What is the "domain"? What is a "model"?

• why have a model?
• why prefer Value Objects?
• how does good OOP mirror FP (or vice-versa)?
  • immutability
  • sensible data structures underpinning immutable objects
  • sacrifice performance by default
• how is good OOP different from FP?
  • prefer fine-grained abstraction pushed to "leaf nodes" of the object hierarchy
  • avoid highly generic constructs
• [tbd - domain-v-model.jpg]

Objects capture lifetimes

• nouns to capture ephemeral/lifetime ideas: session (other examples?)
• the lifecycle of an object is more important than mirroring the real world

Non-standard domains

• the web server itself can be a domain
• a scheduler object(s)
• Try: push as much of your code into the "domain" as possible
  • pure
  • immutable
  • small & value-based
  • in clojure, this is capturing more data and less behaviour

Domain through API

• REST v CRUD
• Representational State Transfer - why?
• HTTP verb hacks
• immutability behind the scenes w mutable APIs
• DTOs