The Design And Implementation Of New Event Mechanism Based On CORBA Specification

The existing event mechanism usually uses traditional client/server model.The two-tier structure model has given rise to considerable flexibility,but it gradually reveals the phenomenon of over-loaded on client and server.And it is difficult to extend.With the application and popularity of network technology,the network size is growing fast.The type and kind of computer hardware platform model is different. The software platforms such as operating systems,development platforms, application software platform are multiples.The inconsistencies of hardware platforms and software platforms constitute distributed computer network heterogeneity.A large number of loosely coupled,asynchronous communication need of multi-points.CORBA event service proposed the "event channel" concept.The client and server are only dealing with the event channel,and the receiver of event does not have to care about who is the event sender.So it gives a good solution on difficulty heterogeneous network programming.This paper analyses the status and problems of the existing event mechanism. And it introduces and studies the technology of OMG's CORBA.Then the paper makes improvement in quality of service control to CORBA event,and designs an event mechanism that can control the priority of the event.The new event mechanism is based on CORBA event service.It increases an event priority management mechanism in event service.In this new event mechanism,the higher priority event will be sent in priority.When the network is obstructive on transmissing the event,the higher priority event can be processed firstly.The specific method is to add an event management queue in the event channel.For each event before sending,a priority will be given to the event.The event will be added to the event queue according to its priority.So the first element of the queue is the highest priority event,and it will be sent in priority.Based on this design model,this paper implements the push model CORBA event service.CORBA Event Service provides a loose coupling of the communication mechanism,but it did not provide the information filtering mechanisms and the quality of service control.The new CORBA-based event mechanism model designed in the paper provides the event priority control and improves the quality of service of event service,but it also slows down the speed of events sent.