Class 22: The OOA&D Lifecycle

Held: Thursday, April 22, 2010

Summary: We look at the complete object-oriented design process, as reflected in the Head-First text.

Related Pages:

• EBoard.

Notes:

• Extra credit for today's CS extra.
• Extra credit for tomorrow's CS table.
• Reading for Tuesday: Ch. 1 of Design Patterns (to be distributed).

Overview:

• The OOA&D Lifecycle.
• Dijkstra's Shortest Path Algorithm.
• Subways.
• Reflecting on Head-First.
• Project.

The OOA&D Lifecycle

• The OOAD "Lifecycle" as they describe it, is as follows
  • Feature LIst
  • Use Case Diagrams
  • Break Up The Problem
  • Requirements
  • Domain Analysis
  • Preliminary Design
  • Implementation
  • Delivery
• They also recommend iterating the "Requirements / Domain Analysis / Preliminary Design / Implementation" stages for each smaller problem
• They also insesr an "Understand the Problem" part for each subproblem.
• What do you see as the big differences between the lifecycle diagram given in chapter 10, and the XP model?

Dijkstra's Shortest Path Algorithm

• How many of you don't know Dijkstra's shortest path algorithm?
• How many of you know it well enough to teach it to someone else?
• If we have many people who don't know the algorithm, we'll go through it.
• If we have many people who are confused by the code, we'll go through that, too.

Fun with Subways

We'll explore their subway code in some depth.

• What do you think about their decision not to use a Graph data structure?
• What hidden assumptions might be encoded in the design of a subway that we should explore?
• What do you see as flaws in the code on p. 524? How does that relate to what we've learned in the previous chapter.

Reflecting on Head First Object-Oriented Analysis and Design

• Pedagogy vs. presentation
  • The "stop and think about this" pedagogy is important. It's certainly how I prefer to teach my classes.
  • But it gets lost in the silliness, which I think is geared toward students with different characteristics than yours.
• Big pictures vs. small picture issues.
  • We all seem to dislike a lot of their code.
  • But our dislike of the code does not obscure that they make some important points.

Project

Questions sent to me

• What is the "main" class of our project?
  • To be written
  • There will probably be two main classes: One for the local version and one for the networked version.
• What owns everything?
  • The main class
• How does information flow from the board to the GUI?
  • Covered last class