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

From specification through refinement to implementation : a comparative study

This dissertation investigates the role of specification, refinement and implementation in the software development cycle. Both the structured and object-oriented paradigms are looked at. Particular emphasis is placed on the role of the refinement process. The requirements for the product (system) are determined, the specifications are drawn up, the product is designed, specified, implemented and tested. The stage between the (formal) specification of the system and the implementation of the system is the refinement stage. The refinement process consists out of data refinement, operation refinement, and operation decomposition. In this dissertation, Z, Object-Z and UML (Unified Modelling Language) are used as specification languages and C, C++, Cobol and Object-Oriented Cobol are used as implementation languages. As an illustration a small system, The ITEM System, is specified in Z and UML and implemented in Object-Oriented Cobol.ComputingM. Sc. (Information Systems

Data Refinement in Object-Oriented Verification

Data refinement is a special instance of refinement where a specification is refined by replacing the data type used in the specification. The theory of data refinement guarantees that this replacement does not adversely affect the functional behaviour of the programs that use these specifications. Object-oriented programming languages such as JML and Spec# support the specification and verification of object-oriented programs. We research their capabilities, identifying their strengths and weaknesses from both a specification and a tool-support point of view. This leads us to the conclusion that object-oriented specification languages should support a view of objects that abstracts away from the implementation details. We examine the specification and verification of programs that are written in this way, making use of existing language features, so that data refinements can be verified using existing verification tools. We propose a framework for the specification and verification of modular data refinement within an object-oriented environment. Objects are specified in terms of one data type and implemented in terms of another. Clients who interact with these objects are never concerned with the underlying implementation details as they interact directly with the abstract specification. A proof-of-concept tool is developed to demonstrate the viability and effectiveness of our proposed framework. This tool takes the form of an application that checks whether or not a program conforms to our framework for the modular data refinement of object-oriented programs

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

A Survey of Languages for Specifying Dynamics: A Knowledge Engineering Perspective

A number of formal specification languages for knowledge-based systems has been developed. Characteristics for knowledge-based systems are a complex knowledge base and an inference engine which uses this knowledge to solve a given problem. Specification languages for knowledge-based systems have to cover both aspects. They have to provide the means to specify a complex and large amount of knowledge and they have to provide the means to specify the dynamic reasoning behavior of a knowledge-based system. We focus on the second aspect. For this purpose, we survey existing approaches for specifying dynamic behavior in related areas of research. In fact, we have taken approaches for the specification of information systems (Language for Conceptual Modeling and TROLL), approaches for the specification of database updates and logic programming (Transaction Logic and Dynamic Database Logic) and the generic specification framework of abstract state machine

Observation and abstract behaviour in specification and implementation of state-based systems

Classical algebraic specification is an accepted framework for specification. A criticism which applies is the fact that it is functional, not based on a notion of state as most software development and implementation languages are. We formalise the idea of a state-based object or abstract machine using algebraic means. In contrast to similar approaches we consider dynamic logic instead of equational logic as the framework for specification and implementation. The advantage is a more expressive language allowing us to specify safety and liveness conditions. It also allows a clearer distinction of functional and state-based parts which require different treatment in order to achieve behavioural abstraction when necessary. We shall in particular focus on abstract behaviour and observation. A behavioural notion of satisfaction for state-elements is needed in order to abstract from irrelevant details of the state realisation