Mapping UML Component Specifications to JEE Implementations

Component-based Software Engineering (CbSE) has become a well-accepted approach for developing complex software systems due to its significant advantages on composition and reuse. In practice, however, its use still requires the conjunction of a component specification method that describes how system requirements are satisfied in terms of software components. Such a component specification is then implemented in a variety of software component models (e.g., COM+, CORBA, EJB). To achieve this, a sound mapping from the specification to a designated component model is critical. In addition, for rapid advances on Internet technologies, software systems have gradually been architected as processing in distributed environments. Since a distributed environment involves often synchronous/asynchronous messages communicating among various processes, this paper focuses therefore on the mapping issue from a component specification to a component model that particularly takes into consideration of the communicating of synchronous/asynchronous messages. To illustrate, an on-line e-Learning curriculum order system is modeled for demonstrating the mapping idea. In completing the component specification, we adopt the well-known UML Components method, while in the component model we use the Enterprise Java Beans (EJB) standard in that EJB is the core component model of the JEE (J2EE) platform which supports well distributed operations/services. With such a practical mapping, software systems can be developed in a more effective way by specifying requirements in UML Components and implementing software components in EJB with the communicating of synchronous/asynchronous messages among various processes.