Formal Engineering for Industrial Software Development

Transcription

1 Shaoying Liu Formal Engineering for Industrial Software Development Using the SOFL Method With 90 Figures and 30 Tables Springer

2 Contents Introduction Software Life Cycle The Problem Formal Methods : What Are Formal Methods Some Commonly Used Formal Methods Challenges to Formal Methods Formal Engineering Methods What Is SOFL A Little History of SOFL, Comparison with Related Work Exercises 19 Propositional Logic Propositions Operators Conjunction Disjunction Negation Implication Equivalence Tautology, Contradiction, and Contingency Normal Forms Sequent Proof Inference Rules..." Rules for Conjunction Rules for Disjunction Rules for Negation Rules for Implication 30

3 XVI Contents Rules for Equivalence Properties of Propositional Expressions Exercises 34 3 Predicate Logic Predicates Quantifiers The Universal Quantifier The Existential Quantifier Quantified Expressions with Multiple Bound Variables Multiple Quantifiers de Morgan's Laws Substitution Proof in Predicate Logic Introduction and Elimination of Existential Quantifiers Introduction and Elimination of Universal Quantifiers Validity and Satisfaction Treatment of Partial Predicates Formal Specification with Predicates Exercises 50 4 The Module Module for Abstraction Condition Data Flow Diagrams Processes Data Flows Data Stores Convention for Names Conditional Structures Merging and Separating Structures Diverging Structures Renaming Structure Connecting Structures Important Issues on CDFDs Starting Processes Starting Nodes Terminating Processes Terminating Nodes Enabling and Executing a CDFD Restriction on Parallel Processes Disconnected CDFDs External Processes Associating CDFD with a Module How to Write Comments A Module for the ATM 104

4 Contents XVII 4.16 Compound Expressions The if-then-else Expression The let Expression The case Expression Reference to Pre and Postconditions Function Definitions Ill Explicit and Implicit Specifications ' \. Ill Recursive Functions Exercises 114 Hierarchical CDFDs and Modules Process Decomposition Handling Stores in Decomposition Input and Output Data Flows The Correctness of Decomposition Scope Exercises 132 Explicit Specifications The Structure of an Explicit Specification Assignment Statement Sequential Statements Conditional Statements Multiple Choice Statements The Block Statement The While Statement Method Invocation Input and Output Statements Example Exercises 141 Basic Data Types The Numeric Types The Character Type., The Enumeration Types...: The Boolean Type An Example Exercises 148 The Set Types What Is a Set Set Type Declaration Constructors and Operators on Sets Constructors Operators 154

5 XVIII Contents 8.4 Specification with Set Types Exercises The Sequence and String Types What Is a Sequence Sequence Type Declarations Constructors and Operators on Sequences Constructors Operators Specifications Using Sequences Input and Output Module Membership Management System Exercises The Composite and Product Types Composite Types Constructing a Composite Type Fields Inheritance Constructor Operators Comparison Product Types An Example of Specification Exercises The Map Types What Is a Map The Type Constructor Operators Constructors Operators Specification Using a Map Exercises The Union Types Union Type Declaration A Special Union Type Is Function A Specification with a Union Type Exercises Classes Classes and Objects Class Definition Objects Identity of Objects 214

6 Contents XIX 13.2 Reference and Access Control The Reference of a Current Object Inheritance What Is Inheritance Superclasses and Subclasses Constructor Method Overloading Method Overriding Garbage Collection Polymorphism Generic Classes An Example of Class Hierarchy Example of Using Objects in Modules Exercises The Software Development Process Software Process Using SOFL Requirements Analysis The Informal Specification The Semi-formal Specification Abstract Design Evolution Detailed Design Transformation from Implicit to Explicit Specifications Transformation from Structured to Object-Oriented Specifications Program Validation and Verification Adapting the Process to Specific Applications Exercises Approaches to Constructing Specifications The Top-Down Approach The CDFD-Module-First Strategy The CDFD-Hierarchy-First Strategy The Modules and Classes The Middle-out Approach Comparison of the Approaches Exercises A Case Study - Modeling an ATM Informal User Requirements Specification Semi-formal Functional Specification Formal Abstract Design Specification Formal Detailed Design Specification 287

7 XX Contents 16.5 Summary Exercises Rigorous Review The Principle of Rigorous Review Properties Internal Consistency of a Process Invariant-Conformance Consistency Satisfiability Internal Consistency of CDFD Review Task Tree Review Task Tree Notation Minimal Cut Sets Review Evaluation Property Review Review of Consistency Between Process and Invariant Process Consistency Review Review of Process Satisfiability Review of Internal Consistency of CDFD Constructive and Critical Review Important Points Exercises Specification Testing The Process of Testing Unit Testing Process Testing Invariant Testing Criteria for Test Case Generation Integration Testing Testing Sequential Constructs Testing Conditional Constructs Testing Decompositions Exercises Transformation from Designs to Programs Transformation of Data Types Transformation of Modules and Classes Transformation of Processes Transformation of Single-Port Processes Transformation of Multiple-Port Processes Transformation of CDFD Exercises 369

8 Contents XXI 20 Intelligent Software Engineering Environment Software Engineering Environment Intelligent Software Engineering Environment Ways to Build an ISEE Domain-Driven Approach Method-Driven Approach Combination of Both ISEE and Formalization ISEE for SOFL Support for Requirements Analysis Support for Abstract Design Support for Refinement Support for Verification and Validation Support for Transformation Support for Program Testing Support for System Modification Support for Process Management Exercises 381 References 383 A Syntax of SOFL 391 A.I Specifications 391 A.2 Modules 392 A.3 Processes 392 A.4 Functions 394 A.5 Classes 394 A.6 Types 395 A.7 Expressions 396 A.8 Ordinary Expressions 396 A.8.1 Compound Expressions 396 A.8.2 Unary Expressions 397 A.8.3 Binary Expressions 397 A.8.4 Apply Expressions 397 A.8.5 Basic Expressions 399 A.8.6 Constants 399 A.8.7 Simple Variables 400 A.8.8 Special Keywords 400 A.8.9 Set Expressions 400 A.8.10 Sequence Expressions...." 400 A.8.11 Map Expressions 401 A.8.12 Composite Expressions 401 A.8.13 Product Expressions 401

9 XXII Contents A.9 Predicate Expressions 401 A.9.1 Boolean Variables 401 A.9.2 Relational Expressions 401 A.9.3 Conjunction 402 A.9.4 Disjunction 402 A.9.5 Implication 402 A.9.6 Equivalence 402 A.9.7 Negation 402 A.9.8 Quantified Expressions 402 A.10 Identifiers 403 A.ll Character 403 A.12 Comments 403 Index 405