Class 10: The UML (4): Miscellaneous

Held: Friday, 17 September 2004

Summary: Today we conclude our exploration of the UML with a study of sequence diagrams and some other related issues.

Related Pages:

• EBoard.

Due

• Homework 2: Diagrams.

Assignments

• Start to read the XP book.
• Project, phase 1: Design and implement theWorld.

Notes:

• Today is our last formal UML day. We will continue to use the UML as we diagram our designs.
• The homework assignment will start informally and become more formal.

Overview:

• Sequence diagram example.
• Questions and answers.
• State diagram example.

An Example

• I've drawn four possible "how to display the world" implementations on the board.
• What do the different diagrams suggest?
• Which do you prefer?
• Why are these diagrams better than just writing code?
• Some design issues:
  • Should theWorld and aWorldView be merged into one class? Why or why not?
  • Should aWorldView and drawingWindow be merged into one class? Why or why not?

Questions

• What terms and concepts from the reading are confusing to you?

State Diagrams

• Exercise: Draw the state diagram for a simple, two-button, alarm watch.

Assignment

• Implement bug worlds.
• When you create a new world, it should distribute "stuff" somewhat randomly.
• What stuff is there in a world? For now:
  • Bugs.
  • Food, which can start in the world or be created.
  • Plants, which create food.
  • BugEaters, which eat bugs. You are not responsible for moving BugEaters.
  • Pheremones, which bugs deposit.
  • BugColonies, where bugs live.
• Model your world as a grid of x,y positions.
• Support listeners. Notify listeners when the world changes.
• Support changes to the world. What changes should you support?