III-C.2 The CORBA Event Service

  The CORBA Event Service [4] standardizes the transfer of asynchronous notifications between objects. An object that generates events is called supplier whereas an object which receives events is called consumer. A supplier passes an event to a consumer by invoking an appropriate method on the consumer interface. Suppliers and consumers can be decoupled from each other by event channel objects. An event channel forwards all events it receives from any of its suppliers to all the consumers that have registered with the channel. The events themselves can be either of generic or typed format. A generic event has one single parameter of the OMG IDL datatype any, whereas a typed event may have an arbitrary number of parameters which can be of any OMG IDL datatype.

In the future, the currently standardized CORBA Notification Service developed by the OMG Telecommunications Domain Task Force will provide much more flexible event filtering capabilities. It is then possible to establish user-defined event filters by assigning priorities to events, generate timestamps, and introduce QoS criteria for the handling of events. Mechanisms for modifying the persistency properties of events will also be available.