Evaluating the Reference and Representation of Domain Concepts in APIs

As libraries are the most widespread form of software reuse, the usability of their APIs substantially influences the productivity of programmers in all software development phases. In this paper we develop a framework to characterize domain-specific APIs along two directions: 1) how can the API users reference the domain concepts implemented by the API; 2) how are the domain concepts internally represented in the API. We define metrics that allow the API developer for example to assess the conceptual complexity of his API and the non-uniformity and ambiguities introduced by the API's internal representations of domain concepts, which makes developing and maintaining software that uses the library difficult and error-prone. The aim is to be able to predict these difficulties already during the development of the API, and based on this feedback be able to develop better APIs up front, which will reduce the risks of these difficulties later.