Customizing Adaptive Software to Object-Oriented Software Using Grammars

Numerous researchers have pointed out that object-oriented programs are easier to extend than programs which are not written in an object-oriented style, however object-oriented programs are still rigid to adapt and maintain. This paper builds on an extension of object-oriented programming which allows to write more extensible programs, called adaptive programs, without knowing the details of the input language. A speciic input language is selected after the program has been written by specifying a grammar, called class dictionary. This paper formally studies class dictionaries and how they help with adaptive programming. A class dictionary is a very high-level language which is 1. concise and expressive to describe important aspects of object-oriented designs and programs, 2. the basis for a theory of object-oriented software engineering, 3. the basis for tools for the object-oriented paradigm. A class dictionary is mapped into classes of an object-oriented programming language, for example, C++, CLOS etc. A class dictionary deenes both a set of objects and a set of sentences (a language). We derive a set of restrictions on class dictionaries which permit a simple printing algorithm and its inverse, a parsing algorithm, to be bijection functions between objects and sentences. We review propagation patterns for describing adaptive object-oriented software at a higher level of abstraction than the one used by today's object-oriented programming languages. A propagation pattern is an adaptive program which deenes a family of programs. From the family, we can select a member by giving a class dictionary. The theory presented in this paper has been successfully implemented and used in the Demeter Tools/C++, a set of tools which facilitate evolution during the software development process.