Managed Assertions for Component Contracts

Behavioral specifications in interface contracts are important measures for improving quality of software components. Binary components of different language origins need a common understanding of behavioral contracts to work effectively in component-based systems. We propose a system by which behavioral specifications in the spirit of Design by Contract can accompany binary components and be available at runtime to enable flexible and correct treatment, in a language neutral manner. Behavioral contracts written in different specification notations, for components written in different programming languages, have common runtime semantics. Runtime monitoring is correct with regards to behavioral subtyping, object re-entrance and exception handling. The mechanism also enables runtime reflection of contract constructs. We show our design for this system, as an extension to the Common Language Infrastructure (CLI) standardized by ECMA. We also describe our prototype implementation based on Microsoft’s Shared Source CLI.