Generic and Composable Latecomer Accomodation Service for Centralized Shared Systems

It is important that a shared application allow a latecomer to join other users who are already working together with the application. We have developed a latecomer accommodation service framework for centralized shared systems (applications and infrastructures). It employs an independent latecomer accommodation server that is dynamically composable with its clients. The server, also called the logger, logs a shared application’s user interface (UI) changes in response to calls made by the client, also called the loggable. Later, when the time comes to accommodate a latecomer, the logger replays the logged changes to the loggable, which, in turn, creates the latecomer’s user interface. To deal with UI protocols at different levels of abstraction, we have defined the API in terms of a generic UI model. This reduces the burden on a loggable from a complete service implementation to a translation between its specific UI protocol and our generic UI model. To reduce the space and time overhead, the logger performs complex log compression. The extent of compression depends on the amount of semantic knowledge that the loggable provides to the logger. In this paper, we motivate, describe and illustrate the approach, and outline how it is implemented.