Finding Implicit Contracts in .NET Components

摘要

Are contracts inherent in reusable libraries, or just one design technique among others? To help answer this question, we performed an empirical study of library classes from the .NET Collections library, which doesn't use Design by Contract~(TM), to look for unexpressed contracts. This article reports on the buried contracts we have found, and discusses improvements to the architecture ― especially to the libraries' ease of learning and ease of use ― that may result from making the contracts explicit. It extends previous reports with an analysis of the benefits of an a posteriori addition of contracts for the library users.