Coping with changes in an object management system based on attribute grammars

Abstract

In this paper, we discuss methods of dealing with change in an object management system OS/O, which is a prototype of an attribute grammar based object management model, called Object-Oriented Attribute Grammars(OOAG)[SK 9Oa]. OOAG is a hybrid model that combines features of functional and object-oriented paradigms. Various aspects of software object databases can be described using its capabilities. Software objects in OOAG are managed as autonomous, hierarchical trees containing attributes. The OOAG is also capable of describing software processes as hierarchies of software objects, with data driven process enaction mechanism. Many aspects of changes to such a tree, including the evolution of the tree type definition, or the dynamic transformation of its internal structure can be dealt with easily by the benefits of a combined attribute grammars based and object oriented paradigm. We also introduce a mechanism that helps to provide an efficient way for manipulating changed objects. The mechanism is characterized by meta-objects that are used to control the evaluation of the changes. Meta-objects prove to be a suitable mechanism for handling change management tasks in evolving object environments.