The Event Service

A reactive, event-based, form of programming is also supported by the CORBA Event Service which provides services for the creation and management of CORBA event channels. These may be used by CORBA supplier/consumer clients to propagate events asynchronously on a push or pull basis. Event channels are created and registered with the CORBA Naming Service allowing clients to obtain object references in the usual manner. Communication is anonymous in that the supplier does not require knowledge of the receiving consumers. Publicized inadequacies of the Event Service are a lack of explicit quality of service (QoS) control, the necessity of propagating event data with type CORBA::any, and the absence of event filtering. Nevertheless, by applying a few simple design techniques, these limitations can be largely circumvented and the CORBA Event Service has been usefully employed in the monitoring of hardware devices and in the distribution of recalibrated data to client consumers. The CORBA Event Service is ultimately to be replaced by the CORBA Notification Service which systematically addresses the shortcomings of the Event Service.