SOFTWARE ARCHITECTURE

Transcription

1 SOFTWARE ARCHITECTURE PERSPECTIVES ON AN EMERGING DISCIPLINE MARY SHAW Carnegie Mellon University DAVID GARLAN Carnegie Mellon University An Alan R. Apt Book Prentice Hall, Upper Saddle River, New Jersey 07458

2 CONTENTS CHAPTER 1 Introduction 1.1 What Is Software Architecture? Software Design Levels, An Engineering Discipline for Software What Is Engineering?, The Current State of Software Technology, The Status of Software Architecture The Plan of This Book 17 CHAPTER 2 Architectural Styles 2.1 Architectural Styles Pipes and Filters Data Abstraction and Object-Oriented Organization Event-Based, Implicit Invocation Layered Systems Repositories Interpreters Process Control Process-Control Paradigms, A Software Paradigm for Process Control, Other Familiar Architectures Heterogeneous Architectures 32

3 XVlll CONTENTS CHAPTER 3 Case Studies Key Word in Context Solution 1: Main Program/Subroutine with Shared Data, Solution 2: Abstract Data Types, Solution 3: Implicit Invocation, Solution 4: Pipes and Filters, Comparisons, Instrumentation Software An Object-Oriented Model, A Layered Model, APipe-and-FilterModel, A Modified Pipe-and-Filter Model, Further Specialization, Summary, Mobile Robotics 43 By Marco Schumacher Design Considerations, Solution 1: Control Loop, Solution 2: Layered Architecture, Solution 3: Implicit Invocation, Solution 4: Blackboard Architecture, Comparisons, Cruise Control Object View of Cruise Control, Process-Control View of Cruise Control, Analysis and Discussion, Summary, Three Vignettes in Mixed Style A Layered Design with Different Styles for the Layers, An Interpreter Using Different Idioms for the Components, A Blackboard Globally Recast as an Interpreter, 66 CHAPTER 4 Shared Information Systems Shared Information Systems Database Integration Batch Sequential, Simple Repository, Virtual Repository, Hierarchical Layers, Evolution of Shared Information Systems in Business Data Processing, Integration in Software Development Environments Batch Sequential, Transition from Batch Sequential to Repository, 83

4 CONTENTS xix Repository, Hierarchical Layers, Evolution of Shared Information Systems in Software Development Environments, Integration in the Design of Buildings Repository, Intelligent Control, Evolution of Shared Information Systems in Building Design, Architectural Structures for Shared Information Systems Variants on Dataflow Systems, Variants on Repositories, Some Conclusions 95 CHAPTER 5 Architectural Design Guidance Guidance for User-Interface Architectures 97 by Thomas G. Lane Design Spaces and Rules, A Design Space for User-Interface Architectures, Design Rules for User-Interface Architecture, Applying the Design Space: An Example, A Validation Experiment, How the Design Space Was Prepared, Summary, The Quantified Design Space 116 by Toru Asada, Roy F. Swonger, Nadine Bounds, and Paul Duerig Overview, Background, Quantified Design Space, Conclusion, 127 CHAPTER 6 Formal Models and Specifications The Value of Architectural Formalism Formalizing the Architecture of a Specific System Formalizing an Architectural Style Filters, Pipes, Pipe-and-Filter System, Formalizing an Architectural Design Space Toward a Theory of Software Architecture What Next? Z Notation Used in This Chapter 143

5 XX CONTENTS CHAPTER 7 Linguistic Issues Requirements for Architecture-Description Languages The Linguistic Character of Architectural Description, Desiderata for Architecture-Description Languages, Problems with Existing Languages, First-Class Connectors Current Practice, Problems with Current Practice, A Fresh View of Software System Composition, An Architectural Language with First-Class Connectors, The Promise of Explicit Architectural Notations, Adding Implicit Invocation to Traditional Programming Languages Introduction, Adding Implicit Invocation to Ada, Evaluation, 181 CHAPTER 8 Tools for Architectural Design UniCon: A Universal Connector Language Components and Connectors, Abstraction and Encapsulation, Types and Type Checking, Accommodating Analysis Tools, Exploiting Style in Architectural Design Environments What Is Architectural Style?, Automated Support for Architectural Design, Observations about Environments for Architectural Design, Beyond Definition/Use: Architectural Interconnection Implementation versus Interaction, Example, The WRIGHT Model of Architectural Description, Reasoning about Architectural Descriptions, A Brief Explanation of Our Use of CSP, 211 CHAPTER 9 Education of Software Architects Philosophy and Course Overview Objectives, Approach, Course Description Assignments Purpose, Readings, Architectural Development Tasks, Formal Modeling, 222

6 CONTENTS xxi Analysis and Interpretation of a System, Evaluation Lessons from the Initial Offering, Conclusions About Teaching Software Architecture, 225 Bibliography 227 Index 239