This project focuses on the development of a MIC tool, the Event QoS Aspect Language (EQAL), for the configuration of event services. EQAL is a novel extension to CoSMIC, an MIC toolsuite that supports the development, assembly, and deployment of QoS-enabled component applications. CoSMIC currently uses the Component-Integrated ACE ORB (CIAO), an implementation of CCM, as the default target middleware platform.
CIAO implements a QoS-enabled event service framework that enables the deployment of components with stringent real-time requirements. CIAO presents components with a uniform interface through which a particular CORBA event service can be selected and configured. CIAO allows components to use the CORBA Real-Time Event Channel (RTEC) and COS Notification Service (NS). Additionally, components can elect to have events propagated directly; that is, via standard CORBA invocations that bypass an event service. The direct mechanism is efficient for 1-to-1 publisher-subscriber connections and collocated components, but it does not scale well. For applications that comprise large numbers of distributed components, the event channel or notification service is necessary.
EQAL consists of two complimentary entities: a modeling paradigm, in which event models can be built, and model interpreters, which will synthesize middleware configuration files from the models. The EQAL modeling paradigm allows the specification of an event mechanism (i.e., direct, real-time event channel, or notification service) and the configuration of that mechanism for each component event port. The EQAL model interpreters automatically generate event service configuration files and component property description files.