Showing papers by "Robert Walker published in 2000"

Separating Concerns with Hyper/J TM : An Experience Report

Abstract: In earlier work, we conducted an exploratory investigation of concerns in two existing Java TM packages: jFTPd and gnu.regexp. Two separate developers marked concerns in the source for each package: these concerns were then compared and analyzed. In this paper, we describe the next step of our investigations: the use of the IBM Hyper/J TM tool to separate and configure the identified concerns. We describe the various kinds of hyperspaces, hypermodules, hyperslices, and concern mappings we used to describe our previously identified concerns. We also discuss code restructurings we used to enable the capturing and composition of concerns.

Eliminating Cycles in Composed Class Hierarchies

Abstract: Multiple class hierarchies can be used each to represent a separate requirement or design concern. To yield a working system, these disparate hierarchies must be composed in a semantically meaningful way. However, cycles can arise in the composed inheritance graph that restrict the space of composable hierarchies. This work presents an approach to eliminating these cycles by means of separating the type hierarchy from the implementation hierarchy; separate solutions are provided for languages permitting multiple inheritance, such as C++, and those permitting only interfaces, such as Java. The resulting acyclic class hierarchy will maintain the significant constraints imposed by the original, separate hierarchies, such as type-safety.