EventPorts: preventing legacy componentware

In our work with legacy information systems, we have found two prevalent anti-patterns-tight coupling and code pollution-which, if not addressed in replacement systems, could result in today´s new systems simply becoming tomorrow´s new legacy system. Tight coupling results from Explicit Invocation across collaborating components. Code pollution results from implicit (rather than explicit) reflection of time-ordered collaboration protocols. These anti-patterns diminish component maintainability, flexibility, and reusability. In response, we propose a synthesis of Implicit Invocation (which reduces tight coupling) and Statecharts (which reflect collaboration protocols directly). The paper describes the development of EventPorts, which realize this synthesis and thus encapsulate a novel and promising component collaboration technology