Object oriented reconstruction software for the Instrumented Flux Return of BABAR

Abstract

BABAR experiment is the first High Energy Physics experiment to extensively use object oriented technology and the C++ programming language for online and offline software. Object orientation permits to reach a high level of flexibility and maintainability of the code, which is a key point in a large project with many developers. These goals are reached with the introduction of reusable code elements, with abstraction of code behaviours and polymorphism. Software design, before code implementation, is the key task that determines the achievement of such a goal. We present the experience with the application of object oriented technology and design patterns to the reconstruction software of the Instrumented Flux Return detector of BABAR experiment. The use of abstract interfaces improved the development of reconstruction code and permitted to flexibly apply modification to reconstruction strategies, and eventually to reduce the maintenance load. The experience during the last years of development is presented. An iterative review and improvement of the design has been strategically applied to the code areas which showed to be, on the basis of experience, more delicate.