COMP 325 Lecture 13: Design Workflow
major resources: Object-Oriented and Classical Software Engineering 6ed, Schach 2005, Object-Oriented Software Engineering, Schach 2008, and Designing from Both Sides of the Screen, Isaacs and Walendowski 2002

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Object Oriented Design Workflow

• Can begin working on it before analysis workflow is complete
• Finally address the "how"; attention turns to the implementation domain
• Entails two major activities
1. filling in remaining details of the class diagram
• attributes and their details
• methods, and assigning them to proper class - some guidelines:
• if method modifies attributes, it goes with class having the attributes
• if multiple clients have relationship with it, it goes with the "server" class
• assign it to class that assumes it as responsibility, as revealed through CRC cards
2. developing detailed design of methods using pseudo-code
• the assumption underlying these activities: the classes identified and specified in analysis workflow are retained for the design and implementation
• this represents a major advance for OO versus classical techniques
• vastly simplifies traceability from implementation through design and analysis
• there will inevitably be changes to class diagram info as design and implementation progress
• principle artifacts are finalized class diagram plus method designs
• testing is done through walkthroughs and inspections, just as for requirements and analysis

System design architecture

• architecture refers to overall system structure
• needs to be established early in design
• Even if purely OO, the objects/classes need to be organized and arranged
• e.g. if client-server, some objects assigned to client and others to server and means of communication needs to be established
• e.g. if system architecture is organized by subsystems, then classes need to be assigned to subsystems
• discussion guided by PowerPoint presentation and handout
• subsystem architecture example: robot control system
• repository architecture example: CASE toolset
• abstract-machine architecture example: version management system
• client-server architecture example: file and picture library
• 2-tier, 3-tier, N-tier client-server
• example of domain-specific generic architecture: compiler architecture
• example of domain-specific reference architecture: OSI 7-layer network model
• intro to control models, including call-return, real-time system controller, interrupt-driven and event-driven
• these issues are not covered in Schach software engineering textbook

User Interface Design

• discussion guided by material from Winter 2004 COMP 481 Special Topics: User Interface Design
• UID textbook by Isaacs and Walendowski referenced at top of this page
• Two major aspects of User Interface Design
  • Goals : See COMP 225 Lecture 14
  • Process : See COMP 225 Lecture 15
• these issues are not covered in Schach software engineering textbook