In this paper, we explore how legacy software logic can be re-used in a new context-of-use. In effect, oftentimes existing software is required to evolve or to be integrated into a new complex environment. Technological improvements, new usages, regulations or financial constraints are such reasons for evolution. Parts of the legacy functions are still useful and it is certainly challenging to integrate such code, as legacy systems were designed and implemented for a specific purpose in the past. Nevertheless, they are an expensive investment and transforming them to allow modification and integration with other actors would not only save high investment, but also enable future modifications. We consider that an adequate technique to drive the integration of legacy systems into self-adaptive systems is to transform first the legacy code into a multi-agent system (MAS), from which adaptation within the system and communication with external actors is easier to attain. We refer to this process as "adaptization". We use as an adaptation proxy conceptually intelligent agents conforming to the Belief, Desire, Intention (BDI) model, one of the tools of Agent-Oriented Software Engineering (AOSE). This proxy permits to understand the legacy system in terms of goals to achieve and to address adaptiveness as a goal selection problem at run-time (based on context), thus abstracting away the current implementation to a high level goal-achievement mechanism. We propose  KOALA , a novel stepwise methodology towards adaptization.
['Francois Wavresky', 'Seok-Won Lee']
A methodology towards the adaptization of legacy systems using agent-oriented software engineering