From Textual Scenarios to Message Sequence Charts

Requirements engineering, the first phase of any software development project, is the Achilles’ heel of the whole development process, as requirements documents are often inconsistent and incomplete. In industrial requirements documents natural language is the main presentation means. In such documents, the system behavior is specified in the form of use cases and their scenarios, written as a sequence of sentences in natural language. For the authors of requirements documents some facts are so obvious that they forget to mention them. This surely causes problems for the requirements analyst. By the very nature of omissions, they are difficult to detect by document reviews: Facts that are too obvious to be written down at the time of document writing, mostly remain obvious at the time of review. In such a way, omissions stay undetected. This book chapter presents an approach that analyzes textual scenarios with the means of computational linguistics, identifies where actors or whole actions are missing from the text, completes the missing information, and creates a message sequence chart (MSC) including the information missing from the textual scenario. Finally, this MSC is presented to the requirements analyst for validation. The book chapter presents also a case study where scenarios from a requirement document based on industrial specifications were translated to MSCs. The case study shows feasibility of the approach. DOI: 10.4018/978-1-60566-758-4.ch005