SUMMARY Object-oriented design translates the OOA model of the real world into an
22.6 SUMMARY Object-oriented design translates the OOA model of the real world into an
implementation-specific model that can be realized in software. The OOD process can be described as a pyramid composed of four layers. The foundation layer focuses on the design of subsystems that implement major system functions. The class layer specifies the overall object architecture and the hierarchy of classes required to imple- ment a system. The message layer indicates how collaboration between objects will
be realized, and the responsibilities layer identifies the attributes and operations that characterize each class. Like OOA, there are many different OOD methods. UML is an attempt to provide
a single approach to OOD that is applicable in all application domains. UML and other methods approach the design process through two levels of abstraction—design of subsystems (architecture) and design of individual objects.
During system design, the architecture of the object-oriented system is devel- oped. In addition to developing subsystems, their interactions, and their place- ment in architectural layers, system design considers the user interaction component, a task management component, and a data management compo- nent. These subsystem components provide a design infrastructure that enables the application to operate effectively. The object design process focuses on the description of data structures that implement class attributes, algorithms that implement operations, and messages that enable collaborations and object rela- tionships.
Design patterns allow the designer to create the system architecture by integrat- ing reusable components. Object-oriented programming extends the design model into the executable domain. An OO programming language is used to translate the classes, attributes, operations, and messages into a form that can be executed by a machine.
CHAPTER 22 OBJECT-ORIENTED DESIGN
REFERENCES [BEN99] Bennett, S., S. McRobb, and R. Farmer, Object Oriented System Analysis and
Design Using UML, McGraw-Hill, 1999. [BIH92] Bihari, T. and P. Gopinath, “Object-Oriented Real-Time Systems: Concepts and Examples,” Computer, vol. 25, no. 12, December 1992, pp. 25–32. [BOO94] Booch, G., Object-Oriented Analysis and Design, 2nd ed., Benjamin Cum- mings, 1994. [BOO99] Booch, G., I. Jacobson, J. Rumbaugh, The Unified Modeling Language User Guide, Addison-Wesley, 1999. [BRO91] Brown, A.W., Object-Oriented Databases, McGraw-Hill, 1991. [BUS96] Buschmann, F., et al., A System of Patterns: Pattern Oriented System Archi- tecture, Wiley, 1996. [CHA93] De Champeaux, D., D. Lea, and P. Faure, Object-Oriented System Develop- ment, Addison-Wesley, 1993. [COA91] Coad, P. and E. Yourdon, Object-Oriented Design, Prentice-Hall, 1991. [COX85] Cox, B., "Software ICs and Objective-C," UnixWorld, Spring 1985. [DAV95] Davis, A., “Object-Oriented Requirements to Object-Oriented Design: An Easy Transition?” Journal of Systems Software, vol. 30, 1995, pp. 151–159. [DOU99] Douglass, B., Real-Time UML: Developing Efficient Objects for Embedded Sys- tems, Addison-Wesley, 1999. [FIC92] Fichman, R. and C. Kemerer, "Object-Oriented and Conceptual Design Methodologies," Computer, vol. 25, no. 10, October 1992, pp. 22–39. [GAM95] Gamma, E., et al., Design Patterns, Addison-Wesley, 1995. [GOL83] Goldberg, A. and D. Robson, Smalltalk-80: The Language and Its Implemen- tation, Addison-Wesley, 1983. [JAC92] Jacobson, I., Object-Oriented Software Engineering, Addison-Wesley, 1992. [JAC99] Jacobson, I., G. Booch, J. Rumbaugh, Unified Software Development Process, Addison-Wesley, 1999. [MEY90] Meyer, B., Object-Oriented Software Construction, 2nd ed., Prentice-Hall, 1988. [PRE95] Pree, W., Design Patterns for Object-Oriented Software Development, Addison- Wesley, 1995. [RUM91] Rumbaugh, J., et al., Object-Oriented Modeling and Design, Prentice-Hall, 1991. [RUM99] Rumbaugh, J., I. Jacobson, and G. Booch, The Unified Modeling Language Reference Manual, Addison-Wesley, 1999. [RAO94] Rao, B.A., Object-Oriented Databases: Technology, Applications and Products, McGraw-Hill, 1994. [TAY92} Taylor, D.A., Object-Oriented Information Systems, Wiley, 1992. [WIR90] Wirfs-Brock, R., B. Wilkerson, and L. Weiner, Designing Object-Oriented Soft- ware, Prentice-Hall, 1990.
