This paper deals with the problem of changing software application behavior without changing the code, but by customizing external business rules. The topic is very practical, since program maintainability costs much more than designing a program.

The authors present a prototype called Fusion, which allows for application customization. Two important design issues that are related to the business rules are presented: how to externalize the rules, and which language should be used to describe them. The paper presents the prototype components using Java code and images. A description and an implementation of the language used by the prototype (Calliope) are presented. Finally, the paper contains a good section on future work.

This is mostly a research and development document, addressed to software designers. It contains valuable information and solutions, and covers an interesting topic.