Encapsulated Behaviors

Reading

• Head First Design Patterns, Chapter 1 (excerpt)
  Freeman, Eric, and Elisabeth Robson. Head First Design Patterns. 2nd ed., O’Reilly, 2020.

Important concepts

• interfaces and inheritance
• unintended consequences of code change
• encapsulating the parts that vary, separating them from the parts that don’t
• classes that represent behaviors instead of things

Things to consider (exercises for yourself, not to turn in)

1. Which activities and assignments in this course exemplify the advice in this chapter?
2. Why does the reading say not to create a “Duck” interface too?
3. If a programming tool matters, it’s because it solves a problem. What problem do interfaces solve?

Your response

What was particularly interesting, confusing, or exciting to you in this reading? What question can you ask to expedite your learning?