Pgraphite: an experiment in persistent typed object management

Defining, creating, and manipulating persistent typed objects will be central activities in future software environments. PGRAPHITE is a working prototype through which we are exploring the requirements for the persistent object capability of an object management system in the Arcadia software environment. PGRAPHITE represents both a set of abstractions that define a model for dealing with persistent objects in an environment and a set of implementation strategies for realizing that model. PGRAPHITE currently provides a type definition mechanism for one important class of types, namely directed graphs, and the automatic generation of Ada implementations for the defined types, including their persistence capabilities. We present PGRAPHITE, describe and motivate its model of persistence, outline the implementation strategies that it embodies, and discuss some of our experience with the current version of the system.