Reasoning about implicit invocation

Implicit invocation [SN92, GN91] has become an important architectural style for large-scale system design and evolution. This paper addresses the lack of specification and verification formalisms for such systems. Based on standard notions from process algebra and trace semantics, we define a formal computational model for implicit invocation. A verification methodology is presented that supports linear time temporal logic and compositional reasoning. First, the entire system is partioned into groups of components (methods) that behave independently. Then, local properties are proved for each of the groups. A precise description of the cause and the effect of an event supports this step. Using local correctness, independence of groups, and properties of the delivery of events, we infer the desired property of the overall system. Two detailed examples illustrate the use of our framework.