AN OBJECT-BASED PROGRAMMING-MODEL FOR SHARED DATA

The classical object model supports private data within objects and cl ean interfaces between objects, and by definition does not permit shar ing of data among arbitrary objects. This is a problem for real-world applications, such as advanced financial services and integrated netwo rk management, where the same data logically belong to multiple object s and may be distributed over multiple nodes on the network. Rather th an give up the advantages of encapsulated objects in modeling real-wor ld entities, we propose a new object model that supports shared data i n a distributed environment. The key is separating distribution of com putation units from information-hiding concerns. Minimal units of data and control, called facets, may be shared among multiple objects and are grouped into processes. Thus, a single object, or information-hidi ng unit, may be distributed among multiple processes, or computation u nits. In other words, different facets of the same object may reside i n different address spaces on different machines. We introduce our new object model, describe a motivating example from the financial domain , and then explain facets, objects, and processes, followed by timing and synchronization concerns.