Verification of behavioural elements of UML models using

Verification of behavioural elements of UML models using B Truong, Ninh-Thuan and Souquieres, Jeanine. 2005. In Proceedings of the 2005 ACM Symposium on Applied Computing Santa Fe, New Mexico, March 13 - 17, 2005 Presented by: James T. O’Hara SE 510, Fall 2005

A Tale of Two Tools … ¢ The application of formal methods allows the rigorous definition and analysis of the functionality and the behavior of a system. l It is capable of showing that the system is correct. l B is a method for specifying, designing and coding software systems. ¢ UML is a widely accepted modeling language that can be used to visualize, specify, construct and document the artifacts of a software system. 1

Combining UML with B ¢ The derivation from UML specification into the B formal method is considered as an appropriate way to jointly use UML and B in practical, unified and rigorous software development. ¢ The aim of the study was to use B support tools to analyze UML model properties. 2

THE B METHOD ¢ B is a formal software development method, originally developed by J. R. Abrial. ¢ The B notation is based on set theory, the language of generalized substitutions and first order logic. ¢ Specifications are composed of abstract machines that are similar to modules or classes. 3

The UML Metamodel ¢ The UML metamodel defines the complete semantics for representing object models using UML. Abstract Syntax l Well-Formedness Rules l Semantics l 4

TRANSFORMATION OF UML TO B ¢ The transformation of an attribute of a UML class to a variable of a B abstract machine can be performed as follows: 5

What is a UML Collaboration Diagram ¢ A collaboration diagram describes interactions among objects in terms of sequenced messages. Collaboration diagrams represent a combination of information taken from class, sequence, and use case diagrams describing both the static structure and dynamic behavior of a system. 6

UML Collaboration Diagram ¢ UML collaboration diagrams, are used to explore the dynamic nature of your software. Source: http: //www. agilemodeling. com/style/collaboration. Diagram. htm 7

TRANSFORMATION OF THE COLLABORATION PACKAGE TO B ¢ The Collaboration package is a sub-package of the Behavioral Elements package 8

What is a UML State Diagram Figure 1. A seminar during registration. ¢ UML state machine diagrams depict the various states that an object may be in and the transitions between those states. Source: http: //www. agilemodeling. com/artifacts/state. Machine. Diagram. htm 9

TRANSFORMATION OF THE STATE MACHINE PACKAGE TO B ¢ The State Machine package is a subpackage of the Behavioral Elements package. 10

A CASE STUDY ¢ Modeling of a printing system. l l This system can be described as follows: the printing system is a system to print a file from a computer. The use gives a command to print a file, and the system will respond according to its messages. Figure 3. Collaboration diagram of the printing system. 11

Interaction B Abstract Machine 12

Verification of UML Model Properties ¢ The well-formedness rules of the Messages class applied on the Collaboration package and their B machines counterparts can be evaluated for completeness and consistency. l UML well-formedness rules can be represented by system invariants. 13

CONCLUSION In this paper, the author’s have presented a technique to transform the UML behavioral diagrams to a B specification. ¢ With the contribution of the transformation of UML metamodel and their well-formedness rules into B, the semantics of the UML models can be translated into B properties. ¢ Formal methods can then be used to specify and verify object-oriented systems. ¢ 14

Additional References The B-Book: Assigning Programs to Meanings, Cambridge University Press 1996. ISBN 0 -521 -49619 -5 ¢ The Object Primer: Agile Model-Driven Development with UML 2. 0 Scott Ambler, Cambridge University Press, Paperback, 3 rd edition, 2004 ¢ 15