A Formal Approach for Consistency Management in UML Models

Consistency is a significant indicator to measure the correctness of a software system in its lifecycle. It is inevitable to introduce inconsistencies between different software artifacts in the software development process. In practice, developers perform consistency checking to detect inconsistencies, and apply their corresponding repairs to restore consistencies. Even if all inconsistencies can be repaired, how to preserve consistencies in the subsequent evolution should be considered. Consistency management (consistency checking and consistency preservation) is a challenging task, especially in the multi-view model-driven software development process. Although there are some efforts to discuss consistency management, most of them lack the support of formal methods. Our work aims to provide a framework for formal consistency management, which may be used in the practical software development process. A formal model, called a Structure model, is first presented for specifying the overall model-based structure of the software system. Next, the definition of consistency is given based on consistency rules. We then investigate consistency preservation under the following two situations. One is that if the initial system is inconsistent, then the consistency can be restored through repairs. The other is that if the initial system is consistent, then the consistency can be maintained through update propagation. To demonstrate the effectiveness of our approach, we finally present a case study with a prototype tool.