On Components with Explicit Protocols Satisfying a Notion of Correctness by Construction

Component-based programming, which promises to facilitate the construction of large-scale applications, relies to a large degree on interfaces. Interfaces on most component models only declare types and sets of services that components implement, and are not expressive enough to formulate structural and behavioral properties of components. In this paper we show how to integrate one important class of behavioral properties: constraints on the sequentialization of services. We are interested in operators for the construction of components, satisfying a correctness property, allowing a component to be substituted by another one. We define a set of protocol composition operators satisfying the correctness property, we provide a first step toward the integration of additional abstract state information into protocols, and we apply our theory to two widely-used component models: JavaBeans and Enterprise JavaBeans.