2. Something Small We Can Build

A Simple Calculation

• Beer is Malted Barley, Water, Yeast and Hops
  • Bitterness comes from alpha acids in hops
  • Hops also have an aroma component
  • Alpha acid varies with weather, where grown, fertilizers used, etc.
• Homebrew Bitterness Units Calculator

Applet Overview

We will design a Java applet which will do any of the three related calculations which related bitterness with alpha acid content and weight.

• HBU = Alpha Acid (%) * Weight (oz.)
  • From Acid and Weight, compute HBU’s
  • From HBU’s and Acid, compute Weight

OO Lifecycle

• OOAnalysis
  • Object Model - describe the elements of a bitterness unit calculator
  • Dynamic Model - describe the interactions among the elements
  • Functional Model - describe data flow between elements
• System Design - make “high level” implementation decisions
• Detailed Design
  • Object - describe the Java classes used to construct the calculator
  • Dynamic Model - descibe the interactions among the elements
  • Functional Models - describe dataflow between the elements
• Code - Write the calculator in Java

• Step 1 - Analysis
  • Analysis-Level Object Model
  • Analysis-Level Dynamic Model
  • Analysis-Level Functional Model
• Step 2 - System Design
  • Subsystems
  • Boundary Conditions
  • Tradeoff Priorities
• Step 3 - Detailed Design
  • Model Design
  • Design-Level Object Model
  • Design-Level Dynamic Model
  • Design-Level Functional Model
  • View Design
  • View’s Picture
  • Design-Level Object Model
  • Design-Level Dynamic Model
  • Design-Level Functional Model
• Step 4 - Code
  • imports
  • class NumTextField extends TextField
  • class Hops extends Observable
  • // class Hops, private state change method
  • // class Hops, public interface
  • public class HopsDemo extends java.applet.Applet implements java.util.Observer
  • // class HopsDemo
  • // class HopsDemo
  • // class HopsDemo