class hierarchies). The pattern presented in this paper helps control these features by separating them into explicit components and by allowing the components to be attached to the base system at multiple points. The pattern shows interesting use of crosscutting, not only for ease of implementation (reuse), but also for dynamic control and composition of features. The paper presents some example adaptive features to illustrate how aspect-oriented interceptors’ pattern is used in the implementation of the Cougaar agent-based middleware. The paper concludes with a discussion of how the aspect-oriented interceptors’ pattern compares with emerging Aspect Oriented Programming languages.
