From Object-Oriented Specification to Implementation: A Formal Refinement Methodology.

Traditionally, software development models use different methods and techniques in each phase from specification through design to implementation. Significant changes in the representations between phases have been common. The formal development method based on formal specification and stepwise development has been suggested to reduce the change in representation. The formal development method consists of a formal specification and verified design. In the formal specification step, a formal specification language is used to specify an accurate, consistent, and complete system. Vienna Development Method (VDM) is one of the most widely used formal specification languages. A verified design guides the development of the system from specification to executable code. A refinement method is used in VDM for that purpose. The use of the object-oriented paradigm is another important trend in software engineering. Initially, object-oriented methods were applied primarily during the implementation phase using object-oriented languages. Eiffel is an object-oriented programming language which has many strong facilities such as assertions and genericity. Numerous object-oriented specification languages exist, including object-oriented extensions to VDM. We defined Object-VDM to help remove limitations from existing object-oriented VDM languages. In this dissertation, we investigate a formal development method in the object-oriented environment since limited research hss been done in the area. We defined a refinement method that refines an Object-VDM specification to Eiffel code. There are three stages in this refinement: data refinement, operation refinement, and structure refinement. In data refinement, the mathematical data models in Object-VDM are converted to Eiffel data structures by creating Eiffel libraries. We proved the correctness of the conversion. In operation refinement, we modified and added rules to the original refinement to obtain Eiffel code. Object-oriented features are converted in the structure refinement step. In summary, this research provides a refinement method in object-oriented environments. Specifically, the refinement converts Object-VDM specifications to Eiffel codes

Formal specification techniques in object-oriented analysis: a comparative view.

During the last decade, object orientation has been advanced as a promising paradigm for software construction. In addition several authors have advocated the use of formal specification techniques during software development. Formal methods enable reasoning (in a mathematical sense) about properties of programs and systems. It is clear that also object oriented software development can benefit from the use of formal techniques.But although the object oriented analysis (OOA) methods claim to provide the necessary concepts and tools to improve the quality of software development, they are in general informal. This is surprising as the modeling techniques used in OOA have a high potential for formalization. The purpose of this study is to compare the specification techniques used in current OOA-methods. In particular, the degree of formality provided by most of the methods is discussed and evaluated from a quality control perspective.Software; Methods; Programs; Systems; Studies; Quality control;

Rigorous object-oriented analysis

Object-oriented methods for analysis, design and programming are commonly used by software engineers. Formal description techniques, however, are mainly used in a research environment. We have investigated how rigour can be introduced into the analysis phase of the software development process by combining object-oriented analysis (OOA) methods with formal description techniques. The main topics of this investigation are a formal interpretation of the OOA constructs using LOTOS, a mathematical definition of the basic OOA concepts using a simple denotational semantics and a new method for object- oriented analysis that we call the Rigorous Object-Oriented Analysis method (ROOA). The LOTOS interpretation of the OOA concepts is an intrinsic part of the ROOA method. It was designed in such a way that software engineers with no experience in LOTOS, can still use ROOA. The denotational semantics of the concepts of object-oriented analysis illuminates the formal syntactic transformations within ROOA and guarantees that the basic object- oriented concepts can be understood independently of the specification language we use. The ROOA method starts from a set of informal requirements and an object model and produces a formal object-oriented analysis model that acts as a requirements specification. The resulting formal model integrates the static, dynamic and functional properties of a system in contrast to existing OOA methods which are informal and produce three separate models that are difficult to integrate and keep consistent. ROOA provides a systematic development process, by proposing a set of rules to be followed during the analysis phase. During the application of these rules, auxiliary structures are created to help in tracing the requirements through to the final formal model. As LOTOS produces executable specifications, prototyping can be used to check the conformance of the specification against the original requirements and to detect inconsistencies, omissions and ambiguities early in the development process

Foundations of the Unified Modeling Language.

Object-oriented analysis and design is an increasingly popular software development method. The Unified Modeling Language (UML) has recently been proposed as a standard language for expressing object-oriented designs. Unfor- tunately, in its present form the UML lacks precisely defined semantics. This means that it is difficult to determine whether a design is consistent, whether a design modification is correct and whether a program correctly implements a design. Formal methods provide the rigor which is lacking in object-oriented design notations. This provision is often at the expense of clarity of exposition for the non-expert. Formal methods aim to use mathematical techniques in order to allow software development activities to be precisely defined, checked and ultimately automated. This paper aims to present an overview of work being undertaken to provide (a sub-set of) the UML with formal semantics. The semantics will facilitate the use of the UML in the software development process by allowing development steps to be defined and checked

Modal logics for reasoning about object-based component composition

Component-oriented development of software supports the adaptability and maintainability of large systems, in particular if requirements change over time and parts of a system have to be modified or replaced. The software architecture in such systems can be described by components and their composition. In order to describe larger architectures, the composition concept becomes crucial. We will present a formal framework for component composition for object-based software development. The deployment of modal logics for defining components and component composition will allow us to reason about and prove properties of components and compositions