Method for the analysis and design of class characteristic migrations during object system evolution

Abstract We propose a method to assist designers in the analysis and design of the migrations of class characteristics (attributes and methods) during object system evolution. This method advocates: • to analyze a migration by identifying transfer links that will be used to transfer class characteristics; • to design the graph of the transfer links of a migration by decomposing it into components that minimize the amount of work required to carry out the modifications of the classes concerned by the migration, that can be studied separately and then possibly dispatching to designers; these components are groups of classes strongly coupled and separate (i.e. the classes making up each component are strongly coupled by transfer links, and no links occur between the classes of different components). Among the partitions of a migration obtained with such components, the best ones are those whose components minimize the amount of work required to carry out the modifications of the classes concerned by the migration. These partitions are such that classes are implicated in the minimum number components. In case several best partitions are found, we choose the ones which have the fewest components. The components of a migration are represented by maximal bipartite complete subgraphs of the graph of transfers of a migration that defines a partition of a set of its arcs. Efficient algorithms for building a partition of a directed graph by searching for such subgraphs do not exist in the graph theory. We propose three approaches for building a partition of the graph of transfers of a migration: a departure approach that places emphasis on the classes from which class characteristics are transferred, an arrival approach that places emphasis on the classes to which class characteristics are transferred, and a simulated annealing approach used in operations research.