Object Interconnections Distributed Callbacks and Decoupled Communication in CORBA

We’re changing gears in this column. Our recent columns have used a distributed stock quoting example to focus on different concurrency models for developing multithreaded server applications. In this column, we’ll start looking at another aspect of distributed object computing systems: decoupling the relationship between “clients” and “servers.” Our examples to date have focused exclusively on request/response communication. In this approach, requests flow from client to server and responses flow back from server to client. In this column, we’ll discuss distributed callbacks and extend our stock quoting example to show why they’re useful. We’ll also briefly discuss the OMG Events object service [1], which supports decoupled peer-to-peer relationships between consumers and suppliers. We intend to cover the OMG Events object service in more detail in future columns.