UML

• UML stands for the Unified Modeling Language
• It is a tool for visualizing classes
  • And other things.
• I use the software UMLentino
  • On line or download and run on your computer.
  • There are others, but this works well.
• There is a brief reference in appendix D (P 1083)
  • UMLentio is fairly self documenting.
  • I use this book as my reference.
• This language is huge, but we will only use the class portion.
• Let's take a look at FastFood from the last assignment.
  • What class should you have built?
  • What are the possible "objects" in the game
    • A Sticker
    • The collection of stickers
    • Prize
    • Coach
    • Team
  • Which of these are real objects in the program?
    • Probably not the coach and the team.
  • Which have both data and operations
    • A sticker are just exist or not, so they don't
  • We are left with
    • The collection of stickers
    • A prize
  • Let's start with a prize
  • So what are the member operations and data of the prize
    • The data is easy:
      • a prize amount
      • a vector of ticket id's needed.
      • Let's do the UML for that.
      • 
      • The Methods
        • Constructor.
        • Do we need the big 3?
        • Add Prize, Get Prize
        • Add Sticker
      • We now have a decision to make
        • Does a prize decided if it has been won?
        • When designing classes we need to have clear lines of responsibility.
        • We can put this anywhere, but we need the methods to support it.
        • If yes, we need a method that takes a container of stickers and returns
          • The prize value of those stickers.
          • Possibly a modified sticker list with those stickers removed.
        • If no, we need a way to get the list of stickers required.
        • I like the second for this program.
    • How about the sticker collection
      • The data is an array of stickers.
      • The methods
        • Constructor (stickerCount)
        • ChangeSticker (id, quantity)
        • GetSticker(id)
      • 
  • Let's consider a coach type.
    • Data
      • An array of PrizeT
      • A StickerCollectionT
    • Operations
      • AddPrize
      • AddSticker
      • CalculateWinnings
    • 
    • This is an instance of a "has a" relationship.
      • A coach has a list of prizes
      • A coach has a StickerCollection.
    • In the first case, prizes can exist without a coach
      • So this is an Aggregation
      • Draw with a empty diamond from prize to coach
      • This is a forced example.
      • Think "a pond has a frog".
        • Frogs can exist without ponds
    • In the second case, let's say a sticker collection can not exist without a coach
      • This is a composition
      • Use a solid diamond.
      • This is a forced example.
      • Think "A frog has a heart".
        • Outside of biology class, a heart does not exist without a frog.
        • When the frog is destroyed, the heart is destroyed.
    • 
    • Sometimes we show the diagram without details (high level)
    •