A Unified Approach to OOD
22.1.4 A Unified Approach to OOD
In Chapter 21, we noted that Grady Booch, James Rumbaugh, and Ivar Jacobson com- bined the best features of their individual object-oriented analysis and design meth- ods into a unified method. The result, called the Unified Modeling Language has become
WebRef
widely used throughout the industry. 4 An extensive tutorial and
listing of UML resources During analysis modeling (Chapter 21), the user model and structural model views
including tools, papers, are represented. These provide insight into the usage scenarios for the system (pro- and examples can be
viding guidance for behavioral modeling) and establish a foundation for the imple- found at
mini.net/cetus/
mentation and environment model views by identifying and describing the static
oo_uml.html
structural elements of the system. UML is organized into two major design activities: system design and object design. The primary objective of UML system design is to represent the software architecture. Bennett, McRobb, and Farmer [BEN99] discuss this issue in the following way:
In terms of object-oriented development, the conceptual architecture is concerned with the structure of the static class model and the connections between components of the model. The module architecture describes the way the system is divided into subsystems or mod- ules and how they communicate by exporting and importing data. The code architecture defines how the program code is organized into files and directories and grouped into libraries. The execution architecture focuses on the dynamic aspects of the system and the communication between components as tasks and operations execute.
The definition of the “subsystems” noted by Bennett et al. is a primary concern dur- System design focuses ing UML system design. on software
UML object design focuses on a description of objects and their interactions with architecture and the
definition of one another. A detailed specification of attribute data structures and a procedural subsystems. Object 5 design of all operations are created during object design. The visibility for all class
design describes attributes is defined and interfaces between objects are elaborated to define the details objects at a level of
of a complete messaging model. detail that can be
System and object design in UML are extended to consider the design of user interfaces, implemented in a
programming data management with the system to be built, and task management for the subsystems language.
that have been specified. User interface design in UML draws on the same concepts and principles discussed in Chapter 15. The user model view drives the user interface design process, providing a scenario that is elaborated iteratively to become a set of interface classes. 6
4 Booch, Rumbaugh, and Jacobson have written a set of three definitive books on UML. The inter- ested reader should see [BOO99], [RUM99], and [JAC99]. 5 Visibility indicates whether an attribute is public (available across all instantiations of the class), private (available only for the class that specifies it), or protected (an attribute that may be used by the class that specifies it and its subclasses). 6 Today, most interface classes are part of a library of reusable software components. This expe- dites the design and implementation of GUIs.
CHAPTER 22
OBJECT-ORIENTED DESIGN
F I G U R E 22.3
Process flow for OOD
Object-oriented analysis System design
Task management
design Object
design
Data management
design Human interface
design
Data management design establishes a set of classes and collaborations that allow the system (product) to manage persistent data (e.g., files and databases). Task manage- ment design establishes the infrastructure that organizes subsystems into tasks and then manages task concurrency. The process flow for design is illustrated in Figure 22.3. 7
Throughout the UML design process, the user model view and structure model view are elaborated into the design representation outlined above. This elaboration activity is discussed in the sections that follow.
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,
Show more