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Parts
» The Concurrent Development Model
» SUMMARY Software engineering is a discipline that integrates process, methods, and tools for
» PEOPLE In a study published by the IEEE [CUR88], the engineering vice presidents of three
» THE PROCESS The generic phases that characterize the software process—definition, development,
» THE PROJECT In order to manage a successful software project, we must understand what can go
» METRICS IN THE PROCESS AND PROJECT DOMAINS
» Extended Function Point Metrics
» METRICS FOR SOFTWARE QUALITY
» INTEGRATING METRICS WITHIN THE SOFTWARE PROCESS
» METRICS FOR SMALL ORGANIZATIONS
» ESTABLISHING A SOFTWARE METRICS PROGRAM
» Obtaining Information Necessary for Scope
» An Example of LOC-Based Estimation
» QUALITY CONCEPTS 1 It has been said that no two snowflakes are alike. Certainly when we watch snow
» SUMMARY Software quality assurance is an umbrella activity that is applied at each step in the
» R diagram 1.4 <part-of> data model; data model <part-of> design specification;
» SYSTEM MODELING Every computer-based system can be modeled as an information transform using an
» Facilitated Application Specification Techniques
» Data Objects, Attributes, and Relationships
» Entity/Relationship Diagrams
» Hatley and Pirbhai Extensions
» Creating an Entity/Relationship Diagram
» SUMMARY Design is the technical kernel of software engineering. During design, progressive
» Data Modeling, Data Structures, Databases, and the Data Warehouse
» Data Design at the Component Level
» A Brief Taxonomy of Styles and Patterns
» Quantitative Guidance for Architectural Design
» Isolate the transform center by specifying incoming and outgoing
» SUMMARY Software architecture provides a holistic view of the system to be built. It depicts the
» The User Interface Design Process
» Defining Interface Objects and Actions
» D E S I G N E VA L U AT I O N
» Testing for Real-Time Systems
» Organizing for Software Testing
» Criteria for Completion of Testing
» The Transition to a Quantitative View
» The Attributes of Effective Software Metrics
» Architectural Design Metrics
» Component-Level Design Metrics
» SUMMARY Software metrics provide a quantitative way to assess the quality of internal product
» Encapsulation, Inheritance, and Polymorphism
» Identifying Classes and Objects
» The Common Process Framework for OO
» OO Project Metrics and Estimation
» Event Identification with Use-Cases
» SUMMARY Object-oriented analysis methods enable a software engineer to model a problem by
» Partitioning the Analysis Model
» Designing Algorithms and Data Structures
» Program Components and Interfaces
» SUMMARY Object-oriented design translates the OOA model of the real world into an
» Testing Surface Structure and Deep Structure
» Deficiencies of Less Formal Approaches 1
» What Makes Cleanroom Different?
» Design Refinement and Verification
» SUMMARY Cleanroom software engineering is a formal approach to software development that
» Structural Modeling and Structure Points
» Describing Reusable Components
» SUMMARY Component-based software engineering offers inherent benefits in software quality,
» Guidelines for Distributing Application Subsystems
» Middleware and Object Request Broker Architectures
» An Overview of a Design Approach
» Consider expert Web developer will create a complete design, but time and cost can be appropriate
» A Software Reengineering Process Model
» Reverse Engineering to Understand Data
» Forward Engineering for Client/Server Architectures
» SUMMARY Reengineering occurs at two different levels of abstraction. At the business level,
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