Instant Consistency Checking for the UML.pdfVIP

Instant Consistency Checking for the UML Alexander Egyed Teknowledge Corporation 4640 Admiralty Way, Suite 1010 Marina Del Rey, CA 90292, USA aegyed@ ABSTRACT Inconsistencies in design models should be detected immediately to save the engineer from unnecessary rework. Yet, tools are not capable of keeping up with the engineers’ rate of model changes. This paper presents an approach for quickly, correctly, and automatically deciding what consistency rules to evaluate when a model changes. The approach does not require consistency rules with special annotations. Instead, it treats consistency rules as black-box entities and observes their behavior during their evaluation to identify what model elements they access. The UML/Analyzer tool, integrated with IBM Rational Rose?, fully implements this approach. It was used to evaluate 29 models with tens-of-thousands of model elements, evaluated on 24 types of consistency rules over 140,000 times. We found that the approach provided design feedback correctly and required, in average, less than 9ms evaluation time per model change with a worst case of less than 2 seconds at the expense of a linearly increasing memory need. This is a significant improvement over the state-of-the-art. Categories and Subject Descriptors D.2.10 [Design]: Validation General Terms Measurement, Documentation, Design, Languages, Verification. Keywords Incremental Analysis, Consistency, Design Feedback. 1. INTRODUCTION The UML [19] is a collection of loosely-connected, diagram- centric design notations. It allows engineers to explore the design of a software system through independent views. However, our work with engineers from industry (e.g., Boeing Company, SwRI) has shown that it is all too easy to make contradictory design decisions and that it is hard to recognize these inconsistencies. After decades of progress on model consistency [8] and consistency rules [18], this revelation is disturbing. Some